diff options
| -rw-r--r-- | 41160-0.txt | 399 | ||||
| -rw-r--r-- | 41160-0.zip | bin | 196686 -> 0 bytes | |||
| -rw-r--r-- | 41160-8.txt | 9272 | ||||
| -rw-r--r-- | 41160-8.zip | bin | 196157 -> 0 bytes | |||
| -rw-r--r-- | 41160-h.zip | bin | 1152796 -> 0 bytes | |||
| -rw-r--r-- | 41160-h/41160-h.htm | 425 | ||||
| -rw-r--r-- | 41160.txt | 9272 | ||||
| -rw-r--r-- | 41160.zip | bin | 196045 -> 0 bytes |
8 files changed, 5 insertions, 19363 deletions
diff --git a/41160-0.txt b/41160-0.txt index bb1a7c8..7e9e151 100644 --- a/41160-0.txt +++ b/41160-0.txt @@ -1,42 +1,4 @@ -Project Gutenberg's The Romance of Modern Invention, by Archibald Williams - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org - - -Title: The Romance of Modern Invention - Containing Interesting Descriptions in Non-technical - Language of Wireless Telegraphy, Liquid Air, Modern - Artillery, Submarines, Dirigible Torpedoes, Solar Motors, - Airships, &c. &c. - -Author: Archibald Williams - -Release Date: October 24, 2012 [EBook #41160] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK THE ROMANCE OF MODERN INVENTION *** - - - - -Produced by Chris Curnow, Matthew Wheaton and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - - - - - - - +*** START OF THE PROJECT GUTENBERG EBOOK 41160 *** [Illustration: _The Sun-Motor used on the Pasadena Ostrich-farm, California. It works a pump capable of delivering @@ -8912,361 +8874,4 @@ comparatively economical. End of the Project Gutenberg EBook of The Romance of Modern Invention, by Archibald Williams -*** END OF THIS PROJECT GUTENBERG EBOOK THE ROMANCE OF MODERN INVENTION *** - -***** This file should be named 41160-0.txt or 41160-0.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/4/1/1/6/41160/ - -Produced by Chris Curnow, Matthew Wheaton and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - -Updated editions will replace the previous one--the old editions -will be renamed. - -Creating the works from public domain print editions means that no -one owns a United States copyright in these works, so the Foundation -(and you!) can copy and distribute it in the United States without -permission and without paying copyright royalties. Special rules, -set forth in the General Terms of Use part of this license, apply to -copying and distributing Project Gutenberg-tm electronic works to -protect the PROJECT GUTENBERG-tm concept and trademark. Project -Gutenberg is a registered trademark, and may not be used if you -charge for the eBooks, unless you receive specific permission. If you -do not charge anything for copies of this eBook, complying with the -rules is very easy. You may use this eBook for nearly any purpose -such as creation of derivative works, reports, performances and -research. They may be modified and printed and given away--you may do -practically ANYTHING with public domain eBooks. Redistribution is -subject to the trademark license, especially commercial -redistribution. - - - -*** START: FULL LICENSE *** - -THE FULL PROJECT GUTENBERG LICENSE -PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK - -To protect the Project Gutenberg-tm mission of promoting the free -distribution of electronic works, by using or distributing this work -(or any other work associated in any way with the phrase "Project -Gutenberg"), you agree to comply with all the terms of the Full Project -Gutenberg-tm License available with this file or online at - www.gutenberg.org/license. - - -Section 1. General Terms of Use and Redistributing Project Gutenberg-tm -electronic works - -1.A. By reading or using any part of this Project Gutenberg-tm -electronic work, you indicate that you have read, understand, agree to -and accept all the terms of this license and intellectual property -(trademark/copyright) agreement. If you do not agree to abide by all -the terms of this agreement, you must cease using and return or destroy -all copies of Project Gutenberg-tm electronic works in your possession. -If you paid a fee for obtaining a copy of or access to a Project -Gutenberg-tm electronic work and you do not agree to be bound by the -terms of this agreement, you may obtain a refund from the person or -entity to whom you paid the fee as set forth in paragraph 1.E.8. - -1.B. "Project Gutenberg" is a registered trademark. It may only be -used on or associated in any way with an electronic work by people who -agree to be bound by the terms of this agreement. There are a few -things that you can do with most Project Gutenberg-tm electronic works -even without complying with the full terms of this agreement. See -paragraph 1.C below. There are a lot of things you can do with Project -Gutenberg-tm electronic works if you follow the terms of this agreement -and help preserve free future access to Project Gutenberg-tm electronic -works. See paragraph 1.E below. - -1.C. The Project Gutenberg Literary Archive Foundation ("the Foundation" -or PGLAF), owns a compilation copyright in the collection of Project -Gutenberg-tm electronic works. Nearly all the individual works in the -collection are in the public domain in the United States. If an -individual work is in the public domain in the United States and you are -located in the United States, we do not claim a right to prevent you from -copying, distributing, performing, displaying or creating derivative -works based on the work as long as all references to Project Gutenberg -are removed. Of course, we hope that you will support the Project -Gutenberg-tm mission of promoting free access to electronic works by -freely sharing Project Gutenberg-tm works in compliance with the terms of -this agreement for keeping the Project Gutenberg-tm name associated with -the work. You can easily comply with the terms of this agreement by -keeping this work in the same format with its attached full Project -Gutenberg-tm License when you share it without charge with others. - -1.D. The copyright laws of the place where you are located also govern -what you can do with this work. Copyright laws in most countries are in -a constant state of change. If you are outside the United States, check -the laws of your country in addition to the terms of this agreement -before downloading, copying, displaying, performing, distributing or -creating derivative works based on this work or any other Project -Gutenberg-tm work. The Foundation makes no representations concerning -the copyright status of any work in any country outside the United -States. - -1.E. Unless you have removed all references to Project Gutenberg: - -1.E.1. The following sentence, with active links to, or other immediate -access to, the full Project Gutenberg-tm License must appear prominently -whenever any copy of a Project Gutenberg-tm work (any work on which the -phrase "Project Gutenberg" appears, or with which the phrase "Project -Gutenberg" is associated) is accessed, displayed, performed, viewed, -copied or distributed: - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org - -1.E.2. If an individual Project Gutenberg-tm electronic work is derived -from the public domain (does not contain a notice indicating that it is -posted with permission of the copyright holder), the work can be copied -and distributed to anyone in the United States without paying any fees -or charges. If you are redistributing or providing access to a work -with the phrase "Project Gutenberg" associated with or appearing on the -work, you must comply either with the requirements of paragraphs 1.E.1 -through 1.E.7 or obtain permission for the use of the work and the -Project Gutenberg-tm trademark as set forth in paragraphs 1.E.8 or -1.E.9. - -1.E.3. If an individual Project Gutenberg-tm electronic work is posted -with the permission of the copyright holder, your use and distribution -must comply with both paragraphs 1.E.1 through 1.E.7 and any additional -terms imposed by the copyright holder. Additional terms will be linked -to the Project Gutenberg-tm License for all works posted with the -permission of the copyright holder found at the beginning of this work. - -1.E.4. Do not unlink or detach or remove the full Project Gutenberg-tm -License terms from this work, or any files containing a part of this -work or any other work associated with Project Gutenberg-tm. - -1.E.5. Do not copy, display, perform, distribute or redistribute this -electronic work, or any part of this electronic work, without -prominently displaying the sentence set forth in paragraph 1.E.1 with -active links or immediate access to the full terms of the Project -Gutenberg-tm License. - -1.E.6. You may convert to and distribute this work in any binary, -compressed, marked up, nonproprietary or proprietary form, including any -word processing or hypertext form. However, if you provide access to or -distribute copies of a Project Gutenberg-tm work in a format other than -"Plain Vanilla ASCII" or other format used in the official version -posted on the official Project Gutenberg-tm web site (www.gutenberg.org), -you must, at no additional cost, fee or expense to the user, provide a -copy, a means of exporting a copy, or a means of obtaining a copy upon -request, of the work in its original "Plain Vanilla ASCII" or other -form. Any alternate format must include the full Project Gutenberg-tm -License as specified in paragraph 1.E.1. - -1.E.7. Do not charge a fee for access to, viewing, displaying, -performing, copying or distributing any Project Gutenberg-tm works -unless you comply with paragraph 1.E.8 or 1.E.9. - -1.E.8. You may charge a reasonable fee for copies of or providing -access to or distributing Project Gutenberg-tm electronic works provided -that - -- You pay a royalty fee of 20% of the gross profits you derive from - the use of Project Gutenberg-tm works calculated using the method - you already use to calculate your applicable taxes. The fee is - owed to the owner of the Project Gutenberg-tm trademark, but he - has agreed to donate royalties under this paragraph to the - Project Gutenberg Literary Archive Foundation. Royalty payments - must be paid within 60 days following each date on which you - prepare (or are legally required to prepare) your periodic tax - returns. Royalty payments should be clearly marked as such and - sent to the Project Gutenberg Literary Archive Foundation at the - address specified in Section 4, "Information about donations to - the Project Gutenberg Literary Archive Foundation." - -- You provide a full refund of any money paid by a user who notifies - you in writing (or by e-mail) within 30 days of receipt that s/he - does not agree to the terms of the full Project Gutenberg-tm - License. You must require such a user to return or - destroy all copies of the works possessed in a physical medium - and discontinue all use of and all access to other copies of - Project Gutenberg-tm works. - -- You provide, in accordance with paragraph 1.F.3, a full refund of any - money paid for a work or a replacement copy, if a defect in the - electronic work is discovered and reported to you within 90 days - of receipt of the work. - -- You comply with all other terms of this agreement for free - distribution of Project Gutenberg-tm works. - -1.E.9. If you wish to charge a fee or distribute a Project Gutenberg-tm -electronic work or group of works on different terms than are set -forth in this agreement, you must obtain permission in writing from -both the Project Gutenberg Literary Archive Foundation and Michael -Hart, the owner of the Project Gutenberg-tm trademark. Contact the -Foundation as set forth in Section 3 below. - -1.F. - -1.F.1. Project Gutenberg volunteers and employees expend considerable -effort to identify, do copyright research on, transcribe and proofread -public domain works in creating the Project Gutenberg-tm -collection. Despite these efforts, Project Gutenberg-tm electronic -works, and the medium on which they may be stored, may contain -"Defects," such as, but not limited to, incomplete, inaccurate or -corrupt data, transcription errors, a copyright or other intellectual -property infringement, a defective or damaged disk or other medium, a -computer virus, or computer codes that damage or cannot be read by -your equipment. - -1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the "Right -of Replacement or Refund" described in paragraph 1.F.3, the Project -Gutenberg Literary Archive Foundation, the owner of the Project -Gutenberg-tm trademark, and any other party distributing a Project -Gutenberg-tm electronic work under this agreement, disclaim all -liability to you for damages, costs and expenses, including legal -fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT -LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE -PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE FOUNDATION, THE -TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE -LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR -INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH -DAMAGE. - -1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a -defect in this electronic work within 90 days of receiving it, you can -receive a refund of the money (if any) you paid for it by sending a -written explanation to the person you received the work from. If you -received the work on a physical medium, you must return the medium with -your written explanation. The person or entity that provided you with -the defective work may elect to provide a replacement copy in lieu of a -refund. If you received the work electronically, the person or entity -providing it to you may choose to give you a second opportunity to -receive the work electronically in lieu of a refund. If the second copy -is also defective, you may demand a refund in writing without further -opportunities to fix the problem. - -1.F.4. Except for the limited right of replacement or refund set forth -in paragraph 1.F.3, this work is provided to you 'AS-IS', WITH NO OTHER -WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO -WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PURPOSE. - -1.F.5. Some states do not allow disclaimers of certain implied -warranties or the exclusion or limitation of certain types of damages. -If any disclaimer or limitation set forth in this agreement violates the -law of the state applicable to this agreement, the agreement shall be -interpreted to make the maximum disclaimer or limitation permitted by -the applicable state law. The invalidity or unenforceability of any -provision of this agreement shall not void the remaining provisions. - -1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the -trademark owner, any agent or employee of the Foundation, anyone -providing copies of Project Gutenberg-tm electronic works in accordance -with this agreement, and any volunteers associated with the production, -promotion and distribution of Project Gutenberg-tm electronic works, -harmless from all liability, costs and expenses, including legal fees, -that arise directly or indirectly from any of the following which you do -or cause to occur: (a) distribution of this or any Project Gutenberg-tm -work, (b) alteration, modification, or additions or deletions to any -Project Gutenberg-tm work, and (c) any Defect you cause. - - -Section 2. Information about the Mission of Project Gutenberg-tm - -Project Gutenberg-tm is synonymous with the free distribution of -electronic works in formats readable by the widest variety of computers -including obsolete, old, middle-aged and new computers. It exists -because of the efforts of hundreds of volunteers and donations from -people in all walks of life. - -Volunteers and financial support to provide volunteers with the -assistance they need are critical to reaching Project Gutenberg-tm's -goals and ensuring that the Project Gutenberg-tm collection will -remain freely available for generations to come. In 2001, the Project -Gutenberg Literary Archive Foundation was created to provide a secure -and permanent future for Project Gutenberg-tm and future generations. -To learn more about the Project Gutenberg Literary Archive Foundation -and how your efforts and donations can help, see Sections 3 and 4 -and the Foundation information page at www.gutenberg.org - - -Section 3. Information about the Project Gutenberg Literary Archive -Foundation - -The Project Gutenberg Literary Archive Foundation is a non profit -501(c)(3) educational corporation organized under the laws of the -state of Mississippi and granted tax exempt status by the Internal -Revenue Service. The Foundation's EIN or federal tax identification -number is 64-6221541. Contributions to the Project Gutenberg -Literary Archive Foundation are tax deductible to the full extent -permitted by U.S. federal laws and your state's laws. - -The Foundation's principal office is located at 4557 Melan Dr. S. -Fairbanks, AK, 99712., but its volunteers and employees are scattered -throughout numerous locations. Its business office is located at 809 -North 1500 West, Salt Lake City, UT 84116, (801) 596-1887. Email -contact links and up to date contact information can be found at the -Foundation's web site and official page at www.gutenberg.org/contact - -For additional contact information: - Dr. Gregory B. Newby - Chief Executive and Director - gbnewby@pglaf.org - -Section 4. Information about Donations to the Project Gutenberg -Literary Archive Foundation - -Project Gutenberg-tm depends upon and cannot survive without wide -spread public support and donations to carry out its mission of -increasing the number of public domain and licensed works that can be -freely distributed in machine readable form accessible by the widest -array of equipment including outdated equipment. Many small donations -($1 to $5,000) are particularly important to maintaining tax exempt -status with the IRS. - -The Foundation is committed to complying with the laws regulating -charities and charitable donations in all 50 states of the United -States. Compliance requirements are not uniform and it takes a -considerable effort, much paperwork and many fees to meet and keep up -with these requirements. We do not solicit donations in locations -where we have not received written confirmation of compliance. To -SEND DONATIONS or determine the status of compliance for any -particular state visit www.gutenberg.org/donate - -While we cannot and do not solicit contributions from states where we -have not met the solicitation requirements, we know of no prohibition -against accepting unsolicited donations from donors in such states who -approach us with offers to donate. - -International donations are gratefully accepted, but we cannot make -any statements concerning tax treatment of donations received from -outside the United States. U.S. laws alone swamp our small staff. - -Please check the Project Gutenberg Web pages for current donation -methods and addresses. Donations are accepted in a number of other -ways including checks, online payments and credit card donations. -To donate, please visit: www.gutenberg.org/donate - - -Section 5. General Information About Project Gutenberg-tm electronic -works. - -Professor Michael S. Hart was the originator of the Project Gutenberg-tm -concept of a library of electronic works that could be freely shared -with anyone. For forty years, he produced and distributed Project -Gutenberg-tm eBooks with only a loose network of volunteer support. - -Project Gutenberg-tm eBooks are often created from several printed -editions, all of which are confirmed as Public Domain in the U.S. -unless a copyright notice is included. Thus, we do not necessarily -keep eBooks in compliance with any particular paper edition. - -Most people start at our Web site which has the main PG search facility: - - www.gutenberg.org - -This Web site includes information about Project Gutenberg-tm, -including how to make donations to the Project Gutenberg Literary -Archive Foundation, how to help produce our new eBooks, and how to -subscribe to our email newsletter to hear about new eBooks. +*** END OF THE PROJECT GUTENBERG EBOOK 41160 *** diff --git a/41160-0.zip b/41160-0.zip Binary files differdeleted file mode 100644 index 4d84381..0000000 --- a/41160-0.zip +++ /dev/null diff --git a/41160-8.txt b/41160-8.txt deleted file mode 100644 index f2209fc..0000000 --- a/41160-8.txt +++ /dev/null @@ -1,9272 +0,0 @@ -Project Gutenberg's The Romance of Modern Invention, by Archibald Williams - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org - - -Title: The Romance of Modern Invention - Containing Interesting Descriptions in Non-technical - Language of Wireless Telegraphy, Liquid Air, Modern - Artillery, Submarines, Dirigible Torpedoes, Solar Motors, - Airships, &c. &c. - -Author: Archibald Williams - -Release Date: October 24, 2012 [EBook #41160] - -Language: English - -Character set encoding: ISO-8859-1 - -*** START OF THIS PROJECT GUTENBERG EBOOK THE ROMANCE OF MODERN INVENTION *** - - - - -Produced by Chris Curnow, Matthew Wheaton and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - - - - - - - - - [Illustration: _The Sun-Motor used on the Pasadena - Ostrich-farm, California. It works a pump capable of delivering - 1,400 gallons per minute._ [_See pp. 210, 211._] ] - - - - - THE ROMANCE OF MODERN INVENTION - - CONTAINING INTERESTING DESCRIPTIONS IN - NON-TECHNICAL LANGUAGE OF WIRELESS - TELEGRAPHY, LIQUID AIR, MODERN ARTILLERY, - SUBMARINES, DIRIGIBLE TORPEDOES, - SOLAR MOTORS, AIRSHIPS, _&c. &c._ - - BY - - ARCHIBALD WILLIAMS - - AUTHOR OF "THE ROMANCE OF MODERN MECHANISM" - "THE ROMANCE OF MODERN ENGINEERING" - _&c. &c._ - - WITH TWENTY-FIVE ILLUSTRATIONS - - LONDON - SEELEY AND CO. LIMITED - 38 GREAT RUSSELL STREET - 1907 - - - - -Preface - - -The object of this book is to set before young people in a bright and -interesting way, and without the use of technical language, accounts -of some of the latest phases of modern invention; and also to -introduce them to recent discoveries of which the full development is -yet to be witnessed. - -The author gratefully acknowledges the help given him as regards both -literary matter and illustrations by:--Mr. Cuthbert Hall (the Marconi -Wireless Telegraphy Co.); Mr. William Sugg; Mr. Hans Knudsen; Mr. F. -C. B. Cole; Mr. E. J. Ryves; Mr. Anton Pollak; the Telautograph Co.; -the Parsons Steam Turbine Co.; the Monotype Co.; the Biograph Co.; the -Locomobile Co.; the Speedwell Motor Co. - -_September 1902._ - - - - - Contents - - - WIRELESS TELEGRAPHY - - HIGH-SPEED TELEGRAPHY - - THE TELEPHONE--WIRELESS TELEPHONY - - THE PHONOGRAPH--THE HOTOGRAPHOPHONE--THE TELEPHONOGRAPH - - THE TELAUTOGRAPH - - MODERN ARTILLERY--RIFLES--MACHINE GUNS--HEAVY - ORDNANCE--EXPLOSIVES--IN THE GUN FACTORY - - DIRIGIBLE TORPEDOES - - SUBMARINE BOATS - - ANIMATED PICTURES - - THE GREAT PARIS TELESCOPE - - PHOTOGRAPHING THE INVISIBLE--PHOTOGRAPHY IN THE DARK - - SOLAR MOTORS - - LIQUID AIR - - HORSELESS CARRIAGES - - HIGH-SPEED RAILWAYS - - SEA EXPRESSES - - MECHANICAL FLIGHT - - TYPE-SETTING BY MACHINERY - - PHOTOGRAPHY IN COLOURS - - LIGHTING - - - - - List of Illustrations - - - THE SUN MOTOR USED ON THE PASADENA OSTRICH-FARM - - A CORNER OF MR. MARCONI'S CABIN - - MR. MARCONI'S TRAVELLING STATION - - THE POLDHU TOWER - - GUGLIELMO MARCONI - - HIGH-SPEED TELEGRAPHY: A RECEIVING INSTRUMENT - - HIGH-SPEED TELEGRAPHY. SPECIMEN OF PUNCHED TAPE - - A UNIQUE GROUP OF PHONOGRAPHS - - THE TELAUTOGRAPH: RECEIVER AND TRANSMITTER - - THE TELAUTOGRAPH, SHOWING THE PRINCIPAL PARTS - - THE TELAUTOGRAPH, SPECIMEN OF THE WORK DONE - - THE SIMMS ARMOUR-CLAD MOTOR CAR - - THE "HOLLAND" SUBMARINE BOAT - - AN INTERIOR VIEW OF THE "HOLLAND" - - THE "HOLLAND" SUBMARINE IN THE LAST STAGES OF SUBMERSION - - THE GREAT PARIS TELESCOPE - - THE LIQUID AIR COMPANY'S FACTORY AT PIMLICO - - M. SERPOLLET ON THE "EASTER EGG" - - A MOTOR CAR DRIVEN BY LIQUID AIR - - DIAGRAM OF LIQUID AIR MOTOR CAR - - H.M.S. TORPEDO DESTROYER "VIPER" - - AIRSHIP OF M. SANTOS-DUMONT ROUNDING THE EIFFEL TOWER - - M. SANTOS-DUMONT'S AIRSHIP RETURNING TO LONGCHAMPS - - THE LINOTYPE MACHINE - - THE MONOTYPE CASTING MACHINE - - - - -The Romance of Modern Invention - - - - -WIRELESS TELEGRAPHY - - -One day in 1845 a man named Tawell, dressed as a Quaker, stepped into -a train at Slough Station on the Great Western Railway, and travelled -to London. When he arrived in London the innocent-looking Quaker was -arrested, much to his amazement and dismay, on the charge of having -committed a foul murder in the neighbourhood of Slough. The news of -the murder and a description of the murderer had been telegraphed from -that place to Paddington, where a detective met the train and shadowed -the miscreant until a convenient opportunity for arresting him -occurred. Tawell was tried, condemned, and hung, and the public for -the first time generally realised the power for good dormant in the as -yet little developed electric telegraph. - -Thirteen years later two vessels met in mid-Atlantic laden with cables -which they joined and paid out in opposite directions, till Ireland -and Newfoundland were reached. The first electric message passed on -August 7th of that year from the New World to the Old. The telegraph -had now become a world-power. - -The third epoch-making event in its history is of recent date. On -December 12, 1901, Guglielmo Marconi, a young Italian, famous all over -the world when but twenty-two years old, suddenly sprang into yet -greater fame. At Hospital Point, Newfoundland, he heard by means of a -kite, a long wire, a delicate tube full of tiny particles of metal, -and a telephone ear-piece, signals transmitted from far-off Cornwall -by his colleagues. No wires connected Poldhu, the Cornish station, and -Hospital Point. The three short dot signals, which in the Morse code -signify the letter S, had been borne from place to place by the -limitless, mysterious ether, that strange substance of which we now -hear so much, of which wise men declare we know so little. - -Marconi's great achievement, which was of immense importance, -naturally astonished the world. Of course, there were not wanting -those who discredited the report. Others, on the contrary, were seized -with panic and showed their readiness to believe that the Atlantic had -been spanned aërially, by selling off their shares in cable companies. -To use the language of the money-market, there was a temporary "slump" -in cable shares. The world again woke up--this time to the fact that -experiments of which it had heard faintly had at last culminated in a -great triumph, marvellous in itself, and yet probably nothing in -comparison with the revolution in the transmission of news that it -heralded. - -The subject of Wireless Telegraphy is so wide that to treat it fully -in the compass of a single chapter is impossible. At the same time it -would be equally impossible to pass it over in a book written with the -object of presenting to the reader the latest developments of -scientific research. Indeed, the attention that it has justly -attracted entitle it, not merely to a place, but to a leading place; -and for this reason these first pages will be devoted to a short -account of the history and theory of Wireless Telegraphy, with some -mention of the different systems by which signals have been sent -through space. - -On casting about for a point at which to begin, the writer is tempted -to attack the great topic of the ether, to which experimenters in many -branches of science are now devoting more and more attention, hoping -to find in it an explanation of and connection between many phenomena -which at present are of uncertain origin. - -What is Ether? In the first place, its very existence is merely -assumed, like that of the atom and the molecule. Nobody can say that -he has actually seen or had any experience of it. The assumption that -there is such a thing is justified only in so far as that assumption -explains and reconciles phenomena of which we have experience, and -enables us to form theories which can be scientifically demonstrated -correct. What scientists now say is this: that everything which we -see and touch, the air, the infinity of space itself, is permeated by -a _something_, so subtle that, no matter how continuous a thing may -seem, it is but a concourse of atoms separated by this something, the -Ether. Reasoning drove them to this conclusion. - -It is obvious that an effect cannot come out of nothing. Put a clock -under a bell-glass and you hear the ticking. Pump out the air and the -ticking becomes inaudible. What is now not in the glass that was there -before? The air. Reason, therefore, obliges us to conclude that air is -the means whereby the ticking is audible to us. No air, no sound. -Next, put a lighted candle on the further side of the exhausted -bell-glass. We can see it clearly enough. The absence of air does not -affect light. But can we believe that there is an absolute gap between -us and the light? No! It is far easier to believe that the bell-glass -is as full as the outside atmosphere of the something that -communicates the sensation of light from the candle to the eye. Again, -suppose we measure a bar of iron very carefully while cold and then -heat it. We shall find that it has expanded a little. The iron atoms, -we say, have become more energetic than before, repel each other and -stand further apart. What then is in the intervening spaces? Not air, -which cannot be forced through iron whether hot or cold. No! the -ether: which passes easily through crevices so small as to bar the way -to the atoms of air. - -[Illustration: _A Corner of M. Marconi's cabin on board S.S. -"Minneapolis," showing instruments used in Wireless Telegraphy._] - -Once more, suppose that to one end of our iron bar we apply the -negative "pole" of an electric battery, and to the other end the -positive pole. We see that a current passes through the bar, whether -hot or cold, which implies that it jumps across all the ether gaps, or -rather is conveyed by them from one atom to another. - -The conclusion then is that ether is not merely omnipresent, -penetrating all things, but the medium whereby heat, light, -electricity, perhaps even thought itself, are transmitted from one -point to another. - -In what manner is the transmission effected? We cannot imagine the -ether behaving in a way void of all system. - -The answer is, by a wave motion. The ether must be regarded as a very -elastic solid. The agitation of a portion of it by what we call heat, -light, or electricity, sets in motion adjoining particles, until they -are moving from side to side, but not forwards; the resultant movement -resembling that of a snake tethered by the tail. - -These ether waves vary immensely in length. Their qualities and -effects upon our bodies or sensitive instruments depend upon their -length. By means of ingenious apparatus the lengths of various waves -have been measured. When the waves number 500 billion per second, and -are but the 40,000th of an inch long they affect our eyes and are -named light--red light. At double the number and half the length, they -give us the sensation of violet light. - -When the number increases and the waves shorten further, our bodies -are "blind" to them; we have no sense to detect their presence. -Similarly, a slower vibration than that of red light is imperceptible -until we reach the comparatively slow pace of 100 vibrations per -second, when we become aware of heat. - -Ether waves may be compared to the notes on a piano, of which we are -acquainted with some octaves only. The gaps, the unknown octaves, are -being discovered slowly but surely. Thus, for example, the famous -X-rays have been assigned to the topmost octave; electric waves to the -notes between light and heat. Forty years ago Professor Clerk Maxwell -suggested that light and electricity were very closely connected, -probably differing only in their wave-length. His theory has been -justified by subsequent research. The velocity of light (185,000 miles -per second) and that of electric currents have been proved identical. -Hertz, a professor in the university of Bonn, also showed (1887-1889) -that the phenomena of light--reflection, refraction, and concentration -of rays--can be repeated with electric currents. - -We therefore take the word of scientists that the origin of the -phenomena called light and electricity is the same--vibration of -ether. It at once occurs to the reader that their behaviour is so -different that they might as well be considered of altogether -different natures. - -For instance, interpose the very thinnest sheet of metal between a -candle and the eye, and the light is cut off. But the sheet will very -readily convey electricity. On the contrary, glass, a substance that -repels electricity, is transparent, _i.e._ gives passage to light. And -again, electricity can be conveyed round as many corners as you -please, whereas light will travel in straight lines only. - -To clear away our doubts we have only to take the lighted candle and -again hold up the metal screen. Light does not pass through, but heat -does. Substitute for the metal a very thin tank filled with a solution -of alum, and then light passes, but heat is cut off. So that heat and -electricity _both_ penetrate what is impenetrable to light; while -light forces a passage securely barred against both electricity and -heat. And we must remember that open space conveys all alike from the -sun to the earth. - -On meeting what we call solid matter, ether waves are influenced, not -because ether is wanting in the solid matter, but because the presence -of something else than ether affects the intervening ether itself. -Consequently glass, to take an instance, so affects ether that a very -rapid succession of waves (light) are able to continue their way -through its interstices, whereas long electric waves are so hampered -that they die out altogether. Metal on the other hand welcomes slow -vibrations (_i.e._ long waves), but speedily kills the rapid shakes of -light. In other words, _transparency_ is not confined to light alone. -All bodies are transparent to some variety of rays, and many bodies to -several varieties. It may perhaps even be proved that there is no -such thing as absolute resistance, and that our inability to detect -penetration is due to lack of sufficiently delicate instruments. - -The cardinal points to be remembered are these:-- - -That the ether is a universal medium, conveying all kinds and forms of -energy. - -That these forms of energy differ only in their rates of vibration. - -That the rate of vibration determines what power of penetration the -waves shall have through any given substance. - -Now, it is generally true that whereas matter of any kind offers -resistance to light--that is, is not so perfect a conductor as the -ether--many substances, especially metals, are more sensitive than -ether to heat and electricity. How quickly a spoon inserted into a hot -cup of tea becomes uncomfortably hot, though the hand can be held very -close to the liquid without feeling more than a gentle warmth. And we -all have noticed that the very least air-gap in an electric circuit -effectively breaks a current capable of traversing miles of wire. If -the current is so intense that it insists on passing the gap, it leaps -across with a report, making a spark that is at once intensely bright -and hot. Metal wires are to electricity what speaking tubes are to -sound; they are as it were electrical tubes through the air and ether. -But just as a person listening outside a speaking tube might faintly -hear the sounds passing through it, so an instrument gifted with an -"electric ear" would detect the currents passing through the wire. -Wireless telegraphy is possible because mankind has discovered -instruments which act as _electric ears or eyes_, catching and -recording vibrations that had hitherto remained undetected. - -The earliest known form of wireless telegraphy is transmission of -messages by light. A man on a hill lights a lamp or a fire. This -represents his instrument for agitating the ether into waves, which -proceed straight ahead with incredible velocity until they reach the -receiver, the eye of a man watching at a point from which the light is -visible. - -Then came electric telegraphy. - -At first a complete circuit (two wires) was used. But in 1838 it was -discovered that if instead of two wires only one was used, the other -being replaced by an earth connection, not only was the effect equally -powerful, but even double of what it was with the metallic circuit. - -Thus the first step had been taken towards wireless electrical -telegraphy. - -The second was, of course, to abolish the other wire. - -This was first effected by Professor Morse, who, in 1842, sent signals -across the Susquehanna River without metallic connections of any sort. -Along each bank of the river was stretched a wire three times as long -as the river was broad. In the one wire a battery and transmitter were -inserted, in the other a receiving instrument or galvanometer. Each -wire terminated at each end in a large copper plate sunk in the water. -Morse's conclusions were that provided the wires were long enough and -the plates large enough messages could be transmitted for an -indefinite distance; the current passing from plate to plate, though a -large portion of it would be lost in the water.[1] - - [1] It is here proper to observe that the term _wireless_ - telegraphy, as applied to electrical systems, is misleading, - since it implies the absence of wires; whereas in all systems - wires are used. But since it is generally understood that by - wireless telegraphy is meant telegraphy without _metal - connections_, and because the more improved methods lessen more - and more the amount of wire used, the phrase has been allowed - to stand. - -About the same date a Scotchman, James Bowman Lindsay of Dundee, a man -as rich in intellectual attainments as he was pecuniarily poor, sent -signals in a similar manner across the River Tay. In September, 1859, -Lindsay read a paper before the British Association at Dundee, in -which he maintained that his experiments and calculations assured him -that by running wires along the coasts of America and Great Britain, -by using a battery having an acting surface of 130 square feet and -immersed sheets of 3000 square feet, and a coil weighing 300 lbs., he -could send messages from Britain to America. Want of money prevented -the poor scholar of Dundee from carrying out his experiments on a -large enough scale to obtain public support. He died in 1862, leaving -behind him the reputation of a man who in the face of the greatest -difficulties made extraordinary electrical discoveries at the cost of -unceasing labour; and this in spite of the fact that he had undertaken -and partly executed a gigantic dictionary in fifty different -languages! - -[Illustration: _M. Marconi's Travelling Station for Wireless -Telegraphy._] - -The transmission of electrical signals through matter, metal, earth, -or water, is effected by _conduction_, or the _leading_ of the -currents in a circuit. When we come to deal with aërial transmission, -_i.e._ where one or both wires are replaced by the ether, then two -methods are possible, those of _induction_ and Hertzian waves. - -To take the induction method first. Whenever a current is sent through -a wire magnetism is set up in the ether surrounding the wire, which -becomes the core of a "magnetic field." The magnetic waves extend for -an indefinite distance on all sides, and on meeting a wire _parallel_ -to the electrified wire _induce_ in it a _dynamical_ current similar -to that which caused them. Wherever electricity is present there is -magnetism also, and _vice versâ_. Electricity--produces -magnetism--produces electricity. The invention of the Bell telephone -enabled telegraphers to take advantage of this law. - -In 1885 Sir William Preece, now consulting electrical engineer to the -General Post-Office, erected near Newcastle two insulated squares of -wire, each side 440 yards long. The squares were horizontal, parallel, -and a quarter of a mile apart. On currents being sent through the one, -currents were detected in the other by means of a telephone, which -remained active even when the squares were separated by 1000 yards. -Sir William Preece thus demonstrated that signals could be sent -without even an earth connection, _i.e._ entirely through the ether. -In 1886 he sent signals between two parallel telegraph wires 4-1/2 -miles apart. And in 1892 established a regular communication between -Flatholm, an island fort in the Bristol Channel, and Lavernock, a -point on the Welsh coast 3-1/3 miles distant. - -The inductive method might have attained to greater successes had not -a formidable rival appeared in the Hertzian waves. - -In 1887 Professor Hertz discovered that if the discharge from a Leyden -jar were passed through wires containing an air-gap across which the -discharge had to pass, sparks would also pass across a gap in an -almost complete circle or square of wire held at some distance from -the jar. This "electric eye," or detector, could have its gap so -regulated by means of a screw that at a certain width its effect would -be most pronounced, under which condition the detector, or receiver, -was "in tune" with the exciter, or transmitter. Hertz thus established -three great facts, that-- - - (_a_) A discharge of static (_i.e._ collected) electricity - across an air-gap produced strong electric waves in the ether - on all sides. - - (_b_) That these waves could be _caught_. - - (_c_) That under certain conditions the catcher worked most - effectively. - -Out of these three discoveries has sprung the latest phase of wireless -telegraphy, as exploited by Signor Marconi. He, in common with -Professors Branly of Paris, Popoff of Cronstadt, and Slaby of -Charlottenburg, besides many others, have devoted their attention to -the production of improved means of sending and receiving the Hertzian -waves. Their experiments have shown that two things are required in -wireless telegraphy-- - - (i.) That the waves shall have great penetrating power, so as - to pierce any obstacle. - - (ii.) That they shall retain their energy, so that a _maximum_ - of their original force shall reach the receiver. - -The first condition is fulfilled best by waves of great length; the -second by those which, like light, are of greatest frequency. For best -telegraphic results a compromise must be effected between these -extremes, neither the thousand-mile long waves of an alternating -dynamo nor the light waves of many thousands to an inch being of use. -The Hertzian waves are estimated to be 230,000,000 per second; at -which rate they would be 1-1/2 yards long. They vary considerably, -however, on both sides of this rate and dimension. - -Marconi's transmitter consists of three parts--a battery; an induction -coil, terminating in a pair of brass balls, one on each side of the -air-gap; and a Morse transmitting-key. Upon the key being depressed, a -current from the battery passes through the coil and accumulates -electricity on the brass balls until its tension causes it to leap -from one to the other many millions of times in what is called a -spark. The longer the air-gap the greater must be the accumulation -before the leap takes place, and the greater the power of the -vibrations set up. Marconi found that by connecting a kite or balloon -covered with tinfoil by an aluminium wire with one of the balls, the -effect of the waves was greatly increased. Sometimes he replaced the -kite or balloon by a conductor placed on poles two or three hundred -feet high, or by the mast of a ship. - -We now turn to the receiver. - -In 1879 Professor D. E. Hughes observed that a microphone, in -connection with a telephone, produced sounds in the latter even when -the microphone was at a distance of several feet from coils through -which a current was passing. A microphone, it may be explained, is in -its simplest form a loose connection in an electric circuit, which -causes the current to flow in fits and starts at very frequent -intervals. He discovered that a metal microphone stuck, or cohered, -after a wave had influenced it, but that a carbon microphone was -self-restoring, _i.e._ regained its former position of loose contact -as soon as a wave effect had ceased. - -In 1891 Professor Branly of Paris produced a "coherer," which was -nothing more than a microphone under another name. Five years later -Marconi somewhat altered Branly's contrivance, and took out a patent -for a coherer of his own. - -It is a tiny glass tube, about two inches long and a tenth of an inch -in diameter inside. A wire enters it at each end, the wires -terminating in two silver plugs fitting the bore of the tube. A space -of 1/32 inch is left between the plugs, and this space is filled with -special filings, a mixture of 96 parts of nickel to 4 of silver, and -the merest trace of mercury. The tube is exhausted of almost all its -air before being sealed. - -This little gap filled with filings is, except when struck by an -electric wave, to all practical purposes a non-conductor of -electricity. The metal particles touch each other so lightly that they -offer great resistance to a current. - -But when a Hertzian wave flying through the ether strikes the coherer, -the particles suddenly press hard on one another, and make a bridge -through which a current can pass. The current works a "relay," or -circuit through which a stronger current passes, opening and closing -it as often as the coherer is influenced by a wave. The relay actuates -a tapper that gently taps the tube after each wave-influence, causing -the particles to _de_cohere in readiness for the succeeding wave, and -also a Morse instrument for recording words in dots and dashes on a -long paper tape. - -The coherer may be said to resemble an engine-driver, and the "relay" -an engine. The driver is not sufficiently strong to himself move a -train, but he has strength enough to turn on steam and make the engine -do the work. The coherer is not suitable for use with currents of the -intensity required to move a Morse recorder, but it easily switches a -powerful current into another circuit. - -Want of space forbids a detailed account of Marconi's successes with -his improved instruments, but the appended list will serve to show -how he gradually increased the distance over which he sent signals -through space. - -In 1896 he came to England. That year he signalled from a room in the -General Post-Office to a station on the roof 100 yards distant. -Shortly afterwards he covered 2 miles on Salisbury Plain. - -In May, 1897, he sent signals from Lavernock Point to Flatholm, 3-1/3 -miles. This success occurred at a critical time, for Sir W. Preece had -already, as we have seen, bridged the same gap by his induction -method, and for three days Marconi failed to accomplish the feat with -his apparatus, so that it appeared as though the newer system were the -less effective of the two. But by carrying the transmitting instrument -on to the beach below the cliff on which it had been standing, and -joining it by a wire to the pole already erected on the top of the -cliff, Mr. Marconi, thanks to a happy inspiration, did just what was -needed; he got a greater length of wire to send off his waves from. -Communication was at once established with Flatholm, and on the next -day with Brean Down, on the other side of the Bristol Channel, and -8-2/3 miles distant. Then we have-- - - Needles Hotel to Swanage 17-1/2 miles. - Salisbury to Bath 34 " - French Coast to Harwich 90 " - Isle of Wight to The Lizard 196 " - At Sea (1901) 350 " - Dec. 17, 1901, England to America 2099 " - -[Illustration: _Poldhu Towers, the Station put down by the Marconi -Wireless Telegraph Company, Limited, for carrying on a system of -transatlantic wireless telegraphy between England and America. From -the four towers are suspended the ærial wires which are carried into -the buildings in the centre. The towers are 215 feet in height, and -are made of wood._] - -A more pronounced, though perhaps less sensational, success than even -this last occurred at the end of February, 1902. Mr. Marconi, during a -voyage to America on the s.s. _Philadelphia_ remained in communication -with Poldhu, Cornwall, until the vessel was 1550 miles distant, -receiving messages on a Morse recorder for any one acquainted with the -code to read. Signals arrived for a further 500 miles, but owing to -his instruments not being of sufficient strength, Mr. Marconi could -not reply. - -When the transatlantic achievement was announced at the end of 1901, -there was a tendency in some quarters to decry the whole system. The -critics laid their fingers on two weak points. - -In the first place, they said, the speed at which the messages could -be transmitted was too slow to insure that the system would pay. Mr. -Marconi replied that there had been a time when one word per minute -was considered a good working rate across the Atlantic cable; whereas -he had already sent twenty-two words per minute over very long -distances. A further increase of speed was only a matter of time. - -The second objection raised centred on the lack of secrecy resulting -from signals being let loose into space to strike any instrument -within their range; and also on the confusion that must arise when the -ether was traversed by many sets of electric waves. - -The young Italian inventor had been throughout his experiments aware -of these defects and sought means to remedy them. In his earliest -attempts we find him using parabolic metal screens to project his -waves in any required direction and prevent their going in any other. -He also employed strips of metal in conjunction with the coherer, the -strips or "wings" being of such a size as to respond most readily to -waves of a certain length. - -The electric oscillations coming from the aerial wires carried on -poles, kites, &c., were of great power, but their energy dispersed -very quickly into space in a series of rapidly diminishing vibrations. -This fact made them affect to a greater or less degree any receiver -they might encounter on their wanderings. If you go into a room where -there is a piano and make a loud noise near the instrument a jangle of -notes results. But if you take a tuning-fork and after striking it -place it near the strings, only one string will respond, _i.e._ that -of the same pitch as the fork. - -What is required in wireless telegraphy is a system corresponding to -the use of the tuning-fork. Unfortunately, it has been discovered that -the syntony or tuning of transmitter and receiver reduces the distance -over which they are effective. An electric "noise" is more -far-reaching than an electric "note." - -Mr. Marconi has, however, made considerable advances towards combining -the sympathy and secrecy of the tuning system with the power of the -"noise" system. By means of delicately adjusted "wings" and coils he -has brought it about that a series of waves having small individual -strength, but great regularity, shall produce on the receiver a -_cumulative_ effect, storing, as it were, electricity on the surface -of the receiver "wings" until it is of sufficient power to overcome -the resistance of the coherer. - -That tuned wireless telegraphy is, over moderate distances, at least -as secret as that through wires (which can be tapped by induction) is -evident from the fact that during the America Cup Yacht Races Mr. -Marconi sent daily to the _New York Herald_ messages of 4000 total -words, and kept them private in spite of all efforts to intercept -them. He claims to have as many as 250 "tunes"; and, indeed, there -seems to be no limit to their number, so that the would-be "tapper" is -in the position of a man trying to open a letter-lock of which he does -not know the cipher-word. He _may_ discover the right tune, but the -chances are greatly against him. We may be certain that the rapid -advance in wireless telegraphy will not proceed much further before -syntonic messages can be transmitted over hundreds if not thousands of -miles. - -It is hardly necessary to dwell upon the great prospect that the new -telegraphy opens to mankind. The advantages arising out of a ready -means of communication, freed from the shackles of expensive -connecting wires and cables are, in the main, obvious enough. We have -only to imagine all the present network of wires replaced or -supplemented by ether-waves, which will be able to act between points -(_e.g._ ships and ships, ships and land, moving and fixed objects -generally) which cannot be connected by metallic circuits. - -Already ocean voyages are being shortened as regards the time during -which passengers are out of contact with the doings of the world. The -transatlantic journey has now a newsless period of but three days. -Navies are being fitted out with instruments that may play as -important a part as the big guns themselves in the next naval war. A -great maritime nation like our own should be especially thankful that -the day is not far distant when our great empire will be connected by -invisible electric links that no enemy may discover and cut. - -The romantic side of wireless telegraphy has been admirably touched in -some words uttered by Professor Ayrton in 1899, after the reading of a -paper by Mr. Marconi before the Institution of Electrical Engineers. - -"If a person wished to call to a friend" (said the Professor), "he -would use a loud electro-magnetic voice, audible only to him who had -the electro-magnetic ear. - -"'Where are you?' he would say. - -"The reply would come--'I am at the bottom of a coal mine,' or -'Crossing the Andes,' or 'In the middle of the Pacific.' Or, perhaps, -in spite of all the calling, no reply would come, and the person would -then know his friend was dead. Let them think of what that meant; of -the calling which went on every day from room to room of a house, -and then imagine that calling extending from pole to pole; not a noisy -babble, but a call audible to him who wanted to hear and absolutely -silent to him who did not." - -[Illustration: _Guglielmo Marconi._] - -When will Professor Ayrton's forecast come true? Who can say? Science -is so full of surprises that the ordinary man wonders with a semi-fear -what may be the next development; and wise men like Lord Kelvin humbly -confess that in comparison with what has yet to be learnt about the -mysterious inner workings of Nature their knowledge is but as -ignorance. - - - - -HIGH-SPEED TELEGRAPHY. - - -The wonderful developments of wireless telegraphy must not make us -forget that some very interesting and startling improvements have been -made in connection with the ordinary wire-circuit method: notably in -the matter of speed. - -At certain seasons of the year or under special circumstances which -can scarcely be foreseen, a great rush takes place to transmit -messages over the wires connecting important towns. Now, the best -telegraphists can with difficulty keep up a transmitting speed of even -fifty words a minute for so long as half-an-hour. The Morse alphabet -contains on the average three signals for each letter, and the average -length of a word is six letters. Fifty words would therefore contain -between them 900 signals, or fifteen a second. The strain of sending -or noting so many for even a brief period is very wearisome to the -operator. - -Means have been found of replacing the telegraph clerk, so far as the -actual signalling is concerned, by mechanical devices. - -In 1842 Alexander Bain, a watchmaker of Thurso, produced what is known -as a "chemical telegraph." The words to be transmitted were set up in -large metal type, all capitals, connected with the positive pole of -a battery, the negative pole of which was connected to earth. A metal -brush, divided into five points, each terminating a wire, was passed -over the metal type. As often as a division of the brush touched metal -it completed the electric circuit in the wire to which it was joined, -and sent a current to the receiving station, where a similar brush was -passing at similar speed over a strip of paper soaked in iodide of -potassium. The action of the electricity decomposed the solution, -turning it blue or violet. The result was a series of letters divided -longitudinally into five belts separated by white spaces representing -the intervals between the contact points of the brush. - -[Illustration: _The receiving instrument used by Messrs. Pollak & -Virag in their high-speed system of telegraphy. This instrument is -capable of receiving and photographically recording messages at the -astonishing speed of 50,000 words an hour._] - -The Bain Chemical Telegraph was able to transmit the enormous number -of 1500 words per minute; that is, at ten times the rate of ordinary -conversation! But even when improvements had reduced the line wires -from five to one, the system, on account of the method of composing -the message to be sent, was not found sufficiently practical to come -into general use. - -Its place was taken by slower but preferable systems: those of duplex -and multiplex telegraphy. - -When a message is sent over the wires, the actual time of making the -signals is more than is required for the current to pass from place to -place. This fact has been utilised by the inventors of methods whereby -two or more messages may not only be sent the _same_ way along the -same wire, but may also be sent in _different_ directions. Messages -are "duplex" when they travel across one another, "multiplex" when -they travel together. - -The principle whereby several instruments are able to use the same -wire is that of _distributing_ among the instruments the time during -which they are in contact with the line. - -Let us suppose that four transmitters are sending messages -simultaneously from London to Edinburgh. - -Wires from all four instruments are led into a circular contact-maker, -divided into some hundreds of insulated segments connected in rotation -with the four transmitters. Thus instrument A will be joined to -segments 1, 5, 9, 13; instrument B to segments 2, 6, 10, 14; -instrument C with segments 3, 7, 11, 15; and so on. - -Along the top of the segments an arm, connected with the telegraph -line to Edinburgh, revolves at a uniform rate. For about 1/500 of a -second it unites a segment with an instrument. If there are 150 -segments on the "distributor," and the arm revolves three times a -second, each instrument will be put into contact with the line rather -oftener than 110 times per second. And if the top speed of fifty words -a minute is being worked to, each of the fifteen signals occurring in -each second will be on the average divided among seven moments of -contact. - -A similar apparatus at Edinburgh receives the messages. It is evident -that for the system to work satisfactorily, or even to escape dire -confusion, the revolving arms must run at a level speed in perfect -unison with one another. When the London arm is over segment 1, the -Edinburgh arm must cover the same number. The greatest difficulty in -multiplex telegraphy has been to adjust the timing exactly. - -Paul la Cour of Copenhagen invented for driving the arms a device -called the Phonic Wheel, as its action was regulated by the vibrations -of a tuning-fork. The wheel, made of soft iron, and toothed on its -circumference, revolves at a short distance from the pole of a magnet. -As often as a current enters the magnet the latter attracts the -nearest tooth of the wheel; and if a regular series of currents pass -through it the motion of the wheel will be uniform. M. la Cour -produced the regularity of current impulses in the motor magnet by -means of a tuning-fork, which is unable to vibrate more than a certain -number of times a second, and at each vibration closed a circuit -sending current into the magnet. To get two tuning-forks of the same -note is an easy matter; and consequently a uniformity of rotation at -both London and Edinburgh stations may be insured. - -So sensitive is this "interrupter" system that as many as sixteen -messages can be sent simultaneously, which means that a single wire is -conveying from 500 to 800 words a minute. We can easily understand the -huge saving that results from such a system; the cost of instruments, -interrupter, &c., being but small in proportion to that of a number -of separate conductors. - -The word-sending capacity of a line may be even further increased by -the use of automatic transmitters able to work much faster in -signal-making than the human brain and hand. Sir Charles Wheatstone's -Automatic Transmitter has long been used in the Post-Office -establishments. - -The messages to be sent are first of all punched on a long tape with -three parallel rows of perforations. The central row is merely for -guiding the tape through the transmitting machine. The positions of -the holes in the two outside rows relatively to each other determine -the character of the signal to be sent. Thus, when three holes -(including the central one) are abreast, a Morse "dot" is signified; -when the left-hand hole is one place behind the right hand, a "dash" -will be telegraphed. - -In the case of a long communication the matter is divided among a -number of clerks operating punching machines. Half-a-dozen operators -could between them punch holes representing 250 to 300 words a minute; -and the transmitter is capable of despatching as many in the same -time, while it has the additional advantage of being tireless. - -The action of the transmitter is based upon the reversal of the -direction or nature of current. The punched tape is passed between an -oscillating lever, carrying two points, and plates connected with the -two poles of the battery. As soon as a hole comes under a pin the pin -drops through and makes a contact. - -At the receiving end the wire is connected with a coil wound round the -pole of a permanent bar-magnet. Such a magnet has what is known as a -north pole and a south pole, the one attractive and the other -repulsive of steel or soft iron. Any bar of soft iron can be made -temporarily into a magnet by twisting round it a few turns of a wire -in circuit with the poles of a battery. But which will be the north -and which the south pole depends on the _direction_ of the current. -If, then, a current passes in one direction round the north pole of a -permanent magnet it will increase the magnet's attractive power, but -will decrease it if sent in the other direction. - -The "dot" holes punched in the tape being abreast cause first a -positive and then a negative current following at a very short -interval; but the "dash" holes not being opposite allow the positive -current to occupy the wires for a longer period. Consequently the -Morse marker rests for correspondingly unequal periods on the -recording "tape," giving out a series of dots and dashes, as the inker -is snatched quickly or more leisurely from the paper. - -The Wheatstone recorder has been worked up to 400 words a minute, and -when two machines are by the multiplex method acting together this -rate is of course doubled. - -As a speed machine it has, however, been completely put in the shade -by a more recent invention of two Hungarian electricians, Anton Pollak -and Josef Virag, which combines the perforated strip method of -transmission with the telephone and photography. The message is sent -off by means of a punched tape, and is recorded by means of a -telephonic diaphragm and light marking a sensitised paper. - -In 1898 the inventors made trials of their system for the benefit of -the United Electrical Company of Buda-Pesth. The Hungarian capital was -connected by two double lines of wire with a station 200 miles -distant, where the two sets were joined so as to give a single circuit -of 400 miles in length. A series of tests in all weathers showed that -the Pollak-Virag system could transmit as many as 100,000 words an -hour over that distance. - -From Hungary the inventors went to the United States, in which country -of "records" no less than 155,000 words were despatched and received -in the sixty minutes. This average--2580 words per minute, 43 per -second--is truly remarkable! Even between New York and Chicago, -separated by 950 odd miles, the wires kept up an average of 1000 per -minute. - -The apparatus that produces these marvellous results is of two types. -The one type records messages in the Morse alphabet, the other makes -clearly-written longhand characters. The former is the faster of the -two, but the legibility of the other more than compensates for the -decrease of speed by one-half. - -[Illustration: _Specimens of the punched tape used for transmitting -messages by the Pollak-Virag system, and of a message as it is -delivered by the receiving machine._] - -The Morse alphabet method closely resembles the Wheatstone system. The -message is prepared for transmission by being punched on a tape. But -there is this difference in the position of the holes, that whereas in -the Wheatstone method two holes are used for each dot and dash, only -one is required in the Pollak-Virag. If to the right of the central -guiding line it signifies a "dash," if to the left, a "dot." - -The "reversal-of-current" method, already explained, causes at the -receiver end an increase or decrease in the power of a permanent -magnet to attract or repel a diaphragm, the centre of which is -connected by a very fine metal bar with the centre of a tiny mirror -hinged at one side on two points. A very slight movement of the -diaphragm produces an exaggerated movement of the mirror, which, as it -tilts backwards and forwards, reflects the light from an electric lamp -on to a lens, which concentrates the rays into a bright spot, and -focuses them on to a surface of sensitised paper. - -In their earliest apparatus the inventors attached the paper to the -circumference of a vertical cylinder, which revolved at an even pace -on an axle, furnished at the lower end with a screw thread, so that -the portion of paper affected by the light occupied a spiral path from -top to bottom of the cylinder. - -In a later edition, however, an endless band of sensitised paper is -employed, and the lamp is screened from the mirror by a horizontal -mantle in which is cut a helical slit making one complete turn of the -cylinder in its length. The mantle is rotated in unison with the -machinery driving the sensitised band; and as it revolves, the spot at -which the light from the filament can pass through the slit to the -mirror is constantly shifting from right to left, and the point at -which the reflected light from the mirror strikes the sensitised paper -from left to right. At the moment when a line is finished, the right -extremity of the mantle begins to pass light again, and the bright -spot of light recommences its work at the left edge of the band, which -has now moved on a space. - -The movements of the mirror backwards and forwards produce on the -paper a zigzag tracing known as syphon-writing. The record, which is -continuous from side to side of the band, is a series of zigzag -up-and-down strokes, corresponding to the dots and dashes of the Morse -alphabet. - -The apparatus for transmitting longhand characters is more complicated -than that just described. Two telephones are now used, and the punched -tape has in it five rows of perforations. - -If we take a copy-book and examine the letters, we shall see that they -all occupy one, two, or three bands of space. For instance, _a_, -between the lines, occupies one band; _g_, two bands; and _f_, three. -In forming letters, the movements of the fingers trace curves and -straight lines, the curves being the resultants of combined horizontal -and vertical movements. - -Messrs. Pollak and Virag, in order to produce curves, were obliged to -add a second telephone, furnished also with a metal bar joined to the -mirror, which rests on three points instead of on two. One of these -points is fixed, the other two represent the ends of the two diaphragm -bars, which move the mirror vertically and horizontally respectively, -either separately or simultaneously. - -A word about the punched paper before going further. It contains, as -we have said, five rows of perforations. The top three of these are -concerned only with the up-and-down strokes of the letters, the bottom -two with the cross strokes. When a hole of one set is acting in unison -with a hole of the other set a composite movement or curve results. - -The topmost row of all sends through the wires a negative current of -known strength; this produces upward and return strokes in the upper -zone of the letters: for instance, the upper part of a _t_. The second -row passes _positive_ currents of equal strength with the negative, -and influences the up-and-down strokes of the centre zone, _e.g._ -those of _o_; the third row passes positive currents _twice_ as strong -as the negative, and is responsible for double-length vertical strokes -in the centre and lower zones, _e.g._ the stroke in _p_. - -In order that the record shall not be a series of zigzags it is -necessary that the return strokes in the vertical elements shall be on -the same path as the out strokes; and as the point of light is -continuously tending to move from left to right of the paper there -must at times be present a counteracting tendency counterbalancing it -exactly, so that the path of the light point is purely vertical. At -other times not merely must the horizontal movements balance each -other, but the right-to-left element must be stronger than the -left-to-right, so that strokes such as the left curve of an _e_ may be -possible. To this end rows 4 and 5 of the perforations pass currents -working the second telephone diaphragm, which moves the mirror on a -vertical axis so that it reflects the ray horizontally. - -It will be noticed that the holes in rows 3, 4, 5 vary in size to -permit the passage of currents during periods of different length. In -this manner the little junction-hooks of such letters as _r_, _w_, -_v_, _b_ are effected. - -As fast as the sensitised paper strip is covered with the movements of -the dancing spot of light it is passed on over rollers through -developing and fixing chemical baths; so that the receiving of -messages is purely automatic. - -The reader can judge for himself the results of this ingenious system -as shown in a short section of a message transmitted by Mr. Pollak. -The words shown actually occupied two seconds in transmission. They -are beautifully clear. - -It is said that by the aid of a special "multiplex" device thirty sets -of Pollak-Virag apparatus can be used simultaneously on a line! The -reader will be able, by the aid of a small calculation, to arrive at -some interesting figures as regards their united output. - - - - -THE TELEPHONE. - - -A common enough sight in any large town is a great sheaf of fine wires -running across the streets and over the houses. If you traced their -career in one direction you would find that they suddenly terminate, -or rather combine into cables, and disappear into the recesses of a -house, which is the Telephone Exchange. If you tracked them the other -way your experience would be varied enough. Some wires would lead you -into public institutions, some into offices, some into snug rooms in -private houses. At one time your journey would end in the town, at -another you would find yourself roaming far into the country, through -green fields and leafy lanes until at last you ran the wire to earth -in some large mansion standing in a lordly park. Perhaps you might -have to travel hundreds of miles, having struck a "trunk" line -connecting two important cities; or you might even be called upon to -turn fish and plunge beneath the sea for a while, groping your way -along a submarine cable. - -In addition to the visible overhead wires that traverse a town there -are many led underground through special conduits. And many telephone -wires never come out of doors at all, their object being to furnish -communication between the rooms of the same house. The telephone and -its friend, the electric-bell, are now a regular part of the equipment -of any large premises. The master of the house goes to his telephone -when he wishes to address the cook or the steward, or the -head-gardener or the coachman. It saves time and labour. - -Should he desire to speak to his town-offices he will, unless -connected direct, "ring up" the Exchange, into which, as we have seen, -flow all the wires of the subscribers to the telephone system of that -district. The ringing-up is usually done by rapidly turning a handle -which works an electric magnet and rings a bell in the Exchange. The -operator there, generally a girl, demands the number of the person -with whom the ringer wants to speak, rings up that number, and -connects the wires of the two parties. - -In some exchanges, _e.g._ the new Post-Office telephone exchanges, the -place of electric-bells is taken by lamps, to the great advantage of -the operators, whose ears are thus freed from perpetual jangling. The -action of unhooking the telephone receiver at the subscriber's end -sends a current into a relay which closes the circuit of an electric -lamp opposite the subscriber's number in the exchange. Similarly, when -the conversation is completed the action of hanging up the receiver -again lights another lamp of a different colour, given the exchange -warning that the wires are free again. - -In America, the country of automatic appliances, the operator is -sometimes entirely dispensed with. A subscriber is able, by means of -a mechanical contrivance, to put himself in communication with any -other subscriber unless that subscriber is engaged, in which case a -dial records the fact. - -The popularity of the telephone may be judged from the fact that in -1901 the National Telephone Company's system transmitted over 807 -millions of messages, as compared with 89 millions of telegrams sent -over the Post Office wires. In America and Germany, however, the -telephone is even more universally employed than in England. In the -thinly populated prairies of West America the farm-houses are often -connected with a central station many miles off, from which they -receive news of the outer world and are able to keep in touch with one -another. We are not, perhaps, as a nation sufficiently alive to the -advantages of an efficient telephone system; and on this account many -districts remain telephoneless because sufficient subscribers cannot -be found to guarantee use of a system if established. It has been -seriously urged that much of our country depopulation might be -counteracted by a universal telephone service, which would enable -people to live at a distance from the towns and yet be in close -contact with them. At present, for the sake of convenience and ease of -"getting at" clients and customers, many business men prefer to have -their homes just outside the towns where their business is. A cheap -and efficient service open to every one would do away with a great -deal of travelling that is necessary under existing circumstances, -and by making it less important to live near a town allow people to -return to the country. - -Even Norway has a good telephone system. The telegraph is little used -in the more thinly inhabited districts, but the telephone may be found -in most unexpected places, in little villages hidden in the recesses -of the fiords. Switzerland, another mountainous country, but very -go-ahead in all electrical matters, is noted for the cheapness of its -telephone services. At Berne or Geneva a subscriber pays £4 the first -year, £2, 12s. the second year, and but £1, 12s. the third. Contrast -these charges with those of New York, where £15, 10s. to £49, 10s. is -levied annually according to service. - -The telephone as a public benefactor is seen at its best at -Buda-Pesth, the twin-capital of Hungary. In 1893, one Herr Theodore -Buschgasch founded in that city a "newspaper"--if so it may be -called--worked entirely on the telephone. The publishing office was a -telephone exchange; the wires and instruments took the place of -printed matter. The subscribers were to be informed entirely by ear of -the news of the day. - -The _Telefon Hirmondo_ or "Telephonic Newsteller," as the "paper" was -named, has more than six thousand subscribers, who enjoy their -telephones for the very small payment of eighteen florins, or about a -penny a day, for twelve hours a day. - -News is collected at the central office in the usual journalistic way -by telephone, telegraph, and reporters. It is printed by lithography -on strips of paper six inches wide and two feet long. These strips are -handed to "stentors," or men with powerful and trained voices, who -read the contents to transmitting instruments in the offices, whence -it flies in all directions to the ears of the subscribers. - -These last know exactly when to listen and what description of -information they will hear, for each has over his receiver a programme -which is rigidly adhered to. It must be explained at once that the -_Telefon Hirmondo_ is more than a mere newspaper, for it adds to its -practical use as a first-class journal that of entertainer, lecturer, -preacher, actor, political speaker, musician. The _Telefon_ offices -are connected by wire with the theatres, churches, and public halls, -drawing from them by means of special receivers the sounds that are -going on there, and transmitting them again over the wires to the -thousands of subscribers. The Buda-Pesthian has therefore only to -consult his programme to see when he will be in touch with his -favourite actor or preacher. The ladies know just when to expect the -latest hints about the fashions of the day. Nor are the children -forgotten, for a special period is set aside weekly for their -entertainment in the shape of lectures or concerts. - -The advertising fiend, too, must have his say, though he pays dearly -for it. On payment of a florin the stentors will shout the virtues of -his wares for a space of twelve seconds. The advertising periods are -sandwiched in between items of news, so that the subscriber is bound -to hear the advertisements unless he is willing to risk missing some -of the news if he hangs up his receiver until the "puff" is finished. - -Thanks to the _Telefon Hirmondo_ the preacher, actor, or singer is -obliged to calculate his popularity less by the condition of the seats -in front of him than by the number of telephones in use while he is -performing his part. On the other hand, the subscriber is spared a -vast amount of walking, waiting, cab-hire, and expense generally. In -fact, if the principle is much further developed, we shall begin to -doubt whether a Buda-Pesthian will be able to discover reasons for -getting out of bed at all if the receiver hanging within reach of his -hand is the entrance to so many places of delight. Will he become a -very lazy person; and what will be the effect on his entertainers when -they find themselves facing benches that are used less every day? Will -the sight of a row of telephone trumpets rouse the future Liddon, -Patti, Irving, or Gladstone to excel themselves? It seems rather -doubtful. Telephones cannot look interested or applaud. - -What is inside the simple-looking receiver that hangs on the wall -beside a small mahogany case, or rests horizontally on a couple of -crooks over the case? In the older type of instrument the transmitter -and receiver are separate, the former fixed in front of the case, the -latter, of course, movable so that it can be applied to the ear. But -improved patterns have transmitter and receiver in a single movable -handle, so shaped that the earpiece is by the ear while the -mouthpiece curves round opposite the mouth. By pressing a small lever -with the fingers the one or the other is brought into action when -required. - -The construction of the instrument, of which we are at first a little -afraid, and with which we later on learn to become rather angry, is in -its general lines simple enough. The first practical telephone, -constructed in 1876 by Graham Bell, a Scotchman, consisted of a long -wooden or ebonite handle down the centre of which ran a permanent -bar-magnet, having at one end a small coil of fine insulated wire -wound about it The ends of the wire coil are led through the handles -to two terminals for connection with the line wires. At a very short -distance from the wire-wound pole of the magnet is firmly fixed by its -edges a thin circular iron plate, covered by a funnel-shaped -mouthpiece. - -The iron plate is, when at rest, concave, its centre being attracted -towards the pole of the magnet. When any one speaks into the -mouthpiece the sound waves agitate the diaphragm (or plate), causing -its centre to move inwards and outwards. The movements of the -diaphragm affect the magnetism of the magnet, sometimes strengthening -it, sometimes weakening it, and consequently exciting electric -currents of varying strength in the wire coil. These currents passing -through the line wires to a similar telephone excite the coil in it, -and in turn affect the magnetism of the distant magnet, which -attracts or releases the diaphragm near its pole, causing undulations -of the air exactly resembling those set up by the speaker's words. To -render the telephone powerful enough to make conversation possible -over long distances it was found advisable to substitute for the one -telephone a special transmitter, and to insert in the circuit a -battery giving a much stronger current than could possibly be excited -by the magnet in the telephone at the speaker's end. - -Edison in 1877 invented a special transmitter made of carbon. He -discovered that the harder two faces of carbon are pressed together -the more readily will they allow current to pass; the reason probably -being that the points of contact increase in number and afford more -bridges for the current. - -Accordingly his transmitter contains a small disc of lampblack (a form -of carbon) connected to the diaphragm, and another carbon or platinum -disc against which the first is driven with varying force by the -vibrations of the voice. - -The Edison transmitter is therefore in idea only a modification of the -microphone. It acts as a _regulator_ of current, in distinction to the -Bell telephone, which is only an _exciter_ of current. Modern forms of -telephones unite the Edison transmitter with the Bell receiver. - -The latter is extremely sensitive to electric currents, detecting them -even when of the minutest power. We have seen that Marconi used a -telephone in his famous transatlantic experiments to distinguish the -signals sent from Cornwall. A telephone may be used with an "earth -return" instead of a second wire; but as this exposes it to stray -currents by induction from other wires carried on the same poles or -from the earth itself, it is now usual to use two wires, completing -the metallic circuit. Even so a subscriber is liable to overhear -conversations on wires neighbouring his own; the writer has lively -recollections of first receiving news of the relief of Ladysmith in -this manner. - -Owing to the self-induction of wires in submarine cables and the -consequent difficulty of forcing currents through them, the telephone -is at present not used in connection with submarine lines of more than -a very moderate length. England has, however, been connected with -France by a telephone cable from St. Margaret's Bay to Sangatte, 23 -miles; and Scotland with Ireland, Stranraer to Donaghadee, 26 miles. -The former cable enables speech between London and Marseilles, a -distance of 900 miles; and the latter makes it possible to speak from -London to Dublin _viâ_ Glasgow. The longest direct line in existence -is that between New York and Chicago, the complete circuit of which -uses 1900 miles of stout copper wire, raised above the ground on poles -35 feet high. - -The efficiency of the telephone on a well laid system is so great that -it makes very little difference whether the persons talking with one -another are 50 or 500 miles apart. There is no reason why a -Cape-to-Cairo telephone should not put the two extremities of Africa -in clear vocal communication. We may even live to see the day when a -London business man will be able to talk with his agent in Sydney, -Melbourne, or Wellington. - -A step towards this last achievement has been taken by M. Germain, a -French electrician, who has patented a telephone which can be used -with stronger currents than are possible in ordinary telephones; -thereby, of course, increasing the range of speech on submarine -cables. - -The telephone that we generally use has a transmitter which permits -but a small portion of the battery power to pass into the wires, owing -to the resistance of the carbon diaphragm. The weakness of the current -is to a great extent compensated by the exceedingly delicate nature of -the receiver. - -M. Germain has reversed the conditions with a transmitter that allows -a very high percentage of the current to flow into the wires, and a -comparatively insensitive receiver. The result is a "loud-speaking -telephone"--not a novelty, for Edison invented one as long ago as -1877--which is capable of reproducing speech in a wonderfully powerful -fashion. - -M. Germain, with the help of special tubular receivers, has actually -sent messages through a line having the same resistance as that of the -London-Paris line, so audibly that the words could be heard fifteen -yards from the receiver in the open air! - - - - -The Telephone - -WIRELESS TELEPHONY. - - -In days when wireless telegraphy is occupying such a great deal of the -world's attention, it is not likely to cause much astonishment in the -reader to learn that wireless transmission of _speech_ over -considerable distances is an accomplished fact. We have already -mentioned (see "Wireless Telegraphy") that by means of parallel -systems of wires Sir William Preece bridged a large air-gap, and -induced in the one sounds imparted to the other. - -Since then two other methods have been introduced; and as a preface to -the mention of the first we may say a few words about Graham Bell's -_Photophone_. - -In this instrument _light_ is made to do the work of a metal -connection between speaker and listener. Professor Bell, in arranging -the Photophone, used a mouthpiece as in his electric telephone, but -instead of a diaphragm working in front of a magnet to set up electric -impulses along a wire he employed a mirror of very thin glass, -silvered on one side. The effect of sound on this mirror was to cause -rapid alterations of its shape from concave to convex, and consequent -variations of its reflecting power. A strong beam of light was -concentrated on the centre of the mirror through a lens, and reflected -by the mirror at an angle through another lens in the direction of the -receiving instrument. The receiver consisted of a parabolic reflector -to catch the rays and focus them on a selenium cell connected by an -electric circuit with an ordinary telephone earpiece. - -On delivering a message into the mouthpiece the speaker would, by -agitating the mirror, send a succession of light waves of varying -intensity towards the distant selenium cell. Selenium has the peculiar -property of offering less resistance to electrical currents when light -is thrown upon it than when it is in darkness: and the more intense is -the light the less is the obstruction it affords. The light-waves from -the mirror, therefore, constantly alter its capacity as a conductor, -allowing currents to pass through the telephone with varying power. - -In this way Professor Bell bridged 800 yards of space; over which he -sent, besides articulate words, musical notes, using for the latter -purpose a revolving perforated disc to interrupt a constant beam of -light a certain number of times per second. As the speed of the disc -increased the rate of the light-flashes increased also, and produced -in the selenium cell the same number of passages to the electric -current, converted into a musical note by the receiver. So that by -means of mechanical apparatus a "playful sunbeam" could literally be -compelled to play a tune. - -From the Photophone we pass to another method of sound transmission by -light, with which is connected the name of Mr. Hammond V. Hayes of -Boston, Massachusetts. It is embodied in the Radiophone, or the -Ray-speaker, for it makes strong rays of light carry the human voice. - -Luminous bodies give off heat. As the light increases, so as a general -rule does the heat also. At present we are unable to create strong -light without having recourse to heat to help us, since we do not know -how to cause other vibrations of sufficient rapidity to yield the -sensation of light. But we can produce heat directly, and heat will -set atoms in motion, and the ether too, giving us light, but taking as -reward a great deal of the energy exerted. Now, the electric arc of a -searchlight produces a large amount of light _and_ heat. The light is -felt by the eye at a distance of many miles, but the body is not -sensitive enough to be aware of the heat emanating from the same -source. Mr. Hayes has, however, found the heat accompanying a -searchlight beam quite sufficient to affect a mechanical "nerve" in a -far-away telephone receiver. - -The transmitting apparatus is a searchlight, through the back of which -run four pairs of wires connected with a telephone mouthpiece after -passing through a switch and resistance-box or regulator. The receiver -is a concave mirror, in the focus of which is a tapering glass bulb, -half filled with carbonised filament very sensitive to heat. The -tapering end of the bulb projects through the back of the mirror into -an ear tube. - -If a message is to be transmitted the would-be speaker turns his -searchlight in the direction of the person with whom he wishes to -converse, and makes the proper signals. On seeing them the other -presents his mirror to the beam and listens. - -The speaker's voice takes control of the searchlight beam. The louder -the sound the more brilliantly glows the electric arc; the stronger -becomes the beam, the greater is the amount of heat passed on to the -mirror and gathered on the sensitive bulb. The filament inside -expands. The tapering point communicates the fact to the earpiece. - -This operation being repeated many times a second the earpiece fills -with sound, in which all the modulations of the far-distant voice are -easily distinguishable. - -Two sets of the apparatus above described are necessary for a -conversation, the functions of the searchlight and the bulb not being -reversible. But inasmuch as all large steamers carry searchlights the -necessary installation may be completed at a small expense. Mr. Hayes' -invention promises to be a rival to wireless telegraphy over -comparatively short distances. It can be relied upon in all weathers, -and is a fast method of communication. Like the photophone it -illustrates the inter-relationship of the phenomena of Sound, Light, -and Heat, and the readiness with which they may be combined to attain -an end. - -Next we turn from air to earth, and to the consideration of the work -of Mr. A. F. Collins of Philadelphia. This electrician merely makes -use of the currents flowing in all directions through the earth, and -those excited by an electric battery connected with earth. The outfit -requisite for sending wireless spoken messages consists of a couple of -convenient stands, as many storage batteries, sets of coils, and -receiving and transmitting instruments. - -The action of the transmitter is to send from the battery a series of -currents through the coils, which transmit them, greatly intensified, -to the earth by means of a wire connected with a buried wire-screen. -The electric disturbances set up in the earth travel in all -directions, and strike a similar screen buried beneath the receiving -instrument, where the currents affect the delicate diaphragm of the -telephone earpiece. - -The system is, in fact, upon all fours with Mr. Marconi's, the -distinguishing feature being that the ether of the atmosphere is used -in the latter case, that of the earth in the former. The intensity -coils are common to both; the buried screens are the counterpart of -the aërial kites or balloons; the telephone transmitter corresponds to -the telegraphic transmitting key; the earpiece to the coherer and -relay. No doubt in time Mr. Collins will "tune" his instruments, so -obtaining below ground the same sympathetic electric vibrations which -Mr. Marconi, Professor Lodge, or others have employed to clothe their -aërial messages in secrecy. - - - - -THE PHONOGRAPH. - - -Even if Thomas Edison had not done wonders with electric lighting, -telephones, electric torpedoes, new processes for separating iron from -its ore, telegraphy, animated photography, and other things too -numerous to mention, he would still have made for himself an enduring -name as the inventor of the Phonograph. He has fitly been called the -"Wizard of the West" from his genius for conjuring up out of what -would appear to the multitude most unpromising materials startling -scientific marvels, among which none is more truly wizard-like than -the instrument that is as receptive of sound as the human ear, and of -illimitable reproducing power. By virtue of its elfishly human -characteristic, articulate speech, it occupies, and always will -occupy, a very high position as a mechanical wonder. When listening to -a telephone we are aware of the fact that the sounds are immediate -reproductions of a living person's voice, speaking at the moment and -at a definite distance from us; but the phonographic utterances are -those of a voice perhaps stilled for ever, and the difference adds -romance to the speaking machine. - -The Phonograph was born in 1876. As we may imagine, its appearance -created a stir. A contributor to the _Times_ wrote in 1877: "Not many -weeks have passed since we were startled by the announcement that we -could converse audibly with each other, although hundreds of miles -apart, by means of so many miles of wire with a little electric magnet -at each end. - -"Another wonder is now promised us--an invention purely mechanical in -its nature, by means of which words spoken by the human voice can be, -so to speak, stored up and reproduced at will over and over again -hundreds, it may be thousands, of times. What will be thought of a -piece of mechanism by means of which a message of any length can be -spoken on to a plate of metal--that plate sent by post to any part of -the world and the message absolutely respoken in the very voice of the -sender, purely by mechanical agency? What, too, shall be said of a -mere machine, by means of which the old familiar voice of one who is -no longer with us on earth can be heard speaking to us in the very -tones and measure to which our ears were once accustomed?" - -The first Edison machine was the climax of research in the realm of -sound. As long ago as 1856 a Mr. Leo Scott made an instrument which -received the formidable name of Phonautograph, on account of its -capacity to register mechanically the vibrations set up in the -atmosphere by the human voice or by musical instruments. A large metal -cone like the mouth of an ear-trumpet had stretched across its smaller -end a membrane, to which was attached a very delicate tracing-point -working on the surface of a revolving cylinder covered with blackened -paper. Any sound entering the trumpet agitated the membrane, which in -turn moved the stylus and produced a line on the cylinder -corresponding to the vibration. Scott's apparatus could only record. -It was, so to speak, the first half of the phonograph. Edison, twenty -years later, added the active half. His machine, as briefly described -in the _Times_, was simple; so very simple that many scientists must -have wondered how they failed to invent it themselves. - -A metal cylinder grooved with a continuous square-section thread of -many turns to the inch was mounted horizontally on a long axle cut at -one end with a screw-thread of the same "pitch" as that on the -cylinder. The axle, working in upright supports, and furnished with a -heavy flywheel to render the rate of revolution fairly uniform, was -turned by a handle. Over the grooved cylinder was stretched a thin -sheet of tinfoil, and on this rested lightly a steel tracing-point, -mounted at the end of a spring and separated from a vibrating -diaphragm by a small pad of rubber tubing. A large mouthpiece to -concentrate sound on to the diaphragm completed the apparatus. - -To make a record with this machine the cylinder was moved along until -the tracing-point touched one extremity of the foil. The person -speaking into the mouthpiece turned the handle to bring a fresh -surface of foil continuously under the point, which, owing to the -thread on the axle and the groove on the cylinder being of the same -pitch, was always over the groove, and burnished the foil down into it -to a greater or less depth according to the strength of the impulses -received from the diaphragm. - -[Illustration: _A unique group of Phonographs. 1. The oldest -phonograph in existence, now in South Kensington Museum. 2. Tinfoil -instrument. 3. A cheaper form of the same. 4. A "spectacle-form" -graphophone. 5. An exactly similar instrument, half-size scale. 6. A -doll fitted with phonograph._] - -The record being finished, the point was lifted off the foil, the -cylinder turned back to its original position, and the point allowed -to run again over the depressions it had made in the metal sheet. The -latter now became the active part, imparting to the air by means of -the diaphragm vibrations similar in duration and quality to those that -affected it when the record was being made. - -It is interesting to notice that the phonograph principle was -originally employed by Edison as a telephone "relay." His attention -had been drawn to the telephone recently produced by Graham Bell, and -to the evil effects of current leakage in long lines. He saw that the -amount of current wasted increased out of proportion to the length of -the lines--even more than in the proportion of the squares of their -lengths--and he hoped that a great saving of current would be effected -if a long line were divided into sections and the sound vibrations -were passed from one to the other by mechanical means. He used as the -connecting link between two sections a strip of moistened paper, which -a needle, attached to a receiver, indented with minute depressions, -that handed on the message to another telephone. The phonograph -proper, as a recording machine, was an after-thought. - -Edison's first apparatus, besides being heavy and clumsy, had in -practice faults which made it fall short of the description given in -the _Times_. Its tone was harsh. The records, so far from enduring a -thousand repetitions, were worn out by a dozen. To these defects must -be added a considerable difficulty in adjusting a record made on one -machine to the cylinder of another machine. - -Edison, being busy with his telephone and electric lamp work, put -aside the phonograph for a time. Graham Bell, his brother, Chichester -Bell, and Charles Sumner Tainter, developed and improved his crude -ideas. They introduced the Graphophone, using easily removable -cylinder records. For the tinfoil was substituted a thin coating of a -special wax preparation on light paper cylinders. Clockwork-driven -motors replaced the hand motion, and the new machines were altogether -more handy and effective. As soon as he had time Edison again entered -the field. He conceived the solid wax cylinder, and patented a small -shaving apparatus by means of which a record could be pared away and a -fresh surface be presented for a new record. - -The phonograph or graphophone of to-day is a familiar enough sight; -but inasmuch as our readers may be less intimately acquainted with its -construction and action than with its effects, a few words will now be -added about its most striking features. - -In the first place, the record remains stationary while the trumpet, -diaphragm and stylus pass over it. The reverse was the case with the -tinfoil instrument. - -The record is cut by means of a tiny sapphire point having a circular -concave end very sharp at the edges, to gouge minute depressions into -the wax. The point is agitated by a delicate combination of weights -and levers connecting it with a diaphragm of French glass 1/140 inch -thick. The reproducing point is a sapphire ball of a diameter equal to -that of the gouge. It passes over the depressions, falling into them -in turn and communicating its movements to a diaphragm, and so -tenderly does it treat the records that a hundred repetitions do not -inflict noticeable damage. - -It is a curious instance of the manner in which man unconsciously -copies nature that the parts of the reproducing attachment of a -phonograph contains parts corresponding in function exactly to those -bones of the ear known as the Hammer, Anvil, and Stirrup. - -To understand the inner working of the phonograph the reader must be -acquainted with the theory of sound. All sound is the result of -impulses transmitted by a moving body usually reaching the ear through -the medium of the air. The quantity of the sound, or loudness, depends -on the violence of the impulse; the tone, or note, on the number of -impulses in a given time (usually fixed as one second); and the -quality, or _timbre_, as musicians say, on the existence of minor -vibrations within the main ones. - -If we were to examine the surface of a phonograph record (or -phonogram) under a powerful magnifying glass we should see a series -of scoops cut by the gouge in the wax, some longer and deeper than -others, long and short, deep and shallow, alternating and recurring in -regular groups. The depth, length, and grouping of the cuts decides -the nature of the resultant note when the reproducing sapphire point -passes over the record--at a rate of about ten inches a second. - -The study of a tracing made on properly prepared paper by a point -agitated by a diaphragm would enable us to understand easily the cause -of that mysterious variation in _timbre_ which betrays at once what -kind of instrument has emitted a note of known pitch. For instance, -let us take middle C, which is the result of a certain number of -atmospheric blows per second on the drum of the ear. The same note may -come from a piano, a violin, a banjo, a man's larynx, an organ, or a -cornet; but we at once detect its source. It is scarcely imaginable -that a piano and a cornet should be mistaken for one another. Now, if -the tracing instrument had been at work while the notes were made -successively it would have recorded a wavy line, each wave of exactly -the same _length_ as its fellows, but varying in its _outline_ -according to the character of the note's origin. We should notice that -the waves were themselves wavy in section, being jagged like the teeth -of a saw, and that the small secondary waves differed in size. - -The minor waves are the harmonics of the main note. Some musical -instruments are richer in these harmonics than others. The fact that -these delicate variations are recorded as minute indentations in the -wax and reproduced is a striking proof of the phonograph's mechanical -perfection. - -Furthermore, the phonograph registers not only these composite notes, -but also chords or simultaneous combinations of notes, each of which -may proceed from a different instrument. In its action it here -resembles a man who by constant practice is able to add up the pounds, -shillings, and pence columns in his ledger at the same time, one wave -system overlapping and blending with another. - -The phonograph is not equally sympathetic with all classes of sounds. -Banjo duets make good records, but the guitar gives a poor result. -Similarly, the cornet is peculiarly effective, but the bass drum -disappointing. The deep chest notes of a man come from the trumpet -with startling truth, but the top notes on which the soprano prides -herself are often sadly "tinny." The phonograph, therefore, even in -its most perfect form is not the equal of the exquisitely sensitive -human ear; and this may partially be accounted for by the fact that -the diaphragm in both recorder and reproducer has its own fundamental -note which is not in harmony with all other notes, whereas the ear, -like the eye, adapts itself to any vibration. - -Yet the phonograph has an almost limitless répertoire. It can justly -be claimed for it that it is many musical instruments rolled into one. -It will reproduce clearly and faithfully an orchestra, an -instrumental soloist, the words of a singer, a stump orator, or a -stage favourite. Consequently we find it every where--at -entertainments, in the drawing-room, and even tempting us at the -railway station or other places of public resort to part with our -superfluous pence. At the London Hippodrome it discourses to audiences -of several thousand persons, and in the nursery it delights the -possessors of ingeniously-constructed dolls which, on a button being -pressed and concealed machinery being brought into action, repeat some -well-known childish melody. - -It must not be supposed that the phonograph is nothing more than a -superior kind of scientific toy. More serious duties than those of -mere entertainment have been found for it. - -At the last Presidential Election in the States the phonograph was -often called upon to harangue large meetings in the interests of the -rival candidates, who were perhaps at the time wearing out their -voices hundreds of miles away with the same words. - -Since the pronunciation of a foreign language is acquired by constant -imitation of sounds, the phonograph, instructed by an expert, has been -used to repeat words and phrases to a class of students until the -difficulties they contain have been thoroughly mastered. The sight of -such a class hanging on the lips--or more properly the trumpet--of a -phonograph gifted with the true Parisian accent may be common enough -in the future. - -As a mechanical secretary and substitute for the shorthand writer the -phonograph has certainly passed the experimental stage. Its daily use -by some of the largest business establishments in the world testify to -its value in commercial life. Many firms, especially American, have -invested heavily in establishing phonograph establishments to save -labour and final expense. The manager, on arriving at his office in -the morning, reads his letters, and as the contents of each is -mastered, dictates an answer to a phonograph cylinder which is -presently removed to the typewriting room, where an assistant, placing -it upon her phonograph and fixing the tubes to her ears, types what is -required. It is interesting to learn that at Ottawa, the seat of the -Canadian Government, phonographs are used for reporting the -parliamentary proceedings and debates. - -There is therefore a prospect that, though the talking-machine may -lose its novelty as an entertainer, its practical usefulness will be -largely increased. And while considering the future of the instrument, -the thought suggests itself whether we shall be taking full advantage -of Mr. Edison's notable invention if we neglect to make records of all -kinds of intelligible sounds which have more than a passing interest. -If the records were made in an imperishable substance they might -remain effective for centuries, due care being taken of them in -special depositories owned by the nation. To understand what their -value would be to future generations we have only to imagine ourselves -listening to the long-stilled thunder of Earl Chatham, to the golden -eloquence of Burke, or the passionate declamations of Mrs. Siddons. -And in the narrower circle of family interests how valuable a part of -family heirlooms would be the phonograms containing a vocal message to -posterity from Grandfather this, or Great-aunt that, whose portraits -in the drawing-room album do little more than call attention to the -changes in dress since the time when their subjects faced the camera! - -_Record-Making and Manufacture._--Phonographic records are of two -shapes, the cylindrical and the flat, the latter cut with a volute -groove continuously diminishing in diameter from the circumference to -the centre. Flat records are used in the Gramophone--a reproducing -machine only. Their manufacture is effected by first of all making a -record on a sheet of zinc coated with a very thin film of wax, from -which the sharp steel point moved by the recording diaphragm removes -small portions, baring the zinc underneath. The plate is then flooded -with an acid solution, which eats into the bared patches, but does not -affect the parts still covered with wax. The etching complete, the wax -is removed entirely, and a cast or electrotype _negative_ record made -from the zinc plate. The indentations of the original are in this -represented by excrescences of like size; and when the negative block -is pressed hard down on to a properly prepared disc of vulcanite or -celluloid, the latter is indented in a manner that reproduces exactly -the tones received on the "master" record. - -Cylindrical records are made in two ways, by moulding or by copying. -The second process is extremely simple. The "master" cylinder is -placed on a machine which also rotates a blank cylinder at a short -distance from and parallel to the first. Over the "master" record -passes a reproducing point, which is connected by delicate levers to a -cutting point resting on the "blank," so that every movement of the -one produces a corresponding movement of the other. - -This method, though accurate in its results, is comparatively slow. -The _moulding_ process is therefore becoming the more general of the -two. Edison has recently introduced a most beautiful process for -obtaining negative moulds from wax positives. Owing to its shape, a -zinc cylinder could not be treated like a flat disc, as, the negative -made, it could not be detached without cutting. Edison, therefore, -with characteristic perseverance, sought a way of electrotyping the -wax, which, being a non-conductor of electricity, would not receive a -deposit of metal. The problem was how to deposit on it. - -Any one who has seen a Crookes' tube such as is used for X-ray work -may have noticed on the glass a black deposit which arises from the -flinging off from the negative pole of minute particles of platinum. -Edison took advantage of this repellent action; and by enclosing his -wax records in a vacuum between two gold poles was able to coat them -with an infinitesimally thin skin of pure gold, on which silver or -nickel could be easily deposited. The deposit being sufficiently thick -the wax was melted out and the surface of the electrotype carefully -cleaned. To make castings it was necessary only to pour in wax, which -on cooling would shrink sufficiently to be withdrawn. The delicacy of -the process may be deduced from the fact that some of the sibilants, -or hissing sounds of the voice, are computed to be represented by -depressions less than a millionth of an inch in depth, and yet they -are most distinctly reproduced! Cylinder records are made in two -sizes, 2-1/2 and 5 inches in diameter respectively. The larger size -gives the most satisfactory renderings, as the indentations are on a -larger scale and therefore less worn by the reproducing point. One -hundred turns to the inch is the standard pitch of the thread; but in -some records the number is doubled. - -Phonographs, Graphophones, and Gramophones are manufactured almost -entirely in America, where large factories, equipped with most perfect -plant and tools, work day and night to cope with the orders that flow -in freely from all sides. One factory alone turns out a thousand -machines a day, ranging in value from a few shillings to forty pounds -each. Records are made in England on a large scale; and now that the -Edison-Bell firm has introduced the unbreakable celluloid form their -price will decrease. By means of the Edison electrotyping process a -customer can change his record without changing his cylinder. He takes -the cylinder to the factory, where it is heated, placed in the mould, -and subjected to great pressure which drives the soft celluloid into -the mould depressions; and behold! in a few moments "Auld Lang Syne" -has become "Home, Sweet Home," or whatever air is desired. Thus -altering records is very little more difficult than getting a fresh -book at the circulating library. - - -THE PHOTOGRAPHOPHONE. - -This instrument is a phonograph working entirely by means of light and -electricity. - -The flame of an electric lamp is brought under the influence of sound -vibrations which cause its brilliancy to vary at every alteration of -pitch or quality. - -The light of the flame is concentrated through a lens on to a -travelling photographic sensitive film, which, on development in the -ordinary way, is found to be covered with dark and bright stripes -proportionate in tone to the strength of the light at different -moments. The film is then passed between a lamp and a selenium plate -connected with an electric circuit and a telephone. The resistance of -the selenium to the current varies according to the power of the light -thrown upon it. When a dark portion of the film intercepts the light -of the lamp the selenium plate offers high resistance; when the light -finds its way through a clear part of the film the resistance weakens. -Thus the telephone is submitted to a series of changes affecting the -"receiver." As in the making of the record speech-vibrations affect -light, and the light affects a sensitive film; so in its reproduction -the film affects a sensitive selenium plate, giving back to a -telephone exactly what it received from the sound vibrations. - -One great advantage of Mr. Ruhmer's method is that from a single film -any number of records can be printed by photography; another, that, as -with the Telegraphone (see below), the same film passed before a -series of lamps successively is able to operate a corresponding number -of telephones. - -The inventor is not content with his success. He hopes to record not -merely sounds but even pictures by means of light and a selenium -plate. - - -THE TELEPHONOGRAPH. - -Having dealt with the phonograph and the telephone separately, we may -briefly consider one or two ingenious combinations of the two -instruments. The word Telephonograph signifies an apparatus for -recording sounds sent from a distance. It takes the place of the human -listener at the telephone receiver. - -Let us suppose that a Reading subscriber wishes to converse along the -wires with a friend in London, but that on ringing up his number he -discovers that the friend is absent from his home or office. He is -left with the alternative of either waiting till his friend returns, -which may cause a serious loss of time, or of dictating his message, a -slow and laborious process. This with the ordinary telephonic -apparatus. But if the London friend be the possessor of a -Telephonograph, the person answering the call-bell can, if desired to -do so, switch the wires into connection with it and start the -machinery; and in a very short time the message will be stored up for -reproduction when the absent friend returns. - -The Telephonograph is the invention of Mr. J. E. O. Kumberg. The -message is spoken into the telephone transmitter in the ordinary way, -and the vibrations set up by the voice are caused to act upon a -recording stylus by the impact of the sound waves at the further end -of the wires. In this manner a phonogram is produced on the wax -cylinder in the house or office of the person addressed, and it may be -read off at leisure. A very sensitive transmitter is employed, and if -desired the apparatus can be so arranged that by means of a -double-channel tube the words spoken are simultaneously conveyed to -the telephone and to an ordinary phonograph, which insures that a -record shall be kept of any message sent. - -The _Telegraphone_, produced by Mr. Valdemar Poulsen, performs the -same functions as the telephonograph, but differs from it in being -entirely electrical. It contains no waxen cylinder, no cutting-point; -their places are taken respectively by a steel wire wound on a -cylindrical drum (each turn carefully insulated from its neighbours) -and by a very small electro-magnet, which has two delicate points that -pass along the wire, one on either side, resting lightly upon it. - -As the drum rotates, the whole of the wire passes gradually between -the two points, into which a series of electric shocks is sent by the -action of the speaker's voice at the further end of the wires. The -shocks magnetise the portion of steel wire which acts as a temporary -bridge between the two points. At the close of three and a half -minutes the magnet has worked from one end of the wire coil to the -other; it is then automatically lifted and carried back to the -starting-point in readiness for reproduction of the sounds. This is -accomplished by disconnecting the telegraphone from the telephone -wires and switching it on to an ordinary telephonic earpiece or -receiver. As soon as the cylinder commences to revolve a second time, -the magnet is influenced by the series of magnetic "fields" in the -wires, and as often as it touches a magnetised spot imparts an impulse -to the diaphragm of the receiver, which vibrates at the rate and with -the same force as the vibrations originally set up in the distant -transmitter. The result is a clear and accurate reproduction of the -message, even though hours and even days may have elapsed since its -arrival. - -As the magnetic effects on the wire coil retain their power for a -considerable period, the message may be reproduced many times. As soon -as the wire-covered drum is required for fresh impressions, the old -one is wiped out by passing a permanent magnet along the wire to -neutralise the magnetism of the last message. - -Mr. Poulsen has made an instrument of a different type to be employed -for the reception of an unusually lengthy communication. Instead of a -wire coil on a cylinder, a ribbon of very thin flat steel spring is -wound from one reel on to another across the poles of _two_ -electro-magnets, which touch the lower side only of the strip. The -first magnet is traversed by a continuous current to efface the -previous record; the second magnetises the strip in obedience to -impulses from the telephone wires. The message complete, the strip is -run back, and the magnets connected with receivers, which give out -loud and intelligent speech as the strip again traverses them. The -Poulsen machine makes the transmission of the same message -simultaneously through several telephones an easy matter, as the strip -can be passed over a series of electro-magnets each connected with a -telephone. - - - - -THE TELAUTOGRAPH. - - -It is a curious experience to watch for the first time the movements -of a tiny Telautograph pen as it works behind a glass window in a -japanned case. The pen, though connected only with two delicate wires, -appears instinct with human reason. It writes in a flowing hand, just -as a man writes. At the end of a word it crosses the t's and dots the -i's. At the end of a line it dips itself in an inkpot. It punctuates -its sentences correctly. It illustrates its words with sketches. It -uses shorthand as readily as longhand. It can form letters of all -shapes and sizes. - -And yet there is no visible reason why it should do what it does. The -japanned case hides the guiding agency, whatever it may be. Our ears -cannot detect any mechanical motion. The writing seems at first sight -as mysterious as that which appeared on the wall to warn King -Belshazzar. - -In reality it is the outcome of a vast amount of patience and -mechanical ingenuity culminating in a wonderful instrument called the -Telautograph. The Telautograph is so named because by its aid we can -send our autographs, _i.e._ our own particular handwriting, -electrically over an indefinite length of wire, as easily as a -telegraph clerk transmits messages in the Morse alphabet. Whatever -the human hand does on one telautograph at one end of the wires, that -will be reproduced by a similar machine at the other end, though the -latter be hundreds of miles away. - -[Illustration: _By kind permission of The Telautograph Co._ - -_The Telautograph. The upper portion is the Receiver, the lower (with -cover removed) is the Transmitter._] - -The instrument stands about eighteen inches high, and its base is as -many inches square. It falls into two parts, the receiver and the -transmitter. The receiver is vertical and forms the upright and back -portion of the telautograph. At one side of it hangs an ordinary -telephone attachment. The transmitter, a sloping desk placed -conveniently for the hand, is the front and horizontal portion. The -receiver of one station is connected with the transmitter of another -station; there being ordinarily no direct communication between the -two parts of the same instrument. - -An attempt will be made to explain, with the help of a simple diagram, -the manner in which the telautograph performs its duties. - -These duties are threefold. In the first place, it must reproduce -whatever is written on the transmitter. Secondly, it must reproduce -only what is _written_, not all the movements of the hand. Thirdly, it -must supply the recording pen with fresh paper to write on, and with -fresh ink to write with. - -In our diagram we must imagine that all the coverings of the -telautograph have been cleared away to lay bare the most essential -parts of the mechanism. For the sake of simplicity not all the coils, -wires, and magnets having functions of their own are represented, and -the drawing is not to scale. But what is shown will enable the reader -to grasp the general principles which work the machine. - -Turning first of all to the transmitter, we have P, a little platform -hinged at the back end, and moving up and down very slightly in front, -according as pressure is put on to or taken off it by the pencil. -Across it a roll of paper is shifted by means of the lever S, which -has other uses as well. To the right of P is an electric bell-push, E, -and on the left K, another small button. - -The pencil is at the junction of two small bars CC', which are hinged -at their other end to the levers AA'. Any motion of the pencil is -transmitted by CC' to AA', and by them to the arms LL', the -extremities of which, two very small brushes ZZ', sweep along the -quadrants RR'. This is the first point to observe, that the position -of the pencil decides on which sections of the quadrants these little -brushes rest, and consequently how much current is to be sent to the -distant station. The quadrants are known technically as rheostats, or -current-controllers. Each quadrant is divided into 496 parts, -separated from each other by insulating materials, so that current can -pass from one to the other only by means of some connecting wire. In -our illustration only thirteen divisions are given, for the sake of -clearness. The dark lines represent the insulation. WW' are the very -fine wire loops connecting each division of the quadrant with its -neighbours. If then a current from the battery B enters the rheostat -at division 1 it will have to pass through all these wires before it -can reach division 13. The current always enters at 1, but the point -of departure from the rheostat depends entirely upon the position of -the brushes Z or Z'. If Z happens to be on No. 6 the current will pass -through five loops of wire, along the arm L, and so through the main -wire to the receiving station; if on No. 13, through twelve loops. - -[Illustration: THE TELAUTOGRAPH] - -Before going any further we must have clear ideas on the subject of -electrical resistance, upon which the whole system of the telautograph -is built up. Electricity resembles water in its objection to flow -through small passages. It is much harder to pump water through a -half-inch pipe than through a one-inch pipe, and the longer the pipe -is, whatever its bore, the more work is required. So then, two things -affect resistance--_size_ of pipe or wire, and _length_ of pipe or -wire. - -The wires WW' are very fine, and offer very high resistance to a -current; so high that by the time the current from battery B has -passed through all the wire loops only one-fifteenth or less of the -original force is left to traverse the long-distance wire. - -The rheostats act independently of one another. As the pencil moves -over the transmitting paper, a succession of currents of varying -intensity is sent off by each rheostat to the receiving station. - -The receiver, to which we must now pay attention, has two arms DD', -and two rods FF', corresponding in size with AA' and CC' of the -transmitter. The arms DD' are moved up and down by the coils TT' which -turn on centres in circular spaces at the bend of the magnets MM'. The -position of these coils relatively to the magnets depend on the -strength of the currents coming from the transmitting station. Each -coil strains at a small spiral spring until it has reached the -position in which its electric force is balanced by the retarding -influence of the spring. One of the cleverest things in the -telautograph is the adjustment of these coils so that they shall -follow faithfully the motions of the rods LL' in the transmitter. - -[Illustration: _By kind permission of_] [_The Telautograph Co._ - -_An example of the work done by the Telautograph. The upper sketch -shows a design drawn on the transmitter; the lower is the same design -as reproduced by the receiving instrument, many miles distant._] - -We are now able to trace the actions of sending a message. The sender -first presses the button E to call the attention of some one at the -receiving station to the fact that a message is coming, either on the -telephone or on the paper. It should be remarked, by-the-bye, that the -same wires serve for both telephone and telautograph, the unhooking of -the telephone throwing the telautograph out of connection for the -time. - -He then presses the lever S towards the left, bringing his transmitter -into connection with the distant receiver, and also moving a fresh -length of paper on to the platform P. With his pencil he writes his -message, pressing firmly on the paper, so that the platform may bear -down against an electric contact, X. As the pencil moves about the -paper the arms CC' are constantly changing their angles, and the -brushes ZZ' are passing along the segments of the rheostats. - -Currents flow in varying intensity away to the coils TT' and work the -arms DD', the wires FF', and the pen, a tiny glass tube. - -In the perfectly regulated telautograph the arms AA' and the arms DD' -will move in unison, and consequently the position of the pen must be -the same from moment to moment as that of the pencil. - -Mr. Foster Ritchie, the clever inventor of this telautograph, had to -provide for many things besides mere slavish imitation of movement. As -has been stated above, the pen must record only those movements of the -pencil which are essential. Evidently, if while the pencil returns to -dot an _i_ a long line were registered by the pen corresponding to the -path of the pencil, confusion would soon ensue on the receiver; and -instead of a neatly-written message we should have an illegible and -puzzling maze of lines. Mr. Ritchie has therefore taken ingenious -precautions against any such mishap. The platen P on being depressed -by the pencil touches a contact, X, which closes an electric circuit -through the long-distance wires and excites a magnet at the receiving -end. That attracts a little arm and breaks another circuit, allowing -the bar Y to fall close to the paper. The wires FF' and the pen are -now able to rest on the paper and trace characters. But as soon as the -platen P rises, on the removal of the pencil from the transmitting -paper, the contact at X is broken, the magnet at the receiver ceases -to act, the arm it attracted falls back and sets up a circuit which -causes the bar to spring up again and lift the pen. So that unless -you are actually pressing the paper with your pencil, the pen is not -marking, though it may be moving. - -As soon as a line is finished a fresh surface of paper is required at -both ends. The operator pushes the lever S sideways, and effects the -change mechanically at his end. At the same time a circuit is formed -which excites certain magnets at the receiver and causes the shifting -forward there also of the paper, and also breaks the _writing_ -current, so that the pen returns for a moment to its normal position -of rest in the inkpot. - -It may be asked: If the wires are passing currents to work the writing -apparatus, how can they simultaneously affect the lifting-bar, Y? The -answer is that currents of two different kinds are used, a direct -current for writing, a vibratory current for depressing the -lifting-bar. The _direct_ current passes from the battery B through -the rheostats RR' along the wires, through the coils working the arms -DD' and into the earth at the far end; but the _vibratory_ current, -changing its direction many times a second and so neutralising itself, -passes up one wire and back down the other through the lifting-bar -connection without interfering with the direct current. - -The message finished, the operator depresses with the point of his -pencil the little push-key, K, and connects his receiver with the -distant transmitter in readiness for an answer. - -The working speed of the telautograph is that of the writer. If -shorthand be employed, messages can be transmitted at the rate of over -100 words per minute. As regards the range of transmission, successful -tests have been made by the postal authorities between Paris and -London, and also between Paris and Lyons. In the latter case the -messages were sent from Paris to Lyons and back directly to Paris, the -lines being connected at Lyons, to give a total distance of over 650 -miles. There is no reason why much greater length of line should not -be employed. - -The telautograph in its earlier and imperfect form was the work of -Professor Elisha Gray, who invented the telephone almost -simultaneously with Professor Graham Bell. His telautograph worked on -what is known as the step-by-step principle, and was defective in that -its speed was very limited. If the operator wrote too fast the -receiving pen lagged behind the transmitting pencil, and confusion -resulted. Accordingly this method, though ingenious, was abandoned, -and Mr. Ritchie in his experiments looked about for some preferable -system, which should be simpler and at the same time much speedier in -its action. After four years of hard work he has brought the rheostat -system, explained above, to a pitch of perfection which will be at -once appreciated by any one who has seen the writing done by the -instrument. - -The advantages of the Telautograph over the ordinary telegraphy may be -briefly summed up as follows:-- - -Anybody who can write can use it; the need of skilled operators is -abolished. - -A record is automatically kept of every message sent. - -The person to whom the message is sent need not be present at the -receiver. He will find the message written out on his return. - -The instrument is silent and so insures secrecy. An ordinary telegraph -may be read by sound; but not the telautograph. - -It is impossible to tap the wires unless, as is most unlikely, the -intercepting party has an instrument in exact accord with the -transmitter. - -It can be used on the same wires as the ordinary telephone, and since -a telephone is combined with it, the subscriber has a double means of -communication. For some items of business the telephone may be used as -preferable; but in certain cases, the telautograph. A telephone -message may be heard by other subscribers; it is impossible to prove -the authenticity of such a message unless witnesses have been present -at the transmitting end; and the message itself may be misunderstood -by reason of bad articulation. But the telautograph preserves secrecy -while preventing any misunderstanding. Anything written by it is for -all practical purposes as valid as a letter. - -We must not forget its extreme usefulness for transmitting sketches. A -very simple diagram often explains a thing better than pages of -letter-press. The telautograph may help in the detection of criminals, -a pictorial presentment of whom can by its means be despatched all -over the country in a very short time. And in warfare an instrument -flashing back from the advance-guard plans of the country and of the -enemy's positions might on occasion prove of the greatest importance. - - - - -MODERN ARTILLERY. - - -The vast subject of artillery in its modern form, including under this -head for convenience' sake not only heavy ordnance but machine-guns -and small-arms, can of necessity only be dealt with most briefly in -this chapter. - -It may therefore be well to take a general survey and to define -beforehand any words or phrases which are used technically in -describing the various operations. - -The employment of firearms dates from a long-distant past, and it is -interesting to note that many an improvement introduced during the -last century is but the revival of a former invention which only lack -of accuracy in tools and appliances had hitherto prevented from being -brought into practical usage. - -So far back as 1498 the art of _rifling_ cannon in straight grooves -was known, and a British patent was taken out in 1635 by Rotsipan. The -grooves were first made spiral or screwed by Koster of Birmingham -about 1620. Berlin possesses a rifled cannon with thirteen grooves -dated 1664. But the first recorded uses of such weapons in actual -warfare was during Louis Napoleon's Italian campaign in 1859, and two -years later by General James of the United States Army. - -The system of _breech-loading_, again, is as old as the sixteenth -century, and we find a British patent of 1741; while the first United -States patent was given in 1811 for a flint-lock weapon. - -_Magazine_ guns of American production appeared in 1849 and 1860, but -these were really an adaptation of the old matchlock revolvers, said -to belong to the period 1480-1500. There is one in the Tower of London -credited to the fifteenth century, and a British patent of 1718 -describes a well-constructed revolver carried on a tripod and of the -dimensions of a modern machine-gun. The inventor gravely explains that -he has provided round chambers for round bullets to shoot Christians, -and square chambers with square missiles for use against the Turks! - -The word "ordnance" is applied to heavy guns of all kinds, and -includes guns mounted on fortresses, naval guns, siege artillery, and -that for use in the field. These guns are all mounted on stands or -carriages, and may be divided into three classes:-- - - (i.) _Cannon_, or heavy guns. - - (ii.) _Howitzers_, for field, mountain, or siege use, which are - lighter and shorter than cannon, and designed to throw hollow - projectiles with comparatively small charges. - - (iii.) _Mortars_, for throwing shells at a great elevation. - -The modern long-range guns and improved howitzers have, however, -virtually superseded mortars. _Machine-guns_ of various forms are -comparatively small and light, transportable by hand, and filling a -place between cannon and small-arms, the latter term embracing the -soldier's personal armament of rifle and pistol or revolver, which are -carried in the hand. - -A group of guns of the like design are generally given the name of -their first inventor, or the place of manufacture: such as the -Armstrong gun, the Vickers-Maxim, the Martini-Henry rifle, or the -Enfield. - -The indifferent use of several expressions in describing the same -weapon is, however, rather confusing. One particular gun may be thus -referred to:--by its _weight_ in tons or cwt., as "the 35-ton gun"; by -the weight of its _projectile_, as "a 68-pounder"; by its _calibre_, -that is, size of bore, as "the 4-inch gun." Of these the heavier -breech-loading (B.-L.) and quick-firing (Q.-F.) guns are generally -known by the size of bore; small Q.-F.'s, field-guns, &c., by the -weight of projectile. It is therefore desirable to enter these -particulars together when making any list of service ordnance for -future reference. - -No individual gun, whether large or small, is a single whole, but -consists of several pieces fastened together by many clever devices. - -The principal parts of a cannon are:-- - - (1) The _chase_, or main tube into which the projectile is - loaded; terminating at one end in the muzzle. - - (2) The _breech-piece_, consisting of (_a_) the chamber, which - is bored out for a larger diameter than the chase to contain - the firing-charge. (_b_) The _breech-plug_, which is closed - before the charge is exploded and screwed tightly into place, - sealing every aperture by means of a special device called the - "obturator," in order to prevent any gases passing out round it - instead of helping to force the projectile forwards towards the - muzzle. - -The whole length of inside tube is termed the _barrel_, as in a -machine-gun, rifle, or sporting-piece, but in the two latter weapons -the breech-opening is closed by sliding or springing back the -breech-block or bolt into firing position. - -Old weapons as a rule were smooth-bored (S.-B.), firing a round -missile between which and the barrel a considerable amount of the -gases generated by the explosion escaped and caused loss of power, -this escape of gas being known as _windage_. - -In all modern weapons we use conical projectiles, fitted near the base -with a soft copper driving-band, the diameter of which is somewhat -larger than that of the bore of the gun, and cut a number of spiral -grooves in the barrel. The enormous pressure generated by the -explosion of the charge forces the projectile down the bore of the gun -and out of the muzzle. The body of the projectile, made of steel or -iron, being smaller in diameter than the bore, easily passes through, -but the driving-band being of greater diameter, and being composed of -soft copper, can only pass down the bore with the projectile by -flowing into the grooves, thus preventing any escape of gas, and being -forced to follow their twist. It therefore rotates rapidly upon its -own longitudinal axis while passing down the barrel, and on leaving -the muzzle two kinds of velocity have been imparted to it;--first, a -velocity of motion through the air; secondly, a velocity of rotation -round its axis which causes it to fly steadily onward in the required -direction, _i.e._ a prolongation of the axis of the gun. Thus extreme -velocity and penetrating power, as well as correctness of aim, are -acquired. - -The path of a projectile through the air is called its _trajectory_, -and if uninterrupted its flight would continue on indefinitely in a -perfectly straight line. But immediately a shot has been hurled from -the gun by the explosion in its rear two other natural forces begin to -act upon it:-- - -Gravitation, which tends to bring it to earth. - -Air-resistance, which gradually checks its speed. - -(Theoretically, a bullet dropped perpendicularly from the muzzle of a -perfectly horizontal rifle would reach the ground at the same moment -as another bullet fired from the muzzle horizontally, the action of -gravity being the same in both cases.) - -Its direct, even course is therefore deflected till it forms a curve, -and sooner or later it returns to earth, still retaining a part of its -velocity. To counteract the attraction of gravity the shot is thrown -upwards by elevating the muzzle, care being taken to direct the gun's -action to the same height above the object as the force of gravitation -would draw the projectile down during the time of flight. The gunner -is enabled to give the proper inclination to his piece by means of the -_sights_; one of these, near the muzzle, being generally fixed, while -that next the breech is adjustable by sliding up an upright bar which -is so graduated that the proper _elevation_ for any required range is -given. - -The greater the velocity the flatter is the trajectory, and the more -dangerous to the enemy. Assuming the average height of a man to be six -feet, all the distance intervening between the point where a bullet -has dropped to within six feet of the earth, and the point where it -actually strikes is dangerous to any one in that interval, which is -called the "danger zone." A higher initial velocity is gained by using -stronger firing charges, and a more extended flight by making the -projectile longer in proportion to its diameter. The reason why a -shell from a cannon travels further than a rifle bullet, both having -the same muzzle velocity, is easily explained. - -A rifle bullet is, let us assume, three times as long as it is thick; -a cannon shell the same. If the shell have ten times the diameter of -the bullet, its "nose" will have 10 × 10 = 100 times the area of the -bullet's nose; but its _mass_ will be 10 × 10 × 10 = 1000 times that of -the bullet. - -In other words, when two bodies are proportional in all their -dimensions their air-resistance varies as the square of their -diameters, but their mass and consequently their momentum varies as -the _cube_ of their diameters. The shell therefore starts with a great -advantage over the bullet, and may be compared to a "crew" of cyclists -on a multicycle all cutting the same path through the air; whereas the -bullet resembles a single rider, who has to overcome as much -air-resistance as the front man of the "crew" but has not the weight -of other riders behind to help him. - -As regards the effect of rifling, it is to keep the bullet from -turning head over heels as it flies through the air, and to maintain -it always point forwards. Every boy knows that a top "sleeps" best -when it is spinning fast. Its horizontal rotation overcomes a tendency -to vertical movement towards the ground. In like manner a rifle -bullet, spinning vertically, overcomes an inclination of its atoms to -move out of their horizontal path. Professor John Perry, F.R.S., has -illustrated this gyroscopic effect, as it is called, of a whirling -body with a heavy flywheel in a case, held by a man standing on a -pivoted table. However much the man may try to turn the top from its -original direction he will fail as long as its velocity of rotation is -high. He may move the top relatively to his body, but the table will -turn so as to keep the centre line of the top always pointing in the -same direction. - - -RIFLES. - -Up to the middle of last century our soldiers were armed with the -flint-lock musket known as "Brown Bess," a smooth-bore barrel 3/4-inch -in diameter, thirty-nine inches long, weighing with its bayonet over -eleven pounds. The round leaden bullet weighed an ounce, and had to be -wrapped in a "patch" or bit of oily rag to make it fit the barrel and -prevent windage; it was then pushed home with a ramrod on to the -powder-charge, which was ignited by a spark passing from the flint -into a priming of powder. How little its accuracy of aim could be -depended upon, however, is proved by the word of command when -advancing upon an enemy, "Wait till you see the whites of their eyes, -boys, before you fire!" - -In the year 1680 each troop of Life Guards was supplied with eight -rifled carbines, a modest allowance, possibly intended to be used -merely by those acting as scouts. After this we hear nothing of them -until in 1800 the 95th Regiment received a 20-bore muzzle-loading -rifle, exchanged about 1835 for the Brunswick rifle firing a spherical -bullet, an improvement that more than doubled its effective range. The -companies so armed became known as the Rifle Brigade. At last, in -1842, the old flint-lock was superseded for the whole army by the -original percussion musket, a smooth-bore whose charge was exploded by -a percussion cap made of copper. [That this copper had some commercial -value was shown by the rush of "roughs" to Aldershot and elsewhere -upon a field-day to collect the split fragments which strewed the -ground after the troops had withdrawn.] - -Soon afterward the barrel was rifled and an elongated bullet brought -into use. This missile was pointed in front, and had a hollowed base -so contrived that it expanded immediately the pressure of exploding -gases was brought to bear on it, and thus filled up the grooves, -preventing any windage. The one adopted by our army in the year 1852 -was the production of M. Minié, a Frenchman, though an expanding -bullet of English invention had been brought forward several years -before. - -Meanwhile the Prussians had their famous needle-gun, a breech-loading -rifled weapon fired by a needle attached to a sliding bolt; as the -bolt is shot forward the needle pierces the charge and ignites the -fulminate by friction. This rifle was used in the Prusso-Austrian war -of 1866 some twenty years after its first inception, and the French -promptly countered it by arming their troops with the Chassepôt rifle, -an improved edition of the same principle. A piece which could be -charged and fired in any position from five to seven times as fast as -the muzzle-loader, which the soldier had to load standing, naturally -caused a revolution in the infantry armament of other nations. - -The English Government, as usual the last to make a change, decided in -1864 upon using breech-loading rifles. Till a more perfect weapon -could be obtained the Enfields were at a small outlay converted into -breech-loaders after the plans of Mr. Snider, and were henceforward -known as Snider-Enfields. Eventually--as the result of open -competition--the Martini-Henry rifle was produced by combining Henry's -system of rifling with Martini's mechanism for breech-loading. This -weapon had seven grooves with one turn in twenty-two inches, and -weighed with bayonet 10 lb. 4 oz. It fired with great accuracy, the -trajectory having a rise of only eight feet at considerable distances, -so that the bullet would not pass over the head of a cavalry man. -Twenty rounds could be fired in fifty-three seconds. - -Now in the latter years of the century all these weapons have been -superseded by magazine rifles, _i.e._ rifles which can be fired -several times without recourse to the ammunition pouch. They differ -from the revolver in having only one firing chamber, into which the -cartridges are one by one brought by a simple action of the breech -mechanism, which also extracts the empty cartridge-case. The bore of -these rifles is smaller and the rifling sharper; they therefore shoot -straighter and harder than the large bore, and owing to the use of new -explosives the recoil is less. - -The French _Lebel_ magazine rifle was the pioneer of all now used by -European nations, though a somewhat similar weapon was familiar to the -Americans since 1849, being first used during the Civil War. The Henry -rifle, as it was called, afterwards became the Winchester. - -The German army rifle is the _Mauser_, so familiar to us in the hands -of the Boers during the South African War--loading five cartridges at -once in a case or "clip" which falls out when emptied. The same rifle -has been adopted by Turkey, and was used by the Spaniards in the late -Spanish-American War. - -The Austrian _Mannlicher_, adopted by several continental nations, and -the Krag-Jorgensen now used in the north of Europe and as the United -States army weapon, resemble the Mauser in most particulars. Each of -these loads the magazine in one movement with a clip. - -The _Hotchkiss_ magazine rifle has its magazine in the stock, holding -five extra cartridges pushed successively into loading position by a -spiral spring. - -Our forces are now armed principally with the _Lee-Enfield_, which is -taking the place of the _Lee-Metford_ issued a few years ago. These -are small-bore rifles of .303 inch calibre, having a detachable box, -which is loaded with ten cartridges (Lee-Metford eight) passed up in -turn by a spring into the breech, whence, when the bolt is closed, -they are pushed into the firing-chamber. The empty case is ejected by -pulling back the bolt, and at the same time another cartridge is -pressed up from the magazine and the whole process repeated. When the -cut-off is used the rifle may be loaded and fired singly, be the -magazine full or empty. - -The Lee-Enfield has five grooves (Lee-Metford ten), making one -complete turn from right to left in every ten inches. It weighs 9 lb. -4 oz., and the barrel is 30.197 inches long. The range averages 3500 -yards. - -We are now falling into line with other powers by adopting the "clip" -form instead of the box for loading. The sealed pattern of the new -service weapon is thus provided, and has also been made somewhat -lighter and shorter while preserving the same velocity. - -We are promised an even more rapid firing rifle than any of these, one -in which the recoil is used to work the breech and lock so that it is -a veritable automatic gun. Indeed, several continental nations have -made trial of such weapons and reported favourably upon them. One -lately tried in Italy works by means of gas generated by the explosion -passing through a small hole to move a piston-rod. It is claimed that -the magazine can hold as many as fifty cartridges and fire up to -thirty rounds a minute; but the barrel became so hot after doing this -that the trial had to be stopped. - -The principal result of automatic action would probably be excessive -waste of cartridges by wild firing in the excitement of an engagement. -It is to-day as true as formerly that it takes on the average a man's -weight of lead to kill him in battle. - -To our neighbours across the Channel the credit also belongs of -introducing _smokeless powder_, now universally used; that of the -Lee-Metford being "cordite." To prevent the bullets flattening on -impact they are coated with a hard metal such as nickel and its -alloys. If the nose is soft, or split beforehand, a terribly enlarged -and lacerated wound is produced; so the Geneva Convention humanely -prohibited the use of such missiles in warfare. - -Before quitting this part of our subject it is as well to add a few -words about _pistols_. - -These have passed through much the same process of evolution as the -rifle, and have now culminated in the many-shotted _revolver_. - -During the period 1480-1500 the match-lock revolver is said to have -been brought into use; and one attributed to this date may be seen in -the Tower of London. - -Two hundred years ago, Richards, a London gunsmith, converted the -ancient wheel-lock into the flint-lock; he also rifled his barrel and -loaded it at the breech. The Richards weapon was double-barrelled, and -unscrewed for loading at the point where the powder-chamber ended; the -ball was placed in this chamber in close contact with the powder, and -the barrel rescrewed. The bullet being a soft leaden ball, was forced, -when the charge was fired, through the rifled barrel with great -accuracy of aim. - -The percussion cap did not oust the flint-lock till less than a -century ago, when many single-barrelled pistols, such as the famous -Derringer, were produced; these in their turn were replaced by the -revolver which _Colt_ introduced in 1836-1850. Smith and Wesson in the -early sixties improved upon it by a device for extracting the empty -cartridges automatically. Livermore and Russell of the United States -invented the "clip," containing several cartridges; but the equally -well-known _Winchester_ has its cartridges arranged in a tube below -the barrel, whence a helical spring feeds them to the breech as fast -as they are needed. - -At the present time each War Department has its own special service -weapon. The German _Mauser_ magazine-pistol for officer's use fires -ten shots in ten seconds, a slight pressure of the trigger setting the -full machinery in motion; the pressure of gas at each explosion does -all the rest of the work--extracts and ejects the cartridge case, -cocks the hammer, and presses springs which reload and close the -weapon, all in a fraction of a second. The _Mannlicher_ is of the same -automatic type, but its barrel moves to the front, leaving space for a -fresh cartridge to come up from the magazine below, while in the -Mauser the breech moves to the rear during recoil. The range is half a -mile. The cartridges are made up in sets of ten in a case, which can -be inserted in one movement. - - -MACHINE-GUNS. - -Intermediate between hand-borne weapons and artillery, and partaking -of the nature of both, come the machine-guns firing small projectiles -with extraordinary rapidity. - -Since the United States made trial of Dr. Gatling's miniature battery -in the Civil War (1862-1865), invention has been busy evolving more -and more perfect types, till the most modern machine-gun is a marvel -of ingenuity and effectiveness. - -The _Gatling_ machine-gun, which has been much improved in late years -by the Accles system of "feed," and is not yet completely out of date, -consists of a circular series of ten barrels--each with its own -lock--mounted on a central shaft and revolved by a suitable gear. The -cartridges are successively fed by automatic actions into the barrels, -and the hammers are so arranged that the entire operation of loading, -closing the breech, firing and withdrawing the empty cartridge-cases -(which is known as their "longitudinal reciprocating motion") is -carried on while the locks are kept in constant revolution, along with -the barrels and breech, by means of a hand-crank. One man places a -feed-case filled with cartridges into the hopper, another turns the -crank. As the gun is rotated the cartridges drop one by one from the -feed-cases into the grooves of the carrier, and its lock loads and -fires each in turn. While the gun revolves further the lock, drawing -back, extracts and drops the empty case; it is then ready for the next -cartridge. - -In action five cartridges are always going through some process of -loading, while five empty shells are in different stages of ejection. -The latest type, fitted with an electro-motor, will fire at the _rate_ -of one thousand rounds per minute, and eighty rounds have actually -been fired within ten seconds! It is not, however, safe to work these -machine-guns so fast, as the cartridges are apt to be occasionally -pulled through unfired and then explode among the men's legs. The -automatic guns, on the contrary, as they only work by the explosion, -are free from any risk of such accidents. - -The feed-drums contain 104 cartridges, and can be replaced almost -instantly. One drumful can be discharged in 5-1/4 seconds. The -small-sized Gatling has a drum-feed of 400 cartridges in sixteen -sections of twenty-five each passed up without interruption. - -The gun is mounted for use so that it can be pointed at any angle, and -through a wide lateral range, without moving the carriage. - -_The Gardner._--The Gatling, as originally made, was for a time -superseded by the _Gardner_, which differed from it in having the -barrels (four or fewer in number) fixed in the same horizontal plane. -This was worked by a rotatory handle on the side of the gun. The -cartridges slid down a feed-case in a column to the barrel, where they -were fired by a spring acting on a hammer. - -_The Nordenfelt._--Mr. Nordenfelt's machine-gun follows this -precedent; its barrels--10, 5, 4, 2, or 1 in number--also being -arranged horizontally in a strong, rigid frame. Each barrel has its -own breech-plug, striker, spring, and extractor, and each fires -independently of the rest, so that all are not out of action together. -The gun has a swivelled mount easily elevated and trained, and the -steel frames take up the force of the discharge. In rapid firing one -gunner can work the firing-handle while another lays and alters the -direction. The firing is operated by a lever working backwards and -forwards by hand, and the gun can be discharged at the rate of 600 -rounds per minute. - -_The Hotchkiss._--The Hotchkiss gun, or revolving cannon, is on a -fresh system, that of intermittent rotation of the barrels without any -rotation of breech or mechanism. There is only one loading piston, one -spring striker, and one extractor for all the barrels. The shock of -discharge is received against a massive fixed breech, which -distributes it to the whole body. - -Like the _Nordenfelt_, however, it can be dismounted and put together -again without the need of tools. The above pattern throws 1 lb. -projectiles. - -_The Maxim._--Differing from all these comes the _Maxim_ gun, so much -in evidence now with both land and sea service. It is made up of two -portions:-- - - (1) _Fixed_: a barrel-casing, which is also a water-jacket, and - breech-casing. - - (2) _Recoiling_: a barrel and two side plates which carry lock - and crank. - -This recoiling portion works inside the fixed. - -The gun is supplied with ammunition by a belt holding 250 cartridges -passing through a feed-block on the top. Its mechanism is worked -_automatically_; first by the explosion of the charge, which causes -the barrel to recoil backwards and extends a strong spring which, on -reasserting itself, carries it forwards again. The recoiling part -moves back about an inch, and this recoil is utilised by bringing -into play mechanism which extracts the empty cartridge-case, and on -the spring carrying the barrel forward again moves a fresh one into -position. Under the barrel casing is the ejector tube through which -the empty cartridge-cases are ejected from the gun. - -The rate of fire of the Maxim gun is 600 rounds per minute. Deliberate -fire means about 70 rounds per minute; rapid fire will explode 450 -rounds in the same time. As the barrel becomes very hot in use the -barrel-casing contains seven pints of water to keep it cool. About -2000 rounds can be fired at short intervals; but in continuous firing -the water boils after some 600 rounds, and needs replenishing after -about 1000. A valved tube allows steam, but not water to escape. - -The operator works this gun by pressing a firing-lever or button. -After starting the machine he merely sits behind the shield, which -protects him from the enemy, directing it, as it keeps on firing -automatically so long as the bands of cartridges are supplied and a -finger held on the trigger or button. By setting free a couple of -levers with his left hand, and pressing his shoulder against the -padded shoulder-piece, he is able to elevate or depress, or train the -barrel horizontally, without in any way interfering with the hail of -missiles. - -We use two sizes, one with .45 bore for the Navy, which takes an -all-lead bullet weighing 480 grains, and the other with .303 bore, the -ordinary nickel-coated rifle bullet for the Army. But as the Maxim -gun can be adapted to every rifle-calibre ammunition it is patronised -by all governments. - -The gun itself weighs 56 lbs., and is mounted for use in various ways: -on a tripod, a field stand, or a field carriage with wheels. This -carriage has sixteen boxes of ammunition, each containing a belt of -250 cartridges, making 4000 rounds altogether. Its total weight is -about half a ton, so that it can be drawn by one horse, and it is -built for the roughest cross-country work. A little machine, which can -be fixed to the wheel, recharges the belts with cartridges by the -working of a handle. - -For ships the Maxim is usually mounted on the ordinary naval cone -mount, or it can be clamped to the bulwark of the deck or the military -"top" on the mast. - -But there is a most ingenious form of parapet mounting, known as the -garrison mount, which turns the Maxim into a "disappearing gun," and -can be used equally well for fortress walls or improvised -entrenchments. The gun is placed over two little wheels on which it -can be run along by means of a handle pushed behind in something the -fashion of a lawn-mower. Arrived at its destination, the handle, which -is really a rack, is turned downwards, and on twisting one of the -wheels the gun climbs it by means of a pinion-cog till it points over -the wall, to which hooks at the end of two projecting bars firmly fix -it, the broadened end of the handle being held by its weight to the -ground. It is locked while in use, but a few turns of the wheel cause -it to sink out of sight in as many seconds. - -The rifle-calibre guns may also be used as very light horse artillery -to accompany cavalry by being mounted on a "galloping carriage" drawn -by a couple of horses, and with two seats for the operators. The -carriage conveys 3000 rounds, and the steel-plated seats turn up and -form shields during action. - -It is interesting to notice that an extra light form of the gun is -made which may be carried strapped on an infantryman's back and fired -from a tripod. Two of these mounted on a double tricycle can be -propelled at a good pace along a fairly level road, and the riders -dismounting have, in a few moments, a valuable little battery at their -disposal. - -The _Pom-pom_, of which we have heard so much in the late war, is a -large edition of the Maxim automatic system with some differences in -the system. Its calibre is 1-1/2 inches. Instead of bullets it emits -explosive shells 1 lb. in weight, fitted with percussion fuses which -burst them into about twelve or fourteen pieces. The effective range -is up to 2000 yards, and it will carry to 4000 yards. An improved -_Pom-pom_ recently brought out hurls a 1-1/4 lb. shell with effect at -a mark 3000 yards away, and as far as 6000 yards before its energy is -entirely exhausted. The muzzle velocity of this weapon is 2350 feet a -second as against the 1800 feet of the older pattern. They both fire -300 rounds a minute. - -The _Colt_ automatic gun is an American invention whose automatic -action is due to explosion of the charge, not to recoil. The force by -which the motions of firing, extracting, and loading are performed is -derived from the powder-gases, a portion of which--passing through a -small vent in the muzzle--acts by means of a lever on the mechanism of -the gun. - -This is also in two parts: (_a_) _barrel_, attached to (_b_) -breech-casing, in which gear for charging, firing, and ejecting is -contained. The barrel, made of a strong alloy of nickel, has its -cartridges fed in by means of belts coiled in boxes attached to the -breech-casing, the boxes moving with the latter so that the movements -of the gun do not affect it. These boxes contain 250 cartridges each -and are easily replaced. - -The feed-belt is inserted, and the lever thrown down and moved -backward--once by hand--as far as it will go; this opens the breech -and passes the first cartridge from the belt to the carrier. The lever -is then released and the spring causes it to fly forward, close the -vent, and transfer the cartridge from the carrier to the barrel, also -compressing the mainspring and opening and closing the breech. - -On pulling the trigger the shot is fired, and after the bullet has -passed the little vent, but is not yet out of the muzzle, the force of -the expanding gas, acting through the vent on the piston, sets a -gas-lever in operation which acts on the breech mechanism, opens -breech, ejects cartridge-case, and feeds another cartridge into the -carrier. The gas-lever returning forces the cartridge home in the -barrel and closes and locks the breech. - -The hammer of the gun acts as the piston of an air-pump, forcing a -strong jet of air into the chamber, and through the barrel, thus -removing all unburnt powder, and thoroughly cleansing it. The metal -employed is strong enough to resist the heaviest charge of -nitro-powder, and the accuracy of its aim is not disturbed by the -vibrations of rapid fire. It does not heat fast, so has no need of a -water-jacket, any surplus heat being removed by a system of radiation. - -The bore is made of any rifle calibre for any small-arm ammunition, -and is fitted with a safety-lock. For our own pieces we use the -Lee-Metford cartridges. Four hundred shots per minute can be fired. - -The gun consists altogether of ninety-four pieces, but the -working-pieces, _i.e._ those only which need be separated for -cleaning, &c., when in the hands of the artilleryman, are less than -twenty. It can be handled in action by one man, the operation -resembling that of firing a pistol. - -The machine weighs 40 lbs., and for use by cavalry or infantry can be -mounted on the _Dundonald Galloping Carriage_. The ammunition-box, -containing 2000 rounds ready for use, carries the gun on its upper -side, and is mounted on a strong steel axle. A pole with a slotted end -is inserted into a revolving funnel on the bend of the shaft, the -limbering-up being completed by an automatic bolt and plug. - -The gun-carriage itself is of steel, with hickory wheels and hickory -and steel shafts, detachable at will. The simple harness suits any -saddled cavalry horse, and the shafts work in sockets behind the -rider's legs. Its whole weight with full load of ammunition is under -four hundredweight. - - -HEAVY ORDNANCE. - -As with rifles and the smaller forms of artillery, so also with heavy -ordnance, the changes and improvements within the last fifty years -have been greater than those made during the course of all the -previous centuries. - -These changes have affected alike not only the materials from which a -weapon is manufactured, the relative size of calibre and length of -bore, the fashion of mounting and firing, but also the form and weight -of the projectile, the velocity with which it is thrown, and even the -substances used in expelling it from the gun. - -Compare for a moment the old cast-iron muzzle-loaders, stubby of -stature, which Wellington's bronzed veterans served with round cannon -balls, well packed in greasy clouts to make them fit tight, or with -shell and grape shot, throughout the hard-fought day of Waterloo, from -a distance which the chroniclers measure by _paces_, so near stood the -opposing ranks to one another. - -Or stand in imagination upon one of Nelson's stately men-o'-war and -watch the grimy guns' crews, eight or ten to each, straining on the -ropes. See the still smoking piece hauled inboard, its bore swabbed -out to clean and cool it, then recharged by the muzzle; home go -powder, wad, and the castor full of balls or the chain shot to -splinter the enemy's masts, rammed well down ere the gun is again run -out through the port-hole. Now the gunner snatches the flaming -lintstock and, signal given, applies it to the powder grains sprinkled -in the touch-hole. A salvo of fifty starboard guns goes off in one -terrific broadside, crashing across the Frenchman's decks at such -close quarters that in two or three places they are set on fire by the -burning wads. Next comes a cry of "Boarders!" and the ships are -grappled as the boarding-party scrambles over the bulwarks to the -enemy's deck, a brisk musket-fire from the crowded rigging protecting -their advance; meanwhile the larboard guns, with their simultaneous -discharge, are greeting a new adversary. - -Such was war a century ago. Compare with it the late South African -Campaign where the range of guns was estimated in _miles_, and after a -combat lasting from morn to eve, the British general could report: "I -do not think we have seen a gun or a Boer all day." - -The days of hand-to-hand fighting have passed, the mêlée in the ranks -may be seen no more; in a few years the bayonet may be relegated to -the limbo of the coat-of-mail or the cast-iron culverin. Yet the -modern battle-scene bristles with the most death-dealing weapons which -the ingenuity of man has ever constructed. The hand-drawn machine-gun -discharges in a couple of minutes as many missiles as a regiment of -Wellington's infantry, with a speed and precision undreamt of by him. -The quick-firing long-range naval guns now in vogue could annihilate a -fleet or destroy a port without approaching close enough to catch a -glimpse of the personnel of their opponents. The deadly torpedo guards -our waterways more effectually than a squadron of ships. - -All resources of civilisation have been drawn upon, every triumph of -engineering secured, to forge such weapons as shall strike the hardest -and destroy the most pitilessly. But strange and unexpected the -result! Where we counted our battle-slain by thousands we now mourn -over the death of hundreds; where whole regiments were mown down our -ambulances gather wounded in scattered units. Here is the bright side -of modern war. - -The muzzle-loading gun has had its day, a very long day and a -successful one. Again and again it has reasserted itself and ousted -its rivals, but at last all difficulties of construction have been -surmounted and the breech-loader has "come to stay." - -However, our services still contain a large number of muzzle-loading -guns, many of them built at quite a recent period, and adapted as far -as possible to modern requirements. So to these we will first turn our -attention. - -The earliest guns were made of cast-iron, but this being prone to -burst with a large charge, bronze, brass, and other tougher materials -were for a long time employed. Most elaborately chased and ornamented -specimens of these old weapons are to be seen in the Tower, and many -other collections. - -In the utilitarian days of the past century cheapness and speed in -manufacture were more sought after than show. Iron was worked in many -new ways to resist the pressure of explosion. - -Armstrong of Elswick conceived the idea of building up a barrel of -_coiled_ iron by joining a series of short welded cylinders together, -and closing them by a solid forged breech-piece. Over all, again, -wrought-iron coils were shrunk. Subsequently he tried a solid -forged-iron barrel bored out to form a tube. Neither make proving very -satisfactory, steel tubes were next used, but were too expensive and -uncertain at that stage of manufacture. Again coiled iron was called -into requisition, and Mr. Frazer of the Royal Gun Factory introduced a -system of double and triple coils which was found very successful, -especially when a thin steel inner tube was substituted for the iron -one (1869). - -All these weapons were rifled, so that there was of necessity a -corresponding difference in the projectile employed. Conical shells -being used, studs were now placed on the body of the shell to fit into -the rifling grooves, which were made few in number and deeply cut. -This was apt to weaken the bore of the gun; but on the other hand -many studs to fit into several shallow grooves weakened the cover of -the shells. - -Various modifications were tried, and finally a gas-check which -expands into the grooves was placed at the base of the shell. - -The muzzle-loader having thus been turned into a very efficient modern -weapon the next problem to be solved was how to throw a projectile -with sufficient force to penetrate the iron and steel armour-plates -then being generally applied to war-ships. "Build larger guns" was the -conclusion arrived at, and presently the arsenals of the Powers were -turning out mammoth weapons up to 100 tons, and even 110 tons in -weight with a calibre of 16 inches and more for their huge shells. -Then was the mighty 35-ton "Woolwich Infant" born (1872), and its -younger but still bigger brothers, 81 tons, 16-inch bore, followed by -the Elswick 100-ton giants, some of which were mounted on our defences -in the Mediterranean. But the fearful concussion of such enormous guns -when fixed in action on board ship injured the superstruction, and -even destroyed the boats, and the great improvements made in steel -both for guns and armour soon led to a fresh revolution. Henceforward -instead of mounting a few very heavy guns we have preferred to trust -to the weight of metal projected by an increased number of smaller -size, but much higher velocity. And these guns are the quick-firing -breech-loaders. - -The heaviest of our up-to-date ordnance is of moderate calibre, the -largest breech-loaders being 12-inch, 10-inch, and 9.2-inch guns. But -the elaborateness of its manufacture is such that one big gun takes -nearly as long to "build up" as the ship for which it is destined. -Each weapon has to pass through about sixteen different processes:-- - - (1) The solid (or hollow) ingot is _forged_. - - (2) _Annealed_, to get rid of strains. - - (3) It is placed horizontally on a lathe and _rough-turned_. - - (4) _Rough-bored_ in a lathe. - - (5) _Hardened._ Heated to a high temperature and plunged, while - hot, into a bath of rape oil kept cold by a water-bath. It - cools slowly for seven to eight hours, being moved about at - intervals by a crane. This makes the steel more elastic and - tenacious. - - (6) _Annealed_, _i.e._ reheated to 900° Fahr. and slowly - cooled. Siemens' pyrometer is used in these operations. - - (7) _Tested_ by pieces cut off. - - (8) _Turned_ and _bored_ for the second time. - - (9) Carefully turned again for _shrinkage_. Outer coil expanded - till large enough to fit easily over inner. Inside, set up - vertically in a pit, has outside lowered on to it, water and - gas being applied to make all shrink evenly. Other projections, - hoops, rings, &c., also shrunk on. - - (10) Finish--_bored_ and _chambered_. - - (11) _Broached_, or very fine bored, perhaps _lapped_ with lead - and emery. - - (12) _Rifled_ horizontally in a machine. - - (13) Prepared for breech fittings. - - (14) Taken to the Proof Butts for trial. - - (15) Drilled for sockets, sights, &c. Lined and engraved. - Breech fittings, locks, electric firing gear, &c., added. Small - adjustments made by filing. - - (16) _Browned_ or _painted_. - -When worn the bore can be lined with a new steel tube. - -These lengthy operations completed, our gun has still to be _mounted_ -upon its field-carriage, naval cone, or disappearing mounting, any of -which are complicated and delicately-adjusted pieces of mechanism, the -product of much time and labour, which we have no space here to -describe. - -Some account of the principal parts of these guns has already been -given, but the method by which the breech is closed remains to be -dealt with. - -It will be noticed that though guns now barely reach half the weight -of the monster muzzle-loaders, they are even more effective. Thus the -46-ton (12-inch) gun hurls an 850-lb. projectile with a velocity of -2750 foot-seconds, and uses a comparatively small charge. The famous -"81-ton" needed a very big charge for its 1700-lb. shell, and had -little more than half the velocity and no such power of penetration. -This change has been brought about by using a slower-burning explosive -very powerful in its effects; enlarging the chamber to give it -sufficient air space, and lengthening the chase of the gun so that -every particle of the powder-gas may be brought into action before -the shot leaves the muzzle. This system and the substitution of steel -for the many layers of welded iron, makes our modern guns long and -slim in comparison with the older ones. - -To resist the pressure of the explosion against the breech end, a -tightly-fitting breech-plug must be employed. The most modern and -ingenious is the Welin plug, invented by a Swedish engineer. The -ordinary interrupted screw breech-plug has three parts of its -circumference plane and the other three parts "threaded," or grooved, -to screw into corresponding grooves in the breech; thus only half of -the circumference is engaged by the screw. Mr. Welin has cut steps on -the plug, three of which would be threaded to one plane segment, each -locking with its counterpart in the breech. In this case there are -three segments engaged to each one left plane, and the strength of the -screw is almost irresistible. The plug, which is hinged at the side, -has therefore been shortened by one-third, and is light enough to -swing clear with one touch of the handwheel that first rotates and -unlocks it. - -The method of firing is this: The projectile lifted (by hydraulic -power on a ship) into the loading tray is swung to the mouth of the -breech and pushed into the bore. A driving-band attached near its base -is so notched at the edges that it jams the shell closely and prevents -it slipping back if loaded at a high angle of elevation. The powder -charge being placed in the chamber the breech-plug is now swung-to and -turned till it locks close. The vent-axial or inner part of this -breech-plug (next to the charge), which is called from its shape the -"mushroom-head," encloses between its head and the screw-plug the de -Bange obturator, a flat canvas pad of many layers soaked with mutton -fat tightly packed between discs of tin. When the charge explodes, the -mushroom-head--forced back upon the pad--compresses it till its edges -bulge against the tube and prevent any escape of gas breechwards. - -The electric spark which fires the charge is passed in from outside by -means of a minute and ingenious apparatus fitted into a little vent or -tube in the mushroom-head. As the electric circuit cannot be completed -till the breech-plug is screwed quite home there is now no more fear -of a premature explosion than of double loading. If the electric gear -is disordered the gun can be fired equally well and safely by a -percussion tube. - -This description is of a typical large gun, and may be applied to all -calibres and also to the larger quick-firers. The mechanism as the -breech is swung open again withdraws the empty cartridge. So valuable -has de Bange's obturator proved, however, that guns up to the 6-inch -calibre now have the powder charge thrown into the chamber in bags, -thus saving the weight of the metal tubes hitherto necessary. - -Of course several types of breech-loading guns are used in the -Service, but the above are the most modern. - -The favourite mode of construction at the present time is the -wire-wound barrel, the building up of which is completed by covering -the many layers of wire with an outer tube or jacket expanded by heat -before it is slipped on in order that it may fit closely when cold. A -previous make, without wire, is strengthened by rings or hoops also -shrunk on hot. - -The quick-firers proper are of many sizes, 8-inch, 7.5-inch, 6-inch, -4.7-inch, 4-inch, and 3-inch (12-pounders). The naval type is as a -rule longer and lighter than those made for the rough usage of field -campaigning and have a much greater range. There are also smaller -quick-firers, 3-pounders and 6-pounders with bore something over -1-inch and 2-inch (Nordenfelt, Hotchkiss, Vickers-Maxim). Some of the -high velocity 12-pounders being employed as garrison guns along with -6-inch and 4.7-inch, and the large calibre howitzers. - -We still use howitzer batteries of 5-inch bore in the field and in the -siege-train, all being short, rifled, breech-loading weapons, as they -throw a heavy shell with smallish charges at a high angle of -elevation, but cover a relatively short distance. A new pattern of -8-inch calibre is now under consideration. - -It is interesting to contrast the potencies of some of these guns, all -of which use cordite charges. - - +----------+---------------+-----------+----------------+-----------+ - |Calibre. | Charge. |Weight of |Muzzle Velocity |Number of | - | | | Shot. | in |Rounds per | - | | | | Foot Seconds. | Minute. | - +----------+---------------+-----------+----------------+-----------+ - | 12 inch |207 lbs. | 850 lbs. | 2750 | 1 | - | 8 " | 52 " | 210 " | 2750 | 5 | - | 6 " | 25 " | 100 " | 2775 | 8 | - |4.7 " | 9 " | 45 " | 2600 | 12 | - | 3 " | 2 lbs. 9 oz. |12.5 " | 2600 | 20 | - +----------+---------------+-----------+----------------+-----------+ - -[Illustration: _The Simms armour-clad motor-car for coast defence. -Maxim guns and Pom-pom in action._] - -In the armament of our fine Navy guns are roughly distributed as -follows:--81-ton, 13-1/2-inch, and superseded patterns of machine-guns -such as Gatling's, Gardner's, and Nordenfelt's, besides a few -surviving muzzle-loaders, &c., are carried only by the oldest -battleships. - -The first-class battleships are chiefly supplied with four 12-inch -guns in barbettes, twelve 6-inch as secondary batteries, and a number -of smaller quick-firers on the upper decks and in the fighting tops, -also for use in the boats, to which are added several Maxims. - -The first-class cruisers have 9.2 as their largest calibre, with a -lessened proportion of 6-inch, &c. Some of the newest bear only 7-1/2 -or 6-inch guns as their heaviest ordnance; like the second-class -cruisers which, however, add several 4.7's between these and their -small quick-firers. - -Vessels of inferior size usually carry nothing more powerful than the -4.7. - -All are now armed with torpedo tubes. - -These same useful little quick-firers and machine-guns have been the -lethal weapons which made the armoured trains so formidable. Indeed, -there seems no limit to their value both for offence and defence, for -the battle chariot of the ancient Briton has its modern successor in -the Simms' motor war car lately exhibited at the Crystal Palace. This -armour-plated movable fort is intended primarily for coast defence, -but can work off beaten tracks over almost any sort of country. It is -propelled at the rate of nine miles an hour by a 16-horse-power -motor, carrying all its own fuel, two pom-poms, two small Maxims, and -10,000 rounds of ammunition, besides the necessary complement of men -and searchlights for night use, &c., &c. - -The searchlight, by the way, has taken the place of all former -inventions thrown from guns, such as ground-light balls, or parachute -lights with a time-fuse which burst in the air and remained suspended, -betraying the enemy's proceedings. - -In like manner the linked chain and "double-headed" shot, the -"canister"--iron balls packed in thin iron or tin cylinders which -would travel about 350 yards--the "carcasses" filled with inflammable -composition for firing ships and villages, are as much out of date as -the solid round shot or cannon-ball. Young Shrapnell's invention a -century ago of the form of shell that bears his name, a number of -balls arranged in a case containing also a small bursting-charge fired -either by percussion or by a time-fuse, has practically replaced them -all. Thrown with great precision of aim its effective range is now up -to 5000 yards. A 15-pounder shrapnell shell, for instance, contains -192 bullets, and covers several hundred yards with the scattered -missiles flying with extreme velocity. - -Common shell, from 2-1/2 to 3 calibres long, contains an explosive -only. Another variety is segment shell, made of pieces built up in a -ring with a bursting charge in the centre which presently shatters -it. - -The Palliser shell has a marvellous penetrating power when used -against iron plates. But, _mirabile dictu!_ experiments tried within -the past few months prove that a soft cap added externally enables a -projectile to pierce with ease armour which had previously defied -every attack. - - -EXPLOSIVES. - -Half a century ago gunpowder was still the one driving power which -started the projectile on its flight. It is composed of some 75 parts -of saltpetre or nitrate of potash, 15 parts of carefully prepared -charcoal, and 10 parts of sulphur. This composition imprisons a large -amount of oxygen for combustion and is found to act most successfully -when formed into rather large prismatic grains. - -On the abolition of the old flint-lock its place was taken by a -detonating substance enclosed in a copper cap, and some time later -inventors came forward with new and more powerful explosives to -supersede the use of gunpowder. - -By treating cotton with nitric and sulphuric acid reaction -_gun-cotton_ was produced; and a year later glycerine treated in the -same manner became known to commerce as _nitro-glycerine_. This liquid -form being inconvenient to handle, some inert granular substance such -as infusorial earth was used to absorb the nitro-glycerine, and -_dynamite_ was the result. - -The explosion of gun-cotton was found to be too sudden and rapid for -rifles or cannon; it was liable to burst the piece instead of blowing -out the charge. In order to lessen the rapidity of its ignition -ordinary cotton was mixed with it, or its threads were twisted round -some inert substance. - -When repeating-rifles and machine-guns came into general use a -smokeless powder became necessary. Such powders as a rule contain -nitro-cellulose (gun-cotton) or nitro-glycerine, or both. These are -combined into a plastic, gluey composition, which is then made up into -sticks or pellets of various shapes, and usually of large size to -lessen the extreme rapidity of their combustion. Substances such as -tan, paraffin, starch, bran, peat, &c., &c., and many mineral salts, -are used in forming low explosives from high ones. - -To secure complete combustion some of the larger pellets are made with -a central hole, or even pierced by many holes, so that the fire -penetrates the entire mass and carries off all its explosive -qualities. - -Our _cordite_ consists of nitro-glycerine dissolving di-nitro -cellulose by the acid of a volatile solvent and a mineral jelly or -oil. This compound is semi-fluid, and being passed like macaroni -through round holes in a metal plate it forms strings or cords of -varying size according to the diameter of the holes. Hence the name, -cordite. - -Many experiments in search of more powerful explosives resulted in an -almost universal adoption of picric acid as the base. This acid is -itself produced by the action of nitric acid upon carbolic acid, and -each nation has its own fashion of preparing it for artillery. - -The French began with _mélinite_ in 1885, this being a mixture of -picric acid and gun-cotton. - -The composition of _lyddite_ (named from its place of manufacture, -Lydd, in Kent) is a jealously-guarded British secret. This substance -was first used in 5-inch howitzers during the late Soudan campaign, -playing a part in the bombardment of Omdurman. The effect of the -50-lb. lyddite shells upon the South African kopjes is described as -astounding. When the yellow cloud had cleared away trees were seen -uprooted, rocks pulverised, the very face of the earth had changed. - -Several attempts have been made to utilise dynamite for shells, some -of the guns employing compressed air as their motive power. The United -States some years ago went to great expense in setting up for this -purpose heavy pneumatic plant, which has recently been disposed of as -too cumbrous. Dudley's "Aërial Torpedo" gun discharged a 13-lb. shell -containing explosive gelatine, gun-cotton, and fulminate of mercury by -igniting the small cordite charge in a parallel tube, through a vent -in which the partially cooled gases acted on the projectile in the -barrel. This was rotated in the air by inclined blades on a tailpiece, -as the barrel could not be rifled for fear of the heat set up by -friction. Some guns actuated on much the same principle are said to -have been used with effect in the Hispano-American war. Mr. Hudson -Maxim with his explosive "maximite" claims to throw half a ton of -dynamite about a mile, and a one-ton shell to half that distance. - -But even these inventors are outstripped by Professor Birkeland, who -undertakes to hurl a projectile weighing two tons from an iron tube -coiled with copper wire down which an electric current is passed; thus -doing away entirely with the need of a firing-charge. - - -IN THE GUN FACTORY. - -Let us pay a visit to one of our gun factories and get some idea of -the multiform activities necessary to the turning out complete of a -single piece of ordnance or a complicated machine-gun. We enter the -enormous workshop, glazed as to roof and sides, full of the varied -buzz and whirr and clank of the machinery. Up and down the long bays -stand row upon row of lathes, turning, milling, polishing, boring, -rifling--all moving automatically, and with a precision which leaves -nothing to be desired. The silent attendants seem to have nothing in -their own hands, they simply watch that the cutting does not go too -far, and with a touch of the guiding handles regulate the pace or -occasionally insert a fresh tool. The bits used in these processes are -self-cleaning, so the machinery is never clogged; and on the ground -lie little heaps of brass chips cut away by the minute milling tools; -or in other places it is bestrewn with shavings of brass and steel -which great chisels peel off as easily as a carpenter shaves a deal -board. - -Here an enormous steel ingot, forged solid, heated again and again in -a huge furnace and beaten by steam-hammers, or pressed by hydraulic -power between each heating till it is brought to the desired size and -shape, is having its centre bored through by a special drill which -takes out a solid core. This operation is termed "trepanning," and is -applied to guns not exceeding eight inches; those of larger calibre -being rough-bored on a lathe, and mandrils placed in them during the -subsequent forgings. The tremendous heat generated during the boring -processes--we may recall how Benjamin Thompson made water boil by the -experimental boring of a cannon--is kept down by streams of soapy -water continually pumped through and over the metal. We notice this -flow of lubricating fluid in all directions, from oil dropping slowly -on to the small brass-milling machines to this fountain-play of water -which makes a pleasant undertone amidst the jangle of the machines. -But these machines are less noisy than we anticipated; in their actual -working they emit scarcely the slightest sound. What strikes us more -than the supreme exactness with which each does its portion of the -work, is the great deliberateness of its proceeding. All the hurry and -bustle is above us, caused by the driving-bands from the engine, which -keeps the whole machinery of the shed in motion. Suddenly, with harsh -creakings, a great overhead crane comes jarring along the bay, drops a -chain, grips up a gun-barrel, and, handling this mass of many tons' -weight as easily as we should lift a walking-stick, swings it off to -undergo another process of manufacture. - -We pass on to the next lathe where a still larger forging is being -turned externally, supported on specially devised running gear, many -different cutters acting upon it at the same time, so that it is -gradually assuming the tapering, banded appearance familiar to us in -the completed state. - -We turn, fairly bewildered, from one stage of manufacture to another. -Here is a gun whose bore is being "chambered" to the size necessary -for containing the firing charge. Further along we examine a more -finished weapon in process of preparation to receive the breech-plug -and other fittings. Still another we notice which has been -"fine-bored" to a beautifully smooth surface but is being improved yet -more by "lapping" with lead and emery powder. - -In the next shed a marvellous machine is rifling the interior of a -barrel with a dexterity absolutely uncanny, for the tool which does -the rifling has to be rotated in order to give the proper "twist" at -the same moment as it is advancing lengthwise down the bore. The -grooves are not made simultaneously but as a rule one at a time, the -distance between them being kept by measurements on a prepared disc. - -Now we have reached the apparatus for the wire-wound guns, a principle -representing the _ne plus ultra_ of strength and durability hitherto -evolved. The rough-bored gun is placed upon a lathe which revolves -slowly, drawing on to it from a reel mounted at one side a continuous -layer of steel ribbon about a quarter of an inch wide. On a 12-inch -gun there is wound some 117 miles of this wire! fourteen layers of it -at the muzzle end and seventy-five at the breech end. Heavy weights -regulate the tension of the wire, which varies for each layer, the -outermost being at the lowest tension, which will resist a pressure of -over 100 tons to the square inch. - -We next enter the division in which the gun cradles and mounts are -prepared, where we see some of the heaviest work carried out by -electric dynamos, the workman sitting on a raised platform to keep -careful watch over his business. - -Passing through this with interested but cursory inspection of the -cone mountings for quick-firing naval guns, some ingenious elevating -and training gear and a field carriage whose hydraulic buffers merit -closer examination, we come to the shell department where all kinds of -projectiles are manufactured. Shrapnel in its various forms, -armour-piercing shells, forged steel or cast-iron, and small brass -cartridges for the machine-guns may be found here; and the beautifully -delicate workmanship of the fuse arrangements attracts our admiration. -But we may not linger; the plant for the machine-guns themselves claim -our attention. - -Owing to the complexity and minute mechanism of these weapons almost a -hundred different machines are needed, some of the milling machines -taking a large selection of cutters upon one spindle. Indeed, in many -parts of the works one notices the men changing their tools for others -of different size or application. Some of the boring machines work two -barrels at the same time, others can drill three barrels or polish a -couple simultaneously. But there are hundreds of minute operations -which need to be done separately, down to the boring of screw holes -and cutting the groove on a screw-head. Many labourers are employed -upon the lock alone. And every portion is gauged correctly to the most -infinitesimal fraction, being turned out by the thousand, that every -separate item may be interchangeable among weapons of the same make. - -Look at the barrel which came grey and dull from its first turning now -as it is dealt with changing into bright silver. Here it is adjusted -upon the hydraulic rifling machine which will prepare it to carry the -small-arm bullet (.303 inch). That one of larger calibre is rifled to -fire a small shell. Further on, the barrels and their jackets are -being fitted together and the different parts assembled and screwed -up. We have not time to follow the perfect implement to its mounting, -nor to do more than glance at those howitzers and the breech mechanism -of the 6-inch quick-firers near which our guide indicates piles of -flat cases to keep the de Bange obturators from warping while out of -use. For the afternoon is waning and the foundry still unvisited. - -To reach it we pass through the smith's shop and pause awhile to watch -a supply of spanners being roughly stamped by an immense machine out -of metal plates and having their edges tidied off before they can be -further perfected. A steam-hammer is busily engaged in driving -mandrils of increasing size through the centre of a red-hot forging. -The heat from the forges is tremendous, and though it is tempered by a -spray of falling water we are glad to escape into the next shed. - -Here we find skilled workmen carefully preparing moulds by taking in -sand the exact impression of a wooden dummy. Fortunately we arrive -just as a series of casts deeply sunk in the ground are about to be -made. Two brawny labourers bear forward an enormous iron crucible, -red-hot from the furnace, filled with seething liquid--manganese -bronze, we are told--which, when an iron bar is dipped into it, throws -up tongues of beautiful greenish-golden flame. The smith stirs and -clears off the scum as coolly as a cook skims her broth! Now it is -ready, the crucible is again lifted and its contents poured into a -large funnel from which it flows into the moulds beneath and fills -them to the level of the floor. At each one a helper armed with an -iron bar takes his stand and stirs again to work up all dross and -air-bubbles to the surface before the metal sets--a scene worthy of a -painter's brush. - -And so we leave them. - - - - -DIRIGIBLE TORPEDOES. - - -The history of warlike inventions is the history of a continual -see-saw between the discovery of a new means of defence and the -discovery of a fresh means of attack. At one time a shield is devised -to repel a javelin; at another a machine to hurl the javelin with -increased violence against the shield; then the shield is reinforced -by complete coats of mail, and so on. The ball of invention has rolled -steadily on into our own times, gathering size as it rolls, and -bringing more and more startling revolutions in the art of war. To-day -it is a battle between the forces of nature, controllable by man in -the shape of "high explosives," and the resisting power of metals -tempered to extreme toughness. - -At present it looks as if, on the sea at least, the attack were -stronger than the defence. Our warships may be cased in the hardest -metal several inches thick until they become floating forts, almost -impregnable to the heaviest shells. They may be provided with terrible -engines able to give blow for blow, and be manned with the stoutest -hearts in the world. And yet, were a sea-fight in progress, a blow, -crushing and resistless, might at any time come upon the vessel from a -quarter whence, even though suspected, its coming might escape -notice--below the waterline. Were it possible to case an ironclad from -deck to keel in foot-thick plating, the metal would crumple like a -biscuit-box under the terrible impact of the torpedo. - -This destructive weapon is an object of awe not so much from what it -has done as from what it can do. The instances of a torpedo shivering -a vessel in actual warfare are but few. Yet its moral effect must be -immense. Even though it may miss its mark, the very fact of its -possible presence will, especially at night-time, tend to keep the -commanding minds of a fleet very much on the stretch, and to destroy -their efficiency. A torpedo knows no half measures. It is either -entirely successful or utterly useless. Its construction entails great -expense, but inasmuch as it can, if directed aright, send a million of -the enemy's money and a regiment of men to the bottom, the discharge -of a torpedo is, after all, but the setting of a sprat to catch a -whale. - -The aim of inventors has been to endow the dirigible torpedo, fit for -use in the open sea, with such qualities that when once launched on -its murderous course it can pursue its course in the required -direction without external help. The difficulties to be overcome in -arriving at a serviceable weapon have been very great owing to the -complexity of the problem. A torpedo cannot be fired through water -like a cannon shell through air. Water, though yielding, is -incompressible, and offers to a moving body a resistance increasing -with the speed of that body. Therefore the torpedo must contain its -own motive power and its own steering apparatus, and be in effect a -miniature submarine vessel complete in itself. To be out of sight and -danger it must travel beneath the surface and yet not sink to the -bottom; to be effective it must possess great speed, a considerable -sphere of action, and be able to counteract any chance currents it may -meet on its way. - -Among purely automobile torpedoes the Whitehead is easily first. After -thirty years it still holds the lead for open sea work. It is a very -marvel of ingenious adaptation of means to an end, and as it has -fulfilled most successfully the conditions set forth above for an -effective projectile it will be interesting to examine in some detail -this most valuable weapon. - -In 1873 one Captain Lupuis of the Austrian navy experimented with a -small fireship which he directed along the surface of the sea by means -of ropes and guiding lines. This fireship was to be loaded with -explosives which should ignite immediately on coming into collision -with the vessel aimed at. The Austrian Government declared his scheme -unworkable in its crude form, and the Captain looked about for some -one to help him throw what he felt to be a sound idea into a practical -shape. He found the man he wanted in Mr. Whitehead, who was at that -time manager of an engineering establishment at Fiume. Mr. Whitehead -fell in enthusiastically with his proposition, at once discarded the -complicated system of guiding ropes, and set to work to solve the -problem on his own lines. At the end of two years, during which he -worked in secret, aided only by a trusted mechanic and a boy, his son, -he constructed the first torpedo of the type that bears his name. It -was made of steel, was fourteen inches in diameter, weighed 300 lbs., -and carried eighteen pounds of dynamite as explosive charge. But its -powers were limited. It could attain a rate of but six knots an hour -under favourable conditions, and then for a short distance only. Its -conduct was uncertain. Sometimes it would run along the surface, at -others make plunges for the bottom. However, the British Government, -recognising the importance of Mr. Whitehead's work, encouraged him to -perfect his instrument, and paid him a large sum for the patent -rights. Pattern succeeded pattern, until comparative perfection was -reached. - -Described briefly, the Whitehead torpedo is cigar-shaped, blunt-nosed -and tapering gradually towards the tail, so following the lines of a -fish. Its length is twelve times its diameter, which varies in -different patterns from fourteen to nineteen inches. At the fore end -is the striker, and at the tail are a couple of three-bladed screws -working on one shaft in opposite directions, to economise power and -obviate any tendency of the torpedo to travel in a curve; and two sets -of rudders, the one horizontal, the other vertical. The latest form of -the torpedo has a speed of twenty-nine knots and a range of over a -thousand yards. - -The torpedo is divided into five compartments by watertight steel -bulkheads. At the front is the _explosive head_, containing wet -gun-cotton, or some other explosive. The "war head," as it is called, -is detachable, and for practice purposes its place is taken by a -dummy-head filled with wood to make the balance correct. - -Next comes the _air chamber_, filled with highly-compressed air to -drive the engines; after it the _balance chamber_, containing the -apparatus for keeping the torpedo at its proper depth; then the -_engine-room_; and, last of all, the _buoyancy chamber_, which is -air-tight and prevents the torpedo from sinking at the end of its run. - -To examine the compartments in order:-- - -In the very front of the torpedo is the pistol and primer-charge for -igniting the gun-cotton. Especial care has been taken over this part -of the mechanism, to prevent the torpedo being as dangerous to friends -as to foes. The pistol consists of a steel plug sliding in a metal -tube, at the back end of which is the fulminating charge. Until the -plug is driven right in against this charge there can be no explosion. -Three precautions are taken against this happening prematurely. In the -first place, there is on the forward end of the plug a thread cut, up -which a screw-fan travels as soon as it strikes the water. Until the -torpedo has run forty-five feet the fan has not reached the end of its -travel, and the plug consequently cannot be driven home. Even when the -plug is quite free only a heavy blow will drive it in, as a little -copper pin has to be sheared through by the impact. And before the -screw can unwind at all, a safety-pin must be withdrawn at the moment -of firing. So that a torpedo is harmless until it has passed outside -the zone of danger to the discharging vessel. - -The detonating charge is thirty-eight grains of fulminate of mercury, -and the primer-charge consists of six one-ounce discs of dry -gun-cotton contained in a copper cylinder, the front end of which is -connected with the striker-tube of the pistol. The fulminate, on -receiving a blow, expands 2500 times, giving a violent shock to the -gun-cotton discs, which in turn explode and impart a shock to the main -charge, 200 lbs. of gun-cotton. - -The _air chamber_ is made of the finest compressed steel, or of -phosphor-bronze, a third of an inch thick. When ready for action this -chamber has to bear a pressure of 1350 lbs. to the square inch. So -severe is the compression that in the largest-sized torpedoes the air -in this chamber weighs no less than 63 lbs. The air is forced in by -very powerful pumps of a special design. Aft of this chamber is that -containing the stop-valve and steering-gear. The stop-valve is a -species of air-tap sealing the air chamber until the torpedo is to be -discharged. The valve is so arranged that it is impossible to insert -the torpedo into the firing-tube before the valve has been opened, -and so brought the air chamber into communication with the -starting-valve, which does not admit air to the engines till after the -projectile has left the tube. - -The _steering apparatus_ is undoubtedly the most ingenious of the many -clever contrivances packed into a Whitehead torpedo. Its function is -to keep the torpedo on an even keel at a depth determined before the -discharge. This is effected by means of two agencies, a swinging -weight, and a valve which is driven in by water pressure as the -torpedo sinks. When the torpedo points head downwards the weight -swings forward, and by means of connecting levers brings the -horizontal rudders up. As the torpedo rises the weight becomes -vertical and the rudder horizontal. This device only insures that the -torpedo shall travel horizontally. The valve makes it keep its proper -depth by working in conjunction with the pendulum. The principle, -which is too complicated for full description, is, put briefly, a -tendency of the valve to correct the pendulum whenever the latter -swings too far. Lest the pendulum should be violently shaken by the -discharge there is a special controlling gear which keeps the rudders -fixed until the torpedo has proceeded a certain distance, when the -steering mechanism is released. The steering-gear does not work -directly on the rudder. Mr. Whitehead found in his earlier experiments -that the pull exerted by the weight and valve was not sufficient to -move the rudders against the pressure of the screws. He therefore -introduced a beautiful little auxiliary engine, called the -servo-motor, which is to the torpedo what the steam steering-gear is -to a ship. The servo-motor, situated in the _engine-room_, is only -four inches long, but the power it exerts by means of compressed air -is so great that a pressure of half an ounce exerted by the -steering-gear produces a pull of 160 lbs. on the rudders. - -The engines consist of three single-action cylinders, their cranks -working at an angle of 120° to one another, so that there is no "dead" -or stopping point in their action. They are very small, but, thanks to -the huge pressure in the air chamber, develop nearly thirty-one -horse-power. Lest they should "race," or revolve too quickly, while -passing from the tube to the water and do themselves serious damage, -they are provided with a "delay action valve," which is opened by the -impact of the torpedo against the water. Further, lest the air should -be admitted to the cylinders at a very high pressure gradually -decreasing to zero, a "reducing valve" or governor is added to keep -the engines running at a constant speed. - -Whitehead torpedoes are fired from tubes above or below the waterline. -Deck tubes have the advantage of being more easily aimed, but when -loaded they are a source of danger, as any stray bullet or shell from -an enemy's ship might explode the torpedo with dire results. There is -therefore an increasing preference for submerged tubes. An ingenious -device is used for aiming the torpedo, which makes allowances for the -speed of the ship from which it is fired, the speed of the ship aimed -at, and the speed of the torpedo itself. When the moment for firing -arrives, the officer in charge presses an electric button, which sets -in motion an electric magnet fixed to the side of the tube. The magnet -releases a heavy ball which falls and turns the "firing rod." -Compressed air or a powder discharge is brought to bear on the rear -end of the torpedo, which, if submerged, darts out from the vessel's -side along a guiding bar, from which it is released at both ends -simultaneously, thus avoiding the great deflection towards the stern -which would occur were a broadside torpedo not held at the nose till -the tail is clear. This guiding apparatus enables a torpedo to leave -the side of a vessel travelling at high speed almost at right angles -to the vessel's path. - -It will be easily understood that a Whitehead torpedo is a costly -projectile, and that its value--£500 or more--makes the authorities -very careful of its welfare. During practice with "blank" torpedoes a -"Holmes light" is attached. This light is a canister full of calcium -phosphide to which water penetrates through numerous holes, causing -gas to be thrown off and rise to the surface, where, on meeting with -the oxygen of the air, it bursts into flame and gives off dense -volumes of heavy smoke, disclosing the position of the torpedo by -night or day. - -At Portsmouth are storehouses containing upwards of a thousand -torpedoes. Every torpedo is at intervals taken to pieces, examined, -tested, and put together again after full particulars have been taken -down on paper. Each steel "baby" is kept bright and clean, coated -with a thin layer of oil, lest a single spot of rust should mar its -beauty. An interesting passage from Lieutenant G. E. Armstrong's book -on "Torpedoes and Torpedo Vessels" will illustrate the scrupulous -exactness observed in all things relating to the torpedo depôts: "As -an example of the care with which the stores are kept it may be -mentioned that a particular tiny pattern of brass screw which forms -part of the torpedo's mechanism and which is valued at about -twopence-halfpenny per gross, is never allowed to be a single number -wrong. On one occasion, when the stocktaking took place, it was found -that instead of 5000 little screws being accounted for by the man who -was told off to count them, there were only 4997. Several foolscap -letters were written and exchanged over these three small screws, -though their value was not more than a small fraction of a farthing." - -The classic instance of the effectiveness of this type of torpedo is -the battle of the Yalu, fought between the Japanese and Chinese fleets -in 1894. The Japanese had been pounding their adversaries for hours -with their big guns without producing decisive results. So they -determined upon a torpedo attack, which was delivered early in the -morning under cover of darkness, and resulted in the destruction of a -cruiser, the _Ting Yuen_. The next night a second incursion of the -Japanese destroyers wrecked another cruiser, the _Lai Yuen_, which -sunk within five minutes of being struck; sank the _Wei Yuen_, an old -wooden vessel used as a training-school; and blew a large steam -launch out of the water on to an adjacent wharf. These hits "below the -belt" were too much for the Chinese, who soon afterwards surrendered -to their more scientific and better equipped foes. - -If a general naval war broke out to-day most nations would undoubtedly -pin their faith to the Whitehead torpedo for use in the open sea, now -that its accuracy has been largely increased by the gyroscope, a heavy -flywheel attachment revolving rapidly at right angles to the path of -the torpedo, and rendering a change of direction almost impossible. - -For harbour defence the Brennan or its American rival, the -Sims-Edison, might be employed. They are both torpedoes dirigible from -a fixed base by means of connecting wires. The presence of these wires -constitutes an obstacle to their being of service in a fleet action. - -The Brennan is used by our naval authorities. It is the invention of a -Melbourne watchmaker. Being a comparatively poor man, Mr. Brennan -applied to the Colonial Government for grants to aid him in the -manufacture and development of his torpedo, and he was supplied with -sufficient money to perfect it. In 1881 he was requested by our -Admiralty to bring his invention to England, where it was experimented -upon, and pronounced so efficient for harbour and creek defence that -at the advice of the Royal Engineers Mr. Brennan was paid large sums -for his patents and services. - -The Brennan torpedo derives its motive power from a very powerful -engine on shore, capable of developing 100 horse-power, with which it -is connected by stout piano wires. One end of these wires is wound on -two reels inside the torpedo, each working a screw; the other end is -attached to two winding drums driven at high velocity by the engine on -shore. As the drums wind in the wire the reels in the torpedo revolve; -consequently, the harder the torpedo is pulled back the faster it -moves forward, liked a trained trotting mare. The steering of the -torpedo is effected by alterations in the relative speeds of the -drums, and consequently of the screws. The drums run loose on the -engine axle, and are thrown in or out of gear by means of a -friction-brake, so that their speed can be regulated without altering -the pace of the engines. Any increase in the speed of one drum causes -a corresponding decrease in the speed of the other. The torpedo can be -steered easily to right or left within an arc of forty degrees on each -side of straight ahead; but when once launched it cannot be retrieved -except by means of a boat. Its path is marked by a Holmes light, -described above. It has a 200-lb. gun-cotton charge, and is fitted -with an apparatus for maintaining a proper depth very similar to that -used in the Whitehead torpedo. - -The Sims-Edison torpedo differs from the Brennan in its greater -obedience to orders and in its motive power being electrically -transmitted through a single connecting cable. It is over thirty feet -in length and two feet in diameter. Attached to the torpedo proper by -rods is a large copper float, furnished with balls to show the -operator the path of the torpedo. The torpedo itself is in four parts: -the explosive head; the magazine of electric cables, which is paid out -as the torpedo travels; the motor room; and the compartment containing -the steering-gear. The projectile has a high speed and long -range--over four thousand yards. It can twist and turn in any -direction, and, if need be, be called to heel. Like the Brennan, it -has the disadvantage of a long trailing wire, which could easily -become entangled; and it might be put out of action by any damage -inflicted on its float by the enemy's guns. But it is likely to prove -a very effective harbour-guard if brought to the test. - -In passing to the Orling-Armstrong torpedo we enter the latest phase -of torpedo construction. Seeing the disadvantages arising from wires, -electricians have sought a means of controlling torpedoes without any -tangible connection. Wireless telegraphy showed that such a means was -not beyond the bounds of possibility. Mr. Axel Orling, a Swede, -working in concert with Mr. J. T. Armstrong, has lately proved that a -torpedo can be steered by waves of energy transmitted along rays of -light, or perhaps it would be more correct to say along shafts of a -form of X-rays. - -Mr. Orling claims for his torpedo that it is capable of a speed of -twenty-two knots or more an hour; that it can be called to heel, and -steered to right or left at will; that as long as it is in sight it is -controllable by rays invisible to the enemy; that not merely one, but -a number of torpedoes can be directed by the same beams of light; -that, as it is submerged, it would, even if detected, be a bad mark -for the enemy's guns. - -The torpedo carries a shaft which projects above the water, and bears -on its upper end a white disc to receive the rays and transmit them to -internal motors to be transmuted into driving power. The rod also -carries at night an electric light, shaded on the enemy's side, but -rendering the whereabouts of the torpedo very visible to the steerer. - -Mr. Orling's torpedo acts throughout in a cruelly calculating manner. -Before its attack a ship would derive small advantage from a crinoline -of steel netting; for the large torpedo conceals in its head a smaller -torpedo, which, as soon as the netting is struck, darts out and blasts -an opening through which its longer brother, after a momentary delay, -can easily follow. The netting penetrated, the torpedo has yet to -strike twice before exploding. On the first impact, a pin, projecting -from the nose, is driven in to reverse the engines, and at the same -time a certain nut commences to travel along a screw. The nut having -worked its way to the end of the thread, the head of the torpedo fills -slowly through a valve, giving it a downward slant in front. The -engines are again reversed and the nut again travels, this time -bringing the head of the torpedo up, so as to strike the vessel at a -very effective angle from below. - -This torpedo has passed beyond the experimental stage. It is reported -that by command of the Swedish Government, to whom Mr. Orling offered -his invention, and of the King, who takes a keen interest in the ideas -of his young countryman, a number of experiments were some time ago -carried out in the Swedish rivers. Torpedoes were sent 2-1/2 miles, -directed as desired, and made to rise or sink--all this without any -tangible connection. The Government was sufficiently satisfied with -the result to take up the patents, as furnishing a cheap means of -defending their coasts. - -Mr. Orling has described what he imagines would happen in case of an -attack on a position protected by his ingenious creations. "Suppose -that I had twelve torpedoes hidden away under ten feet of water in a -convenient little cove, and that I was directed to annihilate a -hostile fleet just appearing above the horizon. Before me, on a little -table perhaps, I should have my apparatus; twelve buttons would be -under my fingers. Against each button there would be a description of -the torpedo to which it was connected; it would tell me its power of -destruction, and the power of its machinery, and for what distance it -would go. On each button, also, would be indicated the time that I -must press it to release the torpedoes. Well now, I perceive a large -vessel in the van of the approaching fleet. I put my fingers on the -button which is connected with my largest and most formidable weapon. -I press the button--perhaps for twelve seconds. The torpedo is pushed -forward from its fastenings by a special spring, a small pin is -extracted from it, and immediately the motive machinery is set in -motion, and underneath the water goes my little agent of destruction, -and there is nothing to tell the ship of its doom. I place my hand on -another button, and according to the time I press it I steer the -torpedo; the rudder answers to the rays, and the rays answer to the -will of my mind."[2] - - [2] _Pearson's Magazine._ - -If this torpedo acts fully up to its author's expectations, naval -warfare, at least as at present conducted, will be impossible. There -appears to be no reason why this torpedo should not be worked from -shipboard; and we cannot imagine that hostile ships possessing such -truly infernal machines would care to approach within miles of one -another, especially if the submarine be reinforced by the aërial -torpedo, different patterns of which are in course of construction by -Mr. Orling and Major Unge, a brother Swede. The Orling type will be -worked by the new rays, strong enough to project it through space. -Major Unge's will depend for its motive power upon a succession of -impulses obtained by the ignition of a slow-burning gas, passing -through a turbine in the rear of the torpedo. The inventor hopes for a -range of at least six miles. - -What defence would be possible against such missiles? Liable to be -shattered from below, or shivered from above, the warship will be -placed at an ever-increasing disadvantage. Its size will only render -it an easier mark; its strength, bought at the expense of weight, will -be but the means of insuring a quicker descent to the sea's bottom. Is -it not probable that sea-fights will become more and more matters of a -few terrible, quickly-delivered blows? Human inventions will hold the -balance more and more evenly between nations of unequal size, first on -sea, then on land, until at last, as we may hope, even the hottest -heads and bravest hearts will shrink from courting what will be less -war than sheer annihilation, and war, man's worst enemy, will be -itself annihilated. - - - - -SUBMARINE BOATS. - - -The introduction of torpedoes for use against an enemy's ships below -the waterline has led by natural stages to the evolution of a vessel -which may approach unsuspected close enough to the object of attack to -discharge its missile effectively. Before the searchlight was adopted -a night surprise gave due concealment to small craft; but now that the -gloom of midnight can be in an instant flooded with the brilliance of -day a more subtle mode of attack becomes necessary. - -Hence the genesis of the submarine or submersible boat, so constructed -as to disappear beneath the sea at a safe distance from the doomed -ship, and when its torpedo has been sped to retrace its invisible -course until outside the radius of destruction. - -To this end many so-called submarine boats have been invented and -experimented with during recent years. The idea is an ancient one -revived, as indeed are the large proportion of our boasted modern -discoveries. - -Aristotle describes a vessel of this kind (a diving-bell rather than a -boat, however), used in the siege of Tyre more than two thousand years -ago; and also refers to the divers being provided with an air-tube, -"like the trunk of an elephant," by means of which they drew a fresh -supply of air from above the surface--a contrivance adopted in more -than one of our modern submarines. Alexander the Great is said to have -employed divers in warfare; Pliny speaks of an ingenious diving -apparatus, and Bacon refers to air-tubes used by divers. We even find -traces of weapons of offence being employed. Calluvius is credited -with the invention of a submarine gun for projecting Greek fire. - -The Bishop of Upsala in the sixteenth century gives a somewhat -elaborate description of certain leather skiffs or boats used to -scuttle ships by attacking them from beneath, two of which he claims -to have personally examined. In 1629 we read that the Barbary corsairs -fixed submarine torpedoes to the enemy's keel by means of divers. - -As early as 1579 an English gunner named William Bourne patented a -submarine boat of his own invention fitted with leather joints, so -contrived as to be made smaller or larger by the action of screws, -ballasted with water, and having an air-pipe as mast. The Campbell-Ash -submarine tried in 1885 was on much the same principle. - -Cornelius van Drebbel, an ingenious Dutchman who settled in England -before 1600, produced certain submersible vessels and obtained for -them the patronage of two kings. He claims to have discovered a means -of re-oxygenating the foul air and so enabling his craft to remain a -long time below water; whether this was done by chemical treatment, -compressed air, or by surface tubes no record remains. Drebbel's -success was such that he was allowed to experiment in the Thames, and -James I. accompanied him on one of his sub-aquatic journeys. In 1626 -Charles I. gave him an order to make "boates to go under water," as -well as "water mines, water petards," &c., presumably for the campaign -against France, but we do not hear of these weapons of destruction -being actually used upon this occasion. - -[Illustration: _The "Holland" Submarine Boat._] - -These early craft seem to have been generally moved by oars working in -air-tight leather sockets; but one constructed at Rotterdam about 1654 -was furnished with a paddle-wheel. - -Coming now nearer to our own times, we find that an American called -Bushnell had a like inspiration in 1773, when he invented his famous -"Turtles," small, upright boats in which one man could sit, submerge -himself by means of leather bottles with the mouths projecting -outside, propel himself with a small set of oars and steer with an -elementary rudder. An unsuccessful attempt was made to blow up the -English fleet with one of these "Turtles" carrying a torpedo, but the -current proved too strong, and the missile exploded at a harmless -distance, the operator being finally rescued from an unpremeditated -sea-trip! Bushnell was the author of the removable safety-keel now -uniformly adopted. - -Soon afterwards another New Englander took up the running, Fulton--one -of the cleverest and least appreciated engineers of the early years -of the nineteenth century. His _Nautilus_, built in the French -dockyards, was in many respects the pattern for our own modern -submarines. The cigar-shaped copper hull, supported by iron ribs, was -twenty-four feet four inches long, with a greatest diameter of seven -feet. Propulsion came from a wheel, rotated by a hand winch, in the -centre of the stern; forward was a small conning-tower, and the boat -was steered by a rudder. There was a detachable keel below; and fitted -into groves on the top were a collapsible mast and sail for use on the -surface of the water. An anchor was also carried externally. In spite -of the imperfect materials at his disposal Fulton had much success. At -Brest he took a crew of three men twenty-five feet down, and on -another day blew up an old hulk. In the Seine two men went down for -twenty minutes and steered back to their starting-point under water. -He also put in air at high pressure and remained submerged for hours. -But France, England, and his own country in turn rejected his -invention; and, completely discouraged, he bent his energies to -designing boat engines instead. - -In 1821 Captain Johnson, also an American, made a submersible vessel -100 feet long, designed to fetch Napoleon from St. Helena, travelling -for the most part upon the surface. This expedition never came off. - -Two later inventions, by Castera and Payerne, in 1827 and 1846 -respectively, were intended for more peaceful objects. Being -furnished with diving-chambers, the occupants could retrieve things -from the bottom of the sea; Castera providing his boat with an -air-tube to the surface. - -Bauer, another inventor, lived for some years in England under the -patronage of Prince Albert, who supplied him with funds for his -experiments. With Brunel's help he built a vessel which was -indiscreetly modified by the naval authorities, and finally sank and -drowned its crew. Going then to Russia he constructed sundry -submarines for the navy; but was in the end thrown over, and, like -Fulton, had to turn himself to other employment. - -The fact is that up to this period the cry for a practical submarine -to use in warfare had not yet arisen, or these inventions would have -met with a far different reception. Within the last half century all -has changed. America and France now rival each other in construction, -while the other nations of Europe look on with intelligent interest, -and in turn make their contributions towards solving the problem of -under-wave propulsion. - -America led the way during the Civil War blockades in 1864, when the -_Housatonic_ was sunk in Charleston harbour, and damage done to other -ships. But these experimental torpedo-boats were clumsy contrivances -compared with their modern successors, for they could only carry their -destructive weapon at the end of a spar projecting from the bows--to -be exploded upon contact with the obstacle, and probably involve the -aggressor in a common ruin. So nothing more was done till the -perfecting of the Whitehead torpedo (see Dirigible Torpedoes) gave the -required impetus to fresh enterprise. - -France, experimenting in the same direction, produced in 1889 Goubet's -submarine, patent of a private inventor, who has also been patronised -by other navies. These are very small boats, the first, 16-1/2 feet -long, carrying a crew of two or three men. _Goubet No. 2_, built in -1899, is 26-1/4 feet long, composed of several layers of gun-metal -united by strong screw-bolts, and so able to resist very great -pressure. They are egg-or spindle-shaped, supplied with compressed -air, able to sink and rise by rearrangement of water-ballast. -Reservoirs in the hull are gradually filled for submersion with water, -which is easily expelled when it is desired to rise again. If this -system goes wrong a false keel of thirty-six hundredweight can be -detached and the boat springs up to the surface. The propulsive force -is electricity, which works the driving-screw at the rear, and the -automobile torpedo is discharged from its tube by compressed air. - -"By the aid of an optical tube, which a pneumatic telescopic apparatus -enables the operator to thrust above the surface and pull down in a -moment, the captain of the _Goubet_ can, when near the surface, see -what is going on all round him. This telescope has a system of prisms -and lenses which cause the image of the sea-surface to be deflected -down to the eye of the observer below. - -"Fresh air for the crew is provided by reservoirs of oxygen, and -accumulations of foul air can be expelled by means of a small pump. -Enough fresh air can be compressed into the reservoirs to last the -crew for a week or more." - -The _Gymnote_, laid down in 1898, is more than double the size of the -_Goubet_; it is cigar-shaped, 29 feet long by 6 feet diameter, with a -displacement of thirty tons. The motive power is also electricity -stored in accumulators for use during submersion, and the speed -expected--but not realised--was to be ten knots. - -Five years later this type was improved upon in the _Gustave Zédé_, -the largest submarine ever yet designed. This boat, built of -phosphor-bronze, with a single screw, measures 131 feet in length and -has a displacement of 266 tons; she can contain a crew of nine -officers and men, carries three torpedoes--though with one torpedo -tube instead of two--has a lightly armoured conning-tower, and is said -to give a surface speed of thirteen knots and to make eight knots when -submerged. At a trial of her powers made in the presence of M. -Lockroy, Minister of Marine, she affixed an unloaded torpedo to the -battleship _Magenta_ and got away unobserved. The whole performance of -the boat on that occasion was declared to be most successful. But its -cost proved excessive considering the small radius of action -obtainable, and a smaller vessel of the same type, the _Morse_ (118 × -9 feet), is now the official size for that particular class. - -In 1896 a competition was held and won by the submersible _Narval_ of -M. Laubeuf, a craft shaped much like the ordinary torpedo-boat. On the -surface or awash the _Narval_ works by means of a Brulé engine burning -oil fuel to heat its boilers; but when submerged for attack with -funnel shut down is driven by electric accumulators. She displaces 100 -odd tons and is provided with four Dzewiecki torpedo tubes. Her radius -of action, steaming awash, is calculated at some 250 miles, or seventy -miles when proceeding under water at five knots an hour. This is the -parent of another class of boats designed for offensive tactics, while -the _Morse_ type is adapted chiefly for coast and harbour defence. The -French navy includes altogether thirty submarine craft, though several -of these are only projected at present, and none have yet been put to -the practical tests of actual warfare--the torpedoes used in -experimenting being, of course, blank. - -Meanwhile in America experiments have also been proceeding since 1887, -when Mr. Holland of New York produced the vessel that bears his name. -This, considerably modified, has now been adopted as model by our Navy -Department, which is building some half-dozen on very similar lines. -Though it is not easy to get any definite particulars concerning -French submarines Americans are less reticent, and we have graphic -accounts of the _Holland_ and her offspring from those who have -visited her. - -These vessels, though cigar-shaped liked most others, in some respects -resemble the _Narval_, being intended for long runs on the surface, -when they burn oil in a four-cylinder gasolene engine of 160 -horse-power. Under water they are propelled by an electric waterproof -motor of seventy horse-power, and proceed at a pace of seven knots per -hour. There is a superstructure for deck, with a funnel for the engine -and a small conning-tower protected by 4-inch armour. The armament -carried comprises five 18-inch Whitehead torpedoes, 11 feet 8 inches -long. One hundred and twenty tons is the displacement, including tank -capacity for 850 gallons of gasolene; the full length is 63 feet 4 -inches, with a beam of 11 feet 9 inches. - -[Illustration: _An interior view of the "Holland." The large pendulum -on the right actuates mechanism to keep the Submarine at the required -depth below the surface._] - -The original Holland boat is thus described by an adventurous -correspondent who took a trip in her[3]: "The _Holland_ is fifty-three -feet long, and in its widest part it is 10-1/4 feet in diameter. It -has a displacement of seventy-four tons, and what is called a reserve -buoyancy of 2-1/2 tons which tends to make it come to the surface. - - [3] _Pearson's Magazine._ - -"The frames of the boat are exact circles of steel. They are set a -little more than a foot apart. They diminish gradually in diameter -from the centre of the boat to the bow and stern. On the top of the -boat a flat superstructure is built to afford a walking platform, and -under this are spaces for exhaust pipes and for the external outfit of -the boat, such as ropes and a small anchor. The steel plates which -cover the frame are from one-half to three-eighths of an inch in -thickness. - -"From what may be called the centre of the boat a turret extends -upwards through the superstructure for about eighteen inches. It is -two feet in diameter, and is the only means of entrance to the boat. -It is the place from which the boat is operated. At the stern is an -ordinary three-bladed propeller and an ordinary rudder, and in -addition there are two horizontal rudders--"diving-rudders" they are -called--which look like the feet of a duck spread out behind as it -swims along the water. - -"From the bow two-thirds of the way to the stern there is a flooring, -beneath which are the storage batteries, the tank for the gasolene, -and the tanks which are filled with water for submerging; in the last -one-third of the boat the flooring drops away, and the space is -occupied by the propelling machinery. - -"There are about a dozen openings in the boat, the chief being three -Kingston valves, by means of which the submerging tanks are filled or -emptied. Others admit water to pressure gauges, which regulate or show -the depth of the vessel under water. There are twelve deadlights in -the top and sides of the craft. To remain under water the boat must be -kept in motion, unless an anchor is used. - -"It can be steered to the surface by the diving rudders, or sent -flying to the top through emptying the storage tanks. If it strikes -bottom, or gets stuck in the mud, it can blow itself loose by means of -its compressed air. It cannot be sunk unless pierced above the -flooring. It has a speed capacity of from eight to ten knots either -on the surface or under water. - -"It can go 1500 miles on the surface without renewing its supply of -gasolene. It can go fully forty knots under water without coming to -the surface, and there is enough compressed air in the tanks to supply -a crew with fresh air for thirty hours, if the air is not used for any -other purpose, such as emptying the submerging tanks. It can dive to a -depth of twenty feet in eight seconds. - -"The interior is simply packed with machinery. As you climb down the -turret you are confronted with it at once. There is a diminutive -compass which must be avoided carefully by the feet. A pressure gauge -is directly in front of the operator's eye as he stands in position. -There are speaking-tubes to various parts of the boat, and a -signal-bell to the engine-room. - -"As the operator's hands hang by his sides, he touches a wheel on the -port side, by turning which he steers the little vessel, and one on -the starboard side, by turning which he controls the diving machinery. -After the top is clamped down the operator can look out through -plate-glass windows, about one inch wide and three inches long, which -encircle the turret. - -"So long as the boat is running on the surface these are valuable, -giving a complete view of the surroundings if the water is smooth. -After the boat goes beneath the surface, these windows are useless; it -is impossible to see through the water. Steering must be done by -compass; until recently considered an impossible task in a submarine -boat. A tiny electric light in the turret shows the operator the -direction in which he is going, and reveals the markings on the depth -gauges. If the boat should pass under an object, such as a ship, a -perceptible shadow would be noticed through the deadlights, but that -is all. The ability to see fishes swimming about in the water is a -pleasant fiction. - -"The only clear space in the body of the boat is directly in front of -the bench on which the man in the turret is standing. It is where the -eighteen-inch torpedo-tube, and the eight and five-eighths inch aërial -gun are loaded. - -"Along the sides of this open space are six compressed-air tanks, -containing thirty cubic feet of air at a pressure of 2000 lbs. to a -square inch. Near by is a smaller tank, containing three cubic feet of -air at a fifty pounds pressure. A still smaller tank contains two -cubic feet of air at a ten pounds pressure. These smaller tanks supply -the compressed air which, with the smokeless powder, is used in -discharging the projectiles from the boat. - -"Directly behind the turret, up against the roof on the port side, is -the little engine by which the vessel is steered; it is worked by -compressed air. Fastened to the roof on the starboard side is the -diving-engine, with discs that look as large as dinner-plates stood on -end. These discs are diaphragms on which the water-pressure exerts an -influence, counteracting certain springs which are set to keep the -diving rudders at a given pitch, and thus insuring an immersion of an -exact depth during a run. - -"At one side is a cubic steel box--the air compressor; and directly in -the centre of this part of the boat is a long pendulum, just as there -is in the ordinary torpedo, which, by swinging backwards and forwards -as the boat dives and rises, checks a tendency to go too far down, or -to come up at too sharp an angle. On the floor are the levers which, -when raised and moved in certain directions, fill or empty the -submerging tanks. On every hand are valves and wheels and pipes in -such apparent confusion as to turn a layman's head. - -"There are also pumps in the boat, a ventilating apparatus, and a -sounding contrivance, by means of which the channel is picked out when -running under water. This sounding contrivance consists of a heavy -weight attached to a piano wire passing from a reel out through a -stuffing-box in the bottom. There are also valves which release fresh -air to the crew, although in ordinary runs of from one-half to one -hour this is not necessary, the fresh air received from the various -exhausts in the boat being sufficient to supply all necessities in -that length of time." - -Another submersible of somewhat different design is the production of -the Swedish inventor, Mr. Nordenfelt. This boat is 9-1/2 metres in -length, and has a displacement of sixty tons. Like the _Goubet_ it -sinks only in a horizontal position, while the _Holland_ plunges -downward at a slight angle. On the surface a steam-engine of 100 -horse-power propels it, and when the funnel is closed down and the -vessel submerges itself, the screws are still driven by superheated -steam from the large reservoir of water boiling at high pressure which -maintains a constant supply, three circulation pumps keeping this in -touch with the boiler. The plunge is accomplished by means of two -protected screws, and when they cease to move the reserve buoyancy of -the boat brings it back to the surface. It is steered by a rudder -which a pendulum regulates. The most modern of these boats is of -English manufacture, built at Barrow, and tried in Southampton Water. - -The vessels hitherto described should be termed submersible rather -than submarine, as they are designed to usually proceed on the -surface, and submerge themselves only for action when in sight of the -enemy. - -American ingenuity has produced an absolutely unique craft to which -the name submarine may with real appropriateness be applied, for, -sinking in water 100 feet deep, it can remain below and run upon three -wheels along the bottom of the sea. This is the _Argonaut_, invented -by Mr. Simon Lake of Baltimore, and its main portion consists of a -steel framework of cylindrical form which is surmounted by a flat, -hollow steel deck. During submersion the deck is filled with water and -thus saved from being crushed by outside pressure as well as helping -to sink the craft. - -When moving on the surface it has the appearance of an ordinary ship, -with its two light masts, a small conning-tower on which is the -steering-wheel, bowsprit, ventilators, a derrick, suction-pump, and -two anchors. A gasolene engine of special design is used for both -surface and submerged cruising under ordinary circumstances, but in -time of war storage batteries are available. An electric dynamo -supplies light to the whole interior, including a 4000 candle-power -searchlight in the extreme bow which illuminates the pathway while -under water. - -On the boat being stopped and the order given to submerge, the crew -first throw out sounding lines to make sure of the depth. They then -close down external openings, and retreat into the boat through the -conning-tower, within which the helmsman takes his stand, continuing -to steer as easily as when outside. The valves which fill the deck and -submersion tanks are opened, and the _Argonaut_ drops gently to the -floor of the ocean. The two apparent masts are in reality 3-inch iron -pipes which rise thirty feet or more above the deck, and so long as no -greater depth is attained, they supply the occupants with fresh air -and let exhausted gases escape, but close automatically when the water -reaches their top. - -Once upon the bottom of the sea this versatile submarine begins its -journey as a tricycle. It is furnished with a driving-wheel on either -side, each of which is 6-1/2 feet in diameter and weighs 5000 lbs.; -and is guided by a third wheel weighing 2000 lbs. journalled in the -rudder. On a hard bottom or against a strong tide the wheels are most -effective owing to their weight, but in passing through soft sand or -mud the screw propeller pushes the boat along, the driving-wheels -running "loose." In this way she can travel through even waist-deep -mud, the screw working more strongly than on the surface, because it -has such a weight of water to help it, and she moves more easily -uphill. - -In construction the _Argonaut_ is shaped something like a huge cigar, -her strong steel frames, spaced twenty inches apart, being clad with -steel plates 3/8-inch thick double riveted over them. Great strength -is necessary to resist the pressure of superincumbent water, which at -a depth of 100 feet amounts to 44 lbs. per square inch. - -Originally she was built 36 feet long, but was subsequently lengthened -by some 20 odd feet, and has 9 feet beam. She weighs fifty-seven tons -when submerged. A false section of keel, 4000 lbs. in weight, can on -emergency be instantly released from inside; and two downhaul weights, -each of 1000 lbs., are used as an extra precaution for safety when -sinking in deep water. - -The interior is divided into various compartments, the living quarters -consisting of the cabin, galley, operating chamber and engine-room. -There are also a division containing stores and telephone, the -intermediate, and the divers' room. The "operating" room contains the -levers, handwheels, and other mechanism by which the boat's movements -are governed. A water gauge shows her exact depth below the surface; a -dial on either side indicates any inclination from the horizontal. -Certain levers open the valves which admit water to the ballast-tanks -in the hold; another releases the false keel; there is a cyclometer to -register the wheel travelling, and other gauges mark the pressure of -steam, speed of engines, &c. - -A compass in the conning-tower enables the navigator to steer a true -course whether above or below the surface. This conning-tower, only -six feet high, rises above the centre of the living quarters, and is -of steel with small windows in the upper part. Encircling it to about -three-quarters of its height is a reservoir for gasolene, which feeds -into a smaller tank within the boat for consumption. The compressed -air is stored in two Mannesmann steel reservoirs which have been -tested to a pressure of 4000 lbs. per square inch. This renews the -air-supply for the crew when the _Argonaut_ is long below, and also -enables the diving operations to be carried on. - -The maximum speed at which the _Argonaut_ travels submerged is five -knots an hour, and when she has arrived at her destination--say a -sunken coal steamer--the working party pass into the "intermediate" -chamber, whose air-tight doors are then closed. A current of -compressed air is then turned on until the air is equal in pressure to -that in the divers' room. The doors of this close over india rubber to -be air and water-tight; one communicates with the "intermediate," the -other is a trap which opens downwards into the sea. Through three -windows in the prow those remaining in the room can watch operations -outside within a radius varying according to the clearness of the -water. The divers assume their suits, to the helmets of which a -telephone is attached, so arranged that they are able to talk to each -other as well as to those in the boat. They are also provided with -electric lamps, and a brilliant flood of light streams upon them from -the bows of the vessel. The derrick can be used with ease under water, -and the powerful suction-pump will "retrieve" coal from a submerged -vessel into a barge above at the rate of sixty tons per hour. - -It will thus be seen how valuable a boat of this kind may be for -salvage operations, as well as for surveying the bottom of harbours, -river mouths, sea coasts, and so on. In war time it can lay or examine -submarine mines for harbour defence, or, if employed offensively, can -enter the enemy's harbour with no chance of detection, and there -destroy his mines or blow up his ships with perfect impunity. - -To return the _Argonaut_ to the surface it is only necessary to force -compressed air into the space below the deck and the four tanks in the -hold. Her buoyancy being thus gradually restored she rises slowly and -steadily till she is again afloat upon the water, and steams for land. - -We have now glanced briefly at some of the most interesting -attempts--out of many dozens--to produce a practicable submarine -vessel in bygone days; and have inquired more closely into the -construction of several modern designs; among these the _Holland_ has -received especial attention, as that is the model adopted by our -Admiralty, and our own new boats only differ in detail from their -American prototype. But before quitting this subject it will be well -to consider what is required from the navigating engineer, and how far -present invention has supplied the demand. - -[Illustration: _The "Holland" Submarine in the last stages of -submersion._] - -The perfect submarine of fiction was introduced by Jules Verne, whose -_Nautilus_ remains a masterpiece of scientific imagination. This -marvellous vessel ploughed the seas with equal power and safety, -whether on the surface or deeply sunk beneath the waves, bearing the -pressure of many atmospheres. It would rest upon the ocean floor while -its inmates, clad in diving suits, issued forth to stroll amid aquatic -forests and scale marine mountains. It gathered fabulous treasures -from pearl beds and sunken galleons; and could ram and sink an -offending ship a thousand times its size without dinting or loosening -a plate on its own hull. No weather deflected its compass, no movement -disturbed its equilibrium. Its crew followed peacefully and cheerfully -in their spacious cabins a daily round of duties which electric power -and automatic gear reduced to a minimum. Save for the misadventure of -a shortened air-supply when exploring the Polar pack, and the clash of -human passions, Captain Nemo's guests would have voyaged in a -floating paradise. - -Compare with this entrancing creation the most practical vessels of -actual experiment. They are small, blind craft, groping their way -perilously when below the surface, the steel and electrical machinery -sadly interfering with any trustworthy working of their compass, and -the best form of periscope hitherto introduced forming a very -imperfect substitute for ordinary vision. - -Their speed, never very fast upon the surface, is reduced by -submersion to that of the oldest and slowest gunboats. Their radius of -action is also circumscribed--that is, they cannot carry supplies -sufficient to go a long distance, deal with a hostile fleet, and then -return to headquarters without replenishment. - -Furthermore, there arise the nice questions of buoyancy combined with -stability when afloat, of sinking quickly out of sight, and of keeping -a correct balance under water. The equilibrium of such small vessels -navigating between the surface and the bottom is extremely sensitive; -even the movements to and fro of the crew are enough to imperil them. -To meet this difficulty the big water-ballast tanks, engines and -accumulators are necessarily arranged at the bottom of the hull, and a -pendulum working a helm automatically is introduced to keep it -longitudinally stable. - -To sink the boat, which is done by changing the angle of the -propeller in the _Goubet_ and some others, and by means of horizontal -rudders and vanes in the _Nordenfelt_ and _Holland_, it must first be -most accurately balanced, bow and stern exactly in trim. Then the boat -must be put into precise equilibrium with the water--_i.e._ must weigh -just the amount of water displaced. For this its specific gravity must -be nearly the same as that of the water (whether salt or fresh), and a -small accident might upset all calculations. Collision, even with a -large fish, could destroy the steering-gear, and a dent in the side -would also tend to plunge it at once to destruction. - -Did it escape these dangers and succeed in steering an accurate course -to its goal, we have up to now little practical proof that the mere -act of discharging its torpedo--though the weight of the missile is -intended to be automatically replaced immediately it drops from the -tube--may not suffice to send the vessel either to bottom or top of -the sea. In the latter case it would be within the danger zone of its -alarmed enemy and at his mercy, its slow speed (even if uninjured) -leaving it little chance of successful flight. - -But whatever the final result, one thing is certain, that--untried as -it is--the possible contingency of a submarine attack is likely to -shake the _morale_ of an aggressive fleet. - -"When the first submarine torpedo-boat goes into action," says Mr. -Holland, "she will bring us face to face with the most perplexing -problem ever met in warfare. She will present the unique spectacle, -when used in attack, of a weapon against which there is no defence.... -You can send nothing against the submarine boat, not even itself.... -You cannot see under water, hence you cannot fight under water. Hence -you cannot defend yourself against an attack under water except by -running away." - -This inventor is, however, an enthusiast about the future awaiting the -submarine as a social factor. His boat has been tested by long voyages -on and below water with complete success. The _Argonaut_ also upon one -occasion travelled a thousand miles with five persons, and proved -herself "habitable, seaworthy, and under perfect control." - -Mr. Holland confidently anticipates in the near future a Channel -service of submerged boats run by automatic steering-gear upon cables -stretched from coast to coast, and eloquently sums up its advantages. - -The passage would be always practicable, for ordinary interruptions -such as fog and storms cannot affect the sea depths. - -An even temperature would prevail summer and winter, the well-warmed -and lighted boats being also free from smoke and spray. - -No nauseating smells would proceed from the evenly-working electric -engines. No motion cause sea-sickness, no collision be apprehended--as -each line would run on its own cable, and at its own specified depth, -a telephone keeping it in communication with shore. - -In like manner a service might be plied over lake bottoms, or across -the bed of wide rivers whose surface is bound in ice. Such is the -submarine boat as hitherto conceived for peace or war--a daring -project for the coming generation to justify. - - - - -ANIMATED PICTURES. - - -Has it ever occurred to the reader to ask himself why rain appears to -fall in streaks though it arrives at earth in drops? Or why the -glowing end of a charred stick produces fiery lines if waved about in -the darkness? Common sense tells us the drop and the burning point -cannot _be_ in two places at one and the same time. And yet apparently -we are able to see both in many positions simultaneously. - -This seeming paradox is due to "persistence of vision," a phenomenon -that has attracted the notice of scientific men for many centuries. -Persistence may be briefly explained thus:-- - -The eye is extremely sensitive to light, and will, as is proved by the -visibility of the electric spark, lasting for less than the millionth -part of a second, _receive_ impressions with marvellous rapidity. - -But it cannot get rid of these impressions at the same speed. The -duration of a visual impression has been calculated as one-tenth to -one-twenty-first of a second. The electric spark, therefore, appears -to last much longer than it really does. - -Hence it is obvious that if a series of impressions follow one another -more rapidly than the eye can free itself of them, the impressions -will overlap, and one of four results will follow. - - (_a_) _Apparently uninterrupted presence_ of an image if the - same image be repeatedly represented. - - (_b_) _Confusion_, if the images be all different and - disconnected. - - (_c_) _Combination_, if the images of two or a very few objects - be presented in regular rotation. - - (_d_) _Motion_, if the objects be similar in all but one part, - which occupies a slightly different portion in each - presentation. - -In connection with (_c_) an interesting story is told of Sir J. -Herschel by Charles Babbage:--[4] - - [4] Quoted from Mr. Henry V. Hopwood's "Living Pictures," to - which book the author is indebted for much of his information - in this chapter. - -"One day Herschel, sitting with me after dinner, amusing himself by -spinning a pear upon the table, suddenly asked whether I could show -him the two sides of a shilling at the same moment. I took out of my -pocket a shilling, and holding it up before the looking-glass, pointed -out my method. 'No,' said my friend, 'that won't do;' then spinning my -shilling upon the table, he pointed out his method of seeing both -sides at once. The next day I mentioned the anecdote to the late Dr. -Fitton, who a few days after brought me a beautiful illustration of -the principle. It consisted of a round disc of card suspended between -two pieces of sewing silk. These threads being held between the finger -and thumb of each hand, were then made to turn quickly, when the disc -of card, of course, revolved also. Upon one side of this disc of card -was painted a bird, upon the other side an empty bird-cage. On turning -the thread rapidly the bird appeared to have got inside the cage. We -soon made numerous applications, as a rat on one side and a trap on -the other, &c. It was shown to Captain Kater, Dr. Wollaston, and many -of our friends, and was, after the lapse of a short time, forgotten. -Some months after, during dinner at the Royal Society Club, Sir Joseph -Banks being in the chair, I heard Mr. Barrow, then secretary to the -Admiralty, talking very loudly about a wonderful invention of Dr. -Paris, the object of which I could not quite understand. It was called -the Thaumatrope, and was said to be sold at the Royal Institution, in -Albemarle Street. Suspecting that it had some connection with our -unnamed toy I went next morning and purchased for seven shillings and -sixpence a thaumatrope, which I afterwards sent down to Slough to the -late Lady Herschel. It was precisely the thing which her son and Dr. -Fitton had contributed to invent, which amused all their friends for a -time, and had then been forgotten." - -The _thaumatrope_, then, did nothing more than illustrate the power of -the eye to weld together a couple of alternating impressions. The toys -to which we shall next pass represent the same principle working in a -different direction towards the production of the living picture. - -Now, when we see a man running (to take an instance) we see the _same_ -body and the same legs continuously, but in different positions, which -merge insensibly the one into the other. No method of reproducing that -impression of motion is possible if only _one_ drawing, diagram, or -photograph be employed. - -A man represented with as many legs as a centipede would not give us -any impression of running or movement; and a blur showing the -positions taken successively by his legs would be equally futile. -Therefore we are driven back to a _series_ of pictures, slightly -different from one another; and in order that the pictures may not be -blurred a screen must be interposed before the eye while the change -from picture to picture is made. The shorter the period of change, and -the greater the number of pictures presented to illustrate a single -motion, the more realistic is the effect. These are the general -principles which have to be observed in all mechanism for the -production of an illusory effect of motion. The persistence of vision -has led to the invention of many optical toys, the names of which, in -common with the names of most apparatus connected with the living -picture, are remarkable for their length. Of these toys we will select -three for special notice. - -In 1833 Plateau of Ghent invented the _phenakistoscope_, "the thing -that gives one a false impression of reality"--to interpret this -formidable word. The phenakistoscope is a disc of card or metal round -the edge of which are drawn a succession of pictures showing a man or -animal in progressive positions. Between every two pictures a narrow -slit is cut. The disc is mounted on an axle and revolved before a -mirror, so that a person looking through the slits see one picture -after another reflected in the mirror. - -The _zoetrope_, or Wheel of Life, which appeared first in 1860, is a -modification of the same idea. In this instrument the pictures are -arranged on the inner side of a hollow cylinder revolving on a -vertical axis, its sides being perforated with slits above the -pictures. As the slit in both cases caused distortion M. Reynaud, a -Frenchman, produced in 1877 the _praxinoscope_, which differed from -the zoetrope in that the pictures were not seen directly through -slits, but were reflected by mirrors set half-way between the pictures -and the axis of the cylinder, a mirror for every picture. Only at the -moment when the mirror is at right angles to the line of sight would -the picture be visible. M. Reynaud also devised a special lantern for -projecting praxinoscope pictures on to a screen. - -These and other somewhat similar contrivances, though ingenious, had -very distinct limitations. They depended for their success upon the -inventiveness and accuracy of the artist, who was confined in his -choice of subject; and could, owing to the construction of the -apparatus, only represent a small series of actions, indefinitely -repeated by the machine. And as a complete action had to be crowded -into a few pictures, the changes of position were necessarily abrupt. - -To make the living picture a success two things were needed; some -method of securing a very rapid series of many pictures, and a machine -for reproducing the series, whatever its length. The method was found -in photography, with the advance of which the living picture's -progress is so closely related, that it will be worth while to notice -briefly the various improvements of photographic processes. The -old-fashioned Daguerreotype process, discovered in 1839, required an -exposure of half-an-hour. The introduction of wet collodion reduced -this tax on a sitter's patience to ten seconds. In 1878 the dry plate -process had still further shortened the exposure to one second; and -since that date the silver-salt emulsions used in photography have had -their sensitiveness to light so much increased, that clear pictures -can now be made in one-thousandth of a second, a period minute enough -to arrest the most rapid movements of animals. - -By 1878, therefore, instantaneous photography was ready to aid the -living picture. Previously to that year series of photographs had been -taken from posed models, without however extending the choice of -subjects to any great extent. But between 1870 and 1880 two men, Marey -and Muybridge, began work with the camera on the movements of horses. -Marey endeavoured to produce a series of pictures round the edge of -one plate with a single lens and repeated exposures.[5] Muybridge, on -the other hand, used a series of cameras. He erected a long white -background parallel to which were stationed the cameras at equal -distances. The shutters of the cameras were connected to threads laid -across the interval between the background and the cameras in such a -manner that a horse driven along the track snapped them at regular -intervals, and brought about successive exposures. Muybridge's method -was carried on by Anschütz, a German, who in 1899 brought out his -electrical Tachyscope, or "quick-seer." Having secured his negatives -he printed off transparent positives on glass, and arranged these last -round the circumference of a large disc rotating in front of a screen, -having in it a hole the size of the transparencies. As each picture -came opposite the hole a Geissler tube was momentarily lit up behind -it by electrical contact, giving a fleeting view of one phase of a -horse's motion. - - [5] A very interesting article in the May, 1902, issue of - _Pearson's Magazine_ deals with the latest work of Professor - Marey in the field of the photographic representation of the - movements of men, birds, and quadrupeds. - -The introduction of the ribbon film in or about 1888 opened much -greater possibilities to the living picture than would ever have -existed had the glass plate been retained. It was now comparatively -easy to take a long series of pictures; and accordingly we find -Messrs. Friese-Greene and Evans exhibiting in 1890 a camera capable of -securing three hundred exposures in half a minute, or ten per second. - - -The next apparatus to be specially mentioned is Edison's Kinetoscope, -which he first exhibited in England in 1894. As early as 1887 Mr. -Edison had tried to produce animated pictures in a manner analogous to -the making of a sound-record on a phonograph (see p. 56). He wrapped -round a cylinder a sheet of sensitized celluloid which was covered, -after numerous exposures, by a spiral line of tiny negatives. The -positives made from these were illuminated in turn by flashes of -electric light. This method was, however, entirely abandoned in the -perfected kinetoscope, an instrument for viewing pictures the size of -a postage stamp, carried on a continuously moving celluloid film -between the eye of the observer and a small electric lamp. The -pictures passed the point of inspection at the rate of forty-six per -second (a rate hitherto never approached), and as each picture was -properly centred a slit in a rapidly revolving shutter made it visible -for a very small fraction of a second. Holes punched at regular -intervals along each side of the film engaged with studs on a wheel, -and insured a regular motion of the pictures. This principle of a -perforated film has been used by nearly all subsequent manufacturers -of animatographs. - -To secure forty-six negatives per second Edison invented a special -exposure device. Each negative would have but one-forty-sixth of a -second to itself, and that must include the time during which the -fresh surface of film was being brought into position before the lens. -He therefore introduced an intermittent gearing, which jerked the -film forwards forty-six times per second, but allowed it to remain -stationary for nine-tenths of the period allotted to each picture. -During the time of movement the lens was covered by the shutter. This -principle of exposure has also been largely adopted by other -inventors. By its means weak negatives are avoided, while pictures -projected on to a screen gain greatly in brilliancy and steadiness. - -The capabilities of a long flexible film-band having been shown by -Edison, he was not long without imitators. Phantoscopes, Bioscopes, -Photoscopes, and many other instruments followed in quick succession. -In 1895 Messrs. Lumière scored a great success with their -Cinematograph, which they exhibited at Marseilles and Paris; throwing -the living picture as we now know it on to a screen for a large -company to see. This camera-lantern opens the era of commercial -animated-photography. The number of patents taken out since 1895 in -connection with living-picture machines is sufficient proof that -inventors have either found in this particular branch of photography a -peculiar fascination, or have anticipated from it a substantial -profit. - -A company known as the Mutoscope and Biograph Company has been formed -for the sole object of working the manufacture and exhibition of the -living picture on a great commercial scale. The present company is -American, but there are subsidiary allied companies in many parts of -the world, including the British Isles, France, Italy, Belgium, -Germany, Austria, India, Australia, South Africa. The part that the -company has played in the development of animated photography will be -easily understood from the short account that follows. - -The company controls three machines, the Mutograph, or camera for -making negatives; the Biograph, or lantern for throwing pictures on to -the screen; and the Mutoscope, a familiar apparatus in which the same -pictures may be seen in a different fashion on the payment of a penny. - -Externally the Mutograph is remarkable for its size, which makes it a -giant of its kind. The complete apparatus weighs, with its -accumulators, several hundreds of pounds. It takes a very large -picture, as animatograph pictures go--two by two-and-a-half inches, -which, besides giving increased detail, require less severe -magnification than is usual with other films. The camera can make up -to a hundred exposures per second, in which time _twenty-two_ feet of -film will have passed before the lens. - -The film is so heavy that were it arrested bodily during each exposure -and then jerked forward again, it might be injured. The mechanism of -the mutograph, driven at regular speed, by an electric motor, has been -so arranged as to halt only that part of the film which is being -exposed, the rest moving forward continuously. The exposed portion, -together with the next surface, which has accumulated in a loop -behind it, is dragged on by two rollers that are in contact with the -film during part only of their revolutions. Thus the jerky motion is -confined to but a few inches of the film, and even at the highest -speeds the camera is peculiarly free from vibration. - -An exposed mutograph film is wound for development round a skeleton -reel, three feet in diameter and seven long, which rotates in a -shallow trough containing the developing solution. Development -complete, the reel is lifted from its supports and suspended over a -succession of other troughs for washing, fixing, and final washing. -When dry the negative film is passed through a special printing frame -in contact with another film, which receives the positive image for -the biograph. The difficulty of handling such films will be -appreciated to a certain extent even by those whose experience is -confined to the snaky behaviour of a short Kodak reel during -development. - -The Mutoscope Company's organisation is as perfect as its machinery. -It has representatives in all parts of the world. Wherever stirring -events are taking place, whether in peace or war, a mutograph operator -will soon be on the spot with his heavy apparatus to secure pictures -for world-wide exhibition. It need hardly be said that great -obstacles, human and physical, have often to be overcome before a film -can be exposed; and considerable personal danger encountered. We read -that an operator, despatched to Cuba during the Spanish-American War -was left three days and nights without food or water to guard his -precious instruments, the party that had landed him having suddenly -put to sea on sighting a Spanish cruiser. Another is reported to have -had a narrow escape from being captured at sea by the Spaniards after -a hot chase. It is also on record that a mutograph set up in Atlantic -City to take a procession of fire-engines was charged and shattered by -one of the engines; that the operators were flung into the crowd: and -that nevertheless the box containing the exposed films was uninjured, -and on development yielded a very sensational series of pictures -lasting to the moment of collision. - -The Mutoscope Company owns several thousand series of views, none -probably more valuable than those of his Holiness the Pope, who -graciously gave Mr. W. K. Dickson five special sittings, during which -no less than 17,000 negatives were made, each one of great interest to -millions of people throughout the world. - -The company spares neither time nor money in its endeavour to supply -the public with what will prove acceptable. A year's output runs into -a couple of hundred miles of film. As much as 700 feet is sometimes -expended on a single series, which may be worth anything up to £1000. - -The energy displayed by the operators is often marvellous. To take -instances. The Derby of 1898 was run at 3.20 P.M. At ten o'clock the -race was run again by Biograph on the great sheet at the Palace -Theatre. On the home-coming of Lord Kitchener from the Soudan -Campaign, a series of photographs was taken at Dover in the afternoon -and exhibited the same evening! Or again, to consider a wider sphere -of action, the Jubilee Procession of 1897 was watched in New York ten -days after the event; two days later in Chicago; and in three more the -films were attracting large audiences in San Francisco, 5000 miles -from the actual scene of the procession! - -One may easily weary of a series of single views passed slowly through -a magic-lantern at a lecture or entertainment. But when the Biograph -is flashing its records at lightning speed there is no cause for -dullness. It is impossible to escape from the fascination of -_movement_. A single photograph gives the impression of mere -resemblance to the original; but a series, each reinforcing the -signification of the last, breathes life into the dead image, and -deludes us into the belief that we see, not the representation of a -thing, but the thing itself. The bill of fare provided by the Biograph -Company is varied enough to suit the most fastidious taste. Now it is -the great Naval Review off Spithead, or President Faure shooting -pheasants on his preserves near Paris. A moment's pause and then the -magnificent Falls of Niagara foam across the sheet; Maxim guns fire -harmlessly; panoramic scenes taken from locomotives running at high -velocity unfold themselves to the delighted spectators, who feel as if -they really were speeding over open country, among towering rocks, or -plunging into the darkness of a tunnel. Here is an express approaching -with all the quiver and fuss of real motion, so faithfully rendered -that it seems as if a catastrophe were imminent; when, snap! we are -transported a hundred miles to watch it glide into a station. The -doors open, passengers step out and shake hands with friends, porters -bustle about after luggage, doors are slammed again, the guard waves -his flag, and the carriages move slowly out of the picture. Then our -attention is switched away to the 10-inch disappearing gun, landing -and firing at Sandy Hook. And next, as though to show that nothing is -beneath the notice of the biograph, we are perhaps introduced to a -family of small pigs feeding from a trough with porcine earnestness -and want of manners. - -It must not be thought that the Living Picture caters for mere -entertainment only. It serves some very practical and useful ends. By -its aid the movements of machinery and the human muscles may be -studied in detail, to aid a mechanical or medical education. It -furnishes art schools with all the poses of a living model. Less -serious pursuits, such as dancing, boxing, wrestling and all athletic -sports and exercise, will find a use for it. As an advertising medium -it stands unrivalled, and we shall owe it a deep debt of gratitude if -it ultimately supplants the flaring posters that disfigure our towns -and desecrate our landscapes. Not so long since, the directors of the -Norddeutscher-Lloyd Steamship Company hired the biograph at the -Palace Theatre, London, to demonstrate to anybody who cared to witness -a very interesting exhibition that their line of vessels should always -be used for a journey between England and America. - -The Living Picture has even been impressed into the service of the -British Empire to promote emigration to the Colonies. Three years ago -Mr. Freer exhibited at the Imperial Institute and in other places in -England a series of films representing the 1897 harvest in Manitoba. -Would-be emigrants were able to satisfy themselves that the great -Canadian plains were fruitful not only on paper. For could they not -see with their own eyes the stately procession of automatic "binders" -reaping, binding, and delivering sheaves of wheat, and puffing engines -threshing out the grain ready for market? A far preferable method this -to the bogus descriptions of land companies such as lured poor -Chuzzlewit and Mark Tapley into the deadly swamps of "Eden." - -Again, what more calculated to recruit boys for our warships than the -fine Polytechnic exhibition known as "Our Navy"? What words, spoken or -printed, could have the effect of a series of vivid scenes truthfully -rendered, of drills on board ship, the manning and firing of big guns, -the limbering-up of smaller guns, the discharge of torpedoes, the -headlong rush of the "destroyers"? - -The Mutoscope, to which reference has been made above, may be found in -most places of public entertainment, in refreshment bars, on piers, -in exhibitions, on promenades. A penny dropped into a slot releases a -handle, the turning of which brings a series of pictures under -inspection. The pictures, enlarged from mutograph films, are mounted -in consecutive order round a cylinder, standing out like the leaves of -a book. When the cylinder is revolved by means of the handle the -picture cards are snapped past the eye, giving an effect similar to -the lifelike projections on a biograph screen. From 900 to 1000 -pictures are mounted on a cylinder. - -The advantages of the mutoscope--its convenient size, its simplicity, -and the ease with which its contents may be changed to illustrate the -topics and events of the day--have made the animated photograph -extremely popular. It does for vision what the phonograph does for -sound. In a short time we shall doubtless be provided with handy -machines combining the two functions and giving us double value for -our penny. - -The real importance and value of animated photography will be more -easily estimated a few years hence than to-day, when it is still more -or less of a novelty. The multiplication of illustrated newspapers and -magazines points to a general desire for pictorial matter to help down -the daily, weekly, or monthly budget of news, even if the -illustrations be imaginative products of Fleet Street rather than -faithful to fact. The reliable living picture (we expect the -"set-scene") which "holds up a mirror to nature," will be a companion -rather than a rival of journalism, following hard on the description -in print of an event that has taken place under the eye of the -recording camera. The zest with which we have watched during the last -two years biographic views of the embarkation and disembarkation of -troops, of the transport of big guns through drifts and difficult -country, and of the other circumstances of war, is largely due to the -descriptions we have already read of the things that we see on the -screen. And, on the other hand, the impression left by a series of -animated views will dwell in our memories long after the contents of -the newspaper columns have become confused and jumbled. It is -therefore especially to be hoped that photographic records will be -kept of historic events, such as the Jubilee, the Queen's Funeral, -King Edward's Coronation, so that future generations may, by the -turning of a handle, be brought face to face with the great doings of -a bygone age. - - - - -THE GREAT PARIS TELESCOPE - - -A telescope so powerful that it brings the moon apparently to within -thirty-five miles of the earth; so long that many a cricketer could -not throw a ball from one end of it to the other; so heavy that it -would by itself make a respectable load for a goods train; so -expensive that astronomically-inclined millionaires might well -hesitate to order a similar one for their private use. - -Such is the huge Paris telescope that in 1900 delighted thousands of -visitors in the French Exposition, where, among the many wonderful -sights to be seen on all sides, it probably attracted more notice than -any other exhibit. This triumph of scientific engineering and dogged -perseverance in the face of great difficulties owes its being to a -suggestion made in 1894 to a group of French astronomers by M. -Deloncle. He proposed to bring astronomy to the front at the coming -Exposition, and to effect this by building a refracting telescope that -in size and power should completely eclipse all existing instruments -and add a new chapter to the "story of the heavens." - -To the mind unversed in astronomy the telescope appeals by the -magnitude of its dimensions, in the same way as do the Forth Bridge, -the Eiffel Tower, the Big Wheel, the statue of Liberty near New York -harbour, the Pyramids, and most human-made "biggest on records." - -At the time of M. Deloncle's proposal the largest refracting telescope -was the Yerkes' at William's Bay, Wisconsin, with an object-glass -forty inches in diameter; and next to it the 36-inch Lick instrument -on Mount Hamilton, California, built by Messrs. Alvan Clark of -Cambridgeport, Massachusetts. Among reflecting telescopes the prior -place is still held by Lord Rosse's, set up on the lawn of Birr Castle -half a century ago. Its speculum, or mirror, weighing three tons, lies -at the lower end of a tube six feet across and sixty feet long. This -huge reflector, being mounted in meridian, moves only in a vertical -direction. A refracting telescope is one of the ordinary pocket type, -having an object-lens at one end and an eyepiece at the other. A -reflector, on the other hand, has no object-lens, its place being -taken by a mirror that gathers the rays entering the tube and reflects -them back into the eyepiece, which is situated nearer the mouth end of -the tube than the mirror itself. - -Each system has its peculiar disadvantages. In reflectors the image is -more or less distorted by "spherical aberration." In refractors the -image is approximately perfect in shape, but liable to "chromatic -aberration," a phenomenon especially noticeable in cheap telescopes -and field-glasses, which often show objects fringed with some of the -colours of the spectrum. This defect arises from the different -refrangibility of different light rays. Thus, violet rays come to a -focus at a shorter distance from the lens than red rays, and when one -set is in focus to the eye the other must be out of focus. In -carefully-made and expensive instruments compound lenses are used, -which by the employment of different kinds of glass bring all the -colours to practically the same focus, and so do away with chromatic -aberration. - -To reduce colour troubles to a _minimum_ M. Deloncle proposed that the -object-lens should have a focal distance of about two hundred feet, -since a long focus is more easily corrected than a short one, and a -diameter of over fifty-nine inches. The need for so huge a lens arises -out of the optical principles of a refractor. The rays from an -object--a star, for instance--strike the object-glass at the near end, -and are bent by it into a converging beam, till they all meet at the -focus. Behind the focus they again separate, and are caught by the -eyepiece, which reduces them to a parallel beam small enough to enter -the pupil. We thus see that though the unaided eye gathers only the -few rays that fall directly from the object on to the pupil, when -helped by the telescope it receives the concentrated rays falling on -the whole area of the object-glass; and it would be sensible of a -greatly increased brightness had not this light to be redistributed -over the image, which is the object magnified by the eyepiece. -Assuming the aperture of the pupil to be one-tenth of an inch, and -the object to be magnified a hundred times, the object-lens should -have a hundred times the diameter of the pupil to render the image as -bright as the object itself. If the lens be five instead of ten inches -across, a great loss of light results, as in the high powers of a -microscope, and the image loses in distinctness what it gains in size. - -As M. Deloncle meant his telescope to beat all records in respect of -magnification, he had no choice but to make a lens that should give -proportionate illumination, and itself be of unprecedented size. - -At first M. Deloncle met with considerable opposition and ridicule. -Such a scheme as his was declared to be beyond accomplishment. But in -spite of many prophecies of ultimate failure he set to work, -entrusting the construction of the various portions of his colossal -telescope to well-tried experts. To M. Gautier was given the task of -making all the mechanical parts of the apparatus; to M. Mantois the -casting of the giant lenses; to M. Despret the casting of the huge -mirror, to which reference will be made immediately. - -The first difficulty to be encountered arose from the sheer size of -the instrument. It was evidently impossible to mount such a leviathan -in the ordinary way. A tube, 180 feet long, could not be made rigid -enough to move about and yet permit careful observation of the stars. -Even supposing that it were satisfactorily mounted on an "equatorial -foot" like smaller glasses, how could it be protected from wind and -weather? To cover it, a mighty dome, two hundred feet or more in -diameter, would be required; a dome exceeding by over seventy feet the -cupola of St. Peter's, Rome; and this dome must revolve easily on its -base at a pace of about fifty feet an hour, so that the telescope -might follow the motion of the heavenly bodies. - -The constructors therefore decided to abandon any idea of making a -telescope that could be moved about and pointed in any desired -direction. The alternative course open to them was to fix the -telescope itself rigidly in position, and to bring the stars within -its field by means of a mirror mounted on a massive iron frame--the -two together technically called a siderostat. The mirror and its -support would be driven by clockwork at the proper sidereal rate. The -siderostat principle had been employed as early as the eighteenth -century, and perfected in recent years by Léon Foucault, so that in -having recourse to it the builders of the telescope were not -committing themselves to any untried device. - -In days when the handling of masses of iron, and the erection of huge -metal constructions have become matters of everyday engineering life, -no peculiar difficulty presented itself in connection with the -metal-work of the telescope. The greatest possible care was of course -observed in every particular. All joints and bearings were adjusted -with an extraordinary accuracy; and all the cylindrical moving parts -of the siderostat verified till they did not vary from perfect -cylindricity by so much as one twenty-five-thousandth of an inch! - -The tube of the telescope, 180 feet long, consisted of twenty-four -sections, fifty-nine inches in diameter, bolted together and supported -on seven massive iron pillars. It weighed twenty-one tons. The -siderostat, twenty-seven feet high, and as many in length, weighed -forty-five tons. The lower portion, which was fixed firmly on a bed of -concrete, had on the top a tank filled with quicksilver, in which the -mirror and its frame floated. The quicksilver supported nine-tenths of -the weight, the rest being taken by the levers used to move the -mirror. Though the total weight of the mirror and frame was thirteen -tons, the quicksilver offered so little resistance that a pull of a -few pounds sufficed to rotate the entire mass. - -The real romance of the construction of this huge telescope centres on -the making of the lenses and mirror. First-class lenses for all -photographic and optical purposes command a very high price on account -of the care and labour that has to be expended on their production; -the value of the glass being trifling by comparison. Few, if any, -trades require greater mechanical skill than that of lensmaking; the -larger the lens the greater the difficulties it presents, first in the -casting, then in the grinding, last of all in the polishing. The -presence of a single air-bubble in the molten glass, the slightest -irregularity of surface in the polishing may utterly destroy the -value of a lens otherwise worth several thousands of pounds. - -[Illustration: _Reproduced by the permission of Proprietors of -"Knowledge."_ - -_General view, of the Great Paris Telescope, showing the eye-end. The -tube is 180 feet long, and 59 inches in diameter. It weighs 21 tons._] - -The object-glass of the great telescope was cast by M. Mantois, famous -as the manufacturer of large lenses. The glass used was boiled and -reboiled many times to get rid of all bubbles. Then it was run into a -mould and allowed to cool very gradually. A whole month elapsed before -the breaking of a mould, when the lens often proved to be cracked on -the surface, owing to the exterior having cooled faster than the -interior and parted company with it. At last, however, a perfect cast -resulted. - -M. Despret undertook the even more formidable task of casting the -mirror at his works at Jeumont, North France. A special furnace and -oven, capable of containing over fifteen tons of molten glass, had to -be constructed. The mirror, 6-1/2 feet in diameter and eleven inches -thick, absorbed 3-3/4 tons of liquid glass; and so great was the -difficulty of cooling it gradually, that out of the twenty casts -eighteen were failures. - -The rough lenses and mirror having been ground to approximate -correctness in the ordinary way, there arose the question of -polishing, which is generally done by one of the most sensitive and -perfect instruments existing-the human hand. In this case, owing to -the enormous size of the objects to be treated, hand work would not -do. The mere hot touch of a workman would raise on the glass a tiny -protuberance, which would be worn level with the rest of the surface -by the polisher, and on the cooling of the part would leave a -depression, only 1-75,000 of an inch deep, perhaps, but sufficient to -produce distortion, and require that the lens should be ground down -again, and the whole surface polished afresh. - -M. Gautier therefore polished by machinery. It proved a very difficult -process altogether, on account of frictional heating, the rise of -temperature in the polishing room, and the presence of dust. To insure -success it was found necessary to warm all the polishing machinery, -and to keep it at a fixed temperature. - -At the end of almost a year the polishing was finished, after the -lenses and mirror had been subjected to the most searching tests, able -to detect irregularities not exceeding 1-250,000 of an inch. M. -Gautier applied to the mirror M. Foucault's test, which is worth -mentioning. A point of light thrown by the mirror is focused through a -telescope. The eyepiece is then moved inwards and outwards so as to -throw the point out of focus. If the point becomes a luminous circle -surrounded by concentric rings, the surface throwing the light point -is perfectly plane or smooth. If, however, a pushing-in shows a -vertical flattening of the point, and a pulling-out a horizontal -flattening, that part is concave; if the reverse happens, convexity is -the cause. - -For the removal of the mirror from Jeumont to Paris a special train -was engaged, and precautions were taken rivalling those by which -travelling Royalty is guarded. The train ran at night without -stopping, and at a constant pace, so that the vibration of the glass -atoms might not vary. On arriving at Paris, the mirror was transferred -to a ponderous waggon, and escorted by a body of men to the Exposition -buildings. The huge object-lens received equally careful treatment. - -The telescope was housed at the Exhibition in a long gallery pointing -due north and south, the siderostat at the north end. At the other, -the eyepiece, end, a large amphitheatre accommodated the public -assembled to watch the projection of stellar or lunar images on to a -screen thirty feet high, while a lecturer explained what was visible -from time to time. The images of the sun and moon as they appeared at -the primary focus in the eyepiece measured from twenty-one to -twenty-two inches in diameter, and the screen projections were -magnified from these about thirty times superficially. - -The eyepiece section consisted of a short tube, of the same breadth as -the main tube, resting on four wheels that travelled along rails. -Special gearing moved this truck-like construction backwards and -forwards to bring a sharp focus into the eyepiece or on to a -photographic plate. Focusing was thus easy enough when once the -desired object came in view; but the observer being unable to control -the siderostat, 250 feet distant, had to telephone directions to an -assistant stationed near the mirror whenever he wished to examine an -object not in the field of vision. - -By the courtesy of the proprietors of the _Strand_ _Magazine_ we are -allowed to quote M. Deloncle's own words describing his emotions on -his first view through the giant telescope:-- - -"As is invariably the case, whenever an innovation that sets at nought -old-established theories is brought forward, the prophecies of failure -were many and loud, and I had more than a suspicion that my success -would cause less satisfaction to others than to myself. Better than -any one else I myself was cognisant of the unpropitious conditions in -which my instrument had to work. The proximity of the river, the dust -raised by hundreds of thousands of trampling feet, the trepidation of -the soil, the working of the machinery, the changes of temperature, -the glare from the thousands of electric lamps in close -proximity--each of these circumstances, and many others of a more -technical nature, which it would be tedious to enumerate, but which -were no less important, would have been more than sufficient to make -any astronomer despair of success even in observatories where all the -surroundings are chosen with the utmost care. - -"In regions pure of calm and serene air large new instruments take -months, more often years, to regulate properly. - -"In spite of everything, however, I still felt confident. Our -calculations had been gone over again and again, and I could see -nothing that in my opinion warranted the worst apprehensions of my -kind critics. - -"It was with ill-restrained impatience that I waited for the first -night when the moon should show herself in a suitable position for -being observed; but the night arrived in due course. - -"Everything was in readiness. The movable portion of the roof of the -building had been slid back, and the mirror of the siderostat stood -bared to the sky. - -"In the dark, square chamber at the other end of the instrument, 200 -feet away, into which the eyepiece of the instrument opened, I had -taken my station with two or three friends. An attendant at the -telephone stood waiting at my elbow to transmit my orders to his -colleague in charge of the levers that regulated the siderostat and -its mirror. - -"The moon had risen now, and her silvery glory shone and sparkled in -the mirror. - -"'A right declension,' I ordered. - -"The telephone bell rang in reply. 'Slowly, still slower; now to the -left--enough; again a right declension--slower; stop now--very, very -slowly.' - -"On the ground-glass before our eyes the moon's image crept up from -one corner until it had overspread the glass completely. And there we -stood in the centre of Paris, examining the surface of our satellite -with all its craters and valleys and bleak desolation. - -"I had won the day." - - - - -PHOTOGRAPHING THE INVISIBLE. - - -Most of us are able to recognise when we see them shadowgraphs taken -by the aid of the now famous X-rays. They generally represent some -part of the structure of men, beasts, birds, or fishes. Very dark -patches show the position of the bones, large and small; lighter -patches the more solid muscles clinging to the bony framework; and -outside these again are shadowy tracts corresponding to the thinnest -and most transparent portions of the fleshy envelope. - -In an age fruitful as this in scientific marvels, it often takes some -considerable time for the public to grasp the full importance of a -fresh discovery. But when, in 1896, it was announced that Professor -Röntgen of Würzburg had actually taken photographs of the internal -organs of still living creatures, and penetrated metal and other -opaque substances with a new kind of ray, great interest was -manifested throughout the civilised world. On the one hand the "new -photography" seemed to upset popular ideas of opacity; on the other it -savoured strongly of the black art, and, by its easy excursions -through the human body, seemed likely to revolutionise medical and -surgical methods. At first many strange ideas about the X-rays got -afloat, attributing to them powers which would have surprised even -their modest discoverer. It was also thought that the records were -made in a camera after the ordinary manner of photography, but as a -matter of fact Röntgen used neither lens nor camera, the operation -being similar to that of casting a shadow on a wall by means of a -lamp. In X-radiography a specially constructed electrically-lit glass -tube takes the place of the lamp, and for the wall is substituted a -sensitised plate. The object to be radiographed is merely inserted -between them, its various parts offering varying resistance to the -rays, so that the plate is affected unequally, and after exposure may -be developed and printed from it the usual way. Photographs obtained -by using X-rays are therefore properly called shadowgraphs or -skiagraphs. - -The discovery that has made Professor Röntgen famous is, like many -great discoveries, based upon the labours of other men in the same -field. Geissler, whose vacuum tubes are so well known for their -striking colour effects, had already noticed that electric discharges -sent through very much rarefied air or gases produced beautiful glows. -Sir William Crookes, following the same line of research, and reducing -with a Sprengel air-pump the internal pressure of the tubes to -1/100000 of an atmosphere, found that a luminous glow streamed from -the cathode, or negative pole, in a straight line, heating and -rendering phosphorescent anything that it met. Crookes regarded the -glow as composed of "radiant matter," and explained its existence as -follows. The airy particles inside the tube, being few in number, are -able to move about with far greater freedom than in the tightly packed -atmosphere outside the tube. A particle, on reaching the cathode, is -repelled violently by it in a straight line, to "bombard" another -particle, the walls of the tube, or any object set up in its path, the -sudden arrest of motion being converted into light and heat. - -By means of special tubes he proved that the "radiant matter" could -turn little vanes, and that the flow continued even when the terminals -of the shocking-coil were _outside_ the glass, thus meeting the -contention of Puluj that the radiant matter was nothing more than -small particles of platinum torn from the terminals. He also showed -that, when intercepted, radiant matter cast a shadow, the intercepting -object receiving the energy of the bombardment; but that when the -obstruction was removed the hitherto sheltered part of the glass wall -of the tube glowed with a brighter phosphorescence than the part which -had become "tired" by prolonged bombardment. Experiments further -revealed the fact that the shaft of "Cathode rays" could be deflected -by a magnet from their course, and that they affected an ordinary -photographic plate exposed to them. - -In 1894 Lenard, a Hungarian, and pupil of the famous Hertz, fitted a -Crookes' tube with a "window" of aluminium in its side replacing a -part of the glass, and saw that the course of the rays could be -traced through the outside air. From this it was evident that -something else than matter must be present in the shaft of energy sent -from the negative terminal of the tube, as there was no direct -communication between the interior and the exterior of the tube to -account for the external phosphorescence. Whatever was the nature of -the rays he succeeded in making them penetrate and impress themselves -on a sensitised plate enclosed in a metal box. - -Then in 1896 came Röntgen's great discovery that the rays from a -Crookes' tube, after traversing the _glass_, could pierce opaque -matter. He covered the tube with thick cardboard, but found that it -would still cast the shadows of books, cards, wood, metals, the human -hand, &c., on to a photographic plate even at the distance of some -feet. The rays would also pass through the wood, metal, or bones in -course of time; but certain bodies, notably metals, offered a much -greater resistance than others, such as wood, leather, and paper. -Professor Röntgen crowned his efforts by showing that a skeleton could -be "shadow-graphed" while its owner was still alive. - -Naturally everybody wished to know not only what the rays could do, -but what they were. Röntgen, not being able to identify them with any -known rays, took refuge in the algebraical symbol of the unknown -quantity and dubbed them X-rays. He discovered this much, however, -that they were invisible to the eye under ordinary conditions; that -they travelled in straight lines only, passing through a prism, water, -or other refracting bodies without turning aside from their path; and -that a magnet exerted no power over them. This last fact was -sufficient of itself to prevent their confusion with the radiant -matter "cathode rays" of the tube. Röntgen thought, nevertheless, that -they might be the cathode rays transmuted in some manner by their -passage through the glass, so as to resemble in their motion -sound-waves, _i.e._ moving straight forward and not swaying from side -to side in a series of zig-zags. The existence of such ether waves had -for some time before been suspected by Lord Kelvin. - -Other authorities have other theories. We may mention the view that X -represents the ultra-violet rays of the spectrum, caused by vibrations -of such extreme rapidity as to be imperceptible to the human eye, just -as sounds of extremely high pitch are inaudible to the ear. This -theory is to a certain extent upheld by the behaviour of the -photographic plate, which is least affected by the colours of the -spectrum at the red end and most by those at the violet end. A -photographer is able to use red or orange light in his dark room -because his plates cannot "see" them, though he can; whereas the -reverse would be the case with X-rays. This ultra-violet theory claims -for X-rays a rate of ether vibration of trillions of waves per -second. - -An alternative theory is to relegate the rays to the gap in the scale -of ether-waves between heatwaves and light-waves. But this does not -explain any more satisfactorily than the other the peculiar phenomenon -of non-refraction. - -The apparatus employed in X-photography consists of a Crookes' tube of -a special type, a powerful shocking or induction coil, a fluorescent -screen and photographic plates and appliances for developing, &c., -besides a supply of high-pressure electricity derived from the main, a -small dynamo or batteries. - -A Crookes' tube is four to five inches in diameter, globular in its -middle portion, but tapering away towards each end. Through one -extremity is led a platinum wire, terminating in a saucer-shaped -platinum plate an inch or so across. At the focus of this, the -negative terminal, is fixed a platinum plate at an angle to the path -of the rays so as to deflect them through the side of the tube. The -positive terminal penetrates the glass at one side. The tube contains, -as we have seen, a very tiny residue of air. If this were entirely -exhausted the action of the tube would cease; so that some tubes are -so arranged that when rarefaction becomes too high the passage of an -electrical current through small bars of chemicals, whose ends project -through the sides of the tube, liberates gas from the bars in -sufficient quantity to render the tube active again. - -When the Ruhmkorff induction coil is joined to the electric circuit a -series of violent discharges of great rapidity occur between the tube -terminals, resembling in their power the discharge of a Leyden jar, -though for want of a dense atmosphere the brilliant spark has been -replaced by a glow and brush-light in the tube. The coil is of large -dimensions, capable of passing a spark across an air-gap of ten to -twelve inches. It will perhaps increase the reader's respect for -X-rays to learn that a coil of proper size contains upwards of -thirteen miles of wire; though indeed this quantity is nothing in -comparison with the 150 miles wound on the huge inductorium formerly -exhibited at the London Polytechnic. - -If we were invited to an X-ray demonstration we should find the -operator and his apparatus in a darkened room. He turns on the current -and the darkness is broken by a velvety glow surrounding the negative -terminal, which gradually extends until the whole tube becomes clothed -in a green phosphorescence. A sharply-defined line athwart the tube -separates the shadowed part behind the receiving plate at the negative -focus--now intensely hot--from that on which the reflected rays fall -directly. - -One of us is now invited to extend a hand close to the tube. The -operator then holds on the near side of the hand his fluorescent -screen, which is nothing more than a framework supporting a paper -smeared on one side with platino-cyanide of barium, a chemical that, -in common with several others, was discovered by Salvioni of Perugia -to be sensitive to the rays and able to make them visible to the human -eye. The value of the screen to the X-radiographer is that of the -ground-glass plate to the ordinary photographer, as it allows him to -see exactly what things are before the sensitised plate is brought -into position, and in fact largely obviates the necessity for making a -permanent record. - -The screen shows clearly and in full detail all the bones of the -hand--so clearly that one is almost irresistibly drawn to peep behind -to see if a real hand is there. One of us now extends an arm and the -screen shows us the _ulna_ and the _radius_ working round each other, -now both visible, now one obscuring the other. On presenting the body -to the course of the rays a remarkable shadow is cast on to the -screen. The spinal column and the ribs; the action of the heart and -lungs are seen quite distinctly. A deep breath causes the movement of -a dark mass--the liver. There is no privacy in presence of the rays. -The enlarged heart, the diseased lung, the ulcerated liver betrays -itself at once. In a second of time the phosphorescent screen reveals -what might baulk medical examination for months. - -If a photographic slide containing a dry-plate be substituted for the -focusing-screen, the rays soon penetrate any covering in which the -plate may be wrapped to protect it from ordinary light rays. The -process of taking a shadowgraph may therefore be conducted in broad -daylight, which is under certain conditions a great advantage, though -the sensitiveness of plates exposed to Röntgen rays entails special -care being taken of them when they are not in use. In the early days -of X-radiography an exposure of some minutes was necessary to secure a -negative, but now, thanks to the improvements in the tubes, a few -seconds is often sufficient. - -The discovery of the X-rays is a great discovery, because it has done -much to promote the noblest possible cause, the alleviation of human -suffering. Not everybody will appreciate a more rapid mode of -telegraphy, or a new method of spinning yarn, but the dullest -intellect will give due credit to a scientific process that helps to -save life and limb. Who among us is not liable to break an arm or leg, -or suffer from internal injuries invisible to the eye? Who among us -therefore should not be thankful on reflecting that, in event of such -a mishap, the X-rays will be at hand to show just what the trouble is, -how to deal with it, and how far the healing advances day by day? The -X-ray apparatus is now as necessary for the proper equipment of a -hospital as a camera for that of a photographic studio. - -It is especially welcome in the hospitals which accompany an army into -the field. Since May 1896 many a wounded soldier has had reason to -bless the patient work that led to the discovery at Würzburg. The -Greek war, the war in Cuba, the Tirah campaign, the Egyptian campaign, -and the war in South Africa, have given a quick succession of fine -opportunities for putting the new photography to the test. There is -now small excuse for the useless and agonising probings that once -added to the dangers and horrors of the military hospital. Even if the -X-ray equipment, by reason of its weight, cannot conveniently be kept -at the front of a rapidly moving army, it can be set up in the -"advanced" or "base" hospitals, whither the wounded are sent after a -first rough dressing of their injuries. The medical staff there -subject their patients to the searching rays, are able to record the -exact position of a bullet or shell-fragment, and the damage it has -done; and by promptly removing the intruder to greatly lessen its -power to harm. - -The Röntgen ray has added to the surgeon's armoury a powerful weapon. -Its possibilities are not yet fully known, but there can be no doubt -that it marks a new epoch in surgical work. And for this reason -Professor Röntgen deserves to rank with Harvey, the discoverer of the -blood's circulation; with Jenner, the father of vaccination; and with -Sir James Young Simpson, the first doctor to use chloroform as an -anæsthetic. - - -PHOTOGRAPHY IN THE DARK. - -Strange as it seems to take photographs with invisible rays, it is -still stranger to be able to affect sensitised plates without -apparently the presence of any kind of rays. - -Professor W. J. Russell, Vice-President of the Royal Society of -London, has discovered that many substances have the power of -impressing their outlines automatically on a sensitive film, if the -substance be placed in a dark cupboard in contact with, or very close -to a dry-plate. - -After some hours, or it may be days, development of the plate will -reveal a distinct impression of the body in question. Dr. Russell -experimented with wood, metal, leaves, drawings, printed matter, lace. -Zinc proved to be an unusually active agent. A plate of the metal, -highly polished and then ruled with patterns, had at the end of a few -days imparted a record of every scratch and mark to the plate. And not -only will zinc impress itself, but it affects substances which are not -themselves active, throwing shadowgraphs on to the plate. This was -demonstrated with samples of lace, laid between a plate and a small -sheet of bright zinc; also with a skeleton leaf. It is curious that -while the interposition of thin films of celluloid, gutta-percha, -vegetable parchment, and gold-beater's skin--all inactive--between the -zinc and the plate has no obstructive effect, a plate of thin glass -counteracts the action of the zinc. Besides zinc, nickel, aluminium, -pewter, lead, and tin among the metals influence a sensitised plate. -Another totally different substance, printer's ink, has a similar -power; or at least some printer's ink, for Professor Russell found -that different samples varied greatly in their effects. What is -especially curious, the printed matter on _both sides_ of a piece of -newspaper appeared on the plate, and that the effect proceeded from -the ink and not from any rays passing from beyond it is proved by the -fact that the type came out _dark_ in the development, whereas if it -had been a case of shadowgraphy, the ink by intercepting rays would -have produced _white_ letters. Professor Russell has also shown that -modern writing ink is incapable of producing an impression unaided, -but that on the other hand paper written on a hundred years ago or a -printed book centuries old will, with the help of zinc, yield a -picture in which even faded and uncertain characters appear quite -distinctly. This opens the way to a practical use of the discovery, in -the deciphering of old and partly obliterated manuscripts. - -A very interesting experiment may be made with that useful -possession--a five-pound note. Place the note printed side next to the -plate, and the printing appears dark; but insert the note between a -zinc sheet and the plate, its back being this time towards the -sensitised surface, and the printing appears _white_; and the zinc, -after contact with the printed side, will itself yield a picture of -the inscription as though it had absorbed some virtue from the note! - -As explanation of this paradoxical dark photography--or whatever it -is--two theories may be advanced. The one--favoured by Professor -Russell--is that all "active" substances give off _vapours_ able to -act on a photographic plate. In support of this may be urged the fact -that the interposition of glass prevents the making of dark pictures. -But on the other hand it must be remembered that celluloid and -sheet-gelatine, also air-tight substances, are able to store up light -and to give it out again. It is well known among photographers that to -allow sunlight to fall on the inside of a camera is apt to have a -"fogging" effect on a plate that is exposed in the camera afterwards, -though the greatest care be taken to keep all external light from the -plate. But here the glass again presents a difficulty, for if this -were a case of reflected light, glass would evidently be _less_ -obstructive than opaque vegetable parchment or gutta-percha. - - - - -SOLAR MOTORS. - - -One day George Stephenson and a friend stood watching a train drawn by -one of his locomotives. - -"What moves that train?" asked Stephenson. - -"The engine," replied his friend. - -"And what moves the engine?" - -"The steam." - -"And what produces the steam?" - -"Coal." - -"And what produces coal?" - -This last query nonplussed his friend, and Stephenson himself replied, -"The sun." - -The "bottled sunshine" that drove the locomotive was stored up -millions of years ago in the dense forests then covering the face of -the globe. Every day vegetation was built by the sunbeams, and in the -course of ages this growth was crushed into fossil form by the -pressure of high-piled rock and débris. To-day we cast "black -diamonds" into our grates and furnaces, to call out the warmth and -power that is a legacy from a period long prior to the advent of -fire-loving man, often forgetful of its real source. - -We see the influence of the sun more directly in the motions of wind -and water. Had not the sun's action deposited snow and rain on the -uplands of the world, there would be no roaring waterfall, no rushing -torrent, no smooth-flowing stream. But for the sun heating the -atmosphere unequally, there would not be that rushing of cool air to -replace hot which we know as wind. - -We press Sol into our service when we burn fuel; our wind-mills and -water-mills make him our slave. Of late years many prophets have -arisen to warn us that we must not be too lavish of our coal; that the -time is not so far distant, reckoning by centuries, when the -coal-seams of the world will be worked out and leave our descendants -destitute of what plays so important a part in modern life. Now, -though waste is unpardonable, and the care for posterity praiseworthy, -there really seems to be no good reason why we should alarm ourselves -about the welfare of the people of the far future. Even if coal fails, -the winds and the rivers will be there, and the huge unharnessed -energy of the tides, and the sun himself is ready to answer appeals -for help, if rightly shaped. He does not demand the prayers of Persian -fire-worshippers, but rather the scientific gathering of his good -gifts. - -Place your hand on a roof lying square to the summer sun, and you will -find it too hot for the touch. Concentrate a beam of sunshine through -a small burning-glass. How fierce is the small glowing focal spot that -makes us draw our hands suddenly away! Suppose now a large glass many -feet across bending several square yards of sun rays to a point, and -at that point a boiler. The boiler would develop steam, and the steam -might be led into cylinders and forced to drudge for us. - -Do many of us realise the enormous energy of a hot summer's day? The -heat falling in the tropics on a single square foot of the earth's -surface has been estimated as the equivalent of one-third of a -horse-power. The force of Niagara itself would on this basis be -matched by the sunshine streaming on to a square mile or so. A -steamship might be propelled by the heat that scorches its decks. - -For many centuries inventors have tried to utilise this huge waste -power. We all know how, according to the story, Archimedes burnt up -the Roman ships besieging his native town, Syracuse, by concentrating -on them the sun heat cast from hundreds of mirrors. This story is less -probable than interesting as a proof that the ancients were aware of -the sun's power. The first genuine solar machine was the work of -Ericsson, the builder of the _Monitor_. He focused sun heat on a -boiler, which gave the equivalent of one horse-power for every hundred -square feet of mirrors employed. This was not what engineers would -call a "high efficiency," a great deal of heat being wasted, but it -led the way to further improvements. - -In America, especially in the dry, arid regions, where fuel is scarce -and the sun shines pitilessly day after day, all the year round, -sun-catchers of various types have been erected and worked -successfully. Dr. William Calver, of Washington, has built in the -barren wastes of Arizona huge frames of mirrors, travelling on -circular rails, so that they may be brought to face the sun at all -hours between sunrise and sunset. Dr. Calver employs no less than 1600 -mirrors. As each of these mirrors develops 10-15 degrees of heat it is -obvious, after an appeal to simple arithmetic, that the united efforts -of these reflectors should produce the tremendous temperature -16,000-24,000 degrees, which, expressed comparatively, means the -paltry 90 degrees in the shade beneath which we grow restive -multiplied hundreds of times. Hitherto the greatest known heat had -been that of the arc of the electric lamp, in which the incandescent -particles between pole and pole attain 6000 degrees Fahrenheit. - -The combined effect of the burning mirrors is irresistible. They can, -we are told, in a few moments reduce Russian iron to the consistency -of warmed wax, though it mocks the heat of many blast-furnaces. They -will bake bricks twenty times as rapidly as any kiln, and the bricks -produced are not the friable blocks which a mason chips easily with -his trowel, but bodies so hard as to scratch case-hardened steel. - -There are at work in California sun-motors of another design. The -reader must imagine a huge conical lamp-shade turned over on to its -smaller end, its inner surface lined with nearly 1800 mirrors 2 feet -long and 3 inches broad, the whole supported on a light iron -framework, and he will have a good idea of the apparatus used on the -Pasadena ostrich farm. The machine is arranged _in meridian_, that is, -at right angles to the path of the sun, which it follows all day long -by the agency of clockwork. In the focus of the mirrors is a boiler, -13 feet 6 inches long, coated with black, heat-absorbing substances. -This boiler holds over 100 gallons of water, and being fed -automatically will raise steam untended all the day through. The steam -is led by pipes to an engine working a pump, capable of delivering -1400 gallons per minute. - -The cheapness of the apparatus in proportion to its utility is so -marked that, in regions where sunshine is almost perpetual, the solar -motor will in time become as common as are windmills and factory -chimneys elsewhere. If the heat falling on a few square yards of -mirror lifts nearly 100,000 gallons of water an hour, there is indeed -hope for the Sahara, the Persian Desert, Arabia, Mongolia, Mexico, -Australia. That is to say, if the water under the earth be in these -parts as plentiful as the sunshine above it. The effect of water on -the most unpromising soil is marvellous. Already in Algeria the French -have reclaimed thousands of square miles by scientific irrigation. In -Australia huge artesian wells have made habitable for man and beast -millions of acres that were before desert. - -It is only a just retribution that the sun should be harnessed and -compelled to draw water for tracts to which he has so long denied it. -The sun-motor is only just entering on its useful career, and at -present we can but dream of the great effects it may have on future -civilisation. Yet its principle is so simple, so scientific, and so -obvious, that it is easy to imagine it at no far distant date a -dangerous rival to King Coal himself. To quarry coal from the bowels -of the earth and transform it into heat, is to traverse two sides of a -triangle, the third being to use the sunshine of the passing hour. - - - - -LIQUID AIR. - - -Among common phenomena few are more interesting than the changes -undergone by the substance called water. Its usual form is a liquid. -Under the influence of frost it becomes hard as iron, brittle as -glass. At the touch of fire it passes into unsubstantial vapour. - -This transformation illustrates the great principle that the form of -every substance in the universe is a question of heat. A metal -transported from the earth to the sun would first melt and then -vaporise; while what we here know only as vapours would in the moon -turn into liquids. - -We notice that, as regards bulk, the most striking change is from -liquid to gaseous form. In steam the atoms and molecules of water are -endowed with enormous repulsive vigour. Each atom suddenly shows a -huge distaste for the company of its neighbours, drives them off, and -endeavours to occupy the largest possible amount of private space. - -Now, though we are accustomed to see water-atoms thus stirred into an -activity which gives us the giant steam as servant, it has probably -fallen to the lot of but few of us to encounter certain gaseous -substances so utterly deprived of their self-assertiveness as to -collapse into a liquid mass, in which shape they are quite strangers -to us. What gaseous body do we know better than the air we breathe? -and what should we less expect to be reducible to the consistency of -water? Yet science has lately brought prominently into notice that -strange child of pressure and cold, Liquid Air; of which great things -are prophesied, and about which many strange facts may be told. - -Very likely our readers have sometimes noticed a porter uncoupling the -air-tube between two railway carriages. He first turns off the tap at -each end of the tube, and then by a twist disconnects a joint in the -centre. At the moment of disconnection what appears to be a small -cloud of steam issues from the joint. This is, however, the result of -cold, not heat, the tube being full of highly-compressed air, which by -its sudden expansion develops cold sufficient to freeze any particles -of moisture in the surrounding air. - -Keep this in mind, and also what happens when you inflate your -cycle-tyre. The air-pump grows hotter and hotter as inflation -proceeds: until at last, if of metal, it becomes uncomfortably warm. -The heat is caused by the forcing together of air-molecules, and -inasmuch as all force produces heat, your strength is transformed into -warmth. - -In these two operations, compression and expansion, we have the key to -the creation of liquid air--the great power, as some say, of -to-morrow. - -[Illustration: _By kind permission of The Liquid Air Co._ - -_A view of the Liquid Air Co.'s factory at Pimlico. On the left are -the three compressors, squeezing the air at pressures of 90, 500 and -2,200 lbs. to the square inch respectively. On the right is the -reservoir in which the liquid is stored._] - -Suppose we take a volume of air and squeeze it into 1/100 of its -original space. The combativeness of the air-atoms is immensely -increased. They pound each other frantically, and become very hot in -the process. Now, by cooling the vessel in which they are, we rob them -of their energy. They become quiet, but they are much closer than -before. Then imagine that all of a sudden we let them loose again. The -life is gone out of them, their heat has departed, and on separating -they shiver grievously. In other words, the heat contained by the -1/100 volume is suddenly compelled to "spread itself thin" over the -whole volume: result--intense cold. And if this air be brought to bear -upon a second vessel filled likewise with compressed air, the cold -will be even more intense, until at last the air-atoms lose all their -strength and collapse into a liquid. - -Liquid air is no new thing. Who first made it is uncertain. The credit -has been claimed for several people, among them Olzewski, a Pole, and -Pictet, a Swiss. As a mere laboratory experiment the manufacture of -liquid air in small quantities has been known for twenty years or -more. The earlier process was one of terrific compression alone, -actually forcing the air molecules by sheer strength into such close -contact that their antagonism to one another was temporarily overcome. -So expensive was the process that the first ounce of liquid air is -estimated to have cost over £600! - -In order to make liquid air an article of commerce the most important -condition was a wholesale decrease in cost of production. In 1857 C. -W. Siemens took out a patent for making the liquid on what is known as -the regenerative principle, whereby the compressed air is chilled by -expanding a part of it. Professor Dewar--a scientist well known for -his researches in the field of liquid gases--had in 1892 produced -liquid air by a modification of the principle at comparatively small -cost; and other inventors have since then still further reduced the -expense, until at the present day there appears to be a prospect of -liquid air becoming cheap enough to prove a dangerous rival to steam -and electricity. - -A company, known as the Liquid Air, Power and Automobile Company, has -established large plants in America and England for the manufacture of -the liquid on a commercial scale. The writer paid a visit to their -depot in Gillingham Street, London, where he was shown the process by -Mr. Hans Knudsen, the inventor of much of the machinery there used. -The reader will doubtless like to learn the "plain, unvarnished truth" -about the creation of this peculiar liquid, and to hear of the freaks -in which it indulges--if indeed those may be called freaks which are -but obedience to the unchanging laws of Nature. - -On entering the factory the first thing that strikes the eye and ear -is the monstrous fifty horse-power gas-engine, pounding away with an -energy that shakes the whole building. From its ponderous flywheels -great leather belts pass to the compressors, three in number, by which -the air, drawn from outside the building through special purifiers, is -subjected to an increasing pressure. Three dials on the wall show -exactly what is going on inside the compressors. The first stands at -90 lbs. to the square inch, the second at 500, and the third at 2200, -or rather less than a ton pressure on the area of a penny! The pistons -of the low-pressure compressor is ten inches in diameter, but that of -the high pressure only two inches, or 1/25 of the area, so great is -the resistance to be overcome in the last stage of compression. - -Now, if the cycle-pump heats our hands, it will be easily understood -that the temperature of the compressors is very high. They are -water-jacketed like the cylinders of a gas-engine, so that a -circulating stream of cold water may absorb some of the heat. The -compressed air is passed through spiral tubes winding through large -tanks of water which fairly boils from the fierceness of the heat of -compression. - -When the air has been sufficiently cooled it is allowed to pass into a -small chamber, expanding as it goes, and from the small into a larger -chamber, where the cold of expansion becomes so acute that the -air-molecules collapse into liquid, which collects in a special -receptacle. Arrangements are made whereby any vapour rising from the -liquid passes through a space outside the expansion chambers, so that -it helps to cool the incoming air and is not wasted. - -The liquid-air tank is inside a great wooden case, carefully protected -from the heat of the atmosphere by non-conducting substances. A tap -being turned, a rush of vapour shoots out, soon followed by a clear, -bluish liquid, which is the air we breathe in a fresh guise. - -A quantity of it is collected in a saucepan. It simmers at first, and -presently boils like water on a fire. The air-heat is _by comparison_ -so great that the liquid cannot resist it, and strives to regain its -former condition. - -You may dip your finger into the saucepan--if you withdraw it again -quickly--without hurt. The cushion of air that your finger takes in -with it protects you against harm--for a moment. But if you held it in -the liquid for a couple of seconds you would be minus a digit. Pour a -little over your coat sleeve. It flows harmlessly to the ground, where -it suddenly expands into a cloud of chilly vapour. - -Put some in a test tube and cork it up. The cork soon flies out with a -report--the pressure of the boiling air drives it. Now watch the -boiling process. The nitrogen being more volatile--as it boils at a -lower temperature than oxygen--passes off first, leaving the pure, -blue oxygen. The temperature of this liquid is over 312 degrees below -zero (as far below the temperature of the air we breathe as the -temperature of molten lead is above it!). A tumbler of liquid oxygen -dipped into water is soon covered with a coating of ice, which can be -detached from the tumbler and itself used as a cup to hold the liquid. -If a bit of steel wire be now twisted round a lighted match and the -whole dipped into the cup, the steel flares fiercely and fuses into -small pellets; which means that an operation requiring 3000 degrees -Fahrenheit has been accomplished in a liquid 300 degrees below zero! - -Liquid air has curious effects upon certain substances. It makes iron -so brittle that a ladle immersed for a few moments may be crushed in -the hands; but, curiously enough, it has a toughening effect on copper -and brass. Meat, eggs, fruit, and all bodies containing water become -hard as steel and as breakable as glass. Mercury is by it congealed to -the consistency of iron; even alcohol, that can brave the utmost -Arctic cold, succumbs to it. The writer was present when some -thermometers, manufactured by Messrs. Negretti and Zambra, were tested -with liquid air. The spirit in the tubes rapidly descended to 250 -degrees below zero, then sank slowly, and at about 260 degrees froze -and burst the bulb. The measuring of such extreme temperatures is a -very difficult matter in consequence of the inability of spirit to -withstand them, and special apparatus, registering cold by the -shrinkage of metal, must be used for testing some liquid gases, -notably liquid hydrogen, which is so much colder than liquid air that -it actually freezes it into a solid ice form! - -For handling and transporting liquid gases glass receptacles with a -double skin from which all air has been exhausted are employed. The -surrounding vacuum is so perfect an insulator that a "Dewar bulb" full -of liquid air scarcely cools the hand, though the intervening space is -less than an inch. This fact is hard to square with the assertion of -scientific men that our atmosphere extends but a hundred or two miles -from the earth's surface, and that the recesses of space are a vacuum. -If it were so, how would heat reach us from the sun, ninety-two -millions of miles away? - -One use at least for liquid air is sufficiently obvious. As a -refrigerating agent it is unequalled. Bulk for bulk its effect is of -course far greater than that of ice; and it has this advantage over -other freezing compounds, that whereas slow freezing has a destructive -effect upon the tissues of meat and fruit, the instantaneous action of -liquid air has no bad results when the thing frozen is thawed out -again. The Liquid Air Company therefore proposes erecting depôts at -large ports for supplying ships, to preserve the food, cool the cabins -in the tropics, and, we hope, to alleviate some of the horrors of the -stokehold. - -Liquid air is already used in medical and surgical science. In surgery -it is substituted for anæsthetics, deadening any part of the body on -which an operation has to be performed. In fever hospitals, too, its -cooling influence will be welcomed; and liquid oxygen takes the places -of compressed oxygen for reviving the flickering flame of life. It -will also prove invaluable for divers and submarine boats. - -In combination with oil and charcoal liquid air, under the name of -"oxyliquit," becomes a powerful blasting agent. Cartridges of paper -filled with the oil and charcoal are provided with a firing primer. -When everything is ready for the blasting the cartridges are dropped -into a vessel full of liquid air, saturated, placed in position, and -exploded. Mr. Knudsen assured the writer that oxyliquit is twice as -powerful as nitro-glycerine, and its cost but one-third of that of the -other explosive. It is also safer to handle, for in case of a misfire -the cartridge becomes harmless in a few minutes, after the liquid air -has evaporated. - -But the greatest use will be found for liquid air when it exerts its -force less violently. It is the result of power; its condition is -abnormal; and its return to its ordinary state is accompanied by a -great development of energy. If it be placed in a closed vessel it is -capable of exerting a pressure of 12,000 lbs. to the square inch. Its -return to atmospheric condition may be regulated by exposing it more -or less to the heat of the atmosphere. So long as it remains liquid -it represents so much _stored force_, like the electricity stored in -accumulators. The Liquid Air Company have at their Gillingham Street -depôt a neat little motor car worked by liquid air. A copper -reservoir, carefully protected, is filled with the liquid, which is by -mechanical means squirted into coils, in which it rapidly expands, and -from them passes to the cylinders. A charge of eighteen gallons will -move the car forty miles at an average pace of twelve miles an hour, -without any of the noise, dirt, smell, or vapour inseparable from the -employment of steam or petroleum. The speed of the car is regulated by -the amount of liquid injected into the expansion coils. - -We now come to the question of cost--the unromantic balance in which -new discoveries are weighed and many found wanting. The storage of -liquid air is feasible for long periods. (A large vacuum bulb filled -and exposed to the atmosphere had some of the liquid still -unevaporated at the end of twenty-two days.) But will it be too costly -for ordinary practical purposes now served by steam and electricity? -The managers of the Liquid Air Company, while deprecating extravagant -prophecies about the future of their commodity, are nevertheless -confident that it has "come to stay." With the small 50 horse-power -plant its production costs upwards of one shilling a gallon, but with -much larger plant of 1000 horse-power they calculate that the expenses -will be covered and a profit left if they retail it at but one penny -the gallon. This great reduction in cost arises from the economising -of "waste energy." In the first place the power of expansion previous -to the liquefaction of the compressed air will be utilised to work -motors. Secondly, the heat of the cooling tanks will be turned to -account, and even the "exhaust" of a motor would be cold enough for -ordinary refrigerating. It is, of course, impossible to get more out -of a thing than has been put into it; and liquid air will therefore -not develop even as much power as was required to form it. But its -handiness and cleanliness strongly recommend it for many purposes, as -we have seen; and as soon as it is turned out in large quantities new -uses will be found for it. Perhaps the day will come when liquid-air -motors will replace the petrol car, and in every village we shall see -hung out the sign, "Liquid air sold here." As the French say, "_Qui -vivra verra_." - - - - -HORSELESS CARRIAGES. - - -A body of enterprising Manchester merchants, in the year 1754, put on -the road a "flying coach," which, according to their special -advertisement, would, "however incredible it may appear, actually, -barring accidents, arrive in London in four and a half days after -leaving Manchester." According to the Lord Chancellor of the time such -swift travelling was considered dangerous as well as wonderful--the -condition of the roads might well make it so--and also injurious to -health. "I was gravely advised," he says, "to stay a day in York on my -journey between Edinburgh and London, as several passengers who had -gone through without stopping had died of apoplexy from the rapidity -of the motion." - -As the coach took a fortnight to pass from the Scotch to the English -capital, at an average pace of between three and four miles an hour, -it is probable that the Chancellor's advisers would be very seriously -indisposed by the mere sight of a motor-car whirling along in its -attendant cloud of dust, could they be resuscitated for the purpose. -And we, on the other hand, should prefer to get out and walk to -"flying" at the safe speed of their mail coaches. - -[Illustration: _By kind permission of The Speedwell Motor Co._ - -_M. Serpollet on the "Easter Egg," which at Nice covered a kilometre -in the record time of 29-4/5 secs. (over 75 miles per hour). This car -is run with steam._] - -The improvement of highroads, and road-making generally, accelerated -the rate of posting. In the first quarter of the nineteenth century an -average of ten or even twelve miles an hour was maintained on the Bath -Road. But that pace was considered inadequate when the era of the -"iron horse" commenced, and the decay of stage-driving followed hard -upon the growth of railways. What should have been the natural -successor of the stage-coach was driven from the road by ill-advised -legislation, which gave the railroads a monopoly of swift transport, -which has but lately been removed. - -The history of the steam-coach, steam-carriage, automobile, -motor-car--to give it its successive names--is in a manner unique, -showing as it does, instead of steady development of a practical means -of locomotion, a sudden and decisive check to an invention worthy of -far better treatment than it received. The compiler of even a short -survey of the automobile's career is obliged to divide his account -into two main portions, linked together by a few solitary engineering -achievements. - -The first period (1800-1836), will, without any desire to arrogate for -England more than her due or to belittle the efforts of any other -nations, be termed the English period, since in it England took the -lead, and produced by far the greatest number of steam-carriages. The -second (1870 to the present day) may, with equal justice, be styled -the Continental period, as witnessing the great developments made in -automobilism by French, German, Belgian, and American engineers: -England, for reasons that will be presently noticed, being until quite -recently too heavily handicapped to take a part in the advance. - -_Historical._--It is impossible to discover who made the first -self-moving carriage. In the sixteenth century one Johann Haustach, a -Nuremberg watchmaker, produced a vehicle that derived its motive power -from coiled springs, and was in fact a large edition of our modern -clockwork toys. About the same time the Dutch, and among them -especially one Simon Stevin, fitted carriages with sails, and there -are records of a steam-carriage as early as the same century. - -But the first practical, and at least semi-successful, automobile -driven by internal force was undoubtedly that of a Frenchman, Nicholas -Joseph Cugnot, who justly merits the title of father of automobilism. -His machine, which is to-day one of the most treasured exhibits in the -Paris Museum of Arts and Crafts, consisted of a large carriage, having -in front a pivoted platform bearing the machinery, and resting on a -solid wheel, which propelled as well as steered the vehicle. The -boiler, of stout riveted copper plates, had below it an enclosed -furnace, from which the flames passed upwards through the water -through a funnel. A couple of cylinders, provided with a simple -reversing gear, worked a ratchet that communicated motion to the -driving-wheel. This carriage did not travel beyond a very slow walking -pace, and Cugnot therefore added certain improvements, after which -(1770) it reached the still very moderate speed of four miles an hour, -and distinguished itself by charging and knocking down a wall, a feat -that is said to have for a time deterred engineers from developing a -seemingly dangerous mode of progression. - -Ten years later Dallery built a steam car, and ran it in the streets -of Amiens--we are not told with what success; and before any further -advance had been made with the automobile the French Revolution put a -stop to all inventions of a peaceful character among our neighbours. - -In England, however, steam had already been recognised as the coming -power. Richard Trevethick, afterwards to become famous as a railroad -engineer, built a steam motor in 1802, and actually drove it from -Cambourne to Plymouth, a distance of ninety miles. But instead of -following up this success, he forsook steam-carriages for the -construction of locomotives, leaving his idea to be expanded by other -men, who were convinced that a vehicle which could be driven over -existing roads was preferable to one that was helpless when separated -from smooth metal rails. Between the years 1800 and 1836 many steam -vehicles for road traffic appeared from time to time, some, such as -David Gordon's (propelled by metal legs pressing upon the ground), -strangely unpractical, but the majority showing a steady improvement -in mechanical design. - -As it will be impossible, without writing a small book, to name all -the English constructors of this period, we must rest content with the -mention of the leading pioneers of the new locomotion. - -Sir Goldsworthy Gurney, an eminent chemist, did for mechanical road -propulsion what George Stephenson was doing for railway development. -He boldly spent large sums on experimental vehicles, which took the -form of six-wheeled coaches. The earliest of these were fitted with -legs as well as driving-wheels, since he thought that in difficult -country wheels alone would not have sufficient grip. (A similar -fallacy was responsible for the cogged wheels on the first railways.) -But in the later types legs were abandoned as unnecessary. His coaches -easily climbed the steepest hills round London, including Highgate -Hill, though a thoughtful mathematician had proved by calculations -that a steam-carriage, so far from mounting a gradient, could not, -without violating all natural laws, so much as move itself on the -level! - -Having satisfied himself of their power, Gurney took his coaches -further afield. In 1829 was published the first account of a motor -trip made by him and three companions through Reading, Devizes, and -Melksham. The pace was, we read, at first only about six miles an -hour, including stoppages. They drove very carefully to avoid injury -to the persons or feelings of the country folk; but at Melksham, where -a fair was in progress, they had to face a shower of stones, hurled by -a crowd of roughs at the instigation of some coaching postilions, who -feared losing their livelihood if the new method of locomotion became -general. Two of the tourists were severely hurt, and Gurney was -obliged to take shelter in a brewery, where constables guarded his -coach. On the return journey the party timed their movements so as to -pass through Melksham while the inhabitants were all safely in bed. - -The coach ran most satisfactorily, improving every mile. "Our pace was -so rapid," wrote one of the company, "that the horses of the mail-cart -which accompanied us were hard put to it to keep up with us. At the -foot of Devizes Hill we met a coach and another vehicle, which stopped -to see us mount this hill, an extremely steep one. We ascended it at a -rapid rate. The coach and passengers, delighted at this unexpected -sight, honoured us with shouts of applause." - -In 1830 Messrs. Ogle and Summers completely beat the road record on a -vehicle fitted with a tubular boiler. This car, put through its trials -before a Special Commission of the House of Commons, attained the -astonishing speed of 35 miles an hour on the level, and mounted a hill -near Southampton at 24-1/2 miles an hour. It worked at a boiler -pressure of 250 lbs. to the square inch, and though not hung on -springs, ran 800 miles without a breakdown. This performance appears -all the more extraordinary when we remember the roads of that day were -not generally as good as they are now, and that in the previous year -Stephenson's "Rocket," running on rails, had not reached a higher -velocity. - -The report of the Parliamentary Commission on horseless carriages was -most favourable. It urged that the steam-driven car was swifter and -lighter than the mail-coaches; better able to climb and descend hills; -safer; more economical; and less injurious to the roads; and, in -conclusion, that the heavy charges levied at the toll-gates (often -twenty times those on horse vehicles) were nothing short of -iniquitous. - -As a result of this report, motor services, inaugurated by Walter -Hancock, Braithwayte, and others, commenced between Paddington and the -Bank, London and Greenwich, London and Windsor, London and Stratford. -Already, in 1829, Sir Charles Dance had a steam-coach running between -Cheltenham and Gloucester. In four months it ran 3500 miles and -carried 3000 passengers, traversing the nine miles in three-quarters -of an hour; although narrow-minded landowners placed ridges of stone -eighteen inches deep on the road by way of protest. - -The most ambitious service of all was that between London and -Birmingham, established in 1833 by Dr. Church. The rolling-stock -consisted of a single very much decorated coach. - -The success of the road-steamer seemed now assured, when a cloud -appeared on the horizon. It had already been too successful. The -railway companies were up in arms. They saw plainly that if once the -roads were covered with vehicles able to transport the public at low -fares quickly from door to door on existing thoroughfares, the -construction of expensive railroads would be seriously hindered, if -not altogether stopped. So, taking advantage of two motor accidents, -the companies appealed to Parliament--full of horse-loving squires and -manufacturers, who scented profit in the railways--and though -scientific opinion ran strongly in favour of the steam-coach, a law -was passed in 1836 which rendered the steamers harmless by robbing -them of their speed. The fiat went forth that in future _every road -locomotive should be preceded at a distance of a hundred yards by a -man on foot carrying a red flag to warn passengers of its approach_. -This law marks the end of the first period of automobilism as far as -England is concerned. At one blow it crippled a great industry, -deprived the community of a very valuable means of transport, and -crushed the energies of many clever inventors who would soon, if we -may judge by the rapid advances already made in construction, have -brought the steam-carriage to a high pitch of perfection. In the very -year in which they were suppressed the steam services had proved their -efficiency and safety. Hancock's London service alone traversed 4200 -miles without serious accident, and was so popular that the coaches -were generally crowded. It is therefore hard to believe that these -vehicles did not supply a public want, or that they were regarded by -those who used them as in any way inferior to horse-drawn coaches. -Yet ignorant prejudice drove them off the road for sixty years; and -to-day it surprises many Englishmen to learn that what is generally -considered a novel method of travelling was already fairly well -developed in the time of their grandfathers. - -_Second Period_ (1870 onwards).--To follow the further development of -the automobile we must cross the Channel once again. French invention -had not been idle while Gurney and Hancock were building their -coaches. In 1835 M. Dietz established a service between Versailles and -Paris, and the same year M. D'Asda carried out some successful trials -of his steam "diligence" under the eyes of Royalty. But we find that -for the next thirty-five years the steam-carriage was not much -improved, owing to want of capital among its French admirers. No -Gurney appeared, ready to spend his thousands in experimenting; also, -though the law left road locomotion unrestricted, the railways offered -a determined opposition to a possibly dangerous rival. So that, on the -whole, road transport by steam fared badly till after the terrible -Franco-Prussian war, when inventors again took courage. M. Bollée, of -Mans, built in 1873 a car, "l'Obéissante," which ran from Mans to -Paris; and became the subject of allusions in popular songs and plays, -while its name was held up as an example to the Paris ladies. Three -years later he constructed a steam omnibus to carry fifty persons, and -in 1878 exhibited a car that journeyed at the rate of eighteen miles -an hour from Paris to Vienna, where it aroused great admiration. - -After the year 1880 French engineers divided their attention between -the heavy motor omnibus and light vehicles for pleasure parties. In -1884 MM. Bouton and Trépardoux, working conjointly with the Comte de -Dion, produced a steam-driven tricycle, and in 1887 M. Serpollet -followed suit with another, fitted with the peculiar form of steam -generator that bears his name. Then came in 1890 a very important -innovation, which has made automobilism what it now is. Gottlieb -Daimler, a German engineer, introduced the _petrol gas-motor_. Its -comparative lightness and simplicity at once stamped it as the thing -for which makers were waiting. Petrol-driven vehicles were soon abroad -in considerable numbers and varieties, but they did not attract public -attention to any great extent until, in 1894, M. Pierre Giffard, an -editor of the _Petit Journal_, organised a motor race from Paris to -Rouen. The proprietors of the paper offered handsome prizes to the -successful competitors. There were ten starters, some on steam, others -on petrol cars. The race showed that, so far as stability went, -Daimler's engine was the equal of the steam cylinder. The next year -another race of a more ambitious character was held, the course being -from Paris to Bordeaux and back. Subscriptions for prizes flowed in -freely. Serpollet, de Dion, and Bollée prepared steam cars that should -win back for steam its lost supremacy, while the petrol faction -secretly built motors of a strength to relegate steam once and for all -to a back place. Electricity, too, made a bid unsuccessfully for the -prize in the Jeantaud car, a special train being engaged in advance to -distribute charged accumulators over the route. The steamers broke -down soon after the start, so that the petrol cars "walked over" and -won a most decisive victory. - -The interest roused in the race led the Comte de Dion to found the -Automobile Club of France, which drew together all the enthusiastic -admirers of the new locomotion. Automobilism now became a sport, a -craze. The French, with their fine straight roads, and a not too -deeply ingrained love of horseflesh, gladly welcomed the flying car, -despite its noisy and malodorous properties. - -Orders flowed in so freely that the motor makers could not keep pace -with the demand, or promise delivery within eighteen months. Rich men -were therefore obliged to pay double prices if they could find any one -willing to sell--a state of things that remains unto this day with -certain makes of French cars. Poorer folks contented themselves with -De Dion motor tricycles, which showed up so well in the 1896 -Paris-Marseilles race; or with the neat little three-wheeled cars of -M. Bollée. Motor racing became the topic of the hour. Journals were -started for the sole purpose of recording the doings of motorists; and -few newspapers of any popularity omitted a special column of motor -news. Successive contests on the highroads at increasing speeds -attracted increased interest. The black-goggled, fur-clad _chauffeur_ -who carried off the prizes found himself a hero. - -In short, the hold which automobilism has over our neighbours may be -gauged from the fact that in 1901 it was estimated that nearly a -thousand motor cars assembled to see the sport on the Longchamps -Course (the scene of that ultra-"horsey" event, the Grand Prix), and -the real interest of the meet did not centre round horses of flesh and -blood. - -The French have not a monopoly of devotion to automobilism. The speedy -motor car is too much in accord with the bustling spirit of the age; -its delights too easily appreciated to be confined to one country. -Allowing France the first place, America, Germany, and Belgium are not -far behind in their addiction to the "sport," and even in Britain, -partially freed since 1896 from the red-flag tyranny, thanks to the -efforts of Sir David Salomons, there are most visible signs that the -era of the horse is beginning its end. - - -TYPES OF CAR. - -Automobiles may be classified according to the purpose they serve, -according to their size and weight, or according to their motive -power. We will first review them under the latter head. - -_A. Petrol._--The petrol motor, suitable alike for large cars of 40 -to 60 horse-power and for the small bicycle weighing 70 lbs. or so, at -present undoubtedly occupies the first place in popular estimation on -account of its comparative simplicity, which more than compensates -certain defects that affect persons off the vehicle more than those on -it--smell and noise. - -The chief feature of the internal explosion motor is that at one -operation it converts fuel directly into energy, by exploding it -inside a cylinder. It is herein more economical than steam, which -loses power while passing from the boiler to the driving-gear. - -Petrol cycles and small cars have usually only one cylinder, but large -vehicles carry two, three, and sometimes four cylinders. Four and more -avoid that bugbear of rotary motion, "dead points," during which the -momentum of the machinery alone is doing work; and for that reason the -engines of racing cars are often quadrupled. - -For the sake of simplicity we will describe the working of a single -cylinder, leaving the reader to imagine it acting alone or in concert -with others as he pleases. - -In the first place the fuel, petrol, is a very inflammable -distillation of petroleum: so ready to ignite that it must be most -rigorously guarded from naked lights; so quick to evaporate that the -receptacles containing it, if not quite airtight, will soon render it -"stale" and unprofitable for motor driving. - -The engine, to mention its most important parts, consists of a -single-action cylinder (giving a thrust one way only); a heavy -flywheel revolving in an airtight circular case, and connected to the -piston by a hinged rod which converts the reciprocating movement of -the piston into a rotary movement of the crank-shaft built in with the -wheel; inlet and outlet valves; a carburettor for generating petrol -gas, and a device to ignite the gas-and-air mixture in the cylinder. - -The action of the engine is as follows: as the piston moves outwards -in its first stroke it sucks through the inlet valve a quantity of -mixed air and gas, the proportions of which are regulated by special -taps. The stroke ended, the piston returns, compressing the mixture -and rendering it more combustible. Just as the piston commences its -second outward stroke an electric spark passed through the mixture -mechanically ignites it, and creates an explosion, which drives the -piston violently forwards. The second return forces the burnt gas -through the exhaust-valve, which is lifted by cog-gear once in every -two revolutions of the crank, into the "silencer." The cycle of -operations is then repeated. - -We see that during three-quarters of the "cycle"--the suction, -compression, and expulsion--the work is performed entirely by the -flywheel. It follows that a single-cylinder motor, to work at all, -must rotate the wheel at a high rate. Once stopped, it can be -restarted only by the action of the handle or pedals; a task often so -unpleasant and laborious that the driver of a car, when he comes to -rest for a short time only, disconnects his motor from the -driving-gear and lets it throb away idly beneath him. - -The means of igniting the gas in the cylinders may be either a Bunsen -burner or an electric spark. Tube ignition is generally considered -inferior to electrical because it does not permit "timing" of the -explosion. Large cars are often fitted with both systems, so as to -have one in reserve should the other break down. - -Electrical ignition is most commonly produced by the aid of an -intensity coil, which consists of an inner core of coarse insulated -wire, called the primary coil; and an outer, or secondary coil, of -very fine wire. A current passes at intervals, timed by a cam on the -exhaust-valve gear working a make-and-break contact blade, from an -accumulator through the primary coil, exciting by induction a current -of much greater intensity in the secondary. The secondary is connected -to a "sparking plug," which screws into the end of the cylinder, and -carries two platinum points about 1/32 of an inch apart. The secondary -current leaps this little gap in the circuit, and the spark, being -intensely hot, fires the compressed gas. Instead of accumulators a -small dynamo, driven by the motor, is sometimes used to produce the -primary current. - -By moving a small lever, known as the "advancing lever," the driver -can control the time of explosion relatively to the compression of the -gas, and raise or lower the speed of the motor. - -The strokes of the petrol-driven cylinder are very rapid, varying from -1000 to 3000 a minute. The heat of very frequent explosions would soon -make the cylinder too hot to work were not measures adopted to keep it -cool. Small cylinders, such as are carried on motor cycles, are -sufficiently cooled by a number of radiating ribs cast in a piece with -the cylinder itself; but for large machines a water jacket or tank -surrounding the cylinder is a necessity. Water is circulated through -the jacket by means of a small centrifugal pump working off the -driving gear, and through a coil of pipes fixed in the front of the -car to catch the draught of progression. So long as the jacket and -tubes are full of water the temperature of the cylinder cannot rise -above boiling point. - -Motion is transmitted from the motor to the driving-wheels by -intermediate gear, which in cycles may be only a leather band or -couple of cogs, but in cars is more or less complicated. Under the -body of the car, running usually across it, is the countershaft, -fitted at each end with a small cog which drives a chain passing also -over much larger cogs fixed to the driving-wheels. The countershaft -engages with the cylinder mechanism by a "friction-clutch," a couple -of circular faces which can be pressed against one another by a lever. -To start his car the driver allows the motor to obtain a considerable -momentum, and then, using the friction lever, brings more and more -stress on to the countershaft until the friction-clutch overcomes the -inertia of the car and produces movement. - -Gearing suitable for level stretches would not be sufficiently -powerful for hills: the motor would slow and probably stop from want -of momentum. A car is therefore fitted with changing gears, which give -two or three speeds, the lower for ascents, the higher for the level: -and on declines the friction-clutch can be released, allowing the car -to "coast." - -_B. Steam Cars._--Though the petrol car has come to the front of late -years it still has a powerful rival in the steam car. Inventors have -made strenuous efforts to provide steam-engines light enough to be -suitable for small pleasure cars. At present the Locomobile (American) -and Serpollet (French) systems are increasing their popularity. The -Locomobile, the cost of which (about £120) contrasts favourably with -that of even the cheaper petrol cars, has a small multitubular boiler -wound on the outside with two or three layers of piano wire, to render -it safe at high pressures. As the boiler is placed under the seat it -is only fit and proper that it should have a large margin of safety. -The fuel, petrol, is passed through a specially designed burner, -pierced with hundreds of fine holes arranged in circles round air -inlets. The feed-supply to the burner is governed by a spring valve, -which cuts off the petrol automatically as soon as the steam in the -boiler reaches a certain pressure. The locomobile runs very evenly and -smoothly, and with very little noise, a welcome change after the very -audible explosion motor. - -The Serpollet system is a peculiar method of generating steam. The -boiler is merely a long coil of tubing, into which a small jet of -water is squirted by a pump at every stroke of the cylinders. The -steam is generated and used in a moment, and the speed of the machine -is regulated by the amount of water thrown by the pumps. By an -ingenious device the fuel supply is controlled in combination with the -water supply, so that there may not be any undue waste in the burner. - -_C. Electricity._--Of electric cars there are many patterns, but at -present they are not commercially so practical as the other two types. -The great drawbacks to electrically-driven cars are the weight of the -accumulators (which often scale nearly as much as all the rest of the -vehicle), and the difficulty of getting them recharged when exhausted. -We might add to these the rapidity with which the accumulators become -worn out, and the consequent expense of renewal. T. A. Edison is -reported at work on an accumulator which will surpass all hitherto -constructed, having a much longer life, and weighing very much less, -power for power. The longest continuous run ever made with -electricity, 187 miles at Chicago, compares badly with the feat of a -petrol car which on November 23, 1900, travelled a thousand miles on -the Crystal Palace track in 48 hours 24 minutes, without a single -stop. Successful attempts have been made by MM. Pieper and Jenatsky to -combine the petrol and electric systems, by an arrangement which -instead of wasting power in the cylinders when less speed is required, -throws into action electric dynamos to store up energy, convertible, -when needed, into motive power by reversing the dynamo into a motor. -But the simple electric car will not be a universal favourite until -either accumulators are so light that a very large store of -electricity can be carried without inconvenient addition of weight, or -until charging stations are erected all over the country at distances -of fifty miles or so apart. - -Whether steam will eventually get the upper hand of the petrol engine -is at present uncertain. The steam car has the advantage over the -gas-engine car in ease of starting, the delicate regulation of power, -facility of reversing, absence of vibration, noise and smell, and -freedom from complicated gears. On the other hand the petrol car has -no boiler to get out of order or burst, no troublesome gauges -requiring constant attention, and there is small difficulty about a -supply of fuel. Petrol sufficient to give motive power for hundreds of -miles can be carried if need be; and as long as there is petrol on -board the car is ready for work at a moment's notice. Judging by the -number of the various types of vehicles actually at work we should -say that while steam is best for heavy traction, the gas-engine is -most often employed on pleasure cars. - -[Illustration: _By kind permission of The Liquid Air Co._ - -_This graceful little motor-car is driven by Liquid Air. It makes -absolutely no smell or noise._] - -_D. Liquid Air_ will also have to be reckoned with as a motive power. -At present it is only on its probation; but the writer has good -authority for stating that before these words appear in print there -will be on the roads a car driven by liquid air, and able to turn off -eighty miles in the hour. - -_Manufacture._--As the English were the pioneers of the steam car, so -are the Germans and French the chief manufacturers of the petrol car. -While the hands of English manufacturers were tied by shortsighted -legislation, continental nations were inventing and controlling -valuable patents, so that even now our manufacturers are greatly -handicapped. Large numbers of petrol cars are imported annually from -France, Germany, and Belgium. Steam cars come chiefly from America and -France. The former country sent us nearly 2000 vehicles in 1901. There -are signs, however, that English engineers mean to make a determined -effort to recover lost ground; and it is satisfactory to learn that in -heavy steam vehicles, such as are turned out by Thorneycroft and Co., -this country holds the lead. We will hope that in a few years we shall -be exporters in turn. - -Having glanced at the history and nature of the various types of car, -it will be interesting to turn to a consideration of their travelling -capacities. As we have seen, a steam omnibus attained, in 1830, a -speed of no less than thirty-five miles an hour on what we should call -bad roads. It is therefore to be expected that on good modern roads -the latest types of car would be able to eclipse the records of -seventy years ago. That such has indeed been the case is evident when -we examine the performances of cars in races organised as tests of -speed. France, with its straight, beautifully-kept, military roads, is -the country _par excellence_ for the _chauffeur_. One has only to -glance at the map to see how the main highways conform to Euclid's -dictum that a straight line is the shortest distance between any two -points, _e.g._ between Rouen and Dieppe, where a park of artillery, -well posted, could rake the road either way for miles. - -The growth of speed in the French races is remarkable. In 1894 the -winning car ran at a mean velocity of thirteen miles an hour; in 1895, -of fifteen. The year 1898 witnessed a great advance to twenty-three -miles, and the next year to thirty miles. But all these speeds paled -before that of the Paris to Bordeaux race of 1901, in which the -winner, M. Fournier, traversed the distance of 327-1/2 miles at a rate -of 53-3/4 miles per hour! The famous Sud express, running between the -same cities, and considered the fastest long-distance express in the -world, was beaten by a full hour. It is interesting to note that in -the same races a motor bicycle, a Werner, weighing 80 lbs. or less, -successfully accomplished the course at an average rate of nearly -thirty miles an hour. The motor-car, after waiting seventy years, had -had its revenge on the railways. - -This was not the only occasion on which an express service showed up -badly against its nimble rival of the roads. In June, 1901, the French -and German authorities forgot old animosities in a common enthusiasm -for the automobile, and organised a race between Paris and Berlin. It -was to be a big affair, in which the cars of all nations should fight -for the speed championship. Every possible precaution was taken to -insure the safety of the competitors and the spectators. Flags of -various colours and placards marked out the course, which lay through -Rheims, Luxembourg, Coblentz, Frankfurt, Eisenach, Leipsic, and -Potsdam to the German capital. About fifty towns and large villages -were "neutralised"--that is to say, the competitors had to consume a -certain time in traversing them. At the entrance to each neutralised -zone a "control" was established. As soon as a competitor arrived, he -must slow down, and a card on which was written the time of his -arrival was handed to a "pilot," who cycled in front of the car to the -other "control" at the farther end of the zone, from which, when the -proper time had elapsed, the car was dismissed. Among other rules -were: that no car should be pushed or pulled during the race by any -one else than the passengers; that at the end of the day only a -certain time should be allowed for cleaning and repairs; and that a -limited number of persons, varying with the size of the car, should -be permitted to handle it during that period. - -A small army of automobile club representatives, besides thousands of -police and soldiers, were distributed along the course to restrain the -crowds of spectators. It was absolutely imperative that for vehicles -propelled at a rate of from 50 to 60 miles an hour a clear path should -be kept. - -At dawn, on July 27th, 109 racing machines assembled at the Fort de -Champigny, outside Paris, in readiness to start for Berlin. Just -before half-past three, the first competitor received the signal; two -minutes later the second; and then at short intervals for three hours -the remaining 107, among whom was one lady, Mme. de Gast. At least -20,000 persons were present, even at that early hour, to give the -racers a hearty farewell, and demonstrate the interest attaching in -France to all things connected with automobilism. - -Great excitement prevailed in Paris during the three days of the race. -Every few minutes telegrams arrived from posts on the route telling -how the competitors fared. The news showed that during the first stage -at least a hard fight for the leading place was in progress. The -French cracks, Fournier, Charron, De Knyff, Farman, and Girardot -pressed hard on Hourgières, No. 2 at the starting-point. Fournier soon -secured the lead, and those who remembered his remarkable driving in -the Paris-Bordeaux race at once selected him as the winner. -Aix-la-Chapelle, 283 miles from Paris and the end of the first -stage, was reached in 6 hours 28 minutes. Fournier first, De Knyff -second by six minutes. - -[Illustration: _By kind permission of The Liquid Air Co._ - -_Diagram of the Liquid Air Motor-Car, showing A, reservoir of liquid -air; B, pipes in which the liquid is transformed into atmospheric air -under great pressure; C, cylinders for driving the rear wheels by -means of chain-gear._] - -On the 28th the racing became furious. Several accidents occurred. -Edge, driving the only English car, wrecked his machine on a culvert, -the sharp curve of which flung the car into the air and broke its -springs. Another ruined his chances by running over and killing a boy. -But Fournier, Antony, De Knyff, and Girardot managed to avoid mishaps -for that day, and covered the ground at a tremendous pace. At -Düsseldorf Girardot won the lead from Fournier, to lose it again -shortly. Antony, driving at a reckless speed, gained ground all day, -and arrived a close second at Hanover, the halting-place, after a run -averaging, in spite of bad roads and dangerous corners, no less than -54 miles an hour! - -The _chauffeur_ in such a race must indeed be a man of iron nerves. -Through the great black goggles which shelter his face from the -dust-laden hurricane set up by the speed he travels at he must keep a -perpetual, piercingly keen watch. Though travelling at express speed, -there are no signals to help him; he must be his own signalman as well -as driver. He must mark every loose stone on the road, every -inequality, every sudden rise or depression; he must calculate the -curves at the corners and judge whether his mechanician, hanging out -on the inward side, will enable a car to round a turn without -slackening speed. His calculations and decisions must be made in the -fraction of a second, for a moment's hesitation might be disaster. His -driving must be furious and not reckless; the timid _chauffeur_ will -never win, the careless one will probably lose. His head must be cool -although the car leaps beneath him like a wild thing, and the wind -lashes his face. At least one well-tried driver found the mere mental -strain too great to bear, and retired from the contest; and we may be -sure that few of the competitors slept much during the nights of the -race. - -At four o'clock on the 29th Fournier started on the third stage, which -witnessed another bout of fast travelling. It was now a struggle -between him and Antony for first place. The pace rose at times to -eighty miles an hour, a speed at which our fastest expresses seldom -travel. Such a speed means huge risks, for stopping, even with the -powerful brakes fitted to the large cars, would be a matter of a -hundred yards or more. Not far from Hanover Antony met with an -accident--Girardot now held second place; and Fournier finished an -easy first. All along the route crowds had cheered him, and hurled -bouquets into the car, and wished him good speed; but in Berlin the -assembled populace went nearly frantic at his appearance. Fournier was -overwhelmed with flowers, laurel wreaths, and other offerings; dukes, -duchesses, and the great people of the land pressed for presentations; -he was the hero of the hour. - -Thus ended what may be termed a peaceful invasion of Germany by the -French. Among other things it had shown that over an immense stretch -of country, over roads in places bad as only German roads can be, the -automobile was able to maintain an average speed superior to that of -the express trains running between Paris and Berlin; also that, in -spite of the large number of cars employed in the race, the accidents -to the public were a negligible quantity. It should be mentioned that -the actual time occupied by Fournier was 16 hours 5 minutes; that out -of the 109 starters 47 reached Berlin; and that Osmont on a motor -cycle finished only 3 hours and 10 minutes behind the winner. - -In England such racing would be undesirable and impossible, owing to -the crookedness of our roads. It would certainly not be permissible so -long as the 12 miles an hour limit is observed. At the present time an -agitation is on foot against this restriction, which, though -reasonable enough among traffic and in towns, appears unjustifiable in -open country. To help to convince the magisterial mind of the ease -with which a car can be stopped, and therefore of its safety even at -comparatively high speeds, trials were held on January 2, 1902, in -Welbeck Park. The results showed that a car travelling at 13 miles an -hour could be stopped dead in 4 yards; at 18 miles in 7 yards; at 20 -miles in 13 yards; or in less than half the distance required to pull -up a horse-vehicle driven at similar speeds. - -_Uses._--Ninety-five per cent of motors, at least in England, are -attached to pleasure vehicles, cycles, voiturettes, and large cars. On -account of the costliness of cars motorists are far less numerous than -cyclists; but those people whose means enable them to indulge in -automobilism find it extremely fascinating. Caricaturists have -presented to us in plenty the gloomier incidents of motoring--the -broken chain, the burst tyre, the "something gone wrong." It requires -personal experience to understand how lightly these mishaps weigh -against the exhilaration of movement, the rapid change of scene, the -sensation of control over power which can whirl one along tirelessly -at a pace altogether beyond the capacities of horseflesh. If proof -were wanted of the motor car's popularity it will be seen in the -unconventional dress of the _chauffeur_. The breeze set up by his -rapid rush is such as would penetrate ordinary clothing; he dons -cumbrous fur cloaks. The dust is all-pervading at times; he swathes -himself in dust-proof overalls, and mounts large goggles edged with -velvet, while a cap of semi-nautical cut tightly drawn down over neck -and ears serves to protect those portions of his anatomy. The -general effect is peculiarly unpicturesque; but even the most -artistically-minded driver is ready to sacrifice appearances to -comfort and the proper enjoyment of his car. - -In England the great grievance of motorists arises from the speed -limit imposed by law. To restrict a powerful car to twelve miles an -hour is like confining a thoroughbred to the paces of a broken-down -cab horse. Careless driving is unpardonable, but its occasional -existence scarcely justifies the intolerant attitude of the law -towards motorists in general. It must, however, be granted in justice -to the police that the _chauffeur_, from constant transgression of the -law, becomes a bad judge of speed, and often travels at a far greater -velocity than he is willing to admit. - -The convenience of the motor car for many purposes is immense, -especially for cross-country journeys, which may be made from door to -door without the monotony or indirectness of railway travel. It bears -the doctor swiftly on his rounds. It carries the business man from his -country house to his office. It delivers goods for the merchant; -parcels for the post office. - -In the warfare of the future, too, it will play its part, whether to -drag heavy ordnance and stores, or to move commanding officers from -point to point, or perform errands of mercy among the wounded. By the -courtesy of the Locomobile Company we are permitted to append the -testimony of Captain R. S. Walker, R.E., to the usefulness of a car -during the great Boer War. - -"Several months ago I noticed a locomobile car at Cape Town, and being -struck with its simplicity and neatness, bought it and took it up -country with me, with a view to making some tests with it over bad -roads, &c. Its first trip was over a rough course round Pretoria, -especially chosen to find out defects before taking it into regular -use. Naturally, as the machine was not designed for this class of -work, there were several. In about a month these had all been found -out and remedied, and the car was in constant use, taking stores, &c., -round the towns and forts. It also performed some very useful work in -visiting out-stations, where searchlights were either installed or -wanted, and in this way visited nearly all the bigger towns in the -Transvaal. It was possible to go round all the likely positions for a -searchlight in one day at every station, which frequently meant -considerably over fifty miles of most indifferent roads--more than a -single horse could have been expected to do--and the car generally -carried two persons on these occasions. The car was also used as a -tender to a searchlight plant, on a gun-carriage and limber, being -utilised to fetch gasolene, carbons, water, &c., &c., and also to run -the dynamo for charging the accumulators used for sparking, thus -saving running the gasolene motor for this purpose. To do this the -trail of the carriage, on which was the dynamo, was lowered on to the -ground, the back of the car was pulled up, one wheel being supported -on the dynamo pulley and the other clear of the ground, and two bolts -were passed through the balance-gear to join it. On one occasion the -car ran a 30 c.m. searchlight for an hour, driving a dynamo in this -way. In consequence of this a trailer has been made to carry a dynamo -and projector for searchlighting in the field, but so far this has -not been so used. The trailer hooks into an eye, passing just behind -the balance-gear. A Maxim, Colt, or small ammunition cart, &c., could -be attached to this same eye. - -"Undoubtedly the best piece of work done by the car so far was its -trial trip with the trailer, when it blew up the mines at Klein Nek. -These mines were laid some eight months previously, and had never been -looked to in the interval. There had been several bad storms, the -Boers and cattle had been frequently through the Nek, it had been on -fire, and finally it was shelled with lyddite. The mines, eighteen in -number, were found to be intact except two, which presumably had been -fired off by the heat of the veldt fire. All the insulation was burnt -off the wires, and the battery was useless. It had been anticipated -that a dynamo exploder would be inadequate to fire these mines, so a -250 volt two h.p. motor, which happened to be in Pretoria, weighing -about three or four hundredweight, was placed on the trailer; a -quarter of a mile of insulated cable, some testing gear, the kits of -three men and their rations for three days, with a case of gasolene -for the car, were also carried on the car and trailer, and the whole -left Pretoria one morning and trekked to Rietfontein. Two of us were -mounted, the third drove the car. At Rietfontein we halted for the -night, and started next morning with an escort through Commando Nek, -round the north of the Magaliesburg, to near Klein Nek, where the road -had to be left, and the car taken across country through bush veldt. -At the bottom the going was pretty easy; only a few bushes had to be -charged down, and the grass, &c., rather wound itself around the -wheels and chain. As the rise became steeper the stones became very -large, and the car had to be taken along very gingerly to prevent -breaking the wheels. A halt was made about a quarter of a mile from -the top of the Nek, where the mines were. These were reconnoitered, -and the wire, &c., was picked up; that portion which was useless was -placed on top of the charges, and the remainder taken to the car. The -dynamo was slid off the trailer, the car backed against it; one wheel -was raised slightly and placed against the dynamo pulley, which was -held up to it by a man using his rifle as a lever; the other wheel was -on the ground with a stone under it. The balance gear being free, the -dynamo was excited without the other wheel moving, and the load being -on for a very short time (that is, from the time of touching lead on -dynamo terminal to firing of the mine) no harm could come to the car. -When all the leads had been joined to the dynamo the car was started, -and after a short time, when it was judged to have excited, the second -terminal was touched, a bang and clouds of dust resulted, and the -Klein Nek Minefield had ceased to exist. The day was extremely hot, -and the work had not been light, so the tea, made with water drawn -direct from the boiler, which we were able to serve round to the main -body of our escort was much appreciated, and washed down the surplus -rations we dispensed with to accommodate the battery and wire, which -we could not leave behind for the enemy. - -"On the return journey we found this extra load too much for the car, -and had great difficulty getting up to Commando Nek, frequently having -to stop to get up steam, so these materials were left at the first -blockhouse, and the journey home continued in comfort. - -"A second night at Rietfontein gave us a rest after our labour, and -the third afternoon saw us on our way back to Pretoria. As luck would -have it, a sandstorm overtook the car, which had a lively time of it. -The storm began by blowing the sole occupant's hat off, so, the two -mounted men being a long way behind, he shut off steam and chased his -hat. In the meantime the wind increased, and the car sailed off 'on -its own,' and was only just caught in time to save a smash. Luckily -the gale was in the right direction, for the fire was blown out, and -it was impossible to light a match in the open. The car sailed into a -poort on the outskirts of Pretoria, got a tow from a friendly cart -through it, and then steamed home after the fire had been relit. - -"The load carried on this occasion (without the battery, &c.) must -have been at least five hundredweight besides the driver, which, -considering the car is designed to carry two on ordinary roads, and -that these roads were by no means ordinary, was no mean feat. The car, -as ordinarily equipped for trekking, carries the following: Blankets, -waterproof sheets, &c., for two men; four planks for crossing ditches, -bogs, stones, &c.; all necessary tools and spare parts, a day's supply -of gasolene, a couple of telephones, and one mile of wire. In -addition, on the trailer, if used for searchlighting: One 30 c.m. -projector, one automatic lamp for projector, one dynamo (100 volts 20 -ampères), two short lengths of wire, two pairs of carbons, tools, &c. -This trailer would normally be carried with the baggage, and only -picked up by the car when wanted as a light; that is, as a rule, after -arriving in camp, when a good many other things could be left behind." - -Perhaps the most useful work in store for the motor is to help relieve -the congestion of our large towns and to restore to the country some -of its lost prosperity. There is no stronger inducement to make people -live in the country than rapid and safe means of locomotion, whether -public or private. At present the slow and congested suburban train -services on some sides of London consume as much time as would suffice -a motor car to cover twice or three times the distance. We must -welcome any form of travel which will tend to restore the balance -between country and town by enabling the worker to live far from his -work. The gain to the health of the nation arising from more even -distribution of population would be inestimable. - -A world's tour is among the latest projects in automobilism. On April -29, 1902, Dr. Lehwess and nine friends started from Hyde Park Corner -for a nine months' tour on three vehicles, the largest of them a -luxuriously appointed 24 horse-power caravan, built to accommodate -four persons. Their route lies through France, Germany, Russia, -Siberia, China, Japan, and the United States. - - - - -HIGH-SPEED RAILWAYS. - - -A century ago a long journey was considered an exploit, and an exploit -to be carried through as quickly as possible on account of the dangers -of the road and the generally uncomfortable conditions of travel. -To-day, though our express speed is many times greater than that of -the lumbering coaches, our carriages comparatively luxurious, the risk -practically nil, the same wish lurks in the breast of ninety-nine out -of a hundred railway passengers--to spend the shortest time in the -train that the time-table permits of. Time differences that to our -grandfathers would have appeared trifling are now matters of -sufficient importance to make rival railway companies anxious to clip -a few minutes off a 100-mile "run" simply because their passengers -appreciate a few minutes' less confinement to the cars. - -During the last fifty years the highest express speeds have not -materially altered. The Great Western Company in its early days ran -trains from Paddington to Slough, 18 miles, in 15-1/2 minutes, or at -an average pace of 69-1/2 miles an hour. - -On turning to the present regular express services of the world we -find America heading the list with a 50-mile run between Atlantic City -and Camden, covered at the average speed of 68 miles an hour; Britain -second with a 33-mile run between Forfar and Perth at 59 miles; and -France a good third with an hourly average of rather more than 58 -miles between Les Aubrais and S. Pierre des Corps. These runs are -longer than that on the Great Western Railway referred to above (which -now occupies twenty-four minutes), but their average velocity is less. -What is the cause of this decrease of speed? Not want of power in -modern engines; at times our trains attain a rate of 80 miles an hour, -and in America a mile has been turned off in the astonishing time of -thirty-two seconds. We should rather seek it in the need for economy -and in the physical limitations imposed by the present system of -plate-laying and railroad engineering. An average speed of ninety -miles an hour would, as things now stand, be too wasteful of coal and -too injurious to the rolling-stock to yield profit to the proprietors -of a line; and, except in certain districts, would prove perilous for -the passengers. Before our services can be much improved the steam -locomotive must be supplanted by some other application of motive -power, and the metals be laid in a manner which will make special -provision for extreme speed. - -Since rapid transit is as much a matter of commercial importance as of -mere personal convenience it must not be supposed that an average of -50 miles an hour will continue to meet the needs of travellers. -Already practical experiments have been made with two systems that -promise us an ordinary speed of 100 miles an hour and an express speed -considerably higher. - -One of these, the monorail or single-rail system, will be employed on -a railroad projected between Manchester and Liverpool. At present -passengers between these two cities--the first to be connected by a -railroad of any kind--enjoy the choice of three rival services -covering 34-1/2 miles in three-quarters of an hour. An eminent -engineer, Mr. F. B. Behr, now wishes to add a fourth of unprecedented -swiftness. Parliamentary powers have been secured for a line starting -from Deansgate, Manchester, and terminating behind the pro-Cathedral -in Liverpool, on which single cars will run every ten minutes at a -velocity of 110 miles an hour. - -A monorail track presents a rather curious appearance. The ordinary -parallel metals are replaced by a single rail carried on the summit of -A-shaped trestles, the legs of which are firmly bolted to sleepers. A -monorail car is divided lengthwise by a gap that allows it to hang -half on either side of the trestles and clear them as it moves. The -double flanged wheels to carry and drive the car are placed at the -apex of the gap. As the "centre of gravity" is below the rail the car -cannot turn over, even when travelling round a sharp curve. - -The first railway built on this system was constructed by M. Charles -Lartigue, a French engineer, in Algeria, a district where an ordinary -two-rail track is often blocked by severe sand-storms. He derived the -idea of balancing trucks over an elevated rail from caravans of camels -laden on each flank with large bags. The camel, or rather its legs, -was transformed by the engineer's eye into iron trestles, while its -burden became a car. A line built as a result of this observation, and -supplied with mules as tractive power, has for many years played an -important part in the esparto-grass trade of Algeria. - -In 1886 Mr. Behr decided that by applying steam to M. Lartigue's -system he could make it successful as a means of transporting -passengers and goods. He accordingly set up in Tothill Fields, -Westminster, on the site of the new Roman Catholic Cathedral, a -miniature railway which during nine months of use showed that the -monorail would be practical for heavy traffic, safe, and more cheaply -maintained than the ordinary double-metal railway. The train travelled -easily round very sharp curves and climbed unusually steep gradients -without slipping. - -Mr. Behr was encouraged to construct a monorail in Kerry, between -Listowel, a country town famous for its butter, and Ballybunion, a -seaside resort of increasing popularity. The line, opened on the 28th -of February 1888, has worked most satisfactorily ever since, without -injury to a single employé or passenger. - -On each side of the trestles, two feet below the apex, run two -guide-rails, against which press small wheels attached to the -carriages to prevent undue oscillation and "tipping" round curves. At -the three stations there are, instead of points, turn-tables or -switches on to which the train runs for transference to sidings. - -Road traffic crosses the rail on drawbridges, which are very easily -worked, and which automatically set signals against the train. The -bridges are in two portions and act on the principle of the Tower -Bridge, each half falling from a perpendicular position towards the -centre, where the ends rest on the rail, specially strengthened at -that spot to carry the extra weight. The locomotive is a twin affair; -has two boilers, two funnels, two fireboxes; can draw 240 tons on the -level at fifteen miles an hour, and when running light travels a mile -in two minutes. The carriages, 18 feet long and carrying twelve -passengers on each side, are divided longitudinally into two parts. -Trucks too are used, mainly for the transport of sand--of which each -carries three tons--from Ballybunion to Listowel: and in the centre of -each train is a queer-looking vehicle serving as a bridge for any one -who may wish to cross from one side of the rail to the other. - -Several lines on the pattern of the Ballybunion-Listowel have been -erected in different countries. Mr. Behr was not satisfied with his -first success, however, and determined to develop the monorail in the -direction of fast travelling, which he thought would be most easily -attained on a trestle-track. In 1893 he startled engineers by -proposing a Lightning-Express service, to transport passengers at a -velocity of 120 miles an hour. But the project seemed too ideal to -tempt money from the pockets of financiers, and Mr. Behr soon saw that -if a high-speed railway after his own heart were constructed it must -be at his own expense. He had sufficient faith in his scheme to spend -£40,000 on an experimental track at the Brussels Exhibition of 1897. -The exhibition was in two parts, connected by an electric railway, the -one at the capital, the other at Tervueren, seven miles away. Mr. Behr -built his line at Tervueren. - -The greatest difficulty he encountered in its construction arose from -the opposition of landowners, mostly small peasant proprietors, who -were anxious to make advantageous terms before they would hear of the -rail passing through their lands. Until he had concluded two hundred -separate contracts, by most of which the peasants benefited, his -platelayers could not get to work. Apart from this opposition the -conditions were not favourable. He was obliged to bridge no less than -ten roads; and the contour of the country necessitated steep -gradients, sharp curves, long cuttings and embankments, the last of -which, owing to a wet summer, could not be trusted to stand quite -firm. The track was doubled for three miles, passing at each end round -a curve of 1600 feet radius. - -The rail ran about four feet above the track on trestles bolted down -to steel sleepers resting on ordinary ballast. The carriage--Mr. Behr -used but one on this line--weighed 68 tons, was 59 feet long and 11 -feet wide, and could accommodate one hundred persons. It was -handsomely fitted up, and had specially-shaped seats which neutralised -the effect of rounding curves, and ended fore and aft in a point, to -overcome the wind-resistance in front and the air-suction behind. -Sixteen pairs of wheels on the under side of the carriage engaged with -the two pairs of guide rails flanking the trestles, and eight large -double-flanged wheels, 4-1/2 feet in diameter, carried the weight of -the vehicle. The inner four of these wheels were driven by as many -powerful electric motors contained, along with the guiding mechanism, -in the lower part of the car. The motors picked up current from the -centre rail and from another steel rail laid along the sleepers on -porcelain insulators. - -The top speed attained was about ninety miles an hour. On the close of -the Exhibition special experiments were made at the request of the -Belgian, French, and Russian Governments, with results that proved -that the Behr system deserved a trial on a much larger scale. - -The engineer accordingly approached the British Government with a Bill -for the construction of a high-speed line between Liverpool and -Manchester. A Committee of the House of Commons rejected the Bill on -representations of the Salford Corporation. The Committee had to -admit, nevertheless, that the evidence called was mainly in favour of -the system; and, the plans of the rail having been altered to meet -certain objections, Parliamentary consent was obtained to commence -operations when the necessary capital had been subscribed. In a few -years the great seaport and the great cotton town will probably be -within a few minutes' run of each other. - -A question that naturally arises in the mind of the reader is this: -could the cars, when travelling at 110 miles an hour, be arrested -quickly enough to avoid an accident if anything got on the line? - -The Westinghouse air-brake has a retarding force of three miles a -second. It would therefore arrest a train travelling at 110 miles per -hour in 37 seconds, or 995 yards. Mr. Behr proposes to reinforce the -Westinghouse with an electric brake, composed of magnets 18 inches -long, exerting on the guide rails by means of current generated by the -reversed motors an attractive force of 200 lbs. per square inch. One -great advantage of this brake is that its efficiency is greatest when -the speed of the train is highest and when it is most needed. The -united brakes are expected to stop the car in half the distance of the -Westinghouse alone; but they would not both be applied except in -emergencies. Under ordinary conditions the slowing of a car would take -place only at the termini, where the line ascends gradients into the -stations. There would, however, be small chance of collisions, the -railway being securely fenced off throughout its entire length, and -free from level crossings, drawbridges and points. Furthermore, each -train would be its own signalman. Suppose the total 34-1/2 miles -divided into "block" lengths of 7 miles. On leaving a terminus the -train sets a danger signal behind it; at 7 miles it sets another, and -at 14 miles releases the first signal. So that the driver of a car -would have at least 7 miles to slow down in after seeing the signals -against him. In case of fog he would consult a miniature signal in his -cabin working electrically in unison with the large semaphores. - -The Manchester-Liverpool rail will be reserved for express traffic -only. Mr. Behr does not believe in mixing speeds, and considers it one -of the advantages of his system that slow cars and waggons of the -ordinary two-rail type cannot be run on the monorail; because if they -could managers might be tempted to place them there. - -A train will consist of a single vehicle for forty, fifty, or seventy -passengers, as the occasion requires. It is calculated that an average -of twelve passengers at one penny per mile would pay all the expenses -of running a car. - -Mr. Behr maintains that monorails can be constructed far more cheaply -than the two-rail, because they permit sharper curves, and thereby -save a lot of cutting and embankment; and also because the monorail -itself, when trestles and rail are specially strengthened, can serve -as its own bridge across roads, valleys and rivers. - -Though the single-rail has come to the front of late, it must not be -supposed that the two-rail track is for ever doomed to moderate speeds -only. German engineers have built an electric two-rail military line -between Berlin and Zossen, seventeen miles long, over which cars have -been run at a hundred miles an hour. The line has very gradual curves, -and in this respect is inferior to the more sinuous monorail. Its -chief virtue is the method of applying motive power--a method common -to both systems. - -The steam locomotive creates its own motive force, and as long as it -has fuel and water can act independently. The electric locomotive, on -the other hand, receives its power through metallic conductors from -some central station. Should the current fail all the traffic on the -line is suspended. So far the advantage rests with the steamer. But -as regards economy the superiority of the current is obvious. In -the electric systems under consideration--the monorail and -Berlin-Zossen--there is less weight per passenger to be shifted, since -a comparatively light motor supersedes the heavy locomotive. The cars -running singly, bridges and track are subjected to less strain, and -cost less to keep in repair. But the greatest saving of all is made in -fuel. A steam locomotive uses coal wastefully, sending a lot of latent -power up the funnel in the shape of half-expanded steam. Want of space -prevents the designer from fitting to a moving engine the more -economical machinery to be found in the central power-station of an -electric railway, which may be so situated--by the water-side or near -a pit's mouth--that fuel can be brought to it at a trifling cost. Not -only is the expense of distributing coal over the system avoided, but -the coal itself, by the help of triple and quadruple expansion engines -should yield two or three times as much energy per ton as is developed -in a locomotive furnace. - -Many schemes are afoot for the construction of high-speed railways. -The South-Eastern plans a monorail between Cannon Street and Charing -Cross to avoid the delay that at present occurs in passing from one -station to the other. We hear also of a projected railway from London -to Brighton, which will reduce the journey to half-an-hour; and of -another to connect Dover and London. It has even been suggested to -establish monorails on existing tracks for fast passenger traffic, the -expresses passing overhead, the slow and goods trains plodding along -the double metals below. - -But the most ambitious programme of all comes from the land of the -Czar. M. Hippolyte Romanoff, a Russian engineer, proposes to unite St. -Petersburg and Moscow by a line that shall cover the intervening 600 -miles in three hours--an improvement of ten hours on the present -time-tables. He will use T-shaped supports to carry two rails, one on -each arm, from which the cars are to hang. The line being thus double -will permit the cars--some four hundred in number--to run to and fro -continuously, urged on their way by current picked up from overhead -wires. Each car is to have twelve wheels, four drivers arranged -vertically and eight horizontally, to prevent derailment by gripping -the rail on either side. The stoppage or breakdown of any car will -automatically stop those following by cutting off the current. - -In the early days of railway history lines were projected in all -directions, regardless of the fact whether they would be of any use or -not. Many of these lines began, where they ended, on paper. And now -that the high-speed question has cropped up, we must not believe that -every projected electric railway will be built, though of the ultimate -prevalence of far higher speeds than we now enjoy there can be no -doubt. - -The following is a time-table drawn up on the two-mile-per-minute -basis. - -A man leaving London at 10 A.M. would reach-- - - Brighton 50 miles away, at 10.25 A.M. - Portsmouth 60 " " 10.30 A.M. - Birmingham 113 " " 10.57 A.M. - Leeds 188 " " 11.34 A.M. - Liverpool 202 " " 11.41 A.M. - Holyhead 262 " " 12.11 P.M. - Edinburgh 400 " " 1.20 P.M. - Aberdeen 540 " " 2.30 P.M. - -What would become of the records established in the "Race to the -North" and by American "fliers"? - -And what about continental travel? - -Assuming that the Channel Tunnel is built--perhaps a rather large -assumption--Paris will be at our very doors. A commercial traveller -will step into the lightning express at London, sleep for two hours -and twenty-four minutes and wake, refreshed, to find the blue-smocked -Paris porters bawling in his ear. Or even if we prefer to keep the -"little silver streak" free from subterranean burrows, he will be able -to catch the swift turbine steamers--of which more anon--at Dover, -slip across to Calais in half-an-hour, and be at the French capital -within four hours of quitting London. And if M. Romanoff's standard be -reached, the latest thing in hats despatched from Paris at noon may -be worn in Regent Street before two o'clock. - -Such speeds would indeed produce a revolution in travelling comparable -to the substitution of the steam locomotive for the stage coach. As -has been pithily said, the effect of steam was to make the bulk of -population travel, whereas they had never travelled before, but the -effect of the electric railway will be to make those who travel travel -much further and much oftener. - - - - -SEA EXPRESSES. - - -In the year 1836 the _Sirius_, a paddle-wheel vessel, crossed the -Atlantic from Cork Harbour to New York in nineteen days. Contrast with -the first steam-passage from the Old World to the New a return journey -of the _Deutschland_, a North German liner, which in 1900 averaged -over twenty-seven miles an hour between Sandy Hook and Plymouth, -accomplishing the whole distance in the record time of five days seven -hours thirty-eight minutes. - -This growth of speed is even more remarkable than might appear from -the mere comparison of figures. A body moving through water is so -retarded by the inertia and friction of the fluid that to quicken its -pace a force quite out of proportion to the increase of velocity must -be exerted. The proportion cannot be reduced to an exact formula, but -under certain conditions the speed and the power required advance in -the ratio of their cubes; that is, to double a given rate of progress -eight times the driving-power is needed; to treble it, twenty-seven -times. - -The mechanism of our fast modern vessels is in every way as superior -to that which moved the _Sirius_, as the beautifully-adjusted safety -cycle is to the clumsy "boneshaker" which passed for a wonder among -our grandfathers. A great improvement has also taken place in the art -of building ships on lines calculated to offer least resistance to the -water, and at the same time afford a good carrying capacity. The big -liner, with its knife-edged bow and tapering hull, is by its shape -alone eloquent of the high speed which has earned it the title -of Ocean Greyhound; and as for the fastest craft of all, -torpedo-destroyers, their designers seem to have kept in mind Euclid's -definition of a line--length without breadth. But whatever its shape, -boat or ship may not shake itself free of Nature's laws. Her -restraining hand lies heavy upon it. A single man paddles his -weight-carrying dinghy along easily at four miles an hour; eight men -in the pink of condition, after arduous training, cannot urge their -light, slender, racing shell more than twelve miles in the same time. - -To understand how mail boats and "destroyers" attain, despite the -enormous resistance of water, velocities that would shame many a -train-service, we have only to visit the stokeholds and engine-rooms -of our sea expresses and note the many devices of marine engineers by -which fuel is converted into speed. - -We enter the stokehold through air-locks, closing one door before we -can open the other, and find ourselves among sweating, grimy men, -stripped to the waist. As though life itself depended upon it they -shovel coal into the rapacious maws of furnaces glowing with a -dazzling glare under the "forced-draught" sent down into the hold by -the fans whirling overhead. The ignited furnace gases on their way to -the outer air surrender a portion of their heat to the water from -which they are separated by a skin of steel. Two kinds of marine -boiler are used--the fire-tube and the water-tube. In fire-tube -boilers the fire passes inside the tubes and the water outside; in -water-tube boilers the reverse is the case, the crown and sides of the -furnace being composed of sheaves of small parallel pipes through -which water circulates. The latter type, as generating steam very -quickly, and being able to bear very high pressures, is most often -found in war vessels of all kinds. The quality sought in boiler -construction is that the heating surface should be very large in -proportion to the quantity of water to be heated. Special coal, -anthracite or Welsh, is used in the navy on account of its great -heating power and freedom from smoke; experiments have also been made -with crude petroleum, or liquid fuel, which can be more quickly put on -board than coal, requires the services of fewer stokers, and may be -stored in odd corners unavailable as coal bunkers. - -From the boiler the steam passes to the engine-room, whither we will -follow it. We are now in a bewildering maze of clanking, whirling -machinery; our noses offended by the reek of oil, our ears deafened -by the uproar of the moving metal, our eyes wearied by the efforts to -follow the motions of the cranks and rods. - -On either side of us is ranged a series of three or perhaps even four -cylinders, of increasing size. The smallest, known as the -high-pressure cylinder, receives steam direct from the boiler. It -takes in through a slide-valve a supply for a stroke; its piston is -driven from end to end; the piston-rod flies through the cylinder-end -and transmits a rotary motion to a crank by means of a connecting-rod. -The half-expanded steam is then ejected, not into the air as would -happen on a locomotive, but into the next cylinder, which has a larger -piston to compensate the reduction of pressure. Number two served, the -steam does duty a third time in number three, and perhaps yet a fourth -time before it reaches the condensers, where its sudden conversion -into water by cold produces a vacuum suction in the last cylinder of -the series. The secret of a marine engine's strength and economy lies -then in its treatment of the steam, which, like clothes in a numerous -family, is not thought to have served its purpose till it has been -used over and over again. - -Reciprocating (_i.e._ cylinder) engines, though brought to a high -pitch of efficiency, have grave disadvantages, the greatest among -which is the annoyance caused by their intense vibration to all -persons in the vessel. A revolving body that is not exactly balanced -runs unequally, and transmits a tremor to anything with which it may -be in contact. Turn a cycle upside down and revolve the driving-wheel -rapidly by means of the pedal. The whole machine soon begins to -tremble violently, and dance up and down on the saddle springs, -because one part of the wheel is heavier than the rest, the mere -weight of the air-valve being sufficient to disturb the balance. Now -consider what happens in the engine-room of high-powered vessels. On -destroyers the screws make 400 revolutions a minute. That is to say, -all the momentum of the pistons, cranks, rods, and valves (weighing -tons), has to be arrested thirteen or fourteen times every second. -However well the moving parts may be balanced, the vibration is felt -from stem to stern of the vessel. Even on luxuriously-appointed -liners, with engines running at a far slower speed, the throbbing of -the screw (_i.e._ engines) is only too noticeable and productive of -discomfort. - -We shall be told, perhaps, that vibration is a necessary consequence -of speed. This is true enough of all vehicles, such as railway trains, -motor-cars, cycles, which are shaken by the irregularities of the -unyielding surface over which they run, but does not apply universally -to ships and boats. A sail or oar-propelled craft may be entirely free -from vibration, whatever its speed, as the motions arising from water -are usually slow and deliberate. In fact, water in its calmer moods is -an ideal medium to travel on, and the trouble begins only with the -introduction of steam as motive force. - -But even steam may be robbed of its power to annoy us. The -steam-turbine has arrived. It works a screw propeller as smoothly as a -dynamo, and at a speed that no cylinder engine could maintain for a -minute without shaking itself to pieces. - -The steam-turbine is most closely connected with the name of the Hon. -Charles Parsons, son of Lord Rosse, the famous astronomer. He was the -first to show, in his speedy little _Turbinia_, the possibilities of -the turbine when applied to steam navigation. The results have been -such as to attract the attention of the whole shipbuilding world. - -The principle of the turbine is seen in the ordinary windmill. To an -axle revolving in a stationary bearing are attached vanes which oppose -a current of air, water, or steam, at an angle to its course, and by -it are moved sideways through a circular path. Mr. Parsons' turbine -has of course been specially adapted for the action of steam. It -consists of a cylindrical, air-tight chest, inside which rotates a -drum, fitted round its circumference with rows of curved vanes. The -chest itself has fixed immovably to its inner side a corresponding -number of vane rings, alternating with those on the drum, and so -arranged as to deflect the steam on to the latter at the most -efficient angle. The diameter of the chest and drum is not constant, -but increases towards the exhaust end, in order to give the expanding -and weakening steam a larger leverage as it proceeds. - -The steam entering the chest from the boiler at a pressure of some -hundreds of pounds to the square inch strikes the first set of vanes -on the drum, passes them and meets the first set of chest-vanes, is -turned from its course on to the second set of drum-vanes, and so on -to the other end of the chest. Its power arises entirely from its -expansive velocity, which, rather than turn a number of sharp corners, -will, if possible, compel the obstruction to move out of its way. If -that obstruction be from any cause difficult to stir, the steam must -pass round it until its pressure overcomes the inertia. Consequently -the turbine differs from the cylinder engine in this respect, that -steam _can_ pass through and be wasted without doing any work at all, -whereas, unless the gear of a cylinder moves, and power is exerted, -all steam ways are closed, and there is no waste. In practice, -therefore, it is found that a turbine is most effective when running -at high speed. - -The first steam-turbines were used to drive dynamos. In 1884 Mr. -Parsons made a turbine in which fifteen wheels of increasing size -moved at the astonishing rate of 300 revolutions per second, and -developed 10 horse-power. In 1888 followed a 120 horse-power turbine, -and in 1892 one of 2000 horse-power, provided with a condenser to -produce suction. So successful were these steam fans for electrical -work, pumping water and ventilating mines, that Mr. Parsons determined -to test them as a means of propelling ships. A small vessel 100 feet -long and 9 feet in beam was fitted with three turbines--high, medium, -and low pressure, of a total 2000 horse-power--a proportion of motive -force to tonnage hitherto not approached. Yet when tried over the test -course the _Turbinia_, as the boat was fitly named, ran in a most -disappointing fashion. The screws revolved _too fast_, producing what -is known as _cavitation_, or the scooping out of the water by the -screws, so that they moved in a partial vacuum and utilised only a -fraction of their force, from lack of anything to "bite" on. This -defect was remedied by employing screws of coarser pitch and larger -blade area, three of which were attached to each of the three -propeller shafts. On a second trial the _Turbinia_ attained 32-3/4 -knots over the "measured mile," and later the astonishing speed of -forty miles an hour, or double that of the fast Channel packets. At -the Spithead Review in 1897 one of the most interesting sights was the -little nimble _Turbinia_ rushing up and down the rows of majestic -warships at the rate of an express train. - -[Illustration: _H.M.S. Torpedo Destroyer "Viper." This vessel was the -fastest afloat, attaining the enormous speed of 41 miles an hour. The -screws were worked by turbines, giving 11,000 horse-power. She was -wrecked on Alderney during the Naval Manoeuvres of 1901._] - -After this success Mr. Parsons erected works at Wallsend-on-Tyne for -the special manufacture of turbines. The Admiralty soon placed with -him an order for a torpedo-destroyer--the _Viper_--of 350 tons; which -on its trial trip exceeded forty-one miles an hour at an estimated -horse-power (11,000) equalling that of our largest battleships. A -sister vessel, the _Cobra_, of like size, proved as speedy. -Misfortune, however, overtook both destroyers. The _Viper_ was wrecked -August 3, 1901, on the coast of Alderney during the autumn naval -manoeuvres, and the _Cobra_ foundered in a severe storm on September -12 of the same year in the North Sea. This double disaster casts no -reflections on the turbine engines; being attributed to fog in the one -case and to structural weakness in the other. The Admiralty has since -ordered another turbine destroyer, and before many years are past we -shall probably see all the great naval powers providing themselves -with like craft to act as the "eyes of the fleet," and travel at even -higher speeds than those of the _Viper_ and _Cobra_. - -The turbine has been applied to mercantile as well as warlike -purposes. There is at the present time a turbine-propelled steamer, -the _King Edward_, running in the Clyde on the Fairlie-Campbelltown -route. This vessel, 250 feet long, 30 broad, 18 deep, contains three -turbines. In each the steam is expanded fivefold, so that by the time -it passes into the condensers it occupies 125 times its boiler volume. -(On the _Viper_ the steam entered the turbine through an inlet eight -inches in diameter, and left them by an outlet four feet square.) In -cylinder engines thirty-fold expansion is considered a high ratio; -hence the turbine extracts a great deal more power in proportion from -its steam. As a turbine cannot be reversed, special turbines are -attached to the two outside of the three propeller shafts to drive the -vessel astern. The steamer attained 20-1/2 knots over the "Skelmorlie -mile" in fair and calm weather, with 3500 horse-power produced at the -turbines. The _King Edward_ is thus the fastest by two or three knots -of all the Clyde steamers, as she is the most comfortable. We are -assured that as far as the turbines are concerned it is impossible by -placing the hand upon the steam-chest to tell whether the drum inside -is revolving or not! - -Every marine engine is judged by its economy in the consumption of -coal. Except in times of national peril extra speed produced by an -extravagant use of fuel would be severely avoided by all owners and -captains of ships. At low speeds the turbine develops less power than -cylinders from the same amount of steam, but when working at high -velocity it gives at least equal results. A careful record kept by the -managers of the Caledonian Steamship Company compares the _King -Edward_ with the _Duchess of Hamilton_, a paddle steamer of equal -tonnage used on the same route and built by the same firm. The record -shows that though the paddle-boat ran a fraction of a mile further -for every ton of coal burnt in the furnaces, the _King Edward_ -averaged two knots an hour faster, a superiority of speed quite out of -proportion to the slight excess of fuel. Were the _Duchess_ driven at -18-1/2 knots instead of 16-1/2 her coal bill would far exceed that of -the turbine. - -As an outcome of these first trials the Caledonian Company are -launching a second turbine vessel. Three high-speed turbine yachts are -also on the stocks; one of 700 tons, another of 1500 tons, and a third -of 170 tons. The last, the property of Colonel M'Calmont, is designed -for a speed of twenty-four knots. - -Mr. Parsons claims for his system the following advantages: Greatly -increased speed; increased carrying power of coal; economy in coal -consumption; increased facilities for navigating shallow waters; -greater stability of vessels; reduced weight of machinery (the -turbines of the _King Edward_ weigh but one-half of cylinders required -to give the same power); cheapness of attending the machinery; absence -of vibration, lessening wear and tear of the ship's hull and assisting -the accurate training of guns; lowered centre of gravity in the -vessel, and consequent greater safety during times of war. - -The inventor has suggested a cruiser of 2800 tons, engined up to -80,000 horse-power, to yield a speed of forty-four knots (about fifty -miles) an hour. Figures such as these suggest that we may be on the -eve of a revolution of ocean travel comparable to that made by the -substitution of steam for wind power. Whether the steam-turbine will -make for increased speed all round, or for greater economy, remains to -be seen; but we may be assured of a higher degree of comfort. We can -easily believe that improvements will follow in this as in other -mechanical contrivances, and that the turbine's efficiency has not yet -reached a maximum; and even if our ocean expresses, naval and -mercantile, do not attain the one-mile-a-minute standard, which is -still regarded as creditable to the fastest methods of land -locomotion, we look forward to a time in the near future when much -higher speeds will prevail, and the tedium of long voyages be greatly -shortened. Already there is talk of a service which shall reduce the -trans-Atlantic journey to three-and-a-half days. The means are at hand -to make it a fact. - - _Note._--In the recently-launched turbine destroyer _Velox_ a - novel feature is the introduction of ordinary reciprocating - engines fitted in conjunction with the steam turbines. These - engines are of triple-compound type, and are coupled direct to - the main turbines. They take steam from the boilers direct and - exhaust into the high-pressure turbine. These reciprocating - engines are for use at cruising speeds. When higher power is - needed the steam will be admitted to the turbines direct from - the boilers, and the cylinders be thrown out of gear. - - - - -MECHANICAL FLIGHT. - - -Few, if any, problems have so strongly influenced the imagination and -exercised the ingenuity of mankind as that of aërial navigation. There -is something in our nature that rebels against being condemned to the -condition of "featherless bipeds" when birds, bats, and even minute -insects have the whole realm of air and the wide heavens open to them. -Who has not, like Solomon, pondered upon "the way of a bird in the -air" with feelings of envy and regret that he is chained to earth by -his gross body; contrasting our laboured movements from point to point -of the earth's surface with the easy gliding of the feathered -traveller? The unrealised wish has found expression in legends of -Dædalus, Pegasus, in the "flying carpet" of the fairy tale, and in the -pages of Jules Verne, in which last the adventurous Robur on his -"Clipper of the Clouds" anticipates the future in a most startling -fashion. - -Aeromobilism--to use its most modern title--is regarded by the crowd -as the mechanical counterpart of the Philosopher's Stone or the Elixir -of Life; a highly desirable but unattainable thing. At times this -incredulity is transformed by highly-coloured press reports into an -equally unreasonable readiness to believe that the conquest of the air -is completed, followed by a feeling of irritation that facts are not -as they were represented in print. - -The proper attitude is of course half-way between these extremes. -Reflection will show us that money, time, and life itself would not -have been freely and ungrudgingly given or risked by many -men--hard-headed, practical men among them--in pursuit of a -Will-o'-the-Wisp, especially in a century when scientific calculation -tends always to calm down any too imaginative scheme. The existing -state of the aërial problem may be compared to that of a railway truck -which an insufficient number of men are trying to move. Ten men may -make no impression on it, though they are putting out all their -strength. Yet the arrival of an eleventh may enable them to overcome -the truck's inertia and move it at an increasing pace. - -Every new discovery of the scientific application of power brings us -nearer to the day when the truck will move. We have metals of -wonderful strength in proportion to their weight; pigmy motors -containing the force of giants; a huge fund of mechanical experience -to draw upon; in fact, to paraphrase the Jingo song, "We've got the -things, we've got the men, we've got the money too"--but we haven't -as yet got the machine that can mock the bird like the flying express -mocks the strength and speed of horses. - -The reason of this is not far to seek. The difficulties attending the -creation of a successful flying-machine are immense, some unique, not -being found in aquatic and terrestrial locomotion. - -In the first place, the airship, flying-machine, aerostat, or whatever -we please to call it, must not merely move, but also lift itself. -Neither a ship nor a locomotive is called upon to do this. Its ability -to lift itself must depend upon either the employment of large -balloons or upon sheer power. In the first case the balloon will, by -reason of its size, be unmanageable in a high wind; in the second -case, a breakdown in the machinery would probably prove fatal. - -Even supposing that our aerostat can lift itself successfully, we -encounter the difficulties connected with steering in a medium -traversed by ever-shifting currents of air, which demands of the -helmsman a caution and capacity seldom required on land or water. Add -to these the difficulties of leaving the ground and alighting safely -upon it; and, what is more serious than all, the fact that though -success can be attained only by experiment, experiment is in this case -extremely expensive and risky, any failure often resulting in total -ruin of the machine, and sometimes in loss of life. The list of those -who have perished in the search for the power of flight is a very long -one. - -Yet in spite of these obstacles determined attempts have been and are -being made to conquer the air. Men in a position to judge are -confident that the day of conquest is not very far distant, and that -the next generation may be as familiar with aerostats as we with -motor-cars. Speculation as to the future is, however, here less -profitable than a consideration of what has been already done in the -direction of collecting forces for the final victory. - -To begin at the beginning, we see that experimenters must be divided -into two great classes: those who pin their faith to airships lighter -than air, _e.g._ Santos Dumont, Zeppelin, Roze; and those who have -small respect for balloons, and see the ideal air-craft in a _machine_ -lifted entirely by means of power and surfaces pressing the air after -the manner of a kite. Sir Hiram Maxim and Professor S. P. Langley, Mr. -Lawrence Hargrave, and Mr. Sydney Hollands are eminent members of the -latter cult. - -As soon as we get on the topic of steerable balloons the name of Mr. -Santos Dumont looms large. But before dealing with his exploits we may -notice the airship of Count Zeppelin, an ingenious and costly -structure that was tested over Lake Constance in 1900. - -The balloon was built in a large wooden shed, 450 by 78 by 66 feet, -that floated on the lake on ninety pontoons. The shed alone cost over -£10,000. - -The balloon itself was nearly 400 feet long, with a cylindrical -diameter of 39 feet, except at its ends, which were conical, to offer -as little resistance as possible to the air. Externally it afforded -the appearance of a single-compartment bag, but in reality it was -divided into seventeen parts, each gas-tight, so that an accident to -one part of the fabric should not imperil the whole. - -A framework of aluminium rods and rings gave the bag a partial -rigidity. - -Its capacity was 12,000 cubic yards of hydrogen gas, which, as our -readers doubtless know, is much lighter though more expensive than -ordinary coal-gas; each inflation costing several hundreds of pounds. - -Under the balloon hung two cars of aluminium, the motors and the -screws; and also a great sliding weight of 600 lbs. for altering the -"tip" of the airship; and rudders to steer its course. - -On June 30 a great number of scientific men and experts assembled to -witness the behaviour of a balloon which had cost £20,000. For two -days wind prevented a start, but on July 2, at 7.30 P.M., the balloon -emerged from its shed, and at eight o'clock commenced its first -journey, with and against a light easterly wind for a distance of -three and a half miles. A mishap to the steering-gear occurred early -in the trip, and prevented the airship appearing to advantage, but a -landing was effected easily and safely. In the following October the -Count made a second attempt, returning against a wind blowing at three -yards a second, or rather more than six miles an hour. - -[Illustration: _The air-ship of M. Santos-Dumont rounding the Eiffel -Tower during its successful run for the Henri Deutsch Prize._] - -Owing to lack of funds the fate of the "Great Eastern" has overtaken -the Zeppelin airship--to be broken up, and the parts sold. - -The aged Count had demonstrated that a petroleum motor could be used -in the neighbourhood of gas without danger. It was, however, reserved -for a younger man to give a more decided proof of the steerableness of -a balloon. - -In 1900 M. Henri Deutsch, a member of the French Aero Club, founded a -prize of £4000, to win which a competitor must start from the Aero -Club Park, near the Seine in Paris, sail to and round the Eiffel -Tower, and be back at the starting-point within a time-limit of -half-an-hour. - -M. Santos Dumont, a wealthy and plucky young Brazilian, had, -previously to this offer, made several successful journeys in motor -balloons in the neighbourhood of the Eiffel Tower. He therefore -determined to make a bid for the prize with a specially constructed -balloon "Santos Dumont V." The third unsuccessful attempt ended in -disaster to the airship, which fell on to the houses, but fortunately -without injuring its occupant. - -Another balloon--"Santos Dumont VI."--was then built. On Saturday, -October 19th, M. Dumont reached the Tower in nine minutes and -recrossed the starting line in 20-1/2 more minutes, thus complying -with the conditions of the prize with half-a-minute to spare. A -dispute, however, arose as to whether the prize had been actually won, -some of the committee contending that the balloon should have come to -earth within the half-hour, instead of merely passing overhead; but -finally the well-merited prize was awarded to the determined young -aeronaut. - -The successful airship was of moderate proportions as compared with -that of Count Zeppelin. The cigar-shaped bag was 112 feet long and 20 -feet in diameter, holding 715 cubic yards of gas. M. Dumont showed -originality in furnishing it with a smaller balloon inside, which -could be pumped full of air so as to counteract any leakage in the -external bag and keep it taut. The motor, on which everything -depended, was a four-cylinder petrol-driven engine, furnished with -"water-jackets" to prevent over-heating. The motor turned a large -screw--made of silk and stretched over light frames--200 times a -minute, giving a driving force of 175 lbs. Behind, a rudder directed -the airship, and in front hung down a long rope suspended by one end -that could be drawn towards the centre of the frame to alter the trim -of the ship. The aeronaut stood in a large wicker basket flanked on -either side by bags of sand ballast. The fact that the motor, once -stopped, could only be restarted by coming to earth again added an -element of great uncertainty to all his trips; and on one occasion the -mis-firing of one of the cylinders almost brought about a collision -with the Eiffel Tower. - -From Paris M. Dumont went to Monaco at the invitation of the prince of -that principality, and cruised about over the bay in his balloon. His -fresh scheme was to cross to Corsica, but it was brought to an abrupt -conclusion by a leakage of gas, which precipitated balloon and -balloonist into the sea. Dumont was rescued, and at once set about new -projects, including a visit to the Crystal Palace, where he would have -made a series of ascents this summer (1902) but for damage done to the -silk of the gas-bag by its immersion in salt water and the other -vicissitudes it had passed through. Dumont's most important -achievement has been, like that of Count Zeppelin, the application of -the gasolene motor to aeromobilism. In proportion to its size this -form of motor develops a large amount of energy, and its mechanism is -comparatively simple--a matter of great moment to the aeronaut. He has -also shown that under favourable conditions a balloon may be steered -against a head-wind, though not with the certainty that is desirable -before air travel can be pronounced an even moderately simple -undertaking. The fact that many inventors, such as Dr. Barton, M. -Roze, Henri Deutsch, are fitting motors to balloons in the hopes of -solving the aërial problem shows that the airship has still a strong -hold on the minds of men. But on reviewing the successes of such -combinations of lifting and driving power it must be confessed, with -all due respect to M. Dumont, that they are somewhat meagre, and do -not show any great advance. - -The question is whether these men are not working on wrong lines, and -whether their utmost endeavours and those of their successors will -ever produce anything more than a very semi-successful craft. Their -efforts appear foredoomed to failure. As Sir Hiram Maxim has observed, -a balloon by its very nature is light and fragile, it is a mere -bubble. If it were possible to construct a motor to develop 100 -horse-power for every pound of its weight, it would still be -impossible to navigate a balloon against a wind of more than a certain -strength. The mere energy of the motor would crush the gas-bag against -the pressure of the wind, deform it, and render it unmanageable. -Balloons therefore must be at the mercy of the wind, and obliged to -submit to it under conditions not always in accordance with the wish -of the aeronaut. - -Sir Hiram in condemning the airship was ready with a substitute. On -looking round on the patterns of Nature, he concluded that, inasmuch -as all things that fly are heavier than air, the problem of aërial -navigation must be solved by a machine whose natural tendency is to -fall to the ground, and which can be sustained only by the exertion of -great force. Its very weight would enable it to withstand, at least to -a far greater extent than the airship, the varying currents of the -air. - -The lifting principle must be analogous to that by which a kite is -suspended. A kite is prevented from rising beyond a certain height by -a string, and the pressure of the wind working against it at an angle -tends to lift it, like a soft wedge continuously driven under it. In -practice it makes no difference whether the kite be stationary in a -wind or towed rapidly through a dead calm; the wedge-like action of -the air remains the same. - -Maxim decided upon constructing what was practically a huge compound -kite driven by very powerful motors. - -But before setting to work on the machine itself he made some useful -experiments to determine the necessary size of his kites or -aeroplanes, and the force requisite to move them. - -He accordingly built a "whirling-table," consisting of a long arm -mounted on a strong pivot at one end, and driven by a 10 horse-power -engine. To the free end, which described a circle of 200 feet in -circumference, he attached small aeroplanes, and by means of delicate -balances discovered that at 40 miles an hour the aeroplane would lift -133 lbs. per horse-power, and at 60 miles per hour every square foot -of surface sustained 8 lbs. weight. He, in common with other -experimenters on the same lines, became aware of the fact that if it -took a certain strain to suspend a stationary weight in the air, _to -advance it rapidly as well as to suspend it took a smaller strain_. -Now, as on sea and land, increased speed means a very rapid increase -in the force required, this is a point in favour of the -flying-machine. Professor Langley found that a brass plate weighing a -pound, when whirled at great speed, was supported in the air by a -pulling pressure of less than one ounce. And, of course, as the speed -increased the plate became more nearly horizontal, offering less -resistance to the air. - -It is on this behaviour of the aeroplane that the hopes of Maxim and -others have been based. The swiftly moving aeroplane, coming -constantly on to fresh air, the inertia of which had not been -disturbed, would resemble the skater who can at high speed traverse -ice that would not bear him at rest. - -Maxim next turned his attention to the construction of the aeroplanes -and engines. He made a special machine for testing fabrics, to decide -which would be most suitable for stretching over strong frames to form -the planes. The fabric must be light, very strong, and offer small -frictional resistance to the air. The testing-machine was fitted with -a nozzle, through which air was forced at a known pace on to the -substance under trial, which met the air current at a certain angle -and by means of indicators showed the strength of its "lift" or -tendency to rise, and that of its "drift" or tendency to move -horizontally in the direction of the air-current. A piece of tin, -mounted at an angle of one in ten to the air-current, showed a "lift" -of ten times its "drift." This proportion was made the standard. -Experiments conducted on velvet, plush, silk, cotton and woollen goods -proved that the drift of crape was several times that of its lift, but -that fine linen had a lift equal to nine times its drift; while a -sample of Spencer's balloon fabric was as good as tin. - -Accordingly he selected this balloon fabric to stretch over light but -strong frames. The stretching of the material was no easy matter, as -uneven tension distorted it; but eventually the aeroplanes were -completed, tight as drumheads. - -The large or central plane was 50 feet wide and 40 long; on either -side were auxiliary planes, five pairs; giving a total area of 5400 -square feet. - -The steam-engine built to give the motive power was perhaps the most -interesting feature of the whole construction. Maxim employed steam in -preference to any other power as being one with which he was most -familiar, and yielding most force in proportion to the weight of the -apparatus. He designed and constructed a pair of high-pressure -compound engines, the high-pressure cylinders 5 inches in diameter, -the low-pressure 8 inches, and both 1 foot stroke. Steam was supplied -to the high-pressure cylinders at 320 lbs. per square inch from a -tubular boiler heated by a gasolene burner so powerful in its action -as to raise the pressure from 100 to 200 lbs. in a minute. The total -weight of the boiler, burner, and engines developing 350 horse-power -was 2000 lbs., or about 6 lbs. per horse-power. - -The two screw-propellers driven by the engine measured 17 feet 11 -inches in diameter. - -The completed flying-machine, weighing 7500 lbs., was mounted on a -railway-truck of 9-foot gauge, in Baldwyn's Park, Kent, not far from -the gun-factories for which Sir Hiram is famous. Outside and parallel -to the 9-foot track was a second track, 35 feet across, with a -reversed rail, so that as soon as the machine should rise from the -inner track long spars furnished with flanged wheels at their -extremities should press against the under side of the outer track and -prevent the machine from rising too far. Dynamometers, or instruments -for measuring strains, were fitted to decide the driving and lifting -power of the screws. Experiments proved that with the engines working -at full power the screw-thrust against the air was 2200 lbs., and the -lifting force of the aeroplanes 10,000 lbs., or 1500 in excess of the -machine's weight. - -Everything being ready the machine was fastened to a dynamometer and -steam run up until it strained at its tether with maximum power; when -the moorings were suddenly released and it bounded forward at a -terrific pace, so suddenly that some of the crew were flung violently -down on to the platform. When a speed of 42 miles was reached the -inner wheels left their track, and the outer wheels came into play. -Unfortunately, the long 35-foot axletrees were too weak to bear the -strain, and one of them broke. The upper track gave way, and for the -first time in the history of the world a flying-machine actually left -the ground fully equipped with engines, boiler, fuel, and a crew. The -journey, however, was a short one, for part of the broken track fouled -the screws, snapped a propeller blade and necessitated the shutting -off of the steam, which done, the machine settled to earth, the wheels -sinking into the sward and showing by the absence of any marks that it -had come directly downwards and not run along the surface. - -The inventor was prevented by other business, and by the want of a -sufficiently large open space, from continuing his experiments, which -had demonstrated that a large machine heavier than air could be made -to lift itself and move at high speed. Misfortune alone prevented its -true capacities being shown. - -Another experimenter on similar lines, but on a less heroic scale than -Sir Hiram Maxim, is Professor S. P. Langley, the secretary of the -Smithsonian Institution, Washington. For sixteen years he has devoted -himself to a persevering course of study of the flying-machine, and -after oft-repeated failures has scored a decided success in his -Aerodrome, which, though only a model, has made considerable flights. -His researches have proved beyond doubt that the amount of energy -required for flight is but one-fiftieth of what was formerly regarded -as a minimum. A French mathematician had proved by figures that a -swallow must develop the power of a horse to maintain its rapid -flight! Professor Langley's aerodrome has told a very different tale, -affording another instance of the truth of the saying that an ounce of -practice is worth a pound of theory. - -A bird is nearly one thousand times heavier than the air it displaces. -As a motor it develops huge power for its weight, and consumes a very -large amount of fuel in doing so. An observant naturalist has -calculated that the homely robin devours per diem, in proportion to -its size, what would be to a man a sausage two hundred feet long and -three inches thick! Any one who has watched birds pulling worms out of -the garden lawn and swallowing them wholesale can readily credit this. - -Professor Langley therefore concentrated himself on the production of -an extremely light and at the same time powerful machine. Like Maxim, -he turned to steam for motive-power, and by rigid economy of weight -constructed an engine with boilers weighing 5 lbs., cylinders of 26 -ozs., and an energy of 1 to 1-1/2 horse-power! Surely a masterpiece of -mechanical workmanship! This he enclosed in a boat-shaped cover which -hung from two pairs of aeroplanes 12-1/2 feet from tip to tip. The -whole apparatus weighed nearly 30 lbs., of which one quarter -represented the machinery. Experiments with smaller aerodromes warned -the Professor that rigidity and balance were the two most difficult -things to attain; also that the starting of the machine on its aerial -course was far from an easy matter. - -A soaring bird does not rise straight from the ground, but opens its -wings and runs along the ground until the pressure of the air raises -it sufficiently to give a full stroke of its pinions. Also it rises -_against_ the wind to get the full benefit of its lifting force. -Professor Langley hired a houseboat on the Potomac River, and on the -top of it built an apparatus from which the aerodrome could be -launched into space at high velocity. - -On May 6, 1896, after a long wait for propitious weather, the -aerodrome was despatched on a trial trip. It rose in the face of the -wind and travelled for over half a mile at the rate of twenty-five -miles an hour. The water and fuel being then exhausted it settled -lightly on the water and was again launched. Its flight on both -occasions was steady, and limited only by the rapid consumption of its -power-producing elements. The Professor believes that larger machines -would remain in the air for a long period and travel at speeds -hitherto unknown to us. - -In both the machines that we have considered the propulsive power was -a screw. No counterpart of it is seen in Nature. This is not a valid -argument against its employment, since no animal is furnished with -driving-wheels, nor does any fish carry a revolving propeller in its -tail. But some inventors are strongly in favour of copying Nature as -regards the employment of wings. Mr. Sydney H. Hollands, an -enthusiastic aeromobilist, has devised an ingenious cylinder-motor so -arranged as to flap a pair of long wings, giving them a much stronger -impulse on the down than on the up stroke. The pectoral muscles of a -bird are reproduced by two strong springs which are extended by the -upward motion of the wings and store up energy for the down-stroke. -Close attention is also being paid to the actual shape of a bird's -wing, which is not flat but hollow on its under side, and at the front -has a slightly downward dip. "Aerocurves" are therefore likely to -supersede the "aeroplane," for Nature would not have built bird's -wings as they are without an object. The theory of the aerocurve's -action is this: that the front of the wing, on striking the air, gives -it a downwards motion, and if the wing were quite flat its rear -portion would strike air already in motion, and therefore less -buoyant. The curvature of a floating bird's wings, which becomes more -and more pronounced towards the rear, counteracts this yielding of the -air by pressing harder upon it as it passes towards their hinder edge. - -[Illustration: _M. Santos Dumont's Airship returning to Longchamps -after doubling the Eiffel Tower, October 19, 1901._] - -The aerocurve has been used by a very interesting group of -experimenters, those who, putting motors entirely aside, have floated -on wings, and learnt some of the secrets of balancing in the air. For -a man to propel himself by flapping wings moved by legs or arms is -impossible. Sir Hiram Maxim, in addressing the Aeronautical Society, -once said that for a man to successfully imitate a bird his lungs must -weigh 40 lbs., to consume sufficient oxygen, his breast muscles 75 -lbs., and his breast bone be extended in front 21 inches. And unless -his total weight were increased his legs must dwindle to the size of -broomsticks, his head to that of an apple! So that for the present we -shall be content to remain as we are! - -Dr. Lilienthal, a German, was the first to try scientific -wing-sailing. He became a regular air gymnast, running down the sides -of an artificial mound until the wings lifted him up and enabled him -to float a considerable distance before reaching earth again. His -wings had an area of 160 square feet, or about a foot to every pound -weight. He was killed by the wings collapsing in mid-air. A similar -fate also overtook Mr. Percy Pilcher, who abandoned the initial run -down a sloping surface in favour of being towed on a rope attached to -a fast-moving vehicle. At present Mr. Octave Chanute, of Chicago, is -the most distinguished member of the "gliding" school. He employs, -instead of wings, a species of kite made up of a number of small -aerocurves placed one on the top of another a small distance apart. -These box kites are said to give a great lifting force for their -weight. - -These and many other experimenters have had the same object in -view--to learn the laws of equilibrium in the air. Until these are -fully understood the construction of large flying-machines must be -regarded as somewhat premature. Man must walk before he can run, and -balance himself before he can fly. - -There is no falling off in the number of aërial machines and schemes -brought from time to time into public notice. We may assure ourselves -that if patient work and experiment can do it the problem of "how to -fly" is not very far from solution at the present moment. - -As a sign of the times, the War Office, not usually very ready to -take up a new idea, has interested itself in the airship, and -commissioned Dr. F. A. Barton to construct a dirigible balloon which -combines the two systems of aerostation. Propulsion is effected by six -sets of triple propellers, three on each side. Ascent is brought about -partly by a balloon 180 feet long, containing 156,000 cubic feet of -hydrogen, partly by nine aeroplanes having a total superficial area of -nearly 2000 square feet. The utilisation of these aeroplanes obviates -the necessity to throw out ballast to rise, or to let out gas for a -descent. The airship, being just heavier than air, is raised by the -135 horse-power motors pressing the aeroplanes against the air at the -proper angle. In descent they act as parachutes. - -The most original feature of this war balloon is the automatic -water-balance. At each end of the "deck" is a tank holding forty -gallons of water. Two pumps circulate water through these tanks, the -amount sent into a tank being regulated by a heavy pendulum which -turns on the cock leading to the end which may be highest in -proportion as it turns off that leading to the lower end. The idea is -very ingenious, and should work successfully when the time of trial -comes. - -Valuable money prizes will be competed for by aeronauts at the coming -World's Fair at St. Louis in 1903. Sir Hiram Maxim has expressed an -intention of spending £20,000 in further experiments and prizes. In -this country, too, certain journals have offered large rewards to any -aeronaut who shall make prescribed journeys in a given time. It has -also been suggested that aeronautical research should be endowed by -the state, since England has nothing to fear more than the flying -machine and the submarine boat, each of which tends to rob her of the -advantages of being an island by exposing her to unexpected and unseen -attacks. - -Tennyson, in a fine passage in "Locksley Hall," turns a poetical eye -towards the future. This is what he sees-- - - "For I dipt into the future, far as human eye could see, - Saw the vision of the world and all the wonder that would be, - Saw the heavens fill with commerce, argosies of magic sail, - Pilots of the purple twilight dropping down with costly bales, - Heard the heavens fill with shouting, then there rained a ghostly dew, - From the nations' airy navies, grappling in the central blue." - -Expressed in more prosaic language, the flying-machine will primarily -be used for military purposes. A country cannot spread a metal -umbrella over itself to protect its towns from explosives dropped from -the clouds. - -Mail services will be revolutionised. The pleasure aerodrome will take -the place of the yacht and motor-car, affording grand opportunities -for the mountaineer and explorer (if the latter could find anything -new to explore). Then there will also be a direct route to the North -Pole over the top of those terrible icefields that have cost -civilisation so many gallant lives. And possibly the ease of transit -will bring the nations closer together, and produce good-fellowship -and concord among them. It is pleasanter to regard the flying-machine -of the future as a bringer of peace than as a novel means of spreading -death and destruction. - - - - -TYPE-SETTING BY MACHINERY. - - -To the Assyrian brickmakers who, thousands of years ago, used blocks -wherewith to impress on their unbaked bricks hieroglyphics and -symbolical characters, must be attributed the first hesitating step -towards that most marvellous and revolutionary of human -discoveries--the art of printing. Not, however, till the early part of -the fifteenth century did Gutenberg and Coster conceive the brilliant -but simple idea of printing from separate types, which could be set in -different orders and combinations to represent different ideas. For -Englishmen, 1474 deserves to rank with 1815, as in that year a very -Waterloo was won on English soil against the forces of ignorance and -oppression, though the effects of the victory were not at once -evident. Considering the stir made at the time by the appearance of -Caxton's first book at Westminster, it seems strange that an invention -of such importance as the printing-press should have been frowned upon -by those in power, and so discouraged that for nearly two centuries -printing remained an ill-used and unprogressive art, a giant half -strangled in his cradle. Yet as soon as prejudice gave it an open -field, improved methods followed close on one another's heels. To-day -we have in the place of Caxton's rude hand-made press great cylinder -machines capable of absorbing paper by the mile, and grinding out -20,000 impressions an hour as easily as a child can unwind a reel of -cotton. - -Side by side with the problem how to produce the greatest possible -number of copies in a given time from one machine, has arisen -another:--how to set up type with a proportionate rapidity. A press -without type is as useless as a chaff-cutter without hay or straw. The -type once assembled, as many casts or stereotypes can be made from it -as there are machines to be worked. But to arrange a large body of -type in a short time brings the printer face to face with the -need of employing the expensive services of a small army of -compositors--unless he can attain his end by some equally efficient -and less costly means. For the last century a struggle has been in -progress between the machine compositor and the human compositor, -mechanical ingenuity against eye and brains. In the last five years -the battle has turned most decidedly in favour of the machine. To-day -there are in existence two wonderful contrivances which enable a man -to set up type six times as fast as he could by hand from a box of -type, with an ease that reminds one of the mythical machine for the -conversion of live pigs into strings of sausages by an uninterrupted -series of movements. - -These machines are called respectively the Linotype and Monotype. -Roughly described, they are to the compositor what a typewriter is to -a clerk--forming words in obedience to the depression of keys on a -keyboard. But whereas the typewriter merely imprints a single -character on paper, the linotype and monotype cast, deliver, and set -up type from which an indefinite number of impressions can be taken. -They meet the compositor more than half-way, and simplify his labour -while hugely increasing his productiveness. - -As far back as 1842 periodicals were mechanically composed by a -machine which is now practically forgotten. Since that time hundreds -of other inventions have been patented, and some scores of different -machines tried, though with small success in most cases; as it was -found that quality of composition was sacrificed to quantity, and that -what at first appeared a short cut to the printing-press was after all -the longest way round, when corrections had all been attended to. A -really economical type-setter must be accurate as well as prolific. -Slipshod work will not pay in the long run. - -Such a machine was perfected a few years ago by Ottmar Mergenthaler of -Baltimore, who devised the plan of casting a whole _line of type_. The -Linotype Composing Machine, to give it its full title, produces type -all ready for the presses in "slugs" or lines--hence the name, Lin' o' -type. It deserves at least a short description. - -The Linotype occupies about six square feet of floor space, weighs one -ton, and is entirely operated by one man. Its most prominent features -are a sloping magazine at the top to hold the brass matrices, or -dies from which the type is cast, a keyboard controlling the machinery -to drop and collect the dies, and a long lever which restores the dies -to the magazine when done with. - -[Illustration: _By kind permission of The Linotype Co._ - -_The Linotype Machine. By pressing keys on the key-board the operator -causes lines of type to be set up, cast, and arranged on the "galley" -ready for the printers._] - -The operator sits facing the keyboard, in which are ninety keys, -variously coloured to distinguish the different kinds of letters. His -hands twinkle over the keys, and the brass dies fly into place. When a -key is depressed a die shoots from the magazine on to a travelling -belt and is whirled off to the assembling-box. Each die is a flat, -oblong brass plate, of a thickness varying with the letter, having a -large V-shaped notch in the top, and the letter cut half-way down on -one of the longer sides. A corresponding letter is stamped on the side -nearest to the operator so that he may see what he is doing and make -needful corrections. - -As soon as a word is complete, he touches the "spacing" lever at the -side of the keyboard. The action causes a "space" to be placed against -the last die to separate it from the following word. The operations -are repeated until the tinkle of a bell warns him that, though there -may be room for one or two more letters, the line will not admit -another whole syllable. The line must therefore be "justified," that -is, the spaces between the words increased till the vacant room is -filled in. In hand composition this takes a considerable time, and is -irksome; but at the linotype the operator merely twists a handle and -the wedge-shaped "spaces," placed thin end upwards, are driven up -simultaneously, giving the lateral expansion required to make the line -of the right measure. - -A word about the "spaces," or space-bands. Were each a single wedge -the pressure would be on the bottom only of the dies, and their tops, -being able to move slightly, would admit lead between them. To obviate -this a small second wedge, thin end _downwards_, is arranged to slide -on the larger wedge, so that in all positions parallelism is secured. -This smaller wedge is of the same shape as the dies and remains -stationary in line with them, the larger one only moving. - -The line of dies being now complete, it is automatically borne off and -pressed into contact with the casting wheel. This wheel, revolving on -its centre, has a slit in it corresponding in length and width to the -size of line required. At first the slit is horizontal, and the dies -fit against it so that the row of sunk letters on the faces are in the -exact position to receive the molten lead, which is squirted through -the slit from behind by an automatic pump, supplied from a metal-pot. -The pot is kept at a proper heat of 550° Fahrenheit by the flames of a -Bunsen burner. - -The lead solidifies in an instant, and the "slug" of type is ready for -removal, after its back has been carefully trimmed by a knife. The -wheel revolves for a quarter-turn, bringing the slit into a vertical -position; a punch drives out the "slug," which is slid into the galley -to join its predecessors. The wheel then resumes its former horizontal -position in readiness for another cast. - -The assembled dies have for the time done their work and must be -returned to the magazine. The mechanism used to effect this is -peculiarly ingenious. - -An arm carrying a ribbed bar descends. The dies are pushed up, leaving -the "spaces" behind to be restored to their proper compartment, till -on a level with the ribbed bar, on to which they are slid by a lateral -movement, the notches of the V-shaped opening in the top side of each -die engaging with the ribs on the bar. The bar then ascends till it is -in line with a longer bar of like section passing over the open top of -the entire magazine. A set of horizontal screw-bars, rotating at high -speed, transfer the dies from the short to the long bar, along which -they move till, as a die comes above its proper division of the -magazine, the arrangement of the teeth allows it to drop. While all -this has been going on, the operator has composed another line of -moulds, which will in turn be transferred to the casting wheel, and -then back to the magazine. So that the three operations of composing, -casting, and sorting moulds are in progress simultaneously in -different parts of the machine; with the result that as many as 20,000 -letters can be formed by an expert in the space of an hour, against -the 1500 letters of a skilled hand compositor. - -How about corrections? Even a comma too few or too many needs the -whole line cast over again. It is a convincing proof of the difference -in speed between the two methods that a column of type can be -corrected much faster by the machine, handicapped as it is by its -solid "slugs," than by hand. No wonder then that more than 1000 -linotypes are to be found in the printing offices of Great Britain. - -The Monotype, like the Linotype, aims at speed in composition, but in -its mechanism it differs essentially from the linotype. In the first -place, the apparatus is constructed in two quite separate parts. There -is a keyboard, which may be on the third floor of the printing -offices, and the casting machine, which ceaselessly casts and sets -type in the basement. Yet they are but one whole. The connecting link -is the long strip of paper punched by the keyboard mechanism, and then -transferred to the casting machine to bring about the formation of -type. The keyboard is the servant of man; the casting machine is the -slave of the keyboard. - -Secondly, the Monotype casts type, not in blocks or a whole line, but -in separate letters. It is thus a complete type-foundry. Order it to -cast G's and it will turn them out by the thousand till another letter -is required. - -Thirdly, by means of the punched paper roll, the same type can be set -up time after time without a second recourse to the keyboard, just as -a tune is ground repeatedly out of a barrel organ. - -The keyboard has a formidable appearance. It contains 225 keys, -providing as many characters; also thirty keys to regulate the spacing -of the words. At the back of the machine a roll of paper runs over -rollers and above a row of thirty little punches worked by the keys. -A key being depressed, an opened valve admits air into two cylinders, -each driving a punch. The punches fly up and cut two neat little holes -in the paper. The roll then moves forward for the next letter. At the -end of the word a special lever is used to register a space, and so on -to the end of the line. The operator then consults an automatic -indicator which tells him exactly how much space is left, and how much -too long or too short the line would be if the spaces were of the -normal size. Supposing, for instance, that there are ten spaces, and -that there is one-tenth of an inch to spare. It is obvious that by -extending each space one-hundredth of an inch the vacant room will be -exactly filled. Similarly, if the ten normal spaces would make the -line one-tenth of an inch too _long_, by _decreasing_ the spaces each -one-hundredth inch the line will also be "justified." - -[Illustration: _By kind permission of_] [_The Monotype Co._ - -_The Monotype Casting Machine. A punched paper roll fed through the -top of the machine automatically casts and sets up type in separate -letters._] - -But the operator need not trouble his head about calculations of this -kind. His indicator, a vertical cylinder covered with tiny squares, in -each of which are printed two figures, tell him exactly what he has to -do. On pressing a certain key the cylinder revolves and comes to rest -with the tip of a pointer over a square. The operator at once presses -down the keys bearing the numbers printed on that square, confident -that the line will be of the proper length. - -As soon as the roll is finished, it is detached from the keyboard and -introduced to the casting machine. Hitherto passive, it now becomes -active. Having been placed in position on the rollers it is slowly -unwound by the machinery. The paper passes over a hollow bar in which -there are as many holes as there were punches in the keyboard, and in -precisely the same position. When a hole in the paper comes over a -hole in the hollow bar air rushes in, and passing through a tube -actuates the type-setting machinery in a certain manner, so as to -bring the desired die into contact with molten lead. The dies are, in -the monotype, all carried in a magazine about three inches square, -which moves backwards or forwards, to right or left, in obedience to -orders from the perforated roll. The dies are arranged in exactly the -same way as the keys on the keyboard. So that, supposing A to have -been stamped on the roll, one of the perforations causes the magazine -to slide one way, while the other shoves it another, until the -combined motions bring the matrix engraved with the A underneath the -small hole through which molten lead is forced. The letter is ejected -and moves sideways through a narrow channel, pushing preceding letters -before it, and the magazine is free for other movements. - -At the end of each word a "space" or blank lead is cast, its size -exactly determined by the "justifying" hole belonging to that line. -Word follows word till the line is complete; then a knife-like lever -rises, and the type is propelled into the "galley." Though a slave the -casting machine will not tolerate injustice. Should the compositor -have made a mistake, so that the line is too long or too short, -automatic machinery at once comes into play, and slips the driving -belt from the fixed to the loose pulley, thus stopping the machine -till some one can attend to it. But if the punching has been correctly -done, the machine will work away unattended till, a whole column of -type having been set up, it comes to a standstill. - -The advantages of the Monotype are easily seen. In order to save money -a man need not possess the complete apparatus. If he has the keyboard -only he becomes to a certain extent his own compositor, able to set up -the type, as it were by proxy, at any convenient time. He can give his -undivided attention to the keyboard, stop work whenever he likes -without keeping a casting-machine idle, and as soon as his roll is -complete forward it to a central establishment where type is set. -There a single man can superintend the completion of half-a-dozen -men's labours at the keyboard. That means a great reduction of -expense. - -In due time he receives back his copy in the shape of set-up type, all -ready to be corrected and transferred to the printing machines. The -type done with, he can melt it down without fear of future regret, for -he knows that the paper roll locked up in his cupboard will do its -work a second time as well as it did the first. Should he need the -same matter re-setting, he has only to send the roll through the post -to the central establishment. - -Thanks to Mr. Lanston's invention we may hope for the day when every -parish will be able to do its own printing, or at least set up its own -magazine. The only thing needful will be a monotype keyboard supplied -by an enlightened Parish Council--as soon as the expense appears -justifiable--and kept in the Post Office or Village Institute. The -payment of a small fee will entitle the Squire to punch out his speech -on behalf of the Conservative Candidate, the Schoolmaster to compose -special information for his pupils, the Rector to reduce to print -pamphlets and appeals to charity. And if those of humbler degree think -they can strike eloquence from the keys, they too will of course be -allowed to turn out their ideas literally by the yard. - - - - -PHOTOGRAPHY IN COLOURS. - - -While photography was still in its infancy many people believed that, -a means having been found of impressing the representation of an -object on a sensitised surface, a short time only would have to elapse -before the discovery of some method of registering the colours as well -as the forms of nature. - -Photography has during the last forty years passed through some -startling developments, especially as regards speed. Experts, such as -M. Marey, have proved the superiority of the camera over the human eye -in its power to grasp the various phases of animal motion. Even rifle -bullets have been arrested in their lightning flight by the sensitised -plate. But while the camera is a valuable aid to the eye in the matter -of form, the eye still has the advantage so far as colour is -concerned. It is still impossible for a photographer by a simple -process similar to that of making an ordinary black-and-white -negative, to affect a plate in such a manner that from it prints may -be made by a single operation showing objects in their natural -colours. Nor, for the matter of that, does colour photography direct -from nature seem any nearer attainment now than it was in the time of -Daguerre. - -There are, however, extant several methods of making colour -photographs in an indirect or roundabout way. These various "dodges" -are, apart from their beautiful results, so extremely ingenious and -interesting that we propose to here examine three of the best known. - -The reader must be careful to banish from his mind those _coloured_ -photographs so often to be seen in railway carriages and shop windows, -which are purely the result of hand-work and mechanical printing, and -therefore not _colour_ photographs at all. - -Before embarking on an explanation of these three methods it will be -necessary to examine briefly the nature of those phenomena on which -all are based--light and colour. The two are really identical, light -is colour and colour is light. - -Scientists now agree that the sensation of light arises from the -wave-like movements of that mysterious fluid, the omnipresent ether. -In a beam of white light several rates of wave vibrations exist side -by side. Pass the beam through a prism and the various rapidities are -sorted out into violet, indigo, blue, green, yellow, orange and red, -which are called the pure colours, since if any of them be passed -again through a prism the result is still that colour. Crimson, brown, -&c., the composite colours, would, if subjected to the prism, at once -split up into their component pure colours. - -There are several points to be noticed about the relationship of the -seven pure colours. In the first place, though they are all allies in -the task of making white light, there is hostility among them, each -being jealous of the others, and only waiting a chance to show it. -Thus, suppose that we have on a strip of paper squares of the seven -colours, and look at the strip through a piece of red glass we see -only one square--the red--in its natural colour, since that square is -in harmony only with red rays. (Compare the sympathy of a piano with a -note struck on another instrument; if C is struck, say on a violin, -the piano strings producing the corresponding note will sound, but the -other strings will be silent.) The orange square suggests orange, but -the green and blue and violet appear black. Red glass has arrested -their ether vibrations and said "no way here." Green and violet would -serve just the same trick on red or on each other. It is from this -readiness to absorb or stop dissimilar rays that we have the different -colours in a landscape flooded by a common white sunlight. The trees -and grass absorb all but the green rays, which they reflect. The -dandelions and buttercups capture and hold fast all but the yellow -rays. The poppies in the corn send us back red only, and the -cornflowers only blue; but the daisy is more generous and gives up all -the seven. Colour therefore is not a thing that can be touched, any -more than sound, but merely the capacity to affect the retina of the -eye with a certain number of ether vibrations per second, and it makes -no difference whether light is reflected from a substance or refracted -through a substance; a red brick and a piece of red glass have similar -effects on the eye. - -This then is the first thing to be clearly grasped, that whenever a -colour has a chance to make prisoners of other colours it will do so. - -The second point is rather more intricate, viz. that this imprisonment -is going on even when friendly concord appears to be the order of the -day. Let us endeavour to present this clearly to the reader. Of the -pure colours, violet, green and red--the extremes and the centre--are -sufficient to produce white, because each contains an element of its -neighbours. Violet has a certain amount of indigo, green some yellow, -red some orange; in fact every colour of the spectrum contains a -greater or less degree of several of the others, but not enough to -destroy its own identity. Now, suppose that we have three lanterns -projecting their rays on to the same portion of a white sheet, and -that in front of the first is placed a violet glass, in front of the -second a green glass, in front of the third a red glass. What is the -result? A white light. Why? Because they meet _on equal terms_, and as -no one of them is in a point of advantage no prisoners can be made and -they must work in harmony. Next, turn down the violet lantern, and -green and red produce a yellow, half-way between them; turn down red -and turn up violet, indigo-blue results. All the way through a -compromise is effected. - -But supposing that the red and green glasses are put in front of the -_same_ lantern and the white light sent through them--where has the -yellow gone to? only a brownish-black light reaches the screen. The -same thing happens with red and violet or green and violet. - -Prisoners have been taken, because one colour has had to _demand -passage_ from the other. Red says to green, "You want your rays to -pass through me, but they shall not." Green retorts, "Very well; but I -myself have already cut off all but green rays, and if they don't pass -you, nothing shall." And the consequence of the quarrel is practical -darkness. - -The same phenomenon may be illustrated with blue and yellow. Lights of -these two colours projected simultaneously on to a sheet yield white; -but white light sent through blue and yellow glass _in succession_ -produces a green light. Also, blue paint mixed with yellow gives -green. In neither case is there darkness or entire cutting-off of -colour, as in the case of Red + Violet or Green + Red. - -The reason is easy to see. - -Blue light is a compromise of violet and green; yellow of green and -red. Hence the two coloured lights falling on the screen make a -combination which can be expressed as an addition sum. - - Blue = green + violet. - Yellow = green + red. - -------------------- - green + violet + red = white. - -But when light is passed _through_ two coloured glasses in succession, -or reflected from two layers of coloured paints, there are prisoners -to be made. - -Blue passes green and violet only. - -Yellow passes green and red only. - -So violet is captured by yellow, and red by blue, green being free to -pass on its way. - -There is, then, a great difference between the _mixing_ of colours, -which evokes any tendency to antagonism, and the _adding_ of colours -under such conditions that they meet on equal terms. The first process -happens, as we have seen, when a ray of light is passed through -colours _in succession_; the second, when lights stream simultaneously -on to an object. A white screen, being capable of reflecting any -colour that falls on to it, will with equal readiness show green, red, -violet, or a combination; but a substance that is in white light red, -or green, or violet will capture any other colour. So that if for the -white screen we substituted a red one, violet or green falling -simultaneously, would yield blackness, because red takes _both_ -prisoners; if it were violet, green would be captured, and so on. - -From this follows another phenomenon: that whereas projection of two -or more lights may yield white, white cannot result from any mixture -of pigments. A person with a whole boxful of paints could not get -white were he to mix them in an infinitude of different ways; but with -the aid of his lanterns and as many differently coloured glasses the -feat is easy enough. - -Any two colours which meet on equal terms to make white are called -_complementary_ colours. - - Thus yellow (= red + green lights) is complementary of violet. - - Thus pink (= red + violet lights) is complementary of green. - - Thus blue (= violet + green lights) is complementary of red. - -This does not of course apply to mixture of paints, for complementary -colours must act together, not in antagonism. - -If the reader has mastered these preliminary considerations he will -have no difficulty in following out the following processes. - -(_a_) _The Joly Process_, invented by Professor Joly of Dublin. A -glass plate is ruled across with fine parallel lines--350 to the inch, -we believe. These lines are filled in alternately with violet, green, -and red matter, every third being violet, green or red as the case may -be. The colour-screen is placed in the camera in front of the -sensitised plate. Upon an exposure being made, all light reflected -from a red object (to select a colour) is allowed to pass through the -red lines, but blocked by all the green and violet lines. So that on -development that part of the negative corresponding to the position of -the red object will be covered with dark lines separated by -transparent belts of twice the breadth. From the negative a positive -is printed, which of course shows transparent lines separated by -opaque belts of twice their breadth. Now, suppose that we take the -colour-screen and place it again in front of the plate in the position -it occupied when the negative was taken, the red lines being opposite -the transparent parts of the positive will be visible, but the green -and violet being blocked by the black deposit behind them will not be -noticeable. So that the object is represented by a number of red -lines, which at a small distance appear to blend into a continuous -whole. - -The violet and green affect the plate in a corresponding manner; and -composite colours will affect two sets of lines in varying degrees, -the lights from the two sets blending in the eye. Thus yellow will -obtain passage from both green and red, and when the screen is held up -against the positive, the light streaming through the green and red -lines will blend into yellow in the same manner as they would make -yellow if projected by lanterns on to a screen. The same applies to -all the colours. - -The advantage of the Joly process is that in it only one negative has -to be made. - -(_b_) _The Ives Process._--Mr. Frederic Eugene Ives, of Philadelphia, -arrives at the same result as Professor Joly, but by an entirely -different means. He takes three negatives of the same object, one -through a violet-blue, another through a green, and a third through a -red screen placed in front of the lens. The red negative is affected -by red rays only; the green by green rays only, and the violet-blue by -violet-blue rays only, in the proper gradations. That is to say, each -negative will have opaque patches wherever the rays of a certain kind -strike it; and the positive printed off will be by consequence -transparent at the same places. By holding the positive made from the -red-screen negative against a piece of red glass, we should see light -only in those parts of the positive which were transparent. Similarly -with the green and violet positives if viewed through glasses of -proper colour. The most ingenious part of Mr. Ives' method is the -apparatus for presenting all three positives (lighted through their -coloured glasses) to the eye simultaneously. When properly adjusted, -so that their various parts exactly coincide, the eye blends the three -together, seeing green, red, or violet separately, or blended in -correct proportions. The Kromoscope, as the viewing apparatus is -termed, contains three mirrors, projecting the reflections from the -positives in a single line. As the three slides are taken -stereoscopically the result gives the impression of solidity as well -as of colour, and is most realistic. - -(_c_) _The Sanger Shepherd Process._--This is employed mostly for -lantern transparencies. As in the Ives process, three negatives and -three transparent positives are made. But instead of coloured glasses -being used to give effect to the positives the positives themselves -are dyed, and placed one on the top of another in close contact, so -that the light from the lantern passes through them in succession. We -have therefore now quitted the realms of harmony for that of discord, -in which prisoners are made; and Mr. Shepherd has had to so arrange -matters that in every case the capture of prisoners does not interfere -with the final result, but conduces to it. - -In the first place, three negatives are secured through violet, green, -and red screens. Positives are printed by the carbon process on thin -celluloid films. The carbon film contains gelatine and bichromate of -potassium. The light acts on the bichromate in such a way as to render -the gelatine insoluble. The result is that, though in the positives -there is at first no colour, patches of gelatine are left which will -absorb dyes of various colours. The dyeing process requires a large -amount of care and patience. - -Now, it would be a mistake to suppose that each positive is dyed in -the colour of the screen through which its negative was taken. A -moment's consideration will show us why. - -Let us assume that we are photographing a red object, a flower-pot for -instance. The red negative represents the pot by a dark deposit. The -positive printed off will consequently show clear glass at that spot, -the unaffected gelatine being soluble. So that to dye the plate would -be to make all red _except_ the very part which we require red; and on -holding it up to the light the flower-pot would appear as a white -transparent patch. - -How then is the problem to be solved? - -Mr. Shepherd's process is based upon an ordered system of -prisoner-taking. Thus, as red in this particular case is wanted it -will be attained by the _other two_ positives (which are placed in -contact with the red positive, so that all three coincide exactly), -robbing white light of all _but_ its red rays. - -Now if the other positives were dyed green and violet, what would -happen? They would not produce red, but by robbing white light between -them of red, green, and violet, would produce blackness, and we should -be as far as ever from our object. - -The positives are therefore dyed, not in the same colours as the -screens used when the negatives were made, but in their -_complementary_ colours, _i.e._ as explained above, those colours -which added to the colour of the screen would make white. - -The red screen negative is therefore dyed (violet + green) = blue. The -green negative (red + violet) = pink. The violet negative (red + -green) = yellow. - -To return to our flower-pot. The red-screen positive (dyed blue) is, -as we saw, quite transparent where the pot should be. But behind the -transparent gap are the pink and yellow positives. - -White light (= violet + green + red) passes through pink (= violet + -red), and has to surrender all its green rays. The violet and red pass -on and encounter yellow (= green + red), and violet falls a victim to -green, leaving red unmolested. - -If the flower-pot had been white all three positives would have -contained clear patches unaffected by the three dyes, and the white -light would have been unobstructed. The gradations and mixtures of -colours are obtained by two of the screens being influenced by the -colour of the object. Thus, if it were crimson, both violet and -red-screen negatives would be affected by the rays reflected by it, -and the green screen negative not at all. Hence the pink positive -would be pink, the yellow clear, and the blue clear. - -White light passing through is robbed by pink of green, leaving red + -violet = crimson. - - -COLOUR PRINTING. - -Printing in ink colours is done in a manner very similar to the Sanger -Shepherd lantern slide process. Three blocks are made, by the help of -photography, through violet, green and red screens, and etched away -with acid, like ordinary half-tone black-and-white blocks. The three -blocks have applied to them ink of a complementary colour to the -screen they represent, just as in the Sanger Shepherd process the -positives were dyed. The three inks are laid over one another on the -paper by the blocks, the relieved parts of which (corresponding to the -undissolved gelatine of the Shepherd positives) only take the ink. -White light being reflected through layers of coloured inks is treated -in just the same way as it would be were it transmitted through -coloured glasses, yielding all the colours in approximately correct -gradations. - - - - -LIGHTING. - - -The production of fire by artificial means has been reasonably -regarded as the greatest invention in the history of the human race. -Prior to the day when a man was first able to call heat from the -substances about him the condition of our ancestors must have been -wretched indeed. Raw food was their portion; metals mingled with other -matter mocked their efforts to separate them; the cold of winter drove -them to the recesses of gloomy caverns, where night reigned perpetual. - -The production of fire also, of course, entailed the creation of -light, which in its developments has been of an importance second only -to the improved methods of heating. So accustomed are we to our -candles, our lamps, our gas-jets, our electric lights, that it is hard -for us to imagine what an immense effect their sudden and complete -removal would have on our existence. At times, when floods, -explosions, or other accidents cause a temporary stoppage of the gas -or current supply, a town may for a time be plunged into darkness; but -this only for a short period, the distress of which can be alleviated -by recourse to paraffin lamps, or the more homely candle. - -The earliest method of illumination was the rough-and-ready one of -kindling a pile of brushwood or logs. The light produced was very -uncertain and feeble, but possibly sufficient for the needs of the -cave-dweller. With the advance of civilisation arose an increasing -necessity for a more steady illuminant, discovered in vegetable oils, -burned in lamps of various designs. Lamps have been found in old -Egyptian and Etruscan tombs constructed thousands of years ago. These -lamps do not differ essentially from those in use to-day, being -reservoirs fitted with a channel to carry a wick. - -But probably from the difficulty of procuring oil, lamps fell into -comparative disuse, or rather were almost unknown, in many countries -of Europe as late as the fifteenth century; when the cottage and -baronial hall were alike lit by the blazing torch fixed into an iron -sconce or bracket on the wall. - -The rushlight, consisting of a peeled rush, coated by repeated dipping -into a vessel of melted fat, made a feeble effort to dispel the gloom -of long winter evenings. This was succeeded by the tallow and more -scientifically made wax candle, which last still maintains a certain -popularity. - -How our grandmothers managed to "keep their eyes" as they worked at -stitching by the light of a couple of candles, whose advent was the -event of the evening, is now a mystery. To-day we feel aggrieved if -our lamps are not of many candle-power, and protest that our sight -will be ruined by what one hundred and fifty years ago would have -seemed a marvel of illumination. In the case of lighting necessity has -been the mother of invention. The tendency of modern life is to turn -night into day. We go to bed late and we get up late; this is perhaps -foolish, but still we do it. And, what is more, we make increasing use -of places, such as basements, underground tunnels, and "tubes," to -which the light of heaven cannot penetrate during any of the daily -twenty-four hours. - -The nineteenth century saw a wonderful advance in the science of -illumination. As early as 1804 the famous scientist, Sir Humphrey -Davy, discovered the electric arc, presently to be put to such -universal use. About the same time gas was first manufactured and led -about in pipes. But before electricity for lighting purposes had been -rendered sufficiently cheap the discovery of the huge oil deposits in -Pennsylvania flooded the world with an inexpensive illuminant. As -early as the thirteenth century Marco Polo, the explorer, wrote of a -natural petroleum spring at Baku, on the Caspian Sea: "There is a -fountain of great abundance, inasmuch as a thousand shiploads might be -taken from it at one time. This oil is not good to use with food, but -it is _good to burn_; and is also used to anoint camels that have the -mange. People come from vast distances to fetch it, for in all other -countries there is no oil." His last words have been confuted by the -American oil-fields, yielding many thousands of barrels a day--often -in such quantities that the oil runs to waste for lack of a buyer. - -The rivals for pre-eminence in lighting to-day are electricity, coal -gas, petroleum, and acetylene gas. The two former have the advantage -of being easily turned on at will, like water; the third is more -generally available. - -The invention of the dynamo by Gramme in 1870 marks the beginning of -an epoch in the history of illumination. With its aid current of such -intensity as to constantly bridge an air-gap between carbon points -could be generated for a fraction of the cost entailed by other -previous methods. Paul Jablochkoff devised in 1876 his "electric -candle"--a couple of parallel carbon rods separated by an insulating -medium that wasted away under the influence of heat at the same rate -as the rods. The "candles" were used with rapidly-alternating -currents, as the positive "pole" wasted twice as quickly as the -negative. During the Paris Exhibition of 1878 visitors to Paris were -delighted by the new method of illumination installed in some of the -principal streets and theatres. - -The arc-lamp of to-day, such as we see in our streets, factories, and -railway stations, is a modification of M. Jablochkoff's principle. -Carbon rods are used, but they are pointed towards each other, the -distance between their extremities being kept constant by ingenious -mechanical contrivances. Arc-lamps of all types labour under the -disadvantage of being, by necessity, very powerful; and were they only -available the employment of electric lighting would be greatly -restricted. As it is, we have, thanks to the genius of Mr. Edison, a -means of utilising current in but small quantities to yield a gentler -light. The glow-lamp, as it is called, is so familiar to us that we -ought to know something of its antecedents. - -In the arc-lamp the electric circuit is _broken_ at the point where -light is required. In glow or incandescent lamps the current is only -_hindered_ by the interposition of a bad conductor of electricity, -which must also be incombustible. Just as a current of water flows in -less volume as the bore of a pipe is reduced, and requires that -greater pressure shall be exerted to force a constant amount through -the pipe, so is an electric current _choked_ by its conductor being -reduced in size or altered in nature. Edison in 1878 employed as the -current-choker a very fine platinum wire, which, having a melting -temperature of 3450 degrees Fahrenheit, allowed a very white heat to -be generated in it. The wire was enclosed in a glass bulb almost -entirely exhausted of air by a mercury-pump before being sealed. But -it was found that even platinum could not always withstand the heating -effect of a strong current; and accordingly Edison looked about for -some less combustible material. Mr. J. W. Swan of Newcastle-on-Tyne -had already experimented with carbon filaments made from cotton -threads steeped in sulphuric acid. Edison and Swan joined hands to -produce the present well-known lamp, "The Ediswan," the filament of -which is a bamboo fibre, carbonised during the exhaustion of air in -the bulb to one-millionth of an atmosphere pressure by passing the -electric current through it. These bamboo filaments are very elastic -and capable of standing almost any heat. - -Glow-lamps are made in all sizes--from tiny globes small enough to top -a tie-pin to powerful lamps of 1000 candle-power. Their independence -of atmospheric air renders them most convenient in places where other -forms of illumination would be dangerous or impossible; _e.g._ in coal -mines, and under water during diving operations. By their aid great -improvements have been effected in the lighting of theatres, which -require a quick switching on and off of light. They have also been -used in connection with minute cameras to explore the recesses of the -human body. In libraries they illuminate without injuring the books. -In living rooms they do not foul the air or blacken the ceiling like -oil or gas burners. The advantages of the "Edison lamp" are, in short, -multitudinous. - -Cheapness of current to work them is, of course, a very important -condition of their economy. In some small country villages the -cottages are lit by electricity even in England, but these are -generally within easy reach of water power. Mountainous districts, -such as Norway and Switzerland, with their rushing streams and high -water-falls, are peculiarly suited for electric lighting: the cost of -which is mainly represented by the expense of the generating apparatus -and the motive power. - -One of the greatest engineering undertakings in the world is connected -with the manufacture of electric current. Niagara, the "Thunder of the -Waters" as the Indians called it, has been harnessed to produce -electrical energy, convertible at will into motion, heat, or light. -The falls pass all the water overflowing from nearly 100,000 square -miles of lakes, which in turn drain a far larger area of territory. -Upwards of 10,000 cubic yards of water leap over the falls every -second, and are hurled downwards for more than 200 feet, with an -energy of eight or nine million horse-power! In 1886 a company -determined to turn some of this huge force to account. They bought up -land on the American bank, and cut a tunnel 6700 yards long, beginning -a mile and a half above the falls, and terminating below them. Water -drawn from the river thunders into the tunnel through a number of -wheel pits, at the bottom of each of which is a water-turbine -developing 5000 horse-power. The united force of the turbines is said -to approximate 100,000 horse-power; and as if this were but a small -thing, the same Company has obtained concessions to erect plant on the -Canadian bank to double or treble the total power. - -So cheaply is current thus produced that the Company is in a position -to supply it at rates which appear small compared with those that -prevail in this country. A farthing will there purchase what would -here cost from ninepence to a shilling. Under such conditions the -electric lamp need fear no competitor. - -But in less favoured districts gas and petroleum are again holding up -their heads. - -Both coal and oil-gas develop a great amount of heat in proportion to -the light they yield. The hydrogen they contain in large quantities -burns, when pure, with an almost invisible flame, but more hotly than -any other known gas. The particles of carbon also present in the flame -are heated to whiteness by the hydrogen, but they are not sufficient -in number to convert more than a fraction of the heat into light. - -A German, Auer von Welsbach, conceived the idea of suspending round -the flame a circular "mantle" of woven cotton steeped in a solution of -certain rare earths (_e.g._ lanthanum, yttrium, zirconium), to arrest -the heat and compel it to produce bright incandescence in the -arresting substance. - -With the same gas consumption a Welsbach burner yields seven or more -times the light of an ordinary batswing burner. The light itself is -also of a more pleasant description, being well supplied with the blue -rays of the spectrum. - -The mantle is used with other systems than the ordinary gas-jet. -Recently two methods of illumination have been introduced in which the -source of illumination is supplied under pressure. - -The high-pressure incandescent gas installations of Mr. William Sugg -supply gas to burners at five or six times the ordinary pressure of -the mains. The effect is to pulverise the gas as it issues from the -nozzle of the burners, and, by rendering it more inflammable, to -increase its heating power until the surrounding mantle glows with a -very brilliant and white light of great penetration. Gas is forced -through the pipes connected with the lamps by hydraulic rams working -gas-pumps, which alternately suck in and expel the gas under a -pressure of twelve inches (_i.e._ a pressure sufficient to maintain a -column of water twelve inches high). The gas under this pressure -passes into a cylinder of a capacity considerably greater than the -capacity of the pumps. This cylinder neutralises the shock of the -rams, when the stroke changes from up-to downstroke, and _vice versâ_. -On the top of the cylinder is fixed a governor consisting of a strong -leathern gas-holder, which has a stroke of about three inches, and -actuates a lever which opens and closes the valve through which the -supply of water to the rams flows, and reduces the flow of the water -when it exceeds ten or twelve inches pressure, according to -circumstances. The gas-holder of the governor is lifted by the -pressure of the gas in the cylinder, which passes through a small -opening from the cylinder to the governor so as not to cause any -sudden rise or fall of the gas-holder. By this means a nearly constant -pressure is maintained; and from the outlet of the cylinder the gas -passes to another governor sufficient to supply the number of lights -the apparatus is designed for, and to maintain the pressure without -variation whether all or a few lamps are in action. For very large -installations steam is used. - -Each burner develops 300 candle-power. A double-cylinder steam-engine -working a double pump supplies 300 of these burners, giving a total -lighting-power of 90,000 candles. As compared with the cost of -low-pressure incandescent lighting the high-pressure system is very -economical, being but half as expensive for the same amount of light. - -It is largely used in factories and railway stations. It may be seen -on the Tower Bridge, Blackfriars Bridge, Euston Station, and in the -terminus of the Great Central Railway, St. John's Wood. - -Perhaps the most formidable rival to the electric arc-lamp for the -lighting of large spaces and buildings is the Kitson Oil Lamp, now so -largely used in America and this country. - -The lamp is usually placed on the top of an iron post similar to an -ordinary gas-light standard. At the bottom of the post is a chamber -containing a steel reservoir capable of holding from five to forty -gallons of petroleum. Above the oil is an air-space into which air has -been forced at a pressure of fifty lbs. to the square inch, to act as -an elastic cushion to press the oil into the burners. The oil passes -upwards through an extremely fine tube scarcely thicker than electric -incandescent wires to a pair of cross tubes above the burners. The top -one of these acts as a filter to arrest any foreign matter that finds -its way into the oil; the lower one, in diameter about the size of a -lead-pencil and eight inches long, is immediately above the mantles, -the heat from which vaporises the small quantity of oil in the tube. -The oil-gas then passes through a tiny hole no larger than a -needle-point into an open mixing-tube where sufficient air is drawn in -for supporting combustion. The mixture then travels down to the -mantle, inside which it burns. - -An ingenious device has lately been added to the system for -facilitating the lighting of the lamp. At the base of the lamp-post a -small hermetically-closed can containing petroleum ether is placed, -and connected by very fine copper-tubing with a burner under the -vaporising tube. When the lamp is to be lit a small rubber bulb is -squeezed, forcing a quantity of the ether vapour into the burner, -where it is ignited by a platinum wire rendered incandescent by a -current passing from a small accumulator also placed in the lamp-post. -The burner rapidly heats the vaporising tube, and in a few moments -oil-gas is passing into the mantles, where it is ignited by the -burner. - -So economical is the system that a light of 1000 candle-power is -produced by the combustion of about half-a-pint of petroleum per hour! -Comparisons are proverbially odious, but in many cases very -instructive. Professor V. B. Lewes thus tabulates the results of -experiments with various illuminants:-- - -_Cost of 1000 candles per hour._ - - _s. d._ - Electricity Per unit, 3-1/2d. - " Incandescent, 1 2 - " Arc, 0 3-3/4 - Coal-gas Flat flame, 1 6 - " Incandescent, 0 2-1/4 - " " high pressure, 0 1-3/4 - Oil Lamp (oil at 8d. per gall.), 0 7-1/4 - " Incandescent lamp, 0 2-1/4 - " Kitson lamp, 0 1 - -Petroleum, therefore, at present comes in a very good first in -England. - -The system that we have noticed at some length has been adapted for -lighthouse use, as it gives a light peculiarly fog-piercing. It is -said to approximate most closely to ordinary sunlight, and on that -account has been found very useful for the taking of photographs at -night-time. The portability of the apparatus makes it popular with -contractors; and the fact that its installation requires no tearing up -of the streets is a great recommendation with the long-suffering -public of some of our large towns. - -Another very powerful light is produced by burning the gas given off -by carbide of calcium when immersed in water. _Acetylene_ gas, as it -is called, is now widely used in cycle and motor lamps, which emit a -shaft of light sometimes painfully dazzling to those who have to face -it. In Germany the gas is largely employed in village streets; and in -this country it is gaining ground as an illuminant of country houses, -being easy to manufacture--in small gasometers of a few cubic yards -capacity--and economical to burn. - -Well supplied as we are with lights, we find, nevertheless, that -savants are constantly in pursuit of an _ideal_ illuminant. - -From the sun are borne to us through the ether light waves, heat -waves, magnetic waves, and other waves of which we have as yet but a -dim perception. The waves are commingled, and we are unable to -separate them absolutely. And as soon as we try to copy the sun's -effects as a source of heat or light we find the same difficulty. The -fire that cooks our food gives off a quantity of useless light-waves; -the oil-lamp that brightens one's rooms gives off a quantity of -useless, often obnoxious, heat. - -The ideal illuminant and the ideal heating agent must be one in which -the required waves are in a great majority. Unfortunately, even with -our most perfected methods, the production of light is accompanied by -the exertion of a disproportionate amount of wasted energy. In the -ordinary incandescent lamp, to take an instance, only 5 or 6 per cent. -of the energy put into it as electricity results in light. The rest is -dispelled in overcoming the resistance of the filament and agitating -the few air-molecules in the bulb. To this we must add the fact that -the current itself represents but a fraction of the power exerted to -produce it. The following words of Professor Lodge are to the point on -this subject:-- - -"Look at the furnaces and boilers of a steam-engine driving a group of -dynamos, and estimate the energy expended; and then look at the -incandescent filaments of the lamps excited by them, and estimate how -much of their radiated energy is of real service to the eye. It will -be as the energy of a pitch-pipe to an entire orchestra. - -"It is not too much to say that a boy turning a handle could, if his -energy were properly directed, produce quite as much real light as is -produced by all this mass of mechanism and consumption of -material."[6] - - [6] Professor Oliver Lodge, in a lecture to the Ashmolean - Society, 3rd June 1889. - -The most perfect light in nature is probably that of the glow-worm and -firefly--a phosphorescent or "cold" light, illuminating without -combustion owing to the absence of all waves but those of the -requisite frequency. The task before mankind is to imitate the -glow-worm in the production of isolated light-waves. - -The nearest approach to its achievement has occurred in the -laboratories of Mr. Nikola Tesla, the famous electrician. By means of -a special oscillator, invented by himself, he has succeeded in -throwing the ether particles into such an intense state of vibration -that they become luminous. In other words, he has created vibrations -of the enormous rapidity of light, and this without the creation of -heat waves to any appreciable extent. - -An incandescent lamp, mounted on a powerful coil, is lit _without_ -contact by ether waves transmitted from a cable running round the -laboratory, or bulbs and tubes containing highly rarefied gases are -placed between two large plate-terminals arranged on the end walls. As -soon as the bulbs are held in the path of the currents passing through -the ether from plate to plate they become incandescent, shining with a -light which, though weak, is sufficiently strong to take photographs -by with a long exposure. Tesla has also invented what he calls a -"sanitary" light, as he claims for it the germ-killing properties of -sunshine. The lamps are glass tubes several feet long, bent into -spirals or other convolutions, and filled before sealing with a -certain gas. The ends of the glass tube are coated with metal and -provided with hooks to connect the lamp with an electric current. The -gas becomes _luminous_ under the influence of current, but not -strictly incandescent, as there is very little heat engendered. This -means economy in use. The lamps are said to be cheaply manufactured, -but as yet they are not "on the market." We shall hear more of them in -the near future, which will probably witness no more interesting -development than that of lighting. - -Before closing this chapter a few words may be said about new heating -methods. Gas stoves are becoming increasingly popular by reason of the -ease with which they can be put in action and made to maintain an even -temperature. But the most up-to-date heating apparatus is undoubtedly -electrical. Utensils of all sorts are fitted with very thin heating -strips (formed by the deposition of precious metals, such as gold, -platinum, &c., on exceedingly thin mica sheets), through which are -passed powerful currents from the mains. The resistance of the strip -converts the electromotive energy of the current into heat, which is -either radiated into the air or into water for cookery, &c. - -In all parts of the house the electric current may be made to do work -besides that of lighting. It warms the passages by means of special -radiators--replacing the clumsy coal and "stuffy" gas stove; in the -kitchen it boils, stews, and fries, heats the flat-irons and ovens; in -the breakfast room boils the kettle, keeps the dishes, teapots, and -coffee-pots warm; in the bathroom heats the water; in the smoking-room -replaces matches; in the bedroom electrifies footwarmers, and--last -wonder of all--even makes possible an artificially warm bed-quilt to -heat the chilled limbs of invalids! - -The great advantage of electric heating is the freedom from all smell -and smoke that accompanies it. But until current can be provided at -cheaper rates than prevail at present, its employment will be chiefly -restricted to the houses of the wealthy or to large establishments, -such as hotels, where it can be used on a sufficient scale to be -comparatively economical. - - THE END - - - Printed by BALLANTYNE, HANSON & CO. - Edinburgh & London - - - * * * * * - - - The Romance of Modern Invention - - - _BY THE SAME AUTHOR_ - - _Uniform with this Volume_ - - - THE ROMANCE OF MODERN ENGINEERING - - Containing Interesting Descriptions in Non-Technical Language - of the Nile Dam, the Panama Canal, the Tower Bridge, the - Brooklyn Bridge, the Trans-Siberian Railway, the Niagara Falls - Power Co., Bermuda Floating Dock, etc. etc. - - "A series of descriptions which rival one another in - lucidity of explanation and in interest, both of subject and - treatment."--_Manchester Courier._ - - "Men of any age will be interested in this volume; - boys will be fascinated by it."--_Spectator._ - - "If there lives a boy who is fond of engineering and - speaks the English tongue, this is the book for him."--_The - Bookman._ - - - _With 24 Illustrations. Gilt edges. Price 5s._ - - - - THE ROMANCE OF MODERN LOCOMOTION - - Containing Interesting Descriptions in Non-Technical Language - of the Rise and Development of the Railroad Systems in all - Parts of the World. - - - "The book is crisply written, is brimful of incident not - less than instruction, and should be as welcome to an intelligent - lad as a Ballantyne story or a Mayne Reid romance."--_Glasgow - Herald._ - - - _With 25 Illustrations. Crown 8vo, cloth Gilt, Gilt edges. Price 5s._ - - - * * * * * - - _UNIFORM WITH THIS VOLUME_ - - THE LIBRARY OF ROMANCE - - _Extra Crown 8vo. With many illustrations, 5s. each_ - - - "Messrs. Seeley's well-known series of gift books, finely - illustrated and in most attractive bindings." - - _The Northern Whig._ - - "These popular natural history books are written by competent - authorities, and besides being entertaining are instructive and - educative."--_The Liverpool Courier._ - - - By Prof. G. F. SCOTT ELLIOT, M.A., B.Sc. - - THE ROMANCE OF PLANT LIFE - - - By H. COUPIN, D.Sc., & JOHN LEA, B.A. - - THE ROMANCE OF ANIMAL ARTS AND CRAFTS - - - By the Rev. J. C. LAMBERT, M.A., D.D. - - THE ROMANCE OF MISSIONARY HEROISM - - - By G. FIRTH SCOTT - - THE ROMANCE OF POLAR EXPLORATION - - - By ARCHIBALD WILLIAMS, F.R.G.S. - - THE ROMANCE OF EARLY EXPLORATION - THE ROMANCE OF MODERN EXPLORATION - THE ROMANCE OF MODERN MECHANISM - THE ROMANCE OF MODERN INVENTION - THE ROMANCE OF MODERN ENGINEERING - THE ROMANCE OF MODERN LOCOMOTION - THE ROMANCE OF MODERN MINING - - - By CHARLES R. GIBSON, A.I.E.E. - - THE ROMANCE OF MODERN ELECTRICITY - - - By EDMUND SELOUS - - THE ROMANCE OF THE ANIMAL WORLD - THE ROMANCE OF INSECT LIFE - - - By AGNES GIBERNE - - THE ROMANCE OF THE MIGHTY DEEP - - - SEELEY & Co., LIMITED - - - - - -End of the Project Gutenberg EBook of The Romance of Modern Invention, by -Archibald Williams - -*** END OF THIS PROJECT GUTENBERG EBOOK THE ROMANCE OF MODERN INVENTION *** - -***** This file should be named 41160-8.txt or 41160-8.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/4/1/1/6/41160/ - -Produced by Chris Curnow, Matthew Wheaton and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - -Updated editions will replace the previous one--the old editions -will be renamed. - -Creating the works from public domain print editions means that no -one owns a United States copyright in these works, so the Foundation -(and you!) can copy and distribute it in the United States without -permission and without paying copyright royalties. Special rules, -set forth in the General Terms of Use part of this license, apply to -copying and distributing Project Gutenberg-tm electronic works to -protect the PROJECT GUTENBERG-tm concept and trademark. Project -Gutenberg is a registered trademark, and may not be used if you -charge for the eBooks, unless you receive specific permission. If you -do not charge anything for copies of this eBook, complying with the -rules is very easy. You may use this eBook for nearly any purpose -such as creation of derivative works, reports, performances and -research. They may be modified and printed and given away--you may do -practically ANYTHING with public domain eBooks. Redistribution is -subject to the trademark license, especially commercial -redistribution. - - - -*** START: FULL LICENSE *** - -THE FULL PROJECT GUTENBERG LICENSE -PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK - -To protect the Project Gutenberg-tm mission of promoting the free -distribution of electronic works, by using or distributing this work -(or any other work associated in any way with the phrase "Project -Gutenberg"), you agree to comply with all the terms of the Full Project -Gutenberg-tm License available with this file or online at - www.gutenberg.org/license. - - -Section 1. General Terms of Use and Redistributing Project Gutenberg-tm -electronic works - -1.A. By reading or using any part of this Project Gutenberg-tm -electronic work, you indicate that you have read, understand, agree to -and accept all the terms of this license and intellectual property -(trademark/copyright) agreement. If you do not agree to abide by all -the terms of this agreement, you must cease using and return or destroy -all copies of Project Gutenberg-tm electronic works in your possession. -If you paid a fee for obtaining a copy of or access to a Project -Gutenberg-tm electronic work and you do not agree to be bound by the -terms of this agreement, you may obtain a refund from the person or -entity to whom you paid the fee as set forth in paragraph 1.E.8. - -1.B. "Project Gutenberg" is a registered trademark. It may only be -used on or associated in any way with an electronic work by people who -agree to be bound by the terms of this agreement. There are a few -things that you can do with most Project Gutenberg-tm electronic works -even without complying with the full terms of this agreement. See -paragraph 1.C below. There are a lot of things you can do with Project -Gutenberg-tm electronic works if you follow the terms of this agreement -and help preserve free future access to Project Gutenberg-tm electronic -works. See paragraph 1.E below. - -1.C. The Project Gutenberg Literary Archive Foundation ("the Foundation" -or PGLAF), owns a compilation copyright in the collection of Project -Gutenberg-tm electronic works. Nearly all the individual works in the -collection are in the public domain in the United States. If an -individual work is in the public domain in the United States and you are -located in the United States, we do not claim a right to prevent you from -copying, distributing, performing, displaying or creating derivative -works based on the work as long as all references to Project Gutenberg -are removed. Of course, we hope that you will support the Project -Gutenberg-tm mission of promoting free access to electronic works by -freely sharing Project Gutenberg-tm works in compliance with the terms of -this agreement for keeping the Project Gutenberg-tm name associated with -the work. You can easily comply with the terms of this agreement by -keeping this work in the same format with its attached full Project -Gutenberg-tm License when you share it without charge with others. - -1.D. The copyright laws of the place where you are located also govern -what you can do with this work. Copyright laws in most countries are in -a constant state of change. If you are outside the United States, check -the laws of your country in addition to the terms of this agreement -before downloading, copying, displaying, performing, distributing or -creating derivative works based on this work or any other Project -Gutenberg-tm work. The Foundation makes no representations concerning -the copyright status of any work in any country outside the United -States. - -1.E. Unless you have removed all references to Project Gutenberg: - -1.E.1. The following sentence, with active links to, or other immediate -access to, the full Project Gutenberg-tm License must appear prominently -whenever any copy of a Project Gutenberg-tm work (any work on which the -phrase "Project Gutenberg" appears, or with which the phrase "Project -Gutenberg" is associated) is accessed, displayed, performed, viewed, -copied or distributed: - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org - -1.E.2. If an individual Project Gutenberg-tm electronic work is derived -from the public domain (does not contain a notice indicating that it is -posted with permission of the copyright holder), the work can be copied -and distributed to anyone in the United States without paying any fees -or charges. If you are redistributing or providing access to a work -with the phrase "Project Gutenberg" associated with or appearing on the -work, you must comply either with the requirements of paragraphs 1.E.1 -through 1.E.7 or obtain permission for the use of the work and the -Project Gutenberg-tm trademark as set forth in paragraphs 1.E.8 or -1.E.9. - -1.E.3. If an individual Project Gutenberg-tm electronic work is posted -with the permission of the copyright holder, your use and distribution -must comply with both paragraphs 1.E.1 through 1.E.7 and any additional -terms imposed by the copyright holder. Additional terms will be linked -to the Project Gutenberg-tm License for all works posted with the -permission of the copyright holder found at the beginning of this work. - -1.E.4. Do not unlink or detach or remove the full Project Gutenberg-tm -License terms from this work, or any files containing a part of this -work or any other work associated with Project Gutenberg-tm. - -1.E.5. Do not copy, display, perform, distribute or redistribute this -electronic work, or any part of this electronic work, without -prominently displaying the sentence set forth in paragraph 1.E.1 with -active links or immediate access to the full terms of the Project -Gutenberg-tm License. - -1.E.6. You may convert to and distribute this work in any binary, -compressed, marked up, nonproprietary or proprietary form, including any -word processing or hypertext form. However, if you provide access to or -distribute copies of a Project Gutenberg-tm work in a format other than -"Plain Vanilla ASCII" or other format used in the official version -posted on the official Project Gutenberg-tm web site (www.gutenberg.org), -you must, at no additional cost, fee or expense to the user, provide a -copy, a means of exporting a copy, or a means of obtaining a copy upon -request, of the work in its original "Plain Vanilla ASCII" or other -form. Any alternate format must include the full Project Gutenberg-tm -License as specified in paragraph 1.E.1. - -1.E.7. Do not charge a fee for access to, viewing, displaying, -performing, copying or distributing any Project Gutenberg-tm works -unless you comply with paragraph 1.E.8 or 1.E.9. - -1.E.8. You may charge a reasonable fee for copies of or providing -access to or distributing Project Gutenberg-tm electronic works provided -that - -- You pay a royalty fee of 20% of the gross profits you derive from - the use of Project Gutenberg-tm works calculated using the method - you already use to calculate your applicable taxes. The fee is - owed to the owner of the Project Gutenberg-tm trademark, but he - has agreed to donate royalties under this paragraph to the - Project Gutenberg Literary Archive Foundation. Royalty payments - must be paid within 60 days following each date on which you - prepare (or are legally required to prepare) your periodic tax - returns. Royalty payments should be clearly marked as such and - sent to the Project Gutenberg Literary Archive Foundation at the - address specified in Section 4, "Information about donations to - the Project Gutenberg Literary Archive Foundation." - -- You provide a full refund of any money paid by a user who notifies - you in writing (or by e-mail) within 30 days of receipt that s/he - does not agree to the terms of the full Project Gutenberg-tm - License. You must require such a user to return or - destroy all copies of the works possessed in a physical medium - and discontinue all use of and all access to other copies of - Project Gutenberg-tm works. - -- You provide, in accordance with paragraph 1.F.3, a full refund of any - money paid for a work or a replacement copy, if a defect in the - electronic work is discovered and reported to you within 90 days - of receipt of the work. - -- You comply with all other terms of this agreement for free - distribution of Project Gutenberg-tm works. - -1.E.9. If you wish to charge a fee or distribute a Project Gutenberg-tm -electronic work or group of works on different terms than are set -forth in this agreement, you must obtain permission in writing from -both the Project Gutenberg Literary Archive Foundation and Michael -Hart, the owner of the Project Gutenberg-tm trademark. Contact the -Foundation as set forth in Section 3 below. - -1.F. - -1.F.1. Project Gutenberg volunteers and employees expend considerable -effort to identify, do copyright research on, transcribe and proofread -public domain works in creating the Project Gutenberg-tm -collection. Despite these efforts, Project Gutenberg-tm electronic -works, and the medium on which they may be stored, may contain -"Defects," such as, but not limited to, incomplete, inaccurate or -corrupt data, transcription errors, a copyright or other intellectual -property infringement, a defective or damaged disk or other medium, a -computer virus, or computer codes that damage or cannot be read by -your equipment. - -1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the "Right -of Replacement or Refund" described in paragraph 1.F.3, the Project -Gutenberg Literary Archive Foundation, the owner of the Project -Gutenberg-tm trademark, and any other party distributing a Project -Gutenberg-tm electronic work under this agreement, disclaim all -liability to you for damages, costs and expenses, including legal -fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT -LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE -PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE FOUNDATION, THE -TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE -LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR -INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH -DAMAGE. - -1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a -defect in this electronic work within 90 days of receiving it, you can -receive a refund of the money (if any) you paid for it by sending a -written explanation to the person you received the work from. If you -received the work on a physical medium, you must return the medium with -your written explanation. The person or entity that provided you with -the defective work may elect to provide a replacement copy in lieu of a -refund. If you received the work electronically, the person or entity -providing it to you may choose to give you a second opportunity to -receive the work electronically in lieu of a refund. If the second copy -is also defective, you may demand a refund in writing without further -opportunities to fix the problem. - -1.F.4. Except for the limited right of replacement or refund set forth -in paragraph 1.F.3, this work is provided to you 'AS-IS', WITH NO OTHER -WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO -WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PURPOSE. - -1.F.5. Some states do not allow disclaimers of certain implied -warranties or the exclusion or limitation of certain types of damages. -If any disclaimer or limitation set forth in this agreement violates the -law of the state applicable to this agreement, the agreement shall be -interpreted to make the maximum disclaimer or limitation permitted by -the applicable state law. The invalidity or unenforceability of any -provision of this agreement shall not void the remaining provisions. - -1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the -trademark owner, any agent or employee of the Foundation, anyone -providing copies of Project Gutenberg-tm electronic works in accordance -with this agreement, and any volunteers associated with the production, -promotion and distribution of Project Gutenberg-tm electronic works, -harmless from all liability, costs and expenses, including legal fees, -that arise directly or indirectly from any of the following which you do -or cause to occur: (a) distribution of this or any Project Gutenberg-tm -work, (b) alteration, modification, or additions or deletions to any -Project Gutenberg-tm work, and (c) any Defect you cause. - - -Section 2. Information about the Mission of Project Gutenberg-tm - -Project Gutenberg-tm is synonymous with the free distribution of -electronic works in formats readable by the widest variety of computers -including obsolete, old, middle-aged and new computers. It exists -because of the efforts of hundreds of volunteers and donations from -people in all walks of life. - -Volunteers and financial support to provide volunteers with the -assistance they need are critical to reaching Project Gutenberg-tm's -goals and ensuring that the Project Gutenberg-tm collection will -remain freely available for generations to come. In 2001, the Project -Gutenberg Literary Archive Foundation was created to provide a secure -and permanent future for Project Gutenberg-tm and future generations. -To learn more about the Project Gutenberg Literary Archive Foundation -and how your efforts and donations can help, see Sections 3 and 4 -and the Foundation information page at www.gutenberg.org - - -Section 3. Information about the Project Gutenberg Literary Archive -Foundation - -The Project Gutenberg Literary Archive Foundation is a non profit -501(c)(3) educational corporation organized under the laws of the -state of Mississippi and granted tax exempt status by the Internal -Revenue Service. The Foundation's EIN or federal tax identification -number is 64-6221541. Contributions to the Project Gutenberg -Literary Archive Foundation are tax deductible to the full extent -permitted by U.S. federal laws and your state's laws. - -The Foundation's principal office is located at 4557 Melan Dr. S. -Fairbanks, AK, 99712., but its volunteers and employees are scattered -throughout numerous locations. Its business office is located at 809 -North 1500 West, Salt Lake City, UT 84116, (801) 596-1887. Email -contact links and up to date contact information can be found at the -Foundation's web site and official page at www.gutenberg.org/contact - -For additional contact information: - Dr. Gregory B. Newby - Chief Executive and Director - gbnewby@pglaf.org - -Section 4. Information about Donations to the Project Gutenberg -Literary Archive Foundation - -Project Gutenberg-tm depends upon and cannot survive without wide -spread public support and donations to carry out its mission of -increasing the number of public domain and licensed works that can be -freely distributed in machine readable form accessible by the widest -array of equipment including outdated equipment. Many small donations -($1 to $5,000) are particularly important to maintaining tax exempt -status with the IRS. - -The Foundation is committed to complying with the laws regulating -charities and charitable donations in all 50 states of the United -States. Compliance requirements are not uniform and it takes a -considerable effort, much paperwork and many fees to meet and keep up -with these requirements. We do not solicit donations in locations -where we have not received written confirmation of compliance. To -SEND DONATIONS or determine the status of compliance for any -particular state visit www.gutenberg.org/donate - -While we cannot and do not solicit contributions from states where we -have not met the solicitation requirements, we know of no prohibition -against accepting unsolicited donations from donors in such states who -approach us with offers to donate. - -International donations are gratefully accepted, but we cannot make -any statements concerning tax treatment of donations received from -outside the United States. U.S. laws alone swamp our small staff. - -Please check the Project Gutenberg Web pages for current donation -methods and addresses. Donations are accepted in a number of other -ways including checks, online payments and credit card donations. -To donate, please visit: www.gutenberg.org/donate - - -Section 5. General Information About Project Gutenberg-tm electronic -works. - -Professor Michael S. Hart was the originator of the Project Gutenberg-tm -concept of a library of electronic works that could be freely shared -with anyone. For forty years, he produced and distributed Project -Gutenberg-tm eBooks with only a loose network of volunteer support. - -Project Gutenberg-tm eBooks are often created from several printed -editions, all of which are confirmed as Public Domain in the U.S. -unless a copyright notice is included. Thus, we do not necessarily -keep eBooks in compliance with any particular paper edition. - -Most people start at our Web site which has the main PG search facility: - - www.gutenberg.org - -This Web site includes information about Project Gutenberg-tm, -including how to make donations to the Project Gutenberg Literary -Archive Foundation, how to help produce our new eBooks, and how to -subscribe to our email newsletter to hear about new eBooks. diff --git a/41160-8.zip b/41160-8.zip Binary files differdeleted file mode 100644 index 8e252b9..0000000 --- a/41160-8.zip +++ /dev/null diff --git a/41160-h.zip b/41160-h.zip Binary files differdeleted file mode 100644 index 46d85a5..0000000 --- a/41160-h.zip +++ /dev/null diff --git a/41160-h/41160-h.htm b/41160-h/41160-h.htm index 913970f..e99b2b1 100644 --- a/41160-h/41160-h.htm +++ b/41160-h/41160-h.htm @@ -4,7 +4,7 @@ <head> - <meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1" /> + <meta http-equiv="Content-Type" content="text/html;charset=UTF-8" /> <meta http-equiv="Content-Style-Type" content="text/css" /> <link rel="coverpage" href="images/cover.jpg" /> @@ -303,49 +303,7 @@ </head> <body> - - -<pre> - -Project Gutenberg's The Romance of Modern Invention, by Archibald Williams - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org - - -Title: The Romance of Modern Invention - Containing Interesting Descriptions in Non-technical - Language of Wireless Telegraphy, Liquid Air, Modern - Artillery, Submarines, Dirigible Torpedoes, Solar Motors, - Airships, &c. &c. - -Author: Archibald Williams - -Release Date: October 24, 2012 [EBook #41160] - -Language: English - -Character set encoding: ISO-8859-1 - -*** START OF THIS PROJECT GUTENBERG EBOOK THE ROMANCE OF MODERN INVENTION *** - - - - -Produced by Chris Curnow, Matthew Wheaton and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - - - - - -</pre> - +<div>*** START OF THE PROJECT GUTENBERG EBOOK 41160 ***</div> <div class="figcenter"> <img id="frontcover" src="images/cover.jpg" width="347" height="600" alt="" /> @@ -9576,383 +9534,6 @@ THE ROMANCE OF THE MIGHTY DEEP</p> <p class="center">SEELEY & Co., LIMITED</p> </div> - - - - - - - -<pre> - - - - - -End of the Project Gutenberg EBook of The Romance of Modern Invention, by -Archibald Williams - -*** END OF THIS PROJECT GUTENBERG EBOOK THE ROMANCE OF MODERN INVENTION *** - -***** This file should be named 41160-h.htm or 41160-h.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/4/1/1/6/41160/ - -Produced by Chris Curnow, Matthew Wheaton and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - -Updated editions will replace the previous one--the old editions -will be renamed. - -Creating the works from public domain print editions means that no -one owns a United States copyright in these works, so the Foundation -(and you!) can copy and distribute it in the United States without -permission and without paying copyright royalties. Special rules, -set forth in the General Terms of Use part of this license, apply to -copying and distributing Project Gutenberg-tm electronic works to -protect the PROJECT GUTENBERG-tm concept and trademark. Project -Gutenberg is a registered trademark, and may not be used if you -charge for the eBooks, unless you receive specific permission. If you -do not charge anything for copies of this eBook, complying with the -rules is very easy. You may use this eBook for nearly any purpose -such as creation of derivative works, reports, performances and -research. They may be modified and printed and given away--you may do -practically ANYTHING with public domain eBooks. Redistribution is -subject to the trademark license, especially commercial -redistribution. - - - -*** START: FULL LICENSE *** - -THE FULL PROJECT GUTENBERG LICENSE -PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK - -To protect the Project Gutenberg-tm mission of promoting the free -distribution of electronic works, by using or distributing this work -(or any other work associated in any way with the phrase "Project -Gutenberg"), you agree to comply with all the terms of the Full Project -Gutenberg-tm License available with this file or online at - www.gutenberg.org/license. - - -Section 1. General Terms of Use and Redistributing Project Gutenberg-tm -electronic works - -1.A. By reading or using any part of this Project Gutenberg-tm -electronic work, you indicate that you have read, understand, agree to -and accept all the terms of this license and intellectual property -(trademark/copyright) agreement. If you do not agree to abide by all -the terms of this agreement, you must cease using and return or destroy -all copies of Project Gutenberg-tm electronic works in your possession. -If you paid a fee for obtaining a copy of or access to a Project -Gutenberg-tm electronic work and you do not agree to be bound by the -terms of this agreement, you may obtain a refund from the person or -entity to whom you paid the fee as set forth in paragraph 1.E.8. - -1.B. "Project Gutenberg" is a registered trademark. It may only be -used on or associated in any way with an electronic work by people who -agree to be bound by the terms of this agreement. There are a few -things that you can do with most Project Gutenberg-tm electronic works -even without complying with the full terms of this agreement. See -paragraph 1.C below. There are a lot of things you can do with Project -Gutenberg-tm electronic works if you follow the terms of this agreement -and help preserve free future access to Project Gutenberg-tm electronic -works. See paragraph 1.E below. - -1.C. The Project Gutenberg Literary Archive Foundation ("the Foundation" -or PGLAF), owns a compilation copyright in the collection of Project -Gutenberg-tm electronic works. Nearly all the individual works in the -collection are in the public domain in the United States. If an -individual work is in the public domain in the United States and you are -located in the United States, we do not claim a right to prevent you from -copying, distributing, performing, displaying or creating derivative -works based on the work as long as all references to Project Gutenberg -are removed. Of course, we hope that you will support the Project -Gutenberg-tm mission of promoting free access to electronic works by -freely sharing Project Gutenberg-tm works in compliance with the terms of -this agreement for keeping the Project Gutenberg-tm name associated with -the work. You can easily comply with the terms of this agreement by -keeping this work in the same format with its attached full Project -Gutenberg-tm License when you share it without charge with others. - -1.D. The copyright laws of the place where you are located also govern -what you can do with this work. Copyright laws in most countries are in -a constant state of change. If you are outside the United States, check -the laws of your country in addition to the terms of this agreement -before downloading, copying, displaying, performing, distributing or -creating derivative works based on this work or any other Project -Gutenberg-tm work. The Foundation makes no representations concerning -the copyright status of any work in any country outside the United -States. - -1.E. Unless you have removed all references to Project Gutenberg: - -1.E.1. The following sentence, with active links to, or other immediate -access to, the full Project Gutenberg-tm License must appear prominently -whenever any copy of a Project Gutenberg-tm work (any work on which the -phrase "Project Gutenberg" appears, or with which the phrase "Project -Gutenberg" is associated) is accessed, displayed, performed, viewed, -copied or distributed: - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org - -1.E.2. If an individual Project Gutenberg-tm electronic work is derived -from the public domain (does not contain a notice indicating that it is -posted with permission of the copyright holder), the work can be copied -and distributed to anyone in the United States without paying any fees -or charges. If you are redistributing or providing access to a work -with the phrase "Project Gutenberg" associated with or appearing on the -work, you must comply either with the requirements of paragraphs 1.E.1 -through 1.E.7 or obtain permission for the use of the work and the -Project Gutenberg-tm trademark as set forth in paragraphs 1.E.8 or -1.E.9. - -1.E.3. If an individual Project Gutenberg-tm electronic work is posted -with the permission of the copyright holder, your use and distribution -must comply with both paragraphs 1.E.1 through 1.E.7 and any additional -terms imposed by the copyright holder. Additional terms will be linked -to the Project Gutenberg-tm License for all works posted with the -permission of the copyright holder found at the beginning of this work. - -1.E.4. Do not unlink or detach or remove the full Project Gutenberg-tm -License terms from this work, or any files containing a part of this -work or any other work associated with Project Gutenberg-tm. - -1.E.5. Do not copy, display, perform, distribute or redistribute this -electronic work, or any part of this electronic work, without -prominently displaying the sentence set forth in paragraph 1.E.1 with -active links or immediate access to the full terms of the Project -Gutenberg-tm License. - -1.E.6. You may convert to and distribute this work in any binary, -compressed, marked up, nonproprietary or proprietary form, including any -word processing or hypertext form. However, if you provide access to or -distribute copies of a Project Gutenberg-tm work in a format other than -"Plain Vanilla ASCII" or other format used in the official version -posted on the official Project Gutenberg-tm web site (www.gutenberg.org), -you must, at no additional cost, fee or expense to the user, provide a -copy, a means of exporting a copy, or a means of obtaining a copy upon -request, of the work in its original "Plain Vanilla ASCII" or other -form. Any alternate format must include the full Project Gutenberg-tm -License as specified in paragraph 1.E.1. - -1.E.7. Do not charge a fee for access to, viewing, displaying, -performing, copying or distributing any Project Gutenberg-tm works -unless you comply with paragraph 1.E.8 or 1.E.9. - -1.E.8. You may charge a reasonable fee for copies of or providing -access to or distributing Project Gutenberg-tm electronic works provided -that - -- You pay a royalty fee of 20% of the gross profits you derive from - the use of Project Gutenberg-tm works calculated using the method - you already use to calculate your applicable taxes. The fee is - owed to the owner of the Project Gutenberg-tm trademark, but he - has agreed to donate royalties under this paragraph to the - Project Gutenberg Literary Archive Foundation. Royalty payments - must be paid within 60 days following each date on which you - prepare (or are legally required to prepare) your periodic tax - returns. Royalty payments should be clearly marked as such and - sent to the Project Gutenberg Literary Archive Foundation at the - address specified in Section 4, "Information about donations to - the Project Gutenberg Literary Archive Foundation." - -- You provide a full refund of any money paid by a user who notifies - you in writing (or by e-mail) within 30 days of receipt that s/he - does not agree to the terms of the full Project Gutenberg-tm - License. You must require such a user to return or - destroy all copies of the works possessed in a physical medium - and discontinue all use of and all access to other copies of - Project Gutenberg-tm works. - -- You provide, in accordance with paragraph 1.F.3, a full refund of any - money paid for a work or a replacement copy, if a defect in the - electronic work is discovered and reported to you within 90 days - of receipt of the work. - -- You comply with all other terms of this agreement for free - distribution of Project Gutenberg-tm works. - -1.E.9. If you wish to charge a fee or distribute a Project Gutenberg-tm -electronic work or group of works on different terms than are set -forth in this agreement, you must obtain permission in writing from -both the Project Gutenberg Literary Archive Foundation and Michael -Hart, the owner of the Project Gutenberg-tm trademark. Contact the -Foundation as set forth in Section 3 below. - -1.F. - -1.F.1. Project Gutenberg volunteers and employees expend considerable -effort to identify, do copyright research on, transcribe and proofread -public domain works in creating the Project Gutenberg-tm -collection. Despite these efforts, Project Gutenberg-tm electronic -works, and the medium on which they may be stored, may contain -"Defects," such as, but not limited to, incomplete, inaccurate or -corrupt data, transcription errors, a copyright or other intellectual -property infringement, a defective or damaged disk or other medium, a -computer virus, or computer codes that damage or cannot be read by -your equipment. - -1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the "Right -of Replacement or Refund" described in paragraph 1.F.3, the Project -Gutenberg Literary Archive Foundation, the owner of the Project -Gutenberg-tm trademark, and any other party distributing a Project -Gutenberg-tm electronic work under this agreement, disclaim all -liability to you for damages, costs and expenses, including legal -fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT -LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE -PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE FOUNDATION, THE -TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE -LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR -INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH -DAMAGE. - -1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a -defect in this electronic work within 90 days of receiving it, you can -receive a refund of the money (if any) you paid for it by sending a -written explanation to the person you received the work from. If you -received the work on a physical medium, you must return the medium with -your written explanation. The person or entity that provided you with -the defective work may elect to provide a replacement copy in lieu of a -refund. If you received the work electronically, the person or entity -providing it to you may choose to give you a second opportunity to -receive the work electronically in lieu of a refund. If the second copy -is also defective, you may demand a refund in writing without further -opportunities to fix the problem. - -1.F.4. Except for the limited right of replacement or refund set forth -in paragraph 1.F.3, this work is provided to you 'AS-IS', WITH NO OTHER -WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO -WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PURPOSE. - -1.F.5. Some states do not allow disclaimers of certain implied -warranties or the exclusion or limitation of certain types of damages. -If any disclaimer or limitation set forth in this agreement violates the -law of the state applicable to this agreement, the agreement shall be -interpreted to make the maximum disclaimer or limitation permitted by -the applicable state law. The invalidity or unenforceability of any -provision of this agreement shall not void the remaining provisions. - -1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the -trademark owner, any agent or employee of the Foundation, anyone -providing copies of Project Gutenberg-tm electronic works in accordance -with this agreement, and any volunteers associated with the production, -promotion and distribution of Project Gutenberg-tm electronic works, -harmless from all liability, costs and expenses, including legal fees, -that arise directly or indirectly from any of the following which you do -or cause to occur: (a) distribution of this or any Project Gutenberg-tm -work, (b) alteration, modification, or additions or deletions to any -Project Gutenberg-tm work, and (c) any Defect you cause. - - -Section 2. Information about the Mission of Project Gutenberg-tm - -Project Gutenberg-tm is synonymous with the free distribution of -electronic works in formats readable by the widest variety of computers -including obsolete, old, middle-aged and new computers. It exists -because of the efforts of hundreds of volunteers and donations from -people in all walks of life. - -Volunteers and financial support to provide volunteers with the -assistance they need are critical to reaching Project Gutenberg-tm's -goals and ensuring that the Project Gutenberg-tm collection will -remain freely available for generations to come. In 2001, the Project -Gutenberg Literary Archive Foundation was created to provide a secure -and permanent future for Project Gutenberg-tm and future generations. -To learn more about the Project Gutenberg Literary Archive Foundation -and how your efforts and donations can help, see Sections 3 and 4 -and the Foundation information page at www.gutenberg.org - - -Section 3. Information about the Project Gutenberg Literary Archive -Foundation - -The Project Gutenberg Literary Archive Foundation is a non profit -501(c)(3) educational corporation organized under the laws of the -state of Mississippi and granted tax exempt status by the Internal -Revenue Service. The Foundation's EIN or federal tax identification -number is 64-6221541. Contributions to the Project Gutenberg -Literary Archive Foundation are tax deductible to the full extent -permitted by U.S. federal laws and your state's laws. - -The Foundation's principal office is located at 4557 Melan Dr. S. -Fairbanks, AK, 99712., but its volunteers and employees are scattered -throughout numerous locations. Its business office is located at 809 -North 1500 West, Salt Lake City, UT 84116, (801) 596-1887. Email -contact links and up to date contact information can be found at the -Foundation's web site and official page at www.gutenberg.org/contact - -For additional contact information: - Dr. Gregory B. Newby - Chief Executive and Director - gbnewby@pglaf.org - -Section 4. Information about Donations to the Project Gutenberg -Literary Archive Foundation - -Project Gutenberg-tm depends upon and cannot survive without wide -spread public support and donations to carry out its mission of -increasing the number of public domain and licensed works that can be -freely distributed in machine readable form accessible by the widest -array of equipment including outdated equipment. Many small donations -($1 to $5,000) are particularly important to maintaining tax exempt -status with the IRS. - -The Foundation is committed to complying with the laws regulating -charities and charitable donations in all 50 states of the United -States. Compliance requirements are not uniform and it takes a -considerable effort, much paperwork and many fees to meet and keep up -with these requirements. We do not solicit donations in locations -where we have not received written confirmation of compliance. To -SEND DONATIONS or determine the status of compliance for any -particular state visit www.gutenberg.org/donate - -While we cannot and do not solicit contributions from states where we -have not met the solicitation requirements, we know of no prohibition -against accepting unsolicited donations from donors in such states who -approach us with offers to donate. - -International donations are gratefully accepted, but we cannot make -any statements concerning tax treatment of donations received from -outside the United States. U.S. laws alone swamp our small staff. - -Please check the Project Gutenberg Web pages for current donation -methods and addresses. Donations are accepted in a number of other -ways including checks, online payments and credit card donations. -To donate, please visit: www.gutenberg.org/donate - - -Section 5. General Information About Project Gutenberg-tm electronic -works. - -Professor Michael S. Hart was the originator of the Project Gutenberg-tm -concept of a library of electronic works that could be freely shared -with anyone. For forty years, he produced and distributed Project -Gutenberg-tm eBooks with only a loose network of volunteer support. - -Project Gutenberg-tm eBooks are often created from several printed -editions, all of which are confirmed as Public Domain in the U.S. -unless a copyright notice is included. Thus, we do not necessarily -keep eBooks in compliance with any particular paper edition. - -Most people start at our Web site which has the main PG search facility: - - www.gutenberg.org - -This Web site includes information about Project Gutenberg-tm, -including how to make donations to the Project Gutenberg Literary -Archive Foundation, how to help produce our new eBooks, and how to -subscribe to our email newsletter to hear about new eBooks. - - -</pre> - +<div>*** END OF THE PROJECT GUTENBERG EBOOK 41160 ***</div> </body> </html> diff --git a/41160.txt b/41160.txt deleted file mode 100644 index 80f22b2..0000000 --- a/41160.txt +++ /dev/null @@ -1,9272 +0,0 @@ -Project Gutenberg's The Romance of Modern Invention, by Archibald Williams - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org - - -Title: The Romance of Modern Invention - Containing Interesting Descriptions in Non-technical - Language of Wireless Telegraphy, Liquid Air, Modern - Artillery, Submarines, Dirigible Torpedoes, Solar Motors, - Airships, &c. &c. - -Author: Archibald Williams - -Release Date: October 24, 2012 [EBook #41160] - -Language: English - -Character set encoding: ASCII - -*** START OF THIS PROJECT GUTENBERG EBOOK THE ROMANCE OF MODERN INVENTION *** - - - - -Produced by Chris Curnow, Matthew Wheaton and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - - - - - - - - - [Illustration: _The Sun-Motor used on the Pasadena - Ostrich-farm, California. It works a pump capable of delivering - 1,400 gallons per minute._ [_See pp. 210, 211._] ] - - - - - THE ROMANCE OF MODERN INVENTION - - CONTAINING INTERESTING DESCRIPTIONS IN - NON-TECHNICAL LANGUAGE OF WIRELESS - TELEGRAPHY, LIQUID AIR, MODERN ARTILLERY, - SUBMARINES, DIRIGIBLE TORPEDOES, - SOLAR MOTORS, AIRSHIPS, _&c. &c._ - - BY - - ARCHIBALD WILLIAMS - - AUTHOR OF "THE ROMANCE OF MODERN MECHANISM" - "THE ROMANCE OF MODERN ENGINEERING" - _&c. &c._ - - WITH TWENTY-FIVE ILLUSTRATIONS - - LONDON - SEELEY AND CO. LIMITED - 38 GREAT RUSSELL STREET - 1907 - - - - -Preface - - -The object of this book is to set before young people in a bright and -interesting way, and without the use of technical language, accounts -of some of the latest phases of modern invention; and also to -introduce them to recent discoveries of which the full development is -yet to be witnessed. - -The author gratefully acknowledges the help given him as regards both -literary matter and illustrations by:--Mr. Cuthbert Hall (the Marconi -Wireless Telegraphy Co.); Mr. William Sugg; Mr. Hans Knudsen; Mr. F. -C. B. Cole; Mr. E. J. Ryves; Mr. Anton Pollak; the Telautograph Co.; -the Parsons Steam Turbine Co.; the Monotype Co.; the Biograph Co.; the -Locomobile Co.; the Speedwell Motor Co. - -_September 1902._ - - - - - Contents - - - WIRELESS TELEGRAPHY - - HIGH-SPEED TELEGRAPHY - - THE TELEPHONE--WIRELESS TELEPHONY - - THE PHONOGRAPH--THE HOTOGRAPHOPHONE--THE TELEPHONOGRAPH - - THE TELAUTOGRAPH - - MODERN ARTILLERY--RIFLES--MACHINE GUNS--HEAVY - ORDNANCE--EXPLOSIVES--IN THE GUN FACTORY - - DIRIGIBLE TORPEDOES - - SUBMARINE BOATS - - ANIMATED PICTURES - - THE GREAT PARIS TELESCOPE - - PHOTOGRAPHING THE INVISIBLE--PHOTOGRAPHY IN THE DARK - - SOLAR MOTORS - - LIQUID AIR - - HORSELESS CARRIAGES - - HIGH-SPEED RAILWAYS - - SEA EXPRESSES - - MECHANICAL FLIGHT - - TYPE-SETTING BY MACHINERY - - PHOTOGRAPHY IN COLOURS - - LIGHTING - - - - - List of Illustrations - - - THE SUN MOTOR USED ON THE PASADENA OSTRICH-FARM - - A CORNER OF MR. MARCONI'S CABIN - - MR. MARCONI'S TRAVELLING STATION - - THE POLDHU TOWER - - GUGLIELMO MARCONI - - HIGH-SPEED TELEGRAPHY: A RECEIVING INSTRUMENT - - HIGH-SPEED TELEGRAPHY. SPECIMEN OF PUNCHED TAPE - - A UNIQUE GROUP OF PHONOGRAPHS - - THE TELAUTOGRAPH: RECEIVER AND TRANSMITTER - - THE TELAUTOGRAPH, SHOWING THE PRINCIPAL PARTS - - THE TELAUTOGRAPH, SPECIMEN OF THE WORK DONE - - THE SIMMS ARMOUR-CLAD MOTOR CAR - - THE "HOLLAND" SUBMARINE BOAT - - AN INTERIOR VIEW OF THE "HOLLAND" - - THE "HOLLAND" SUBMARINE IN THE LAST STAGES OF SUBMERSION - - THE GREAT PARIS TELESCOPE - - THE LIQUID AIR COMPANY'S FACTORY AT PIMLICO - - M. SERPOLLET ON THE "EASTER EGG" - - A MOTOR CAR DRIVEN BY LIQUID AIR - - DIAGRAM OF LIQUID AIR MOTOR CAR - - H.M.S. TORPEDO DESTROYER "VIPER" - - AIRSHIP OF M. SANTOS-DUMONT ROUNDING THE EIFFEL TOWER - - M. SANTOS-DUMONT'S AIRSHIP RETURNING TO LONGCHAMPS - - THE LINOTYPE MACHINE - - THE MONOTYPE CASTING MACHINE - - - - -The Romance of Modern Invention - - - - -WIRELESS TELEGRAPHY - - -One day in 1845 a man named Tawell, dressed as a Quaker, stepped into -a train at Slough Station on the Great Western Railway, and travelled -to London. When he arrived in London the innocent-looking Quaker was -arrested, much to his amazement and dismay, on the charge of having -committed a foul murder in the neighbourhood of Slough. The news of -the murder and a description of the murderer had been telegraphed from -that place to Paddington, where a detective met the train and shadowed -the miscreant until a convenient opportunity for arresting him -occurred. Tawell was tried, condemned, and hung, and the public for -the first time generally realised the power for good dormant in the as -yet little developed electric telegraph. - -Thirteen years later two vessels met in mid-Atlantic laden with cables -which they joined and paid out in opposite directions, till Ireland -and Newfoundland were reached. The first electric message passed on -August 7th of that year from the New World to the Old. The telegraph -had now become a world-power. - -The third epoch-making event in its history is of recent date. On -December 12, 1901, Guglielmo Marconi, a young Italian, famous all over -the world when but twenty-two years old, suddenly sprang into yet -greater fame. At Hospital Point, Newfoundland, he heard by means of a -kite, a long wire, a delicate tube full of tiny particles of metal, -and a telephone ear-piece, signals transmitted from far-off Cornwall -by his colleagues. No wires connected Poldhu, the Cornish station, and -Hospital Point. The three short dot signals, which in the Morse code -signify the letter S, had been borne from place to place by the -limitless, mysterious ether, that strange substance of which we now -hear so much, of which wise men declare we know so little. - -Marconi's great achievement, which was of immense importance, -naturally astonished the world. Of course, there were not wanting -those who discredited the report. Others, on the contrary, were seized -with panic and showed their readiness to believe that the Atlantic had -been spanned aerially, by selling off their shares in cable companies. -To use the language of the money-market, there was a temporary "slump" -in cable shares. The world again woke up--this time to the fact that -experiments of which it had heard faintly had at last culminated in a -great triumph, marvellous in itself, and yet probably nothing in -comparison with the revolution in the transmission of news that it -heralded. - -The subject of Wireless Telegraphy is so wide that to treat it fully -in the compass of a single chapter is impossible. At the same time it -would be equally impossible to pass it over in a book written with the -object of presenting to the reader the latest developments of -scientific research. Indeed, the attention that it has justly -attracted entitle it, not merely to a place, but to a leading place; -and for this reason these first pages will be devoted to a short -account of the history and theory of Wireless Telegraphy, with some -mention of the different systems by which signals have been sent -through space. - -On casting about for a point at which to begin, the writer is tempted -to attack the great topic of the ether, to which experimenters in many -branches of science are now devoting more and more attention, hoping -to find in it an explanation of and connection between many phenomena -which at present are of uncertain origin. - -What is Ether? In the first place, its very existence is merely -assumed, like that of the atom and the molecule. Nobody can say that -he has actually seen or had any experience of it. The assumption that -there is such a thing is justified only in so far as that assumption -explains and reconciles phenomena of which we have experience, and -enables us to form theories which can be scientifically demonstrated -correct. What scientists now say is this: that everything which we -see and touch, the air, the infinity of space itself, is permeated by -a _something_, so subtle that, no matter how continuous a thing may -seem, it is but a concourse of atoms separated by this something, the -Ether. Reasoning drove them to this conclusion. - -It is obvious that an effect cannot come out of nothing. Put a clock -under a bell-glass and you hear the ticking. Pump out the air and the -ticking becomes inaudible. What is now not in the glass that was there -before? The air. Reason, therefore, obliges us to conclude that air is -the means whereby the ticking is audible to us. No air, no sound. -Next, put a lighted candle on the further side of the exhausted -bell-glass. We can see it clearly enough. The absence of air does not -affect light. But can we believe that there is an absolute gap between -us and the light? No! It is far easier to believe that the bell-glass -is as full as the outside atmosphere of the something that -communicates the sensation of light from the candle to the eye. Again, -suppose we measure a bar of iron very carefully while cold and then -heat it. We shall find that it has expanded a little. The iron atoms, -we say, have become more energetic than before, repel each other and -stand further apart. What then is in the intervening spaces? Not air, -which cannot be forced through iron whether hot or cold. No! the -ether: which passes easily through crevices so small as to bar the way -to the atoms of air. - -[Illustration: _A Corner of M. Marconi's cabin on board S.S. -"Minneapolis," showing instruments used in Wireless Telegraphy._] - -Once more, suppose that to one end of our iron bar we apply the -negative "pole" of an electric battery, and to the other end the -positive pole. We see that a current passes through the bar, whether -hot or cold, which implies that it jumps across all the ether gaps, or -rather is conveyed by them from one atom to another. - -The conclusion then is that ether is not merely omnipresent, -penetrating all things, but the medium whereby heat, light, -electricity, perhaps even thought itself, are transmitted from one -point to another. - -In what manner is the transmission effected? We cannot imagine the -ether behaving in a way void of all system. - -The answer is, by a wave motion. The ether must be regarded as a very -elastic solid. The agitation of a portion of it by what we call heat, -light, or electricity, sets in motion adjoining particles, until they -are moving from side to side, but not forwards; the resultant movement -resembling that of a snake tethered by the tail. - -These ether waves vary immensely in length. Their qualities and -effects upon our bodies or sensitive instruments depend upon their -length. By means of ingenious apparatus the lengths of various waves -have been measured. When the waves number 500 billion per second, and -are but the 40,000th of an inch long they affect our eyes and are -named light--red light. At double the number and half the length, they -give us the sensation of violet light. - -When the number increases and the waves shorten further, our bodies -are "blind" to them; we have no sense to detect their presence. -Similarly, a slower vibration than that of red light is imperceptible -until we reach the comparatively slow pace of 100 vibrations per -second, when we become aware of heat. - -Ether waves may be compared to the notes on a piano, of which we are -acquainted with some octaves only. The gaps, the unknown octaves, are -being discovered slowly but surely. Thus, for example, the famous -X-rays have been assigned to the topmost octave; electric waves to the -notes between light and heat. Forty years ago Professor Clerk Maxwell -suggested that light and electricity were very closely connected, -probably differing only in their wave-length. His theory has been -justified by subsequent research. The velocity of light (185,000 miles -per second) and that of electric currents have been proved identical. -Hertz, a professor in the university of Bonn, also showed (1887-1889) -that the phenomena of light--reflection, refraction, and concentration -of rays--can be repeated with electric currents. - -We therefore take the word of scientists that the origin of the -phenomena called light and electricity is the same--vibration of -ether. It at once occurs to the reader that their behaviour is so -different that they might as well be considered of altogether -different natures. - -For instance, interpose the very thinnest sheet of metal between a -candle and the eye, and the light is cut off. But the sheet will very -readily convey electricity. On the contrary, glass, a substance that -repels electricity, is transparent, _i.e._ gives passage to light. And -again, electricity can be conveyed round as many corners as you -please, whereas light will travel in straight lines only. - -To clear away our doubts we have only to take the lighted candle and -again hold up the metal screen. Light does not pass through, but heat -does. Substitute for the metal a very thin tank filled with a solution -of alum, and then light passes, but heat is cut off. So that heat and -electricity _both_ penetrate what is impenetrable to light; while -light forces a passage securely barred against both electricity and -heat. And we must remember that open space conveys all alike from the -sun to the earth. - -On meeting what we call solid matter, ether waves are influenced, not -because ether is wanting in the solid matter, but because the presence -of something else than ether affects the intervening ether itself. -Consequently glass, to take an instance, so affects ether that a very -rapid succession of waves (light) are able to continue their way -through its interstices, whereas long electric waves are so hampered -that they die out altogether. Metal on the other hand welcomes slow -vibrations (_i.e._ long waves), but speedily kills the rapid shakes of -light. In other words, _transparency_ is not confined to light alone. -All bodies are transparent to some variety of rays, and many bodies to -several varieties. It may perhaps even be proved that there is no -such thing as absolute resistance, and that our inability to detect -penetration is due to lack of sufficiently delicate instruments. - -The cardinal points to be remembered are these:-- - -That the ether is a universal medium, conveying all kinds and forms of -energy. - -That these forms of energy differ only in their rates of vibration. - -That the rate of vibration determines what power of penetration the -waves shall have through any given substance. - -Now, it is generally true that whereas matter of any kind offers -resistance to light--that is, is not so perfect a conductor as the -ether--many substances, especially metals, are more sensitive than -ether to heat and electricity. How quickly a spoon inserted into a hot -cup of tea becomes uncomfortably hot, though the hand can be held very -close to the liquid without feeling more than a gentle warmth. And we -all have noticed that the very least air-gap in an electric circuit -effectively breaks a current capable of traversing miles of wire. If -the current is so intense that it insists on passing the gap, it leaps -across with a report, making a spark that is at once intensely bright -and hot. Metal wires are to electricity what speaking tubes are to -sound; they are as it were electrical tubes through the air and ether. -But just as a person listening outside a speaking tube might faintly -hear the sounds passing through it, so an instrument gifted with an -"electric ear" would detect the currents passing through the wire. -Wireless telegraphy is possible because mankind has discovered -instruments which act as _electric ears or eyes_, catching and -recording vibrations that had hitherto remained undetected. - -The earliest known form of wireless telegraphy is transmission of -messages by light. A man on a hill lights a lamp or a fire. This -represents his instrument for agitating the ether into waves, which -proceed straight ahead with incredible velocity until they reach the -receiver, the eye of a man watching at a point from which the light is -visible. - -Then came electric telegraphy. - -At first a complete circuit (two wires) was used. But in 1838 it was -discovered that if instead of two wires only one was used, the other -being replaced by an earth connection, not only was the effect equally -powerful, but even double of what it was with the metallic circuit. - -Thus the first step had been taken towards wireless electrical -telegraphy. - -The second was, of course, to abolish the other wire. - -This was first effected by Professor Morse, who, in 1842, sent signals -across the Susquehanna River without metallic connections of any sort. -Along each bank of the river was stretched a wire three times as long -as the river was broad. In the one wire a battery and transmitter were -inserted, in the other a receiving instrument or galvanometer. Each -wire terminated at each end in a large copper plate sunk in the water. -Morse's conclusions were that provided the wires were long enough and -the plates large enough messages could be transmitted for an -indefinite distance; the current passing from plate to plate, though a -large portion of it would be lost in the water.[1] - - [1] It is here proper to observe that the term _wireless_ - telegraphy, as applied to electrical systems, is misleading, - since it implies the absence of wires; whereas in all systems - wires are used. But since it is generally understood that by - wireless telegraphy is meant telegraphy without _metal - connections_, and because the more improved methods lessen more - and more the amount of wire used, the phrase has been allowed - to stand. - -About the same date a Scotchman, James Bowman Lindsay of Dundee, a man -as rich in intellectual attainments as he was pecuniarily poor, sent -signals in a similar manner across the River Tay. In September, 1859, -Lindsay read a paper before the British Association at Dundee, in -which he maintained that his experiments and calculations assured him -that by running wires along the coasts of America and Great Britain, -by using a battery having an acting surface of 130 square feet and -immersed sheets of 3000 square feet, and a coil weighing 300 lbs., he -could send messages from Britain to America. Want of money prevented -the poor scholar of Dundee from carrying out his experiments on a -large enough scale to obtain public support. He died in 1862, leaving -behind him the reputation of a man who in the face of the greatest -difficulties made extraordinary electrical discoveries at the cost of -unceasing labour; and this in spite of the fact that he had undertaken -and partly executed a gigantic dictionary in fifty different -languages! - -[Illustration: _M. Marconi's Travelling Station for Wireless -Telegraphy._] - -The transmission of electrical signals through matter, metal, earth, -or water, is effected by _conduction_, or the _leading_ of the -currents in a circuit. When we come to deal with aerial transmission, -_i.e._ where one or both wires are replaced by the ether, then two -methods are possible, those of _induction_ and Hertzian waves. - -To take the induction method first. Whenever a current is sent through -a wire magnetism is set up in the ether surrounding the wire, which -becomes the core of a "magnetic field." The magnetic waves extend for -an indefinite distance on all sides, and on meeting a wire _parallel_ -to the electrified wire _induce_ in it a _dynamical_ current similar -to that which caused them. Wherever electricity is present there is -magnetism also, and _vice versa_. Electricity--produces -magnetism--produces electricity. The invention of the Bell telephone -enabled telegraphers to take advantage of this law. - -In 1885 Sir William Preece, now consulting electrical engineer to the -General Post-Office, erected near Newcastle two insulated squares of -wire, each side 440 yards long. The squares were horizontal, parallel, -and a quarter of a mile apart. On currents being sent through the one, -currents were detected in the other by means of a telephone, which -remained active even when the squares were separated by 1000 yards. -Sir William Preece thus demonstrated that signals could be sent -without even an earth connection, _i.e._ entirely through the ether. -In 1886 he sent signals between two parallel telegraph wires 4-1/2 -miles apart. And in 1892 established a regular communication between -Flatholm, an island fort in the Bristol Channel, and Lavernock, a -point on the Welsh coast 3-1/3 miles distant. - -The inductive method might have attained to greater successes had not -a formidable rival appeared in the Hertzian waves. - -In 1887 Professor Hertz discovered that if the discharge from a Leyden -jar were passed through wires containing an air-gap across which the -discharge had to pass, sparks would also pass across a gap in an -almost complete circle or square of wire held at some distance from -the jar. This "electric eye," or detector, could have its gap so -regulated by means of a screw that at a certain width its effect would -be most pronounced, under which condition the detector, or receiver, -was "in tune" with the exciter, or transmitter. Hertz thus established -three great facts, that-- - - (_a_) A discharge of static (_i.e._ collected) electricity - across an air-gap produced strong electric waves in the ether - on all sides. - - (_b_) That these waves could be _caught_. - - (_c_) That under certain conditions the catcher worked most - effectively. - -Out of these three discoveries has sprung the latest phase of wireless -telegraphy, as exploited by Signor Marconi. He, in common with -Professors Branly of Paris, Popoff of Cronstadt, and Slaby of -Charlottenburg, besides many others, have devoted their attention to -the production of improved means of sending and receiving the Hertzian -waves. Their experiments have shown that two things are required in -wireless telegraphy-- - - (i.) That the waves shall have great penetrating power, so as - to pierce any obstacle. - - (ii.) That they shall retain their energy, so that a _maximum_ - of their original force shall reach the receiver. - -The first condition is fulfilled best by waves of great length; the -second by those which, like light, are of greatest frequency. For best -telegraphic results a compromise must be effected between these -extremes, neither the thousand-mile long waves of an alternating -dynamo nor the light waves of many thousands to an inch being of use. -The Hertzian waves are estimated to be 230,000,000 per second; at -which rate they would be 1-1/2 yards long. They vary considerably, -however, on both sides of this rate and dimension. - -Marconi's transmitter consists of three parts--a battery; an induction -coil, terminating in a pair of brass balls, one on each side of the -air-gap; and a Morse transmitting-key. Upon the key being depressed, a -current from the battery passes through the coil and accumulates -electricity on the brass balls until its tension causes it to leap -from one to the other many millions of times in what is called a -spark. The longer the air-gap the greater must be the accumulation -before the leap takes place, and the greater the power of the -vibrations set up. Marconi found that by connecting a kite or balloon -covered with tinfoil by an aluminium wire with one of the balls, the -effect of the waves was greatly increased. Sometimes he replaced the -kite or balloon by a conductor placed on poles two or three hundred -feet high, or by the mast of a ship. - -We now turn to the receiver. - -In 1879 Professor D. E. Hughes observed that a microphone, in -connection with a telephone, produced sounds in the latter even when -the microphone was at a distance of several feet from coils through -which a current was passing. A microphone, it may be explained, is in -its simplest form a loose connection in an electric circuit, which -causes the current to flow in fits and starts at very frequent -intervals. He discovered that a metal microphone stuck, or cohered, -after a wave had influenced it, but that a carbon microphone was -self-restoring, _i.e._ regained its former position of loose contact -as soon as a wave effect had ceased. - -In 1891 Professor Branly of Paris produced a "coherer," which was -nothing more than a microphone under another name. Five years later -Marconi somewhat altered Branly's contrivance, and took out a patent -for a coherer of his own. - -It is a tiny glass tube, about two inches long and a tenth of an inch -in diameter inside. A wire enters it at each end, the wires -terminating in two silver plugs fitting the bore of the tube. A space -of 1/32 inch is left between the plugs, and this space is filled with -special filings, a mixture of 96 parts of nickel to 4 of silver, and -the merest trace of mercury. The tube is exhausted of almost all its -air before being sealed. - -This little gap filled with filings is, except when struck by an -electric wave, to all practical purposes a non-conductor of -electricity. The metal particles touch each other so lightly that they -offer great resistance to a current. - -But when a Hertzian wave flying through the ether strikes the coherer, -the particles suddenly press hard on one another, and make a bridge -through which a current can pass. The current works a "relay," or -circuit through which a stronger current passes, opening and closing -it as often as the coherer is influenced by a wave. The relay actuates -a tapper that gently taps the tube after each wave-influence, causing -the particles to _de_cohere in readiness for the succeeding wave, and -also a Morse instrument for recording words in dots and dashes on a -long paper tape. - -The coherer may be said to resemble an engine-driver, and the "relay" -an engine. The driver is not sufficiently strong to himself move a -train, but he has strength enough to turn on steam and make the engine -do the work. The coherer is not suitable for use with currents of the -intensity required to move a Morse recorder, but it easily switches a -powerful current into another circuit. - -Want of space forbids a detailed account of Marconi's successes with -his improved instruments, but the appended list will serve to show -how he gradually increased the distance over which he sent signals -through space. - -In 1896 he came to England. That year he signalled from a room in the -General Post-Office to a station on the roof 100 yards distant. -Shortly afterwards he covered 2 miles on Salisbury Plain. - -In May, 1897, he sent signals from Lavernock Point to Flatholm, 3-1/3 -miles. This success occurred at a critical time, for Sir W. Preece had -already, as we have seen, bridged the same gap by his induction -method, and for three days Marconi failed to accomplish the feat with -his apparatus, so that it appeared as though the newer system were the -less effective of the two. But by carrying the transmitting instrument -on to the beach below the cliff on which it had been standing, and -joining it by a wire to the pole already erected on the top of the -cliff, Mr. Marconi, thanks to a happy inspiration, did just what was -needed; he got a greater length of wire to send off his waves from. -Communication was at once established with Flatholm, and on the next -day with Brean Down, on the other side of the Bristol Channel, and -8-2/3 miles distant. Then we have-- - - Needles Hotel to Swanage 17-1/2 miles. - Salisbury to Bath 34 " - French Coast to Harwich 90 " - Isle of Wight to The Lizard 196 " - At Sea (1901) 350 " - Dec. 17, 1901, England to America 2099 " - -[Illustration: _Poldhu Towers, the Station put down by the Marconi -Wireless Telegraph Company, Limited, for carrying on a system of -transatlantic wireless telegraphy between England and America. From -the four towers are suspended the aerial wires which are carried into -the buildings in the centre. The towers are 215 feet in height, and -are made of wood._] - -A more pronounced, though perhaps less sensational, success than even -this last occurred at the end of February, 1902. Mr. Marconi, during a -voyage to America on the s.s. _Philadelphia_ remained in communication -with Poldhu, Cornwall, until the vessel was 1550 miles distant, -receiving messages on a Morse recorder for any one acquainted with the -code to read. Signals arrived for a further 500 miles, but owing to -his instruments not being of sufficient strength, Mr. Marconi could -not reply. - -When the transatlantic achievement was announced at the end of 1901, -there was a tendency in some quarters to decry the whole system. The -critics laid their fingers on two weak points. - -In the first place, they said, the speed at which the messages could -be transmitted was too slow to insure that the system would pay. Mr. -Marconi replied that there had been a time when one word per minute -was considered a good working rate across the Atlantic cable; whereas -he had already sent twenty-two words per minute over very long -distances. A further increase of speed was only a matter of time. - -The second objection raised centred on the lack of secrecy resulting -from signals being let loose into space to strike any instrument -within their range; and also on the confusion that must arise when the -ether was traversed by many sets of electric waves. - -The young Italian inventor had been throughout his experiments aware -of these defects and sought means to remedy them. In his earliest -attempts we find him using parabolic metal screens to project his -waves in any required direction and prevent their going in any other. -He also employed strips of metal in conjunction with the coherer, the -strips or "wings" being of such a size as to respond most readily to -waves of a certain length. - -The electric oscillations coming from the aerial wires carried on -poles, kites, &c., were of great power, but their energy dispersed -very quickly into space in a series of rapidly diminishing vibrations. -This fact made them affect to a greater or less degree any receiver -they might encounter on their wanderings. If you go into a room where -there is a piano and make a loud noise near the instrument a jangle of -notes results. But if you take a tuning-fork and after striking it -place it near the strings, only one string will respond, _i.e._ that -of the same pitch as the fork. - -What is required in wireless telegraphy is a system corresponding to -the use of the tuning-fork. Unfortunately, it has been discovered that -the syntony or tuning of transmitter and receiver reduces the distance -over which they are effective. An electric "noise" is more -far-reaching than an electric "note." - -Mr. Marconi has, however, made considerable advances towards combining -the sympathy and secrecy of the tuning system with the power of the -"noise" system. By means of delicately adjusted "wings" and coils he -has brought it about that a series of waves having small individual -strength, but great regularity, shall produce on the receiver a -_cumulative_ effect, storing, as it were, electricity on the surface -of the receiver "wings" until it is of sufficient power to overcome -the resistance of the coherer. - -That tuned wireless telegraphy is, over moderate distances, at least -as secret as that through wires (which can be tapped by induction) is -evident from the fact that during the America Cup Yacht Races Mr. -Marconi sent daily to the _New York Herald_ messages of 4000 total -words, and kept them private in spite of all efforts to intercept -them. He claims to have as many as 250 "tunes"; and, indeed, there -seems to be no limit to their number, so that the would-be "tapper" is -in the position of a man trying to open a letter-lock of which he does -not know the cipher-word. He _may_ discover the right tune, but the -chances are greatly against him. We may be certain that the rapid -advance in wireless telegraphy will not proceed much further before -syntonic messages can be transmitted over hundreds if not thousands of -miles. - -It is hardly necessary to dwell upon the great prospect that the new -telegraphy opens to mankind. The advantages arising out of a ready -means of communication, freed from the shackles of expensive -connecting wires and cables are, in the main, obvious enough. We have -only to imagine all the present network of wires replaced or -supplemented by ether-waves, which will be able to act between points -(_e.g._ ships and ships, ships and land, moving and fixed objects -generally) which cannot be connected by metallic circuits. - -Already ocean voyages are being shortened as regards the time during -which passengers are out of contact with the doings of the world. The -transatlantic journey has now a newsless period of but three days. -Navies are being fitted out with instruments that may play as -important a part as the big guns themselves in the next naval war. A -great maritime nation like our own should be especially thankful that -the day is not far distant when our great empire will be connected by -invisible electric links that no enemy may discover and cut. - -The romantic side of wireless telegraphy has been admirably touched in -some words uttered by Professor Ayrton in 1899, after the reading of a -paper by Mr. Marconi before the Institution of Electrical Engineers. - -"If a person wished to call to a friend" (said the Professor), "he -would use a loud electro-magnetic voice, audible only to him who had -the electro-magnetic ear. - -"'Where are you?' he would say. - -"The reply would come--'I am at the bottom of a coal mine,' or -'Crossing the Andes,' or 'In the middle of the Pacific.' Or, perhaps, -in spite of all the calling, no reply would come, and the person would -then know his friend was dead. Let them think of what that meant; of -the calling which went on every day from room to room of a house, -and then imagine that calling extending from pole to pole; not a noisy -babble, but a call audible to him who wanted to hear and absolutely -silent to him who did not." - -[Illustration: _Guglielmo Marconi._] - -When will Professor Ayrton's forecast come true? Who can say? Science -is so full of surprises that the ordinary man wonders with a semi-fear -what may be the next development; and wise men like Lord Kelvin humbly -confess that in comparison with what has yet to be learnt about the -mysterious inner workings of Nature their knowledge is but as -ignorance. - - - - -HIGH-SPEED TELEGRAPHY. - - -The wonderful developments of wireless telegraphy must not make us -forget that some very interesting and startling improvements have been -made in connection with the ordinary wire-circuit method: notably in -the matter of speed. - -At certain seasons of the year or under special circumstances which -can scarcely be foreseen, a great rush takes place to transmit -messages over the wires connecting important towns. Now, the best -telegraphists can with difficulty keep up a transmitting speed of even -fifty words a minute for so long as half-an-hour. The Morse alphabet -contains on the average three signals for each letter, and the average -length of a word is six letters. Fifty words would therefore contain -between them 900 signals, or fifteen a second. The strain of sending -or noting so many for even a brief period is very wearisome to the -operator. - -Means have been found of replacing the telegraph clerk, so far as the -actual signalling is concerned, by mechanical devices. - -In 1842 Alexander Bain, a watchmaker of Thurso, produced what is known -as a "chemical telegraph." The words to be transmitted were set up in -large metal type, all capitals, connected with the positive pole of -a battery, the negative pole of which was connected to earth. A metal -brush, divided into five points, each terminating a wire, was passed -over the metal type. As often as a division of the brush touched metal -it completed the electric circuit in the wire to which it was joined, -and sent a current to the receiving station, where a similar brush was -passing at similar speed over a strip of paper soaked in iodide of -potassium. The action of the electricity decomposed the solution, -turning it blue or violet. The result was a series of letters divided -longitudinally into five belts separated by white spaces representing -the intervals between the contact points of the brush. - -[Illustration: _The receiving instrument used by Messrs. Pollak & -Virag in their high-speed system of telegraphy. This instrument is -capable of receiving and photographically recording messages at the -astonishing speed of 50,000 words an hour._] - -The Bain Chemical Telegraph was able to transmit the enormous number -of 1500 words per minute; that is, at ten times the rate of ordinary -conversation! But even when improvements had reduced the line wires -from five to one, the system, on account of the method of composing -the message to be sent, was not found sufficiently practical to come -into general use. - -Its place was taken by slower but preferable systems: those of duplex -and multiplex telegraphy. - -When a message is sent over the wires, the actual time of making the -signals is more than is required for the current to pass from place to -place. This fact has been utilised by the inventors of methods whereby -two or more messages may not only be sent the _same_ way along the -same wire, but may also be sent in _different_ directions. Messages -are "duplex" when they travel across one another, "multiplex" when -they travel together. - -The principle whereby several instruments are able to use the same -wire is that of _distributing_ among the instruments the time during -which they are in contact with the line. - -Let us suppose that four transmitters are sending messages -simultaneously from London to Edinburgh. - -Wires from all four instruments are led into a circular contact-maker, -divided into some hundreds of insulated segments connected in rotation -with the four transmitters. Thus instrument A will be joined to -segments 1, 5, 9, 13; instrument B to segments 2, 6, 10, 14; -instrument C with segments 3, 7, 11, 15; and so on. - -Along the top of the segments an arm, connected with the telegraph -line to Edinburgh, revolves at a uniform rate. For about 1/500 of a -second it unites a segment with an instrument. If there are 150 -segments on the "distributor," and the arm revolves three times a -second, each instrument will be put into contact with the line rather -oftener than 110 times per second. And if the top speed of fifty words -a minute is being worked to, each of the fifteen signals occurring in -each second will be on the average divided among seven moments of -contact. - -A similar apparatus at Edinburgh receives the messages. It is evident -that for the system to work satisfactorily, or even to escape dire -confusion, the revolving arms must run at a level speed in perfect -unison with one another. When the London arm is over segment 1, the -Edinburgh arm must cover the same number. The greatest difficulty in -multiplex telegraphy has been to adjust the timing exactly. - -Paul la Cour of Copenhagen invented for driving the arms a device -called the Phonic Wheel, as its action was regulated by the vibrations -of a tuning-fork. The wheel, made of soft iron, and toothed on its -circumference, revolves at a short distance from the pole of a magnet. -As often as a current enters the magnet the latter attracts the -nearest tooth of the wheel; and if a regular series of currents pass -through it the motion of the wheel will be uniform. M. la Cour -produced the regularity of current impulses in the motor magnet by -means of a tuning-fork, which is unable to vibrate more than a certain -number of times a second, and at each vibration closed a circuit -sending current into the magnet. To get two tuning-forks of the same -note is an easy matter; and consequently a uniformity of rotation at -both London and Edinburgh stations may be insured. - -So sensitive is this "interrupter" system that as many as sixteen -messages can be sent simultaneously, which means that a single wire is -conveying from 500 to 800 words a minute. We can easily understand the -huge saving that results from such a system; the cost of instruments, -interrupter, &c., being but small in proportion to that of a number -of separate conductors. - -The word-sending capacity of a line may be even further increased by -the use of automatic transmitters able to work much faster in -signal-making than the human brain and hand. Sir Charles Wheatstone's -Automatic Transmitter has long been used in the Post-Office -establishments. - -The messages to be sent are first of all punched on a long tape with -three parallel rows of perforations. The central row is merely for -guiding the tape through the transmitting machine. The positions of -the holes in the two outside rows relatively to each other determine -the character of the signal to be sent. Thus, when three holes -(including the central one) are abreast, a Morse "dot" is signified; -when the left-hand hole is one place behind the right hand, a "dash" -will be telegraphed. - -In the case of a long communication the matter is divided among a -number of clerks operating punching machines. Half-a-dozen operators -could between them punch holes representing 250 to 300 words a minute; -and the transmitter is capable of despatching as many in the same -time, while it has the additional advantage of being tireless. - -The action of the transmitter is based upon the reversal of the -direction or nature of current. The punched tape is passed between an -oscillating lever, carrying two points, and plates connected with the -two poles of the battery. As soon as a hole comes under a pin the pin -drops through and makes a contact. - -At the receiving end the wire is connected with a coil wound round the -pole of a permanent bar-magnet. Such a magnet has what is known as a -north pole and a south pole, the one attractive and the other -repulsive of steel or soft iron. Any bar of soft iron can be made -temporarily into a magnet by twisting round it a few turns of a wire -in circuit with the poles of a battery. But which will be the north -and which the south pole depends on the _direction_ of the current. -If, then, a current passes in one direction round the north pole of a -permanent magnet it will increase the magnet's attractive power, but -will decrease it if sent in the other direction. - -The "dot" holes punched in the tape being abreast cause first a -positive and then a negative current following at a very short -interval; but the "dash" holes not being opposite allow the positive -current to occupy the wires for a longer period. Consequently the -Morse marker rests for correspondingly unequal periods on the -recording "tape," giving out a series of dots and dashes, as the inker -is snatched quickly or more leisurely from the paper. - -The Wheatstone recorder has been worked up to 400 words a minute, and -when two machines are by the multiplex method acting together this -rate is of course doubled. - -As a speed machine it has, however, been completely put in the shade -by a more recent invention of two Hungarian electricians, Anton Pollak -and Josef Virag, which combines the perforated strip method of -transmission with the telephone and photography. The message is sent -off by means of a punched tape, and is recorded by means of a -telephonic diaphragm and light marking a sensitised paper. - -In 1898 the inventors made trials of their system for the benefit of -the United Electrical Company of Buda-Pesth. The Hungarian capital was -connected by two double lines of wire with a station 200 miles -distant, where the two sets were joined so as to give a single circuit -of 400 miles in length. A series of tests in all weathers showed that -the Pollak-Virag system could transmit as many as 100,000 words an -hour over that distance. - -From Hungary the inventors went to the United States, in which country -of "records" no less than 155,000 words were despatched and received -in the sixty minutes. This average--2580 words per minute, 43 per -second--is truly remarkable! Even between New York and Chicago, -separated by 950 odd miles, the wires kept up an average of 1000 per -minute. - -The apparatus that produces these marvellous results is of two types. -The one type records messages in the Morse alphabet, the other makes -clearly-written longhand characters. The former is the faster of the -two, but the legibility of the other more than compensates for the -decrease of speed by one-half. - -[Illustration: _Specimens of the punched tape used for transmitting -messages by the Pollak-Virag system, and of a message as it is -delivered by the receiving machine._] - -The Morse alphabet method closely resembles the Wheatstone system. The -message is prepared for transmission by being punched on a tape. But -there is this difference in the position of the holes, that whereas in -the Wheatstone method two holes are used for each dot and dash, only -one is required in the Pollak-Virag. If to the right of the central -guiding line it signifies a "dash," if to the left, a "dot." - -The "reversal-of-current" method, already explained, causes at the -receiver end an increase or decrease in the power of a permanent -magnet to attract or repel a diaphragm, the centre of which is -connected by a very fine metal bar with the centre of a tiny mirror -hinged at one side on two points. A very slight movement of the -diaphragm produces an exaggerated movement of the mirror, which, as it -tilts backwards and forwards, reflects the light from an electric lamp -on to a lens, which concentrates the rays into a bright spot, and -focuses them on to a surface of sensitised paper. - -In their earliest apparatus the inventors attached the paper to the -circumference of a vertical cylinder, which revolved at an even pace -on an axle, furnished at the lower end with a screw thread, so that -the portion of paper affected by the light occupied a spiral path from -top to bottom of the cylinder. - -In a later edition, however, an endless band of sensitised paper is -employed, and the lamp is screened from the mirror by a horizontal -mantle in which is cut a helical slit making one complete turn of the -cylinder in its length. The mantle is rotated in unison with the -machinery driving the sensitised band; and as it revolves, the spot at -which the light from the filament can pass through the slit to the -mirror is constantly shifting from right to left, and the point at -which the reflected light from the mirror strikes the sensitised paper -from left to right. At the moment when a line is finished, the right -extremity of the mantle begins to pass light again, and the bright -spot of light recommences its work at the left edge of the band, which -has now moved on a space. - -The movements of the mirror backwards and forwards produce on the -paper a zigzag tracing known as syphon-writing. The record, which is -continuous from side to side of the band, is a series of zigzag -up-and-down strokes, corresponding to the dots and dashes of the Morse -alphabet. - -The apparatus for transmitting longhand characters is more complicated -than that just described. Two telephones are now used, and the punched -tape has in it five rows of perforations. - -If we take a copy-book and examine the letters, we shall see that they -all occupy one, two, or three bands of space. For instance, _a_, -between the lines, occupies one band; _g_, two bands; and _f_, three. -In forming letters, the movements of the fingers trace curves and -straight lines, the curves being the resultants of combined horizontal -and vertical movements. - -Messrs. Pollak and Virag, in order to produce curves, were obliged to -add a second telephone, furnished also with a metal bar joined to the -mirror, which rests on three points instead of on two. One of these -points is fixed, the other two represent the ends of the two diaphragm -bars, which move the mirror vertically and horizontally respectively, -either separately or simultaneously. - -A word about the punched paper before going further. It contains, as -we have said, five rows of perforations. The top three of these are -concerned only with the up-and-down strokes of the letters, the bottom -two with the cross strokes. When a hole of one set is acting in unison -with a hole of the other set a composite movement or curve results. - -The topmost row of all sends through the wires a negative current of -known strength; this produces upward and return strokes in the upper -zone of the letters: for instance, the upper part of a _t_. The second -row passes _positive_ currents of equal strength with the negative, -and influences the up-and-down strokes of the centre zone, _e.g._ -those of _o_; the third row passes positive currents _twice_ as strong -as the negative, and is responsible for double-length vertical strokes -in the centre and lower zones, _e.g._ the stroke in _p_. - -In order that the record shall not be a series of zigzags it is -necessary that the return strokes in the vertical elements shall be on -the same path as the out strokes; and as the point of light is -continuously tending to move from left to right of the paper there -must at times be present a counteracting tendency counterbalancing it -exactly, so that the path of the light point is purely vertical. At -other times not merely must the horizontal movements balance each -other, but the right-to-left element must be stronger than the -left-to-right, so that strokes such as the left curve of an _e_ may be -possible. To this end rows 4 and 5 of the perforations pass currents -working the second telephone diaphragm, which moves the mirror on a -vertical axis so that it reflects the ray horizontally. - -It will be noticed that the holes in rows 3, 4, 5 vary in size to -permit the passage of currents during periods of different length. In -this manner the little junction-hooks of such letters as _r_, _w_, -_v_, _b_ are effected. - -As fast as the sensitised paper strip is covered with the movements of -the dancing spot of light it is passed on over rollers through -developing and fixing chemical baths; so that the receiving of -messages is purely automatic. - -The reader can judge for himself the results of this ingenious system -as shown in a short section of a message transmitted by Mr. Pollak. -The words shown actually occupied two seconds in transmission. They -are beautifully clear. - -It is said that by the aid of a special "multiplex" device thirty sets -of Pollak-Virag apparatus can be used simultaneously on a line! The -reader will be able, by the aid of a small calculation, to arrive at -some interesting figures as regards their united output. - - - - -THE TELEPHONE. - - -A common enough sight in any large town is a great sheaf of fine wires -running across the streets and over the houses. If you traced their -career in one direction you would find that they suddenly terminate, -or rather combine into cables, and disappear into the recesses of a -house, which is the Telephone Exchange. If you tracked them the other -way your experience would be varied enough. Some wires would lead you -into public institutions, some into offices, some into snug rooms in -private houses. At one time your journey would end in the town, at -another you would find yourself roaming far into the country, through -green fields and leafy lanes until at last you ran the wire to earth -in some large mansion standing in a lordly park. Perhaps you might -have to travel hundreds of miles, having struck a "trunk" line -connecting two important cities; or you might even be called upon to -turn fish and plunge beneath the sea for a while, groping your way -along a submarine cable. - -In addition to the visible overhead wires that traverse a town there -are many led underground through special conduits. And many telephone -wires never come out of doors at all, their object being to furnish -communication between the rooms of the same house. The telephone and -its friend, the electric-bell, are now a regular part of the equipment -of any large premises. The master of the house goes to his telephone -when he wishes to address the cook or the steward, or the -head-gardener or the coachman. It saves time and labour. - -Should he desire to speak to his town-offices he will, unless -connected direct, "ring up" the Exchange, into which, as we have seen, -flow all the wires of the subscribers to the telephone system of that -district. The ringing-up is usually done by rapidly turning a handle -which works an electric magnet and rings a bell in the Exchange. The -operator there, generally a girl, demands the number of the person -with whom the ringer wants to speak, rings up that number, and -connects the wires of the two parties. - -In some exchanges, _e.g._ the new Post-Office telephone exchanges, the -place of electric-bells is taken by lamps, to the great advantage of -the operators, whose ears are thus freed from perpetual jangling. The -action of unhooking the telephone receiver at the subscriber's end -sends a current into a relay which closes the circuit of an electric -lamp opposite the subscriber's number in the exchange. Similarly, when -the conversation is completed the action of hanging up the receiver -again lights another lamp of a different colour, given the exchange -warning that the wires are free again. - -In America, the country of automatic appliances, the operator is -sometimes entirely dispensed with. A subscriber is able, by means of -a mechanical contrivance, to put himself in communication with any -other subscriber unless that subscriber is engaged, in which case a -dial records the fact. - -The popularity of the telephone may be judged from the fact that in -1901 the National Telephone Company's system transmitted over 807 -millions of messages, as compared with 89 millions of telegrams sent -over the Post Office wires. In America and Germany, however, the -telephone is even more universally employed than in England. In the -thinly populated prairies of West America the farm-houses are often -connected with a central station many miles off, from which they -receive news of the outer world and are able to keep in touch with one -another. We are not, perhaps, as a nation sufficiently alive to the -advantages of an efficient telephone system; and on this account many -districts remain telephoneless because sufficient subscribers cannot -be found to guarantee use of a system if established. It has been -seriously urged that much of our country depopulation might be -counteracted by a universal telephone service, which would enable -people to live at a distance from the towns and yet be in close -contact with them. At present, for the sake of convenience and ease of -"getting at" clients and customers, many business men prefer to have -their homes just outside the towns where their business is. A cheap -and efficient service open to every one would do away with a great -deal of travelling that is necessary under existing circumstances, -and by making it less important to live near a town allow people to -return to the country. - -Even Norway has a good telephone system. The telegraph is little used -in the more thinly inhabited districts, but the telephone may be found -in most unexpected places, in little villages hidden in the recesses -of the fiords. Switzerland, another mountainous country, but very -go-ahead in all electrical matters, is noted for the cheapness of its -telephone services. At Berne or Geneva a subscriber pays L4 the first -year, L2, 12s. the second year, and but L1, 12s. the third. Contrast -these charges with those of New York, where L15, 10s. to L49, 10s. is -levied annually according to service. - -The telephone as a public benefactor is seen at its best at -Buda-Pesth, the twin-capital of Hungary. In 1893, one Herr Theodore -Buschgasch founded in that city a "newspaper"--if so it may be -called--worked entirely on the telephone. The publishing office was a -telephone exchange; the wires and instruments took the place of -printed matter. The subscribers were to be informed entirely by ear of -the news of the day. - -The _Telefon Hirmondo_ or "Telephonic Newsteller," as the "paper" was -named, has more than six thousand subscribers, who enjoy their -telephones for the very small payment of eighteen florins, or about a -penny a day, for twelve hours a day. - -News is collected at the central office in the usual journalistic way -by telephone, telegraph, and reporters. It is printed by lithography -on strips of paper six inches wide and two feet long. These strips are -handed to "stentors," or men with powerful and trained voices, who -read the contents to transmitting instruments in the offices, whence -it flies in all directions to the ears of the subscribers. - -These last know exactly when to listen and what description of -information they will hear, for each has over his receiver a programme -which is rigidly adhered to. It must be explained at once that the -_Telefon Hirmondo_ is more than a mere newspaper, for it adds to its -practical use as a first-class journal that of entertainer, lecturer, -preacher, actor, political speaker, musician. The _Telefon_ offices -are connected by wire with the theatres, churches, and public halls, -drawing from them by means of special receivers the sounds that are -going on there, and transmitting them again over the wires to the -thousands of subscribers. The Buda-Pesthian has therefore only to -consult his programme to see when he will be in touch with his -favourite actor or preacher. The ladies know just when to expect the -latest hints about the fashions of the day. Nor are the children -forgotten, for a special period is set aside weekly for their -entertainment in the shape of lectures or concerts. - -The advertising fiend, too, must have his say, though he pays dearly -for it. On payment of a florin the stentors will shout the virtues of -his wares for a space of twelve seconds. The advertising periods are -sandwiched in between items of news, so that the subscriber is bound -to hear the advertisements unless he is willing to risk missing some -of the news if he hangs up his receiver until the "puff" is finished. - -Thanks to the _Telefon Hirmondo_ the preacher, actor, or singer is -obliged to calculate his popularity less by the condition of the seats -in front of him than by the number of telephones in use while he is -performing his part. On the other hand, the subscriber is spared a -vast amount of walking, waiting, cab-hire, and expense generally. In -fact, if the principle is much further developed, we shall begin to -doubt whether a Buda-Pesthian will be able to discover reasons for -getting out of bed at all if the receiver hanging within reach of his -hand is the entrance to so many places of delight. Will he become a -very lazy person; and what will be the effect on his entertainers when -they find themselves facing benches that are used less every day? Will -the sight of a row of telephone trumpets rouse the future Liddon, -Patti, Irving, or Gladstone to excel themselves? It seems rather -doubtful. Telephones cannot look interested or applaud. - -What is inside the simple-looking receiver that hangs on the wall -beside a small mahogany case, or rests horizontally on a couple of -crooks over the case? In the older type of instrument the transmitter -and receiver are separate, the former fixed in front of the case, the -latter, of course, movable so that it can be applied to the ear. But -improved patterns have transmitter and receiver in a single movable -handle, so shaped that the earpiece is by the ear while the -mouthpiece curves round opposite the mouth. By pressing a small lever -with the fingers the one or the other is brought into action when -required. - -The construction of the instrument, of which we are at first a little -afraid, and with which we later on learn to become rather angry, is in -its general lines simple enough. The first practical telephone, -constructed in 1876 by Graham Bell, a Scotchman, consisted of a long -wooden or ebonite handle down the centre of which ran a permanent -bar-magnet, having at one end a small coil of fine insulated wire -wound about it The ends of the wire coil are led through the handles -to two terminals for connection with the line wires. At a very short -distance from the wire-wound pole of the magnet is firmly fixed by its -edges a thin circular iron plate, covered by a funnel-shaped -mouthpiece. - -The iron plate is, when at rest, concave, its centre being attracted -towards the pole of the magnet. When any one speaks into the -mouthpiece the sound waves agitate the diaphragm (or plate), causing -its centre to move inwards and outwards. The movements of the -diaphragm affect the magnetism of the magnet, sometimes strengthening -it, sometimes weakening it, and consequently exciting electric -currents of varying strength in the wire coil. These currents passing -through the line wires to a similar telephone excite the coil in it, -and in turn affect the magnetism of the distant magnet, which -attracts or releases the diaphragm near its pole, causing undulations -of the air exactly resembling those set up by the speaker's words. To -render the telephone powerful enough to make conversation possible -over long distances it was found advisable to substitute for the one -telephone a special transmitter, and to insert in the circuit a -battery giving a much stronger current than could possibly be excited -by the magnet in the telephone at the speaker's end. - -Edison in 1877 invented a special transmitter made of carbon. He -discovered that the harder two faces of carbon are pressed together -the more readily will they allow current to pass; the reason probably -being that the points of contact increase in number and afford more -bridges for the current. - -Accordingly his transmitter contains a small disc of lampblack (a form -of carbon) connected to the diaphragm, and another carbon or platinum -disc against which the first is driven with varying force by the -vibrations of the voice. - -The Edison transmitter is therefore in idea only a modification of the -microphone. It acts as a _regulator_ of current, in distinction to the -Bell telephone, which is only an _exciter_ of current. Modern forms of -telephones unite the Edison transmitter with the Bell receiver. - -The latter is extremely sensitive to electric currents, detecting them -even when of the minutest power. We have seen that Marconi used a -telephone in his famous transatlantic experiments to distinguish the -signals sent from Cornwall. A telephone may be used with an "earth -return" instead of a second wire; but as this exposes it to stray -currents by induction from other wires carried on the same poles or -from the earth itself, it is now usual to use two wires, completing -the metallic circuit. Even so a subscriber is liable to overhear -conversations on wires neighbouring his own; the writer has lively -recollections of first receiving news of the relief of Ladysmith in -this manner. - -Owing to the self-induction of wires in submarine cables and the -consequent difficulty of forcing currents through them, the telephone -is at present not used in connection with submarine lines of more than -a very moderate length. England has, however, been connected with -France by a telephone cable from St. Margaret's Bay to Sangatte, 23 -miles; and Scotland with Ireland, Stranraer to Donaghadee, 26 miles. -The former cable enables speech between London and Marseilles, a -distance of 900 miles; and the latter makes it possible to speak from -London to Dublin _via_ Glasgow. The longest direct line in existence -is that between New York and Chicago, the complete circuit of which -uses 1900 miles of stout copper wire, raised above the ground on poles -35 feet high. - -The efficiency of the telephone on a well laid system is so great that -it makes very little difference whether the persons talking with one -another are 50 or 500 miles apart. There is no reason why a -Cape-to-Cairo telephone should not put the two extremities of Africa -in clear vocal communication. We may even live to see the day when a -London business man will be able to talk with his agent in Sydney, -Melbourne, or Wellington. - -A step towards this last achievement has been taken by M. Germain, a -French electrician, who has patented a telephone which can be used -with stronger currents than are possible in ordinary telephones; -thereby, of course, increasing the range of speech on submarine -cables. - -The telephone that we generally use has a transmitter which permits -but a small portion of the battery power to pass into the wires, owing -to the resistance of the carbon diaphragm. The weakness of the current -is to a great extent compensated by the exceedingly delicate nature of -the receiver. - -M. Germain has reversed the conditions with a transmitter that allows -a very high percentage of the current to flow into the wires, and a -comparatively insensitive receiver. The result is a "loud-speaking -telephone"--not a novelty, for Edison invented one as long ago as -1877--which is capable of reproducing speech in a wonderfully powerful -fashion. - -M. Germain, with the help of special tubular receivers, has actually -sent messages through a line having the same resistance as that of the -London-Paris line, so audibly that the words could be heard fifteen -yards from the receiver in the open air! - - - - -The Telephone - -WIRELESS TELEPHONY. - - -In days when wireless telegraphy is occupying such a great deal of the -world's attention, it is not likely to cause much astonishment in the -reader to learn that wireless transmission of _speech_ over -considerable distances is an accomplished fact. We have already -mentioned (see "Wireless Telegraphy") that by means of parallel -systems of wires Sir William Preece bridged a large air-gap, and -induced in the one sounds imparted to the other. - -Since then two other methods have been introduced; and as a preface to -the mention of the first we may say a few words about Graham Bell's -_Photophone_. - -In this instrument _light_ is made to do the work of a metal -connection between speaker and listener. Professor Bell, in arranging -the Photophone, used a mouthpiece as in his electric telephone, but -instead of a diaphragm working in front of a magnet to set up electric -impulses along a wire he employed a mirror of very thin glass, -silvered on one side. The effect of sound on this mirror was to cause -rapid alterations of its shape from concave to convex, and consequent -variations of its reflecting power. A strong beam of light was -concentrated on the centre of the mirror through a lens, and reflected -by the mirror at an angle through another lens in the direction of the -receiving instrument. The receiver consisted of a parabolic reflector -to catch the rays and focus them on a selenium cell connected by an -electric circuit with an ordinary telephone earpiece. - -On delivering a message into the mouthpiece the speaker would, by -agitating the mirror, send a succession of light waves of varying -intensity towards the distant selenium cell. Selenium has the peculiar -property of offering less resistance to electrical currents when light -is thrown upon it than when it is in darkness: and the more intense is -the light the less is the obstruction it affords. The light-waves from -the mirror, therefore, constantly alter its capacity as a conductor, -allowing currents to pass through the telephone with varying power. - -In this way Professor Bell bridged 800 yards of space; over which he -sent, besides articulate words, musical notes, using for the latter -purpose a revolving perforated disc to interrupt a constant beam of -light a certain number of times per second. As the speed of the disc -increased the rate of the light-flashes increased also, and produced -in the selenium cell the same number of passages to the electric -current, converted into a musical note by the receiver. So that by -means of mechanical apparatus a "playful sunbeam" could literally be -compelled to play a tune. - -From the Photophone we pass to another method of sound transmission by -light, with which is connected the name of Mr. Hammond V. Hayes of -Boston, Massachusetts. It is embodied in the Radiophone, or the -Ray-speaker, for it makes strong rays of light carry the human voice. - -Luminous bodies give off heat. As the light increases, so as a general -rule does the heat also. At present we are unable to create strong -light without having recourse to heat to help us, since we do not know -how to cause other vibrations of sufficient rapidity to yield the -sensation of light. But we can produce heat directly, and heat will -set atoms in motion, and the ether too, giving us light, but taking as -reward a great deal of the energy exerted. Now, the electric arc of a -searchlight produces a large amount of light _and_ heat. The light is -felt by the eye at a distance of many miles, but the body is not -sensitive enough to be aware of the heat emanating from the same -source. Mr. Hayes has, however, found the heat accompanying a -searchlight beam quite sufficient to affect a mechanical "nerve" in a -far-away telephone receiver. - -The transmitting apparatus is a searchlight, through the back of which -run four pairs of wires connected with a telephone mouthpiece after -passing through a switch and resistance-box or regulator. The receiver -is a concave mirror, in the focus of which is a tapering glass bulb, -half filled with carbonised filament very sensitive to heat. The -tapering end of the bulb projects through the back of the mirror into -an ear tube. - -If a message is to be transmitted the would-be speaker turns his -searchlight in the direction of the person with whom he wishes to -converse, and makes the proper signals. On seeing them the other -presents his mirror to the beam and listens. - -The speaker's voice takes control of the searchlight beam. The louder -the sound the more brilliantly glows the electric arc; the stronger -becomes the beam, the greater is the amount of heat passed on to the -mirror and gathered on the sensitive bulb. The filament inside -expands. The tapering point communicates the fact to the earpiece. - -This operation being repeated many times a second the earpiece fills -with sound, in which all the modulations of the far-distant voice are -easily distinguishable. - -Two sets of the apparatus above described are necessary for a -conversation, the functions of the searchlight and the bulb not being -reversible. But inasmuch as all large steamers carry searchlights the -necessary installation may be completed at a small expense. Mr. Hayes' -invention promises to be a rival to wireless telegraphy over -comparatively short distances. It can be relied upon in all weathers, -and is a fast method of communication. Like the photophone it -illustrates the inter-relationship of the phenomena of Sound, Light, -and Heat, and the readiness with which they may be combined to attain -an end. - -Next we turn from air to earth, and to the consideration of the work -of Mr. A. F. Collins of Philadelphia. This electrician merely makes -use of the currents flowing in all directions through the earth, and -those excited by an electric battery connected with earth. The outfit -requisite for sending wireless spoken messages consists of a couple of -convenient stands, as many storage batteries, sets of coils, and -receiving and transmitting instruments. - -The action of the transmitter is to send from the battery a series of -currents through the coils, which transmit them, greatly intensified, -to the earth by means of a wire connected with a buried wire-screen. -The electric disturbances set up in the earth travel in all -directions, and strike a similar screen buried beneath the receiving -instrument, where the currents affect the delicate diaphragm of the -telephone earpiece. - -The system is, in fact, upon all fours with Mr. Marconi's, the -distinguishing feature being that the ether of the atmosphere is used -in the latter case, that of the earth in the former. The intensity -coils are common to both; the buried screens are the counterpart of -the aerial kites or balloons; the telephone transmitter corresponds to -the telegraphic transmitting key; the earpiece to the coherer and -relay. No doubt in time Mr. Collins will "tune" his instruments, so -obtaining below ground the same sympathetic electric vibrations which -Mr. Marconi, Professor Lodge, or others have employed to clothe their -aerial messages in secrecy. - - - - -THE PHONOGRAPH. - - -Even if Thomas Edison had not done wonders with electric lighting, -telephones, electric torpedoes, new processes for separating iron from -its ore, telegraphy, animated photography, and other things too -numerous to mention, he would still have made for himself an enduring -name as the inventor of the Phonograph. He has fitly been called the -"Wizard of the West" from his genius for conjuring up out of what -would appear to the multitude most unpromising materials startling -scientific marvels, among which none is more truly wizard-like than -the instrument that is as receptive of sound as the human ear, and of -illimitable reproducing power. By virtue of its elfishly human -characteristic, articulate speech, it occupies, and always will -occupy, a very high position as a mechanical wonder. When listening to -a telephone we are aware of the fact that the sounds are immediate -reproductions of a living person's voice, speaking at the moment and -at a definite distance from us; but the phonographic utterances are -those of a voice perhaps stilled for ever, and the difference adds -romance to the speaking machine. - -The Phonograph was born in 1876. As we may imagine, its appearance -created a stir. A contributor to the _Times_ wrote in 1877: "Not many -weeks have passed since we were startled by the announcement that we -could converse audibly with each other, although hundreds of miles -apart, by means of so many miles of wire with a little electric magnet -at each end. - -"Another wonder is now promised us--an invention purely mechanical in -its nature, by means of which words spoken by the human voice can be, -so to speak, stored up and reproduced at will over and over again -hundreds, it may be thousands, of times. What will be thought of a -piece of mechanism by means of which a message of any length can be -spoken on to a plate of metal--that plate sent by post to any part of -the world and the message absolutely respoken in the very voice of the -sender, purely by mechanical agency? What, too, shall be said of a -mere machine, by means of which the old familiar voice of one who is -no longer with us on earth can be heard speaking to us in the very -tones and measure to which our ears were once accustomed?" - -The first Edison machine was the climax of research in the realm of -sound. As long ago as 1856 a Mr. Leo Scott made an instrument which -received the formidable name of Phonautograph, on account of its -capacity to register mechanically the vibrations set up in the -atmosphere by the human voice or by musical instruments. A large metal -cone like the mouth of an ear-trumpet had stretched across its smaller -end a membrane, to which was attached a very delicate tracing-point -working on the surface of a revolving cylinder covered with blackened -paper. Any sound entering the trumpet agitated the membrane, which in -turn moved the stylus and produced a line on the cylinder -corresponding to the vibration. Scott's apparatus could only record. -It was, so to speak, the first half of the phonograph. Edison, twenty -years later, added the active half. His machine, as briefly described -in the _Times_, was simple; so very simple that many scientists must -have wondered how they failed to invent it themselves. - -A metal cylinder grooved with a continuous square-section thread of -many turns to the inch was mounted horizontally on a long axle cut at -one end with a screw-thread of the same "pitch" as that on the -cylinder. The axle, working in upright supports, and furnished with a -heavy flywheel to render the rate of revolution fairly uniform, was -turned by a handle. Over the grooved cylinder was stretched a thin -sheet of tinfoil, and on this rested lightly a steel tracing-point, -mounted at the end of a spring and separated from a vibrating -diaphragm by a small pad of rubber tubing. A large mouthpiece to -concentrate sound on to the diaphragm completed the apparatus. - -To make a record with this machine the cylinder was moved along until -the tracing-point touched one extremity of the foil. The person -speaking into the mouthpiece turned the handle to bring a fresh -surface of foil continuously under the point, which, owing to the -thread on the axle and the groove on the cylinder being of the same -pitch, was always over the groove, and burnished the foil down into it -to a greater or less depth according to the strength of the impulses -received from the diaphragm. - -[Illustration: _A unique group of Phonographs. 1. The oldest -phonograph in existence, now in South Kensington Museum. 2. Tinfoil -instrument. 3. A cheaper form of the same. 4. A "spectacle-form" -graphophone. 5. An exactly similar instrument, half-size scale. 6. A -doll fitted with phonograph._] - -The record being finished, the point was lifted off the foil, the -cylinder turned back to its original position, and the point allowed -to run again over the depressions it had made in the metal sheet. The -latter now became the active part, imparting to the air by means of -the diaphragm vibrations similar in duration and quality to those that -affected it when the record was being made. - -It is interesting to notice that the phonograph principle was -originally employed by Edison as a telephone "relay." His attention -had been drawn to the telephone recently produced by Graham Bell, and -to the evil effects of current leakage in long lines. He saw that the -amount of current wasted increased out of proportion to the length of -the lines--even more than in the proportion of the squares of their -lengths--and he hoped that a great saving of current would be effected -if a long line were divided into sections and the sound vibrations -were passed from one to the other by mechanical means. He used as the -connecting link between two sections a strip of moistened paper, which -a needle, attached to a receiver, indented with minute depressions, -that handed on the message to another telephone. The phonograph -proper, as a recording machine, was an after-thought. - -Edison's first apparatus, besides being heavy and clumsy, had in -practice faults which made it fall short of the description given in -the _Times_. Its tone was harsh. The records, so far from enduring a -thousand repetitions, were worn out by a dozen. To these defects must -be added a considerable difficulty in adjusting a record made on one -machine to the cylinder of another machine. - -Edison, being busy with his telephone and electric lamp work, put -aside the phonograph for a time. Graham Bell, his brother, Chichester -Bell, and Charles Sumner Tainter, developed and improved his crude -ideas. They introduced the Graphophone, using easily removable -cylinder records. For the tinfoil was substituted a thin coating of a -special wax preparation on light paper cylinders. Clockwork-driven -motors replaced the hand motion, and the new machines were altogether -more handy and effective. As soon as he had time Edison again entered -the field. He conceived the solid wax cylinder, and patented a small -shaving apparatus by means of which a record could be pared away and a -fresh surface be presented for a new record. - -The phonograph or graphophone of to-day is a familiar enough sight; -but inasmuch as our readers may be less intimately acquainted with its -construction and action than with its effects, a few words will now be -added about its most striking features. - -In the first place, the record remains stationary while the trumpet, -diaphragm and stylus pass over it. The reverse was the case with the -tinfoil instrument. - -The record is cut by means of a tiny sapphire point having a circular -concave end very sharp at the edges, to gouge minute depressions into -the wax. The point is agitated by a delicate combination of weights -and levers connecting it with a diaphragm of French glass 1/140 inch -thick. The reproducing point is a sapphire ball of a diameter equal to -that of the gouge. It passes over the depressions, falling into them -in turn and communicating its movements to a diaphragm, and so -tenderly does it treat the records that a hundred repetitions do not -inflict noticeable damage. - -It is a curious instance of the manner in which man unconsciously -copies nature that the parts of the reproducing attachment of a -phonograph contains parts corresponding in function exactly to those -bones of the ear known as the Hammer, Anvil, and Stirrup. - -To understand the inner working of the phonograph the reader must be -acquainted with the theory of sound. All sound is the result of -impulses transmitted by a moving body usually reaching the ear through -the medium of the air. The quantity of the sound, or loudness, depends -on the violence of the impulse; the tone, or note, on the number of -impulses in a given time (usually fixed as one second); and the -quality, or _timbre_, as musicians say, on the existence of minor -vibrations within the main ones. - -If we were to examine the surface of a phonograph record (or -phonogram) under a powerful magnifying glass we should see a series -of scoops cut by the gouge in the wax, some longer and deeper than -others, long and short, deep and shallow, alternating and recurring in -regular groups. The depth, length, and grouping of the cuts decides -the nature of the resultant note when the reproducing sapphire point -passes over the record--at a rate of about ten inches a second. - -The study of a tracing made on properly prepared paper by a point -agitated by a diaphragm would enable us to understand easily the cause -of that mysterious variation in _timbre_ which betrays at once what -kind of instrument has emitted a note of known pitch. For instance, -let us take middle C, which is the result of a certain number of -atmospheric blows per second on the drum of the ear. The same note may -come from a piano, a violin, a banjo, a man's larynx, an organ, or a -cornet; but we at once detect its source. It is scarcely imaginable -that a piano and a cornet should be mistaken for one another. Now, if -the tracing instrument had been at work while the notes were made -successively it would have recorded a wavy line, each wave of exactly -the same _length_ as its fellows, but varying in its _outline_ -according to the character of the note's origin. We should notice that -the waves were themselves wavy in section, being jagged like the teeth -of a saw, and that the small secondary waves differed in size. - -The minor waves are the harmonics of the main note. Some musical -instruments are richer in these harmonics than others. The fact that -these delicate variations are recorded as minute indentations in the -wax and reproduced is a striking proof of the phonograph's mechanical -perfection. - -Furthermore, the phonograph registers not only these composite notes, -but also chords or simultaneous combinations of notes, each of which -may proceed from a different instrument. In its action it here -resembles a man who by constant practice is able to add up the pounds, -shillings, and pence columns in his ledger at the same time, one wave -system overlapping and blending with another. - -The phonograph is not equally sympathetic with all classes of sounds. -Banjo duets make good records, but the guitar gives a poor result. -Similarly, the cornet is peculiarly effective, but the bass drum -disappointing. The deep chest notes of a man come from the trumpet -with startling truth, but the top notes on which the soprano prides -herself are often sadly "tinny." The phonograph, therefore, even in -its most perfect form is not the equal of the exquisitely sensitive -human ear; and this may partially be accounted for by the fact that -the diaphragm in both recorder and reproducer has its own fundamental -note which is not in harmony with all other notes, whereas the ear, -like the eye, adapts itself to any vibration. - -Yet the phonograph has an almost limitless repertoire. It can justly -be claimed for it that it is many musical instruments rolled into one. -It will reproduce clearly and faithfully an orchestra, an -instrumental soloist, the words of a singer, a stump orator, or a -stage favourite. Consequently we find it every where--at -entertainments, in the drawing-room, and even tempting us at the -railway station or other places of public resort to part with our -superfluous pence. At the London Hippodrome it discourses to audiences -of several thousand persons, and in the nursery it delights the -possessors of ingeniously-constructed dolls which, on a button being -pressed and concealed machinery being brought into action, repeat some -well-known childish melody. - -It must not be supposed that the phonograph is nothing more than a -superior kind of scientific toy. More serious duties than those of -mere entertainment have been found for it. - -At the last Presidential Election in the States the phonograph was -often called upon to harangue large meetings in the interests of the -rival candidates, who were perhaps at the time wearing out their -voices hundreds of miles away with the same words. - -Since the pronunciation of a foreign language is acquired by constant -imitation of sounds, the phonograph, instructed by an expert, has been -used to repeat words and phrases to a class of students until the -difficulties they contain have been thoroughly mastered. The sight of -such a class hanging on the lips--or more properly the trumpet--of a -phonograph gifted with the true Parisian accent may be common enough -in the future. - -As a mechanical secretary and substitute for the shorthand writer the -phonograph has certainly passed the experimental stage. Its daily use -by some of the largest business establishments in the world testify to -its value in commercial life. Many firms, especially American, have -invested heavily in establishing phonograph establishments to save -labour and final expense. The manager, on arriving at his office in -the morning, reads his letters, and as the contents of each is -mastered, dictates an answer to a phonograph cylinder which is -presently removed to the typewriting room, where an assistant, placing -it upon her phonograph and fixing the tubes to her ears, types what is -required. It is interesting to learn that at Ottawa, the seat of the -Canadian Government, phonographs are used for reporting the -parliamentary proceedings and debates. - -There is therefore a prospect that, though the talking-machine may -lose its novelty as an entertainer, its practical usefulness will be -largely increased. And while considering the future of the instrument, -the thought suggests itself whether we shall be taking full advantage -of Mr. Edison's notable invention if we neglect to make records of all -kinds of intelligible sounds which have more than a passing interest. -If the records were made in an imperishable substance they might -remain effective for centuries, due care being taken of them in -special depositories owned by the nation. To understand what their -value would be to future generations we have only to imagine ourselves -listening to the long-stilled thunder of Earl Chatham, to the golden -eloquence of Burke, or the passionate declamations of Mrs. Siddons. -And in the narrower circle of family interests how valuable a part of -family heirlooms would be the phonograms containing a vocal message to -posterity from Grandfather this, or Great-aunt that, whose portraits -in the drawing-room album do little more than call attention to the -changes in dress since the time when their subjects faced the camera! - -_Record-Making and Manufacture._--Phonographic records are of two -shapes, the cylindrical and the flat, the latter cut with a volute -groove continuously diminishing in diameter from the circumference to -the centre. Flat records are used in the Gramophone--a reproducing -machine only. Their manufacture is effected by first of all making a -record on a sheet of zinc coated with a very thin film of wax, from -which the sharp steel point moved by the recording diaphragm removes -small portions, baring the zinc underneath. The plate is then flooded -with an acid solution, which eats into the bared patches, but does not -affect the parts still covered with wax. The etching complete, the wax -is removed entirely, and a cast or electrotype _negative_ record made -from the zinc plate. The indentations of the original are in this -represented by excrescences of like size; and when the negative block -is pressed hard down on to a properly prepared disc of vulcanite or -celluloid, the latter is indented in a manner that reproduces exactly -the tones received on the "master" record. - -Cylindrical records are made in two ways, by moulding or by copying. -The second process is extremely simple. The "master" cylinder is -placed on a machine which also rotates a blank cylinder at a short -distance from and parallel to the first. Over the "master" record -passes a reproducing point, which is connected by delicate levers to a -cutting point resting on the "blank," so that every movement of the -one produces a corresponding movement of the other. - -This method, though accurate in its results, is comparatively slow. -The _moulding_ process is therefore becoming the more general of the -two. Edison has recently introduced a most beautiful process for -obtaining negative moulds from wax positives. Owing to its shape, a -zinc cylinder could not be treated like a flat disc, as, the negative -made, it could not be detached without cutting. Edison, therefore, -with characteristic perseverance, sought a way of electrotyping the -wax, which, being a non-conductor of electricity, would not receive a -deposit of metal. The problem was how to deposit on it. - -Any one who has seen a Crookes' tube such as is used for X-ray work -may have noticed on the glass a black deposit which arises from the -flinging off from the negative pole of minute particles of platinum. -Edison took advantage of this repellent action; and by enclosing his -wax records in a vacuum between two gold poles was able to coat them -with an infinitesimally thin skin of pure gold, on which silver or -nickel could be easily deposited. The deposit being sufficiently thick -the wax was melted out and the surface of the electrotype carefully -cleaned. To make castings it was necessary only to pour in wax, which -on cooling would shrink sufficiently to be withdrawn. The delicacy of -the process may be deduced from the fact that some of the sibilants, -or hissing sounds of the voice, are computed to be represented by -depressions less than a millionth of an inch in depth, and yet they -are most distinctly reproduced! Cylinder records are made in two -sizes, 2-1/2 and 5 inches in diameter respectively. The larger size -gives the most satisfactory renderings, as the indentations are on a -larger scale and therefore less worn by the reproducing point. One -hundred turns to the inch is the standard pitch of the thread; but in -some records the number is doubled. - -Phonographs, Graphophones, and Gramophones are manufactured almost -entirely in America, where large factories, equipped with most perfect -plant and tools, work day and night to cope with the orders that flow -in freely from all sides. One factory alone turns out a thousand -machines a day, ranging in value from a few shillings to forty pounds -each. Records are made in England on a large scale; and now that the -Edison-Bell firm has introduced the unbreakable celluloid form their -price will decrease. By means of the Edison electrotyping process a -customer can change his record without changing his cylinder. He takes -the cylinder to the factory, where it is heated, placed in the mould, -and subjected to great pressure which drives the soft celluloid into -the mould depressions; and behold! in a few moments "Auld Lang Syne" -has become "Home, Sweet Home," or whatever air is desired. Thus -altering records is very little more difficult than getting a fresh -book at the circulating library. - - -THE PHOTOGRAPHOPHONE. - -This instrument is a phonograph working entirely by means of light and -electricity. - -The flame of an electric lamp is brought under the influence of sound -vibrations which cause its brilliancy to vary at every alteration of -pitch or quality. - -The light of the flame is concentrated through a lens on to a -travelling photographic sensitive film, which, on development in the -ordinary way, is found to be covered with dark and bright stripes -proportionate in tone to the strength of the light at different -moments. The film is then passed between a lamp and a selenium plate -connected with an electric circuit and a telephone. The resistance of -the selenium to the current varies according to the power of the light -thrown upon it. When a dark portion of the film intercepts the light -of the lamp the selenium plate offers high resistance; when the light -finds its way through a clear part of the film the resistance weakens. -Thus the telephone is submitted to a series of changes affecting the -"receiver." As in the making of the record speech-vibrations affect -light, and the light affects a sensitive film; so in its reproduction -the film affects a sensitive selenium plate, giving back to a -telephone exactly what it received from the sound vibrations. - -One great advantage of Mr. Ruhmer's method is that from a single film -any number of records can be printed by photography; another, that, as -with the Telegraphone (see below), the same film passed before a -series of lamps successively is able to operate a corresponding number -of telephones. - -The inventor is not content with his success. He hopes to record not -merely sounds but even pictures by means of light and a selenium -plate. - - -THE TELEPHONOGRAPH. - -Having dealt with the phonograph and the telephone separately, we may -briefly consider one or two ingenious combinations of the two -instruments. The word Telephonograph signifies an apparatus for -recording sounds sent from a distance. It takes the place of the human -listener at the telephone receiver. - -Let us suppose that a Reading subscriber wishes to converse along the -wires with a friend in London, but that on ringing up his number he -discovers that the friend is absent from his home or office. He is -left with the alternative of either waiting till his friend returns, -which may cause a serious loss of time, or of dictating his message, a -slow and laborious process. This with the ordinary telephonic -apparatus. But if the London friend be the possessor of a -Telephonograph, the person answering the call-bell can, if desired to -do so, switch the wires into connection with it and start the -machinery; and in a very short time the message will be stored up for -reproduction when the absent friend returns. - -The Telephonograph is the invention of Mr. J. E. O. Kumberg. The -message is spoken into the telephone transmitter in the ordinary way, -and the vibrations set up by the voice are caused to act upon a -recording stylus by the impact of the sound waves at the further end -of the wires. In this manner a phonogram is produced on the wax -cylinder in the house or office of the person addressed, and it may be -read off at leisure. A very sensitive transmitter is employed, and if -desired the apparatus can be so arranged that by means of a -double-channel tube the words spoken are simultaneously conveyed to -the telephone and to an ordinary phonograph, which insures that a -record shall be kept of any message sent. - -The _Telegraphone_, produced by Mr. Valdemar Poulsen, performs the -same functions as the telephonograph, but differs from it in being -entirely electrical. It contains no waxen cylinder, no cutting-point; -their places are taken respectively by a steel wire wound on a -cylindrical drum (each turn carefully insulated from its neighbours) -and by a very small electro-magnet, which has two delicate points that -pass along the wire, one on either side, resting lightly upon it. - -As the drum rotates, the whole of the wire passes gradually between -the two points, into which a series of electric shocks is sent by the -action of the speaker's voice at the further end of the wires. The -shocks magnetise the portion of steel wire which acts as a temporary -bridge between the two points. At the close of three and a half -minutes the magnet has worked from one end of the wire coil to the -other; it is then automatically lifted and carried back to the -starting-point in readiness for reproduction of the sounds. This is -accomplished by disconnecting the telegraphone from the telephone -wires and switching it on to an ordinary telephonic earpiece or -receiver. As soon as the cylinder commences to revolve a second time, -the magnet is influenced by the series of magnetic "fields" in the -wires, and as often as it touches a magnetised spot imparts an impulse -to the diaphragm of the receiver, which vibrates at the rate and with -the same force as the vibrations originally set up in the distant -transmitter. The result is a clear and accurate reproduction of the -message, even though hours and even days may have elapsed since its -arrival. - -As the magnetic effects on the wire coil retain their power for a -considerable period, the message may be reproduced many times. As soon -as the wire-covered drum is required for fresh impressions, the old -one is wiped out by passing a permanent magnet along the wire to -neutralise the magnetism of the last message. - -Mr. Poulsen has made an instrument of a different type to be employed -for the reception of an unusually lengthy communication. Instead of a -wire coil on a cylinder, a ribbon of very thin flat steel spring is -wound from one reel on to another across the poles of _two_ -electro-magnets, which touch the lower side only of the strip. The -first magnet is traversed by a continuous current to efface the -previous record; the second magnetises the strip in obedience to -impulses from the telephone wires. The message complete, the strip is -run back, and the magnets connected with receivers, which give out -loud and intelligent speech as the strip again traverses them. The -Poulsen machine makes the transmission of the same message -simultaneously through several telephones an easy matter, as the strip -can be passed over a series of electro-magnets each connected with a -telephone. - - - - -THE TELAUTOGRAPH. - - -It is a curious experience to watch for the first time the movements -of a tiny Telautograph pen as it works behind a glass window in a -japanned case. The pen, though connected only with two delicate wires, -appears instinct with human reason. It writes in a flowing hand, just -as a man writes. At the end of a word it crosses the t's and dots the -i's. At the end of a line it dips itself in an inkpot. It punctuates -its sentences correctly. It illustrates its words with sketches. It -uses shorthand as readily as longhand. It can form letters of all -shapes and sizes. - -And yet there is no visible reason why it should do what it does. The -japanned case hides the guiding agency, whatever it may be. Our ears -cannot detect any mechanical motion. The writing seems at first sight -as mysterious as that which appeared on the wall to warn King -Belshazzar. - -In reality it is the outcome of a vast amount of patience and -mechanical ingenuity culminating in a wonderful instrument called the -Telautograph. The Telautograph is so named because by its aid we can -send our autographs, _i.e._ our own particular handwriting, -electrically over an indefinite length of wire, as easily as a -telegraph clerk transmits messages in the Morse alphabet. Whatever -the human hand does on one telautograph at one end of the wires, that -will be reproduced by a similar machine at the other end, though the -latter be hundreds of miles away. - -[Illustration: _By kind permission of The Telautograph Co._ - -_The Telautograph. The upper portion is the Receiver, the lower (with -cover removed) is the Transmitter._] - -The instrument stands about eighteen inches high, and its base is as -many inches square. It falls into two parts, the receiver and the -transmitter. The receiver is vertical and forms the upright and back -portion of the telautograph. At one side of it hangs an ordinary -telephone attachment. The transmitter, a sloping desk placed -conveniently for the hand, is the front and horizontal portion. The -receiver of one station is connected with the transmitter of another -station; there being ordinarily no direct communication between the -two parts of the same instrument. - -An attempt will be made to explain, with the help of a simple diagram, -the manner in which the telautograph performs its duties. - -These duties are threefold. In the first place, it must reproduce -whatever is written on the transmitter. Secondly, it must reproduce -only what is _written_, not all the movements of the hand. Thirdly, it -must supply the recording pen with fresh paper to write on, and with -fresh ink to write with. - -In our diagram we must imagine that all the coverings of the -telautograph have been cleared away to lay bare the most essential -parts of the mechanism. For the sake of simplicity not all the coils, -wires, and magnets having functions of their own are represented, and -the drawing is not to scale. But what is shown will enable the reader -to grasp the general principles which work the machine. - -Turning first of all to the transmitter, we have P, a little platform -hinged at the back end, and moving up and down very slightly in front, -according as pressure is put on to or taken off it by the pencil. -Across it a roll of paper is shifted by means of the lever S, which -has other uses as well. To the right of P is an electric bell-push, E, -and on the left K, another small button. - -The pencil is at the junction of two small bars CC', which are hinged -at their other end to the levers AA'. Any motion of the pencil is -transmitted by CC' to AA', and by them to the arms LL', the -extremities of which, two very small brushes ZZ', sweep along the -quadrants RR'. This is the first point to observe, that the position -of the pencil decides on which sections of the quadrants these little -brushes rest, and consequently how much current is to be sent to the -distant station. The quadrants are known technically as rheostats, or -current-controllers. Each quadrant is divided into 496 parts, -separated from each other by insulating materials, so that current can -pass from one to the other only by means of some connecting wire. In -our illustration only thirteen divisions are given, for the sake of -clearness. The dark lines represent the insulation. WW' are the very -fine wire loops connecting each division of the quadrant with its -neighbours. If then a current from the battery B enters the rheostat -at division 1 it will have to pass through all these wires before it -can reach division 13. The current always enters at 1, but the point -of departure from the rheostat depends entirely upon the position of -the brushes Z or Z'. If Z happens to be on No. 6 the current will pass -through five loops of wire, along the arm L, and so through the main -wire to the receiving station; if on No. 13, through twelve loops. - -[Illustration: THE TELAUTOGRAPH] - -Before going any further we must have clear ideas on the subject of -electrical resistance, upon which the whole system of the telautograph -is built up. Electricity resembles water in its objection to flow -through small passages. It is much harder to pump water through a -half-inch pipe than through a one-inch pipe, and the longer the pipe -is, whatever its bore, the more work is required. So then, two things -affect resistance--_size_ of pipe or wire, and _length_ of pipe or -wire. - -The wires WW' are very fine, and offer very high resistance to a -current; so high that by the time the current from battery B has -passed through all the wire loops only one-fifteenth or less of the -original force is left to traverse the long-distance wire. - -The rheostats act independently of one another. As the pencil moves -over the transmitting paper, a succession of currents of varying -intensity is sent off by each rheostat to the receiving station. - -The receiver, to which we must now pay attention, has two arms DD', -and two rods FF', corresponding in size with AA' and CC' of the -transmitter. The arms DD' are moved up and down by the coils TT' which -turn on centres in circular spaces at the bend of the magnets MM'. The -position of these coils relatively to the magnets depend on the -strength of the currents coming from the transmitting station. Each -coil strains at a small spiral spring until it has reached the -position in which its electric force is balanced by the retarding -influence of the spring. One of the cleverest things in the -telautograph is the adjustment of these coils so that they shall -follow faithfully the motions of the rods LL' in the transmitter. - -[Illustration: _By kind permission of_] [_The Telautograph Co._ - -_An example of the work done by the Telautograph. The upper sketch -shows a design drawn on the transmitter; the lower is the same design -as reproduced by the receiving instrument, many miles distant._] - -We are now able to trace the actions of sending a message. The sender -first presses the button E to call the attention of some one at the -receiving station to the fact that a message is coming, either on the -telephone or on the paper. It should be remarked, by-the-bye, that the -same wires serve for both telephone and telautograph, the unhooking of -the telephone throwing the telautograph out of connection for the -time. - -He then presses the lever S towards the left, bringing his transmitter -into connection with the distant receiver, and also moving a fresh -length of paper on to the platform P. With his pencil he writes his -message, pressing firmly on the paper, so that the platform may bear -down against an electric contact, X. As the pencil moves about the -paper the arms CC' are constantly changing their angles, and the -brushes ZZ' are passing along the segments of the rheostats. - -Currents flow in varying intensity away to the coils TT' and work the -arms DD', the wires FF', and the pen, a tiny glass tube. - -In the perfectly regulated telautograph the arms AA' and the arms DD' -will move in unison, and consequently the position of the pen must be -the same from moment to moment as that of the pencil. - -Mr. Foster Ritchie, the clever inventor of this telautograph, had to -provide for many things besides mere slavish imitation of movement. As -has been stated above, the pen must record only those movements of the -pencil which are essential. Evidently, if while the pencil returns to -dot an _i_ a long line were registered by the pen corresponding to the -path of the pencil, confusion would soon ensue on the receiver; and -instead of a neatly-written message we should have an illegible and -puzzling maze of lines. Mr. Ritchie has therefore taken ingenious -precautions against any such mishap. The platen P on being depressed -by the pencil touches a contact, X, which closes an electric circuit -through the long-distance wires and excites a magnet at the receiving -end. That attracts a little arm and breaks another circuit, allowing -the bar Y to fall close to the paper. The wires FF' and the pen are -now able to rest on the paper and trace characters. But as soon as the -platen P rises, on the removal of the pencil from the transmitting -paper, the contact at X is broken, the magnet at the receiver ceases -to act, the arm it attracted falls back and sets up a circuit which -causes the bar to spring up again and lift the pen. So that unless -you are actually pressing the paper with your pencil, the pen is not -marking, though it may be moving. - -As soon as a line is finished a fresh surface of paper is required at -both ends. The operator pushes the lever S sideways, and effects the -change mechanically at his end. At the same time a circuit is formed -which excites certain magnets at the receiver and causes the shifting -forward there also of the paper, and also breaks the _writing_ -current, so that the pen returns for a moment to its normal position -of rest in the inkpot. - -It may be asked: If the wires are passing currents to work the writing -apparatus, how can they simultaneously affect the lifting-bar, Y? The -answer is that currents of two different kinds are used, a direct -current for writing, a vibratory current for depressing the -lifting-bar. The _direct_ current passes from the battery B through -the rheostats RR' along the wires, through the coils working the arms -DD' and into the earth at the far end; but the _vibratory_ current, -changing its direction many times a second and so neutralising itself, -passes up one wire and back down the other through the lifting-bar -connection without interfering with the direct current. - -The message finished, the operator depresses with the point of his -pencil the little push-key, K, and connects his receiver with the -distant transmitter in readiness for an answer. - -The working speed of the telautograph is that of the writer. If -shorthand be employed, messages can be transmitted at the rate of over -100 words per minute. As regards the range of transmission, successful -tests have been made by the postal authorities between Paris and -London, and also between Paris and Lyons. In the latter case the -messages were sent from Paris to Lyons and back directly to Paris, the -lines being connected at Lyons, to give a total distance of over 650 -miles. There is no reason why much greater length of line should not -be employed. - -The telautograph in its earlier and imperfect form was the work of -Professor Elisha Gray, who invented the telephone almost -simultaneously with Professor Graham Bell. His telautograph worked on -what is known as the step-by-step principle, and was defective in that -its speed was very limited. If the operator wrote too fast the -receiving pen lagged behind the transmitting pencil, and confusion -resulted. Accordingly this method, though ingenious, was abandoned, -and Mr. Ritchie in his experiments looked about for some preferable -system, which should be simpler and at the same time much speedier in -its action. After four years of hard work he has brought the rheostat -system, explained above, to a pitch of perfection which will be at -once appreciated by any one who has seen the writing done by the -instrument. - -The advantages of the Telautograph over the ordinary telegraphy may be -briefly summed up as follows:-- - -Anybody who can write can use it; the need of skilled operators is -abolished. - -A record is automatically kept of every message sent. - -The person to whom the message is sent need not be present at the -receiver. He will find the message written out on his return. - -The instrument is silent and so insures secrecy. An ordinary telegraph -may be read by sound; but not the telautograph. - -It is impossible to tap the wires unless, as is most unlikely, the -intercepting party has an instrument in exact accord with the -transmitter. - -It can be used on the same wires as the ordinary telephone, and since -a telephone is combined with it, the subscriber has a double means of -communication. For some items of business the telephone may be used as -preferable; but in certain cases, the telautograph. A telephone -message may be heard by other subscribers; it is impossible to prove -the authenticity of such a message unless witnesses have been present -at the transmitting end; and the message itself may be misunderstood -by reason of bad articulation. But the telautograph preserves secrecy -while preventing any misunderstanding. Anything written by it is for -all practical purposes as valid as a letter. - -We must not forget its extreme usefulness for transmitting sketches. A -very simple diagram often explains a thing better than pages of -letter-press. The telautograph may help in the detection of criminals, -a pictorial presentment of whom can by its means be despatched all -over the country in a very short time. And in warfare an instrument -flashing back from the advance-guard plans of the country and of the -enemy's positions might on occasion prove of the greatest importance. - - - - -MODERN ARTILLERY. - - -The vast subject of artillery in its modern form, including under this -head for convenience' sake not only heavy ordnance but machine-guns -and small-arms, can of necessity only be dealt with most briefly in -this chapter. - -It may therefore be well to take a general survey and to define -beforehand any words or phrases which are used technically in -describing the various operations. - -The employment of firearms dates from a long-distant past, and it is -interesting to note that many an improvement introduced during the -last century is but the revival of a former invention which only lack -of accuracy in tools and appliances had hitherto prevented from being -brought into practical usage. - -So far back as 1498 the art of _rifling_ cannon in straight grooves -was known, and a British patent was taken out in 1635 by Rotsipan. The -grooves were first made spiral or screwed by Koster of Birmingham -about 1620. Berlin possesses a rifled cannon with thirteen grooves -dated 1664. But the first recorded uses of such weapons in actual -warfare was during Louis Napoleon's Italian campaign in 1859, and two -years later by General James of the United States Army. - -The system of _breech-loading_, again, is as old as the sixteenth -century, and we find a British patent of 1741; while the first United -States patent was given in 1811 for a flint-lock weapon. - -_Magazine_ guns of American production appeared in 1849 and 1860, but -these were really an adaptation of the old matchlock revolvers, said -to belong to the period 1480-1500. There is one in the Tower of London -credited to the fifteenth century, and a British patent of 1718 -describes a well-constructed revolver carried on a tripod and of the -dimensions of a modern machine-gun. The inventor gravely explains that -he has provided round chambers for round bullets to shoot Christians, -and square chambers with square missiles for use against the Turks! - -The word "ordnance" is applied to heavy guns of all kinds, and -includes guns mounted on fortresses, naval guns, siege artillery, and -that for use in the field. These guns are all mounted on stands or -carriages, and may be divided into three classes:-- - - (i.) _Cannon_, or heavy guns. - - (ii.) _Howitzers_, for field, mountain, or siege use, which are - lighter and shorter than cannon, and designed to throw hollow - projectiles with comparatively small charges. - - (iii.) _Mortars_, for throwing shells at a great elevation. - -The modern long-range guns and improved howitzers have, however, -virtually superseded mortars. _Machine-guns_ of various forms are -comparatively small and light, transportable by hand, and filling a -place between cannon and small-arms, the latter term embracing the -soldier's personal armament of rifle and pistol or revolver, which are -carried in the hand. - -A group of guns of the like design are generally given the name of -their first inventor, or the place of manufacture: such as the -Armstrong gun, the Vickers-Maxim, the Martini-Henry rifle, or the -Enfield. - -The indifferent use of several expressions in describing the same -weapon is, however, rather confusing. One particular gun may be thus -referred to:--by its _weight_ in tons or cwt., as "the 35-ton gun"; by -the weight of its _projectile_, as "a 68-pounder"; by its _calibre_, -that is, size of bore, as "the 4-inch gun." Of these the heavier -breech-loading (B.-L.) and quick-firing (Q.-F.) guns are generally -known by the size of bore; small Q.-F.'s, field-guns, &c., by the -weight of projectile. It is therefore desirable to enter these -particulars together when making any list of service ordnance for -future reference. - -No individual gun, whether large or small, is a single whole, but -consists of several pieces fastened together by many clever devices. - -The principal parts of a cannon are:-- - - (1) The _chase_, or main tube into which the projectile is - loaded; terminating at one end in the muzzle. - - (2) The _breech-piece_, consisting of (_a_) the chamber, which - is bored out for a larger diameter than the chase to contain - the firing-charge. (_b_) The _breech-plug_, which is closed - before the charge is exploded and screwed tightly into place, - sealing every aperture by means of a special device called the - "obturator," in order to prevent any gases passing out round it - instead of helping to force the projectile forwards towards the - muzzle. - -The whole length of inside tube is termed the _barrel_, as in a -machine-gun, rifle, or sporting-piece, but in the two latter weapons -the breech-opening is closed by sliding or springing back the -breech-block or bolt into firing position. - -Old weapons as a rule were smooth-bored (S.-B.), firing a round -missile between which and the barrel a considerable amount of the -gases generated by the explosion escaped and caused loss of power, -this escape of gas being known as _windage_. - -In all modern weapons we use conical projectiles, fitted near the base -with a soft copper driving-band, the diameter of which is somewhat -larger than that of the bore of the gun, and cut a number of spiral -grooves in the barrel. The enormous pressure generated by the -explosion of the charge forces the projectile down the bore of the gun -and out of the muzzle. The body of the projectile, made of steel or -iron, being smaller in diameter than the bore, easily passes through, -but the driving-band being of greater diameter, and being composed of -soft copper, can only pass down the bore with the projectile by -flowing into the grooves, thus preventing any escape of gas, and being -forced to follow their twist. It therefore rotates rapidly upon its -own longitudinal axis while passing down the barrel, and on leaving -the muzzle two kinds of velocity have been imparted to it;--first, a -velocity of motion through the air; secondly, a velocity of rotation -round its axis which causes it to fly steadily onward in the required -direction, _i.e._ a prolongation of the axis of the gun. Thus extreme -velocity and penetrating power, as well as correctness of aim, are -acquired. - -The path of a projectile through the air is called its _trajectory_, -and if uninterrupted its flight would continue on indefinitely in a -perfectly straight line. But immediately a shot has been hurled from -the gun by the explosion in its rear two other natural forces begin to -act upon it:-- - -Gravitation, which tends to bring it to earth. - -Air-resistance, which gradually checks its speed. - -(Theoretically, a bullet dropped perpendicularly from the muzzle of a -perfectly horizontal rifle would reach the ground at the same moment -as another bullet fired from the muzzle horizontally, the action of -gravity being the same in both cases.) - -Its direct, even course is therefore deflected till it forms a curve, -and sooner or later it returns to earth, still retaining a part of its -velocity. To counteract the attraction of gravity the shot is thrown -upwards by elevating the muzzle, care being taken to direct the gun's -action to the same height above the object as the force of gravitation -would draw the projectile down during the time of flight. The gunner -is enabled to give the proper inclination to his piece by means of the -_sights_; one of these, near the muzzle, being generally fixed, while -that next the breech is adjustable by sliding up an upright bar which -is so graduated that the proper _elevation_ for any required range is -given. - -The greater the velocity the flatter is the trajectory, and the more -dangerous to the enemy. Assuming the average height of a man to be six -feet, all the distance intervening between the point where a bullet -has dropped to within six feet of the earth, and the point where it -actually strikes is dangerous to any one in that interval, which is -called the "danger zone." A higher initial velocity is gained by using -stronger firing charges, and a more extended flight by making the -projectile longer in proportion to its diameter. The reason why a -shell from a cannon travels further than a rifle bullet, both having -the same muzzle velocity, is easily explained. - -A rifle bullet is, let us assume, three times as long as it is thick; -a cannon shell the same. If the shell have ten times the diameter of -the bullet, its "nose" will have 10 x 10 = 100 times the area of the -bullet's nose; but its _mass_ will be 10 x 10 x 10 = 1000 times that of -the bullet. - -In other words, when two bodies are proportional in all their -dimensions their air-resistance varies as the square of their -diameters, but their mass and consequently their momentum varies as -the _cube_ of their diameters. The shell therefore starts with a great -advantage over the bullet, and may be compared to a "crew" of cyclists -on a multicycle all cutting the same path through the air; whereas the -bullet resembles a single rider, who has to overcome as much -air-resistance as the front man of the "crew" but has not the weight -of other riders behind to help him. - -As regards the effect of rifling, it is to keep the bullet from -turning head over heels as it flies through the air, and to maintain -it always point forwards. Every boy knows that a top "sleeps" best -when it is spinning fast. Its horizontal rotation overcomes a tendency -to vertical movement towards the ground. In like manner a rifle -bullet, spinning vertically, overcomes an inclination of its atoms to -move out of their horizontal path. Professor John Perry, F.R.S., has -illustrated this gyroscopic effect, as it is called, of a whirling -body with a heavy flywheel in a case, held by a man standing on a -pivoted table. However much the man may try to turn the top from its -original direction he will fail as long as its velocity of rotation is -high. He may move the top relatively to his body, but the table will -turn so as to keep the centre line of the top always pointing in the -same direction. - - -RIFLES. - -Up to the middle of last century our soldiers were armed with the -flint-lock musket known as "Brown Bess," a smooth-bore barrel 3/4-inch -in diameter, thirty-nine inches long, weighing with its bayonet over -eleven pounds. The round leaden bullet weighed an ounce, and had to be -wrapped in a "patch" or bit of oily rag to make it fit the barrel and -prevent windage; it was then pushed home with a ramrod on to the -powder-charge, which was ignited by a spark passing from the flint -into a priming of powder. How little its accuracy of aim could be -depended upon, however, is proved by the word of command when -advancing upon an enemy, "Wait till you see the whites of their eyes, -boys, before you fire!" - -In the year 1680 each troop of Life Guards was supplied with eight -rifled carbines, a modest allowance, possibly intended to be used -merely by those acting as scouts. After this we hear nothing of them -until in 1800 the 95th Regiment received a 20-bore muzzle-loading -rifle, exchanged about 1835 for the Brunswick rifle firing a spherical -bullet, an improvement that more than doubled its effective range. The -companies so armed became known as the Rifle Brigade. At last, in -1842, the old flint-lock was superseded for the whole army by the -original percussion musket, a smooth-bore whose charge was exploded by -a percussion cap made of copper. [That this copper had some commercial -value was shown by the rush of "roughs" to Aldershot and elsewhere -upon a field-day to collect the split fragments which strewed the -ground after the troops had withdrawn.] - -Soon afterward the barrel was rifled and an elongated bullet brought -into use. This missile was pointed in front, and had a hollowed base -so contrived that it expanded immediately the pressure of exploding -gases was brought to bear on it, and thus filled up the grooves, -preventing any windage. The one adopted by our army in the year 1852 -was the production of M. Minie, a Frenchman, though an expanding -bullet of English invention had been brought forward several years -before. - -Meanwhile the Prussians had their famous needle-gun, a breech-loading -rifled weapon fired by a needle attached to a sliding bolt; as the -bolt is shot forward the needle pierces the charge and ignites the -fulminate by friction. This rifle was used in the Prusso-Austrian war -of 1866 some twenty years after its first inception, and the French -promptly countered it by arming their troops with the Chassepot rifle, -an improved edition of the same principle. A piece which could be -charged and fired in any position from five to seven times as fast as -the muzzle-loader, which the soldier had to load standing, naturally -caused a revolution in the infantry armament of other nations. - -The English Government, as usual the last to make a change, decided in -1864 upon using breech-loading rifles. Till a more perfect weapon -could be obtained the Enfields were at a small outlay converted into -breech-loaders after the plans of Mr. Snider, and were henceforward -known as Snider-Enfields. Eventually--as the result of open -competition--the Martini-Henry rifle was produced by combining Henry's -system of rifling with Martini's mechanism for breech-loading. This -weapon had seven grooves with one turn in twenty-two inches, and -weighed with bayonet 10 lb. 4 oz. It fired with great accuracy, the -trajectory having a rise of only eight feet at considerable distances, -so that the bullet would not pass over the head of a cavalry man. -Twenty rounds could be fired in fifty-three seconds. - -Now in the latter years of the century all these weapons have been -superseded by magazine rifles, _i.e._ rifles which can be fired -several times without recourse to the ammunition pouch. They differ -from the revolver in having only one firing chamber, into which the -cartridges are one by one brought by a simple action of the breech -mechanism, which also extracts the empty cartridge-case. The bore of -these rifles is smaller and the rifling sharper; they therefore shoot -straighter and harder than the large bore, and owing to the use of new -explosives the recoil is less. - -The French _Lebel_ magazine rifle was the pioneer of all now used by -European nations, though a somewhat similar weapon was familiar to the -Americans since 1849, being first used during the Civil War. The Henry -rifle, as it was called, afterwards became the Winchester. - -The German army rifle is the _Mauser_, so familiar to us in the hands -of the Boers during the South African War--loading five cartridges at -once in a case or "clip" which falls out when emptied. The same rifle -has been adopted by Turkey, and was used by the Spaniards in the late -Spanish-American War. - -The Austrian _Mannlicher_, adopted by several continental nations, and -the Krag-Jorgensen now used in the north of Europe and as the United -States army weapon, resemble the Mauser in most particulars. Each of -these loads the magazine in one movement with a clip. - -The _Hotchkiss_ magazine rifle has its magazine in the stock, holding -five extra cartridges pushed successively into loading position by a -spiral spring. - -Our forces are now armed principally with the _Lee-Enfield_, which is -taking the place of the _Lee-Metford_ issued a few years ago. These -are small-bore rifles of .303 inch calibre, having a detachable box, -which is loaded with ten cartridges (Lee-Metford eight) passed up in -turn by a spring into the breech, whence, when the bolt is closed, -they are pushed into the firing-chamber. The empty case is ejected by -pulling back the bolt, and at the same time another cartridge is -pressed up from the magazine and the whole process repeated. When the -cut-off is used the rifle may be loaded and fired singly, be the -magazine full or empty. - -The Lee-Enfield has five grooves (Lee-Metford ten), making one -complete turn from right to left in every ten inches. It weighs 9 lb. -4 oz., and the barrel is 30.197 inches long. The range averages 3500 -yards. - -We are now falling into line with other powers by adopting the "clip" -form instead of the box for loading. The sealed pattern of the new -service weapon is thus provided, and has also been made somewhat -lighter and shorter while preserving the same velocity. - -We are promised an even more rapid firing rifle than any of these, one -in which the recoil is used to work the breech and lock so that it is -a veritable automatic gun. Indeed, several continental nations have -made trial of such weapons and reported favourably upon them. One -lately tried in Italy works by means of gas generated by the explosion -passing through a small hole to move a piston-rod. It is claimed that -the magazine can hold as many as fifty cartridges and fire up to -thirty rounds a minute; but the barrel became so hot after doing this -that the trial had to be stopped. - -The principal result of automatic action would probably be excessive -waste of cartridges by wild firing in the excitement of an engagement. -It is to-day as true as formerly that it takes on the average a man's -weight of lead to kill him in battle. - -To our neighbours across the Channel the credit also belongs of -introducing _smokeless powder_, now universally used; that of the -Lee-Metford being "cordite." To prevent the bullets flattening on -impact they are coated with a hard metal such as nickel and its -alloys. If the nose is soft, or split beforehand, a terribly enlarged -and lacerated wound is produced; so the Geneva Convention humanely -prohibited the use of such missiles in warfare. - -Before quitting this part of our subject it is as well to add a few -words about _pistols_. - -These have passed through much the same process of evolution as the -rifle, and have now culminated in the many-shotted _revolver_. - -During the period 1480-1500 the match-lock revolver is said to have -been brought into use; and one attributed to this date may be seen in -the Tower of London. - -Two hundred years ago, Richards, a London gunsmith, converted the -ancient wheel-lock into the flint-lock; he also rifled his barrel and -loaded it at the breech. The Richards weapon was double-barrelled, and -unscrewed for loading at the point where the powder-chamber ended; the -ball was placed in this chamber in close contact with the powder, and -the barrel rescrewed. The bullet being a soft leaden ball, was forced, -when the charge was fired, through the rifled barrel with great -accuracy of aim. - -The percussion cap did not oust the flint-lock till less than a -century ago, when many single-barrelled pistols, such as the famous -Derringer, were produced; these in their turn were replaced by the -revolver which _Colt_ introduced in 1836-1850. Smith and Wesson in the -early sixties improved upon it by a device for extracting the empty -cartridges automatically. Livermore and Russell of the United States -invented the "clip," containing several cartridges; but the equally -well-known _Winchester_ has its cartridges arranged in a tube below -the barrel, whence a helical spring feeds them to the breech as fast -as they are needed. - -At the present time each War Department has its own special service -weapon. The German _Mauser_ magazine-pistol for officer's use fires -ten shots in ten seconds, a slight pressure of the trigger setting the -full machinery in motion; the pressure of gas at each explosion does -all the rest of the work--extracts and ejects the cartridge case, -cocks the hammer, and presses springs which reload and close the -weapon, all in a fraction of a second. The _Mannlicher_ is of the same -automatic type, but its barrel moves to the front, leaving space for a -fresh cartridge to come up from the magazine below, while in the -Mauser the breech moves to the rear during recoil. The range is half a -mile. The cartridges are made up in sets of ten in a case, which can -be inserted in one movement. - - -MACHINE-GUNS. - -Intermediate between hand-borne weapons and artillery, and partaking -of the nature of both, come the machine-guns firing small projectiles -with extraordinary rapidity. - -Since the United States made trial of Dr. Gatling's miniature battery -in the Civil War (1862-1865), invention has been busy evolving more -and more perfect types, till the most modern machine-gun is a marvel -of ingenuity and effectiveness. - -The _Gatling_ machine-gun, which has been much improved in late years -by the Accles system of "feed," and is not yet completely out of date, -consists of a circular series of ten barrels--each with its own -lock--mounted on a central shaft and revolved by a suitable gear. The -cartridges are successively fed by automatic actions into the barrels, -and the hammers are so arranged that the entire operation of loading, -closing the breech, firing and withdrawing the empty cartridge-cases -(which is known as their "longitudinal reciprocating motion") is -carried on while the locks are kept in constant revolution, along with -the barrels and breech, by means of a hand-crank. One man places a -feed-case filled with cartridges into the hopper, another turns the -crank. As the gun is rotated the cartridges drop one by one from the -feed-cases into the grooves of the carrier, and its lock loads and -fires each in turn. While the gun revolves further the lock, drawing -back, extracts and drops the empty case; it is then ready for the next -cartridge. - -In action five cartridges are always going through some process of -loading, while five empty shells are in different stages of ejection. -The latest type, fitted with an electro-motor, will fire at the _rate_ -of one thousand rounds per minute, and eighty rounds have actually -been fired within ten seconds! It is not, however, safe to work these -machine-guns so fast, as the cartridges are apt to be occasionally -pulled through unfired and then explode among the men's legs. The -automatic guns, on the contrary, as they only work by the explosion, -are free from any risk of such accidents. - -The feed-drums contain 104 cartridges, and can be replaced almost -instantly. One drumful can be discharged in 5-1/4 seconds. The -small-sized Gatling has a drum-feed of 400 cartridges in sixteen -sections of twenty-five each passed up without interruption. - -The gun is mounted for use so that it can be pointed at any angle, and -through a wide lateral range, without moving the carriage. - -_The Gardner._--The Gatling, as originally made, was for a time -superseded by the _Gardner_, which differed from it in having the -barrels (four or fewer in number) fixed in the same horizontal plane. -This was worked by a rotatory handle on the side of the gun. The -cartridges slid down a feed-case in a column to the barrel, where they -were fired by a spring acting on a hammer. - -_The Nordenfelt._--Mr. Nordenfelt's machine-gun follows this -precedent; its barrels--10, 5, 4, 2, or 1 in number--also being -arranged horizontally in a strong, rigid frame. Each barrel has its -own breech-plug, striker, spring, and extractor, and each fires -independently of the rest, so that all are not out of action together. -The gun has a swivelled mount easily elevated and trained, and the -steel frames take up the force of the discharge. In rapid firing one -gunner can work the firing-handle while another lays and alters the -direction. The firing is operated by a lever working backwards and -forwards by hand, and the gun can be discharged at the rate of 600 -rounds per minute. - -_The Hotchkiss._--The Hotchkiss gun, or revolving cannon, is on a -fresh system, that of intermittent rotation of the barrels without any -rotation of breech or mechanism. There is only one loading piston, one -spring striker, and one extractor for all the barrels. The shock of -discharge is received against a massive fixed breech, which -distributes it to the whole body. - -Like the _Nordenfelt_, however, it can be dismounted and put together -again without the need of tools. The above pattern throws 1 lb. -projectiles. - -_The Maxim._--Differing from all these comes the _Maxim_ gun, so much -in evidence now with both land and sea service. It is made up of two -portions:-- - - (1) _Fixed_: a barrel-casing, which is also a water-jacket, and - breech-casing. - - (2) _Recoiling_: a barrel and two side plates which carry lock - and crank. - -This recoiling portion works inside the fixed. - -The gun is supplied with ammunition by a belt holding 250 cartridges -passing through a feed-block on the top. Its mechanism is worked -_automatically_; first by the explosion of the charge, which causes -the barrel to recoil backwards and extends a strong spring which, on -reasserting itself, carries it forwards again. The recoiling part -moves back about an inch, and this recoil is utilised by bringing -into play mechanism which extracts the empty cartridge-case, and on -the spring carrying the barrel forward again moves a fresh one into -position. Under the barrel casing is the ejector tube through which -the empty cartridge-cases are ejected from the gun. - -The rate of fire of the Maxim gun is 600 rounds per minute. Deliberate -fire means about 70 rounds per minute; rapid fire will explode 450 -rounds in the same time. As the barrel becomes very hot in use the -barrel-casing contains seven pints of water to keep it cool. About -2000 rounds can be fired at short intervals; but in continuous firing -the water boils after some 600 rounds, and needs replenishing after -about 1000. A valved tube allows steam, but not water to escape. - -The operator works this gun by pressing a firing-lever or button. -After starting the machine he merely sits behind the shield, which -protects him from the enemy, directing it, as it keeps on firing -automatically so long as the bands of cartridges are supplied and a -finger held on the trigger or button. By setting free a couple of -levers with his left hand, and pressing his shoulder against the -padded shoulder-piece, he is able to elevate or depress, or train the -barrel horizontally, without in any way interfering with the hail of -missiles. - -We use two sizes, one with .45 bore for the Navy, which takes an -all-lead bullet weighing 480 grains, and the other with .303 bore, the -ordinary nickel-coated rifle bullet for the Army. But as the Maxim -gun can be adapted to every rifle-calibre ammunition it is patronised -by all governments. - -The gun itself weighs 56 lbs., and is mounted for use in various ways: -on a tripod, a field stand, or a field carriage with wheels. This -carriage has sixteen boxes of ammunition, each containing a belt of -250 cartridges, making 4000 rounds altogether. Its total weight is -about half a ton, so that it can be drawn by one horse, and it is -built for the roughest cross-country work. A little machine, which can -be fixed to the wheel, recharges the belts with cartridges by the -working of a handle. - -For ships the Maxim is usually mounted on the ordinary naval cone -mount, or it can be clamped to the bulwark of the deck or the military -"top" on the mast. - -But there is a most ingenious form of parapet mounting, known as the -garrison mount, which turns the Maxim into a "disappearing gun," and -can be used equally well for fortress walls or improvised -entrenchments. The gun is placed over two little wheels on which it -can be run along by means of a handle pushed behind in something the -fashion of a lawn-mower. Arrived at its destination, the handle, which -is really a rack, is turned downwards, and on twisting one of the -wheels the gun climbs it by means of a pinion-cog till it points over -the wall, to which hooks at the end of two projecting bars firmly fix -it, the broadened end of the handle being held by its weight to the -ground. It is locked while in use, but a few turns of the wheel cause -it to sink out of sight in as many seconds. - -The rifle-calibre guns may also be used as very light horse artillery -to accompany cavalry by being mounted on a "galloping carriage" drawn -by a couple of horses, and with two seats for the operators. The -carriage conveys 3000 rounds, and the steel-plated seats turn up and -form shields during action. - -It is interesting to notice that an extra light form of the gun is -made which may be carried strapped on an infantryman's back and fired -from a tripod. Two of these mounted on a double tricycle can be -propelled at a good pace along a fairly level road, and the riders -dismounting have, in a few moments, a valuable little battery at their -disposal. - -The _Pom-pom_, of which we have heard so much in the late war, is a -large edition of the Maxim automatic system with some differences in -the system. Its calibre is 1-1/2 inches. Instead of bullets it emits -explosive shells 1 lb. in weight, fitted with percussion fuses which -burst them into about twelve or fourteen pieces. The effective range -is up to 2000 yards, and it will carry to 4000 yards. An improved -_Pom-pom_ recently brought out hurls a 1-1/4 lb. shell with effect at -a mark 3000 yards away, and as far as 6000 yards before its energy is -entirely exhausted. The muzzle velocity of this weapon is 2350 feet a -second as against the 1800 feet of the older pattern. They both fire -300 rounds a minute. - -The _Colt_ automatic gun is an American invention whose automatic -action is due to explosion of the charge, not to recoil. The force by -which the motions of firing, extracting, and loading are performed is -derived from the powder-gases, a portion of which--passing through a -small vent in the muzzle--acts by means of a lever on the mechanism of -the gun. - -This is also in two parts: (_a_) _barrel_, attached to (_b_) -breech-casing, in which gear for charging, firing, and ejecting is -contained. The barrel, made of a strong alloy of nickel, has its -cartridges fed in by means of belts coiled in boxes attached to the -breech-casing, the boxes moving with the latter so that the movements -of the gun do not affect it. These boxes contain 250 cartridges each -and are easily replaced. - -The feed-belt is inserted, and the lever thrown down and moved -backward--once by hand--as far as it will go; this opens the breech -and passes the first cartridge from the belt to the carrier. The lever -is then released and the spring causes it to fly forward, close the -vent, and transfer the cartridge from the carrier to the barrel, also -compressing the mainspring and opening and closing the breech. - -On pulling the trigger the shot is fired, and after the bullet has -passed the little vent, but is not yet out of the muzzle, the force of -the expanding gas, acting through the vent on the piston, sets a -gas-lever in operation which acts on the breech mechanism, opens -breech, ejects cartridge-case, and feeds another cartridge into the -carrier. The gas-lever returning forces the cartridge home in the -barrel and closes and locks the breech. - -The hammer of the gun acts as the piston of an air-pump, forcing a -strong jet of air into the chamber, and through the barrel, thus -removing all unburnt powder, and thoroughly cleansing it. The metal -employed is strong enough to resist the heaviest charge of -nitro-powder, and the accuracy of its aim is not disturbed by the -vibrations of rapid fire. It does not heat fast, so has no need of a -water-jacket, any surplus heat being removed by a system of radiation. - -The bore is made of any rifle calibre for any small-arm ammunition, -and is fitted with a safety-lock. For our own pieces we use the -Lee-Metford cartridges. Four hundred shots per minute can be fired. - -The gun consists altogether of ninety-four pieces, but the -working-pieces, _i.e._ those only which need be separated for -cleaning, &c., when in the hands of the artilleryman, are less than -twenty. It can be handled in action by one man, the operation -resembling that of firing a pistol. - -The machine weighs 40 lbs., and for use by cavalry or infantry can be -mounted on the _Dundonald Galloping Carriage_. The ammunition-box, -containing 2000 rounds ready for use, carries the gun on its upper -side, and is mounted on a strong steel axle. A pole with a slotted end -is inserted into a revolving funnel on the bend of the shaft, the -limbering-up being completed by an automatic bolt and plug. - -The gun-carriage itself is of steel, with hickory wheels and hickory -and steel shafts, detachable at will. The simple harness suits any -saddled cavalry horse, and the shafts work in sockets behind the -rider's legs. Its whole weight with full load of ammunition is under -four hundredweight. - - -HEAVY ORDNANCE. - -As with rifles and the smaller forms of artillery, so also with heavy -ordnance, the changes and improvements within the last fifty years -have been greater than those made during the course of all the -previous centuries. - -These changes have affected alike not only the materials from which a -weapon is manufactured, the relative size of calibre and length of -bore, the fashion of mounting and firing, but also the form and weight -of the projectile, the velocity with which it is thrown, and even the -substances used in expelling it from the gun. - -Compare for a moment the old cast-iron muzzle-loaders, stubby of -stature, which Wellington's bronzed veterans served with round cannon -balls, well packed in greasy clouts to make them fit tight, or with -shell and grape shot, throughout the hard-fought day of Waterloo, from -a distance which the chroniclers measure by _paces_, so near stood the -opposing ranks to one another. - -Or stand in imagination upon one of Nelson's stately men-o'-war and -watch the grimy guns' crews, eight or ten to each, straining on the -ropes. See the still smoking piece hauled inboard, its bore swabbed -out to clean and cool it, then recharged by the muzzle; home go -powder, wad, and the castor full of balls or the chain shot to -splinter the enemy's masts, rammed well down ere the gun is again run -out through the port-hole. Now the gunner snatches the flaming -lintstock and, signal given, applies it to the powder grains sprinkled -in the touch-hole. A salvo of fifty starboard guns goes off in one -terrific broadside, crashing across the Frenchman's decks at such -close quarters that in two or three places they are set on fire by the -burning wads. Next comes a cry of "Boarders!" and the ships are -grappled as the boarding-party scrambles over the bulwarks to the -enemy's deck, a brisk musket-fire from the crowded rigging protecting -their advance; meanwhile the larboard guns, with their simultaneous -discharge, are greeting a new adversary. - -Such was war a century ago. Compare with it the late South African -Campaign where the range of guns was estimated in _miles_, and after a -combat lasting from morn to eve, the British general could report: "I -do not think we have seen a gun or a Boer all day." - -The days of hand-to-hand fighting have passed, the melee in the ranks -may be seen no more; in a few years the bayonet may be relegated to -the limbo of the coat-of-mail or the cast-iron culverin. Yet the -modern battle-scene bristles with the most death-dealing weapons which -the ingenuity of man has ever constructed. The hand-drawn machine-gun -discharges in a couple of minutes as many missiles as a regiment of -Wellington's infantry, with a speed and precision undreamt of by him. -The quick-firing long-range naval guns now in vogue could annihilate a -fleet or destroy a port without approaching close enough to catch a -glimpse of the personnel of their opponents. The deadly torpedo guards -our waterways more effectually than a squadron of ships. - -All resources of civilisation have been drawn upon, every triumph of -engineering secured, to forge such weapons as shall strike the hardest -and destroy the most pitilessly. But strange and unexpected the -result! Where we counted our battle-slain by thousands we now mourn -over the death of hundreds; where whole regiments were mown down our -ambulances gather wounded in scattered units. Here is the bright side -of modern war. - -The muzzle-loading gun has had its day, a very long day and a -successful one. Again and again it has reasserted itself and ousted -its rivals, but at last all difficulties of construction have been -surmounted and the breech-loader has "come to stay." - -However, our services still contain a large number of muzzle-loading -guns, many of them built at quite a recent period, and adapted as far -as possible to modern requirements. So to these we will first turn our -attention. - -The earliest guns were made of cast-iron, but this being prone to -burst with a large charge, bronze, brass, and other tougher materials -were for a long time employed. Most elaborately chased and ornamented -specimens of these old weapons are to be seen in the Tower, and many -other collections. - -In the utilitarian days of the past century cheapness and speed in -manufacture were more sought after than show. Iron was worked in many -new ways to resist the pressure of explosion. - -Armstrong of Elswick conceived the idea of building up a barrel of -_coiled_ iron by joining a series of short welded cylinders together, -and closing them by a solid forged breech-piece. Over all, again, -wrought-iron coils were shrunk. Subsequently he tried a solid -forged-iron barrel bored out to form a tube. Neither make proving very -satisfactory, steel tubes were next used, but were too expensive and -uncertain at that stage of manufacture. Again coiled iron was called -into requisition, and Mr. Frazer of the Royal Gun Factory introduced a -system of double and triple coils which was found very successful, -especially when a thin steel inner tube was substituted for the iron -one (1869). - -All these weapons were rifled, so that there was of necessity a -corresponding difference in the projectile employed. Conical shells -being used, studs were now placed on the body of the shell to fit into -the rifling grooves, which were made few in number and deeply cut. -This was apt to weaken the bore of the gun; but on the other hand -many studs to fit into several shallow grooves weakened the cover of -the shells. - -Various modifications were tried, and finally a gas-check which -expands into the grooves was placed at the base of the shell. - -The muzzle-loader having thus been turned into a very efficient modern -weapon the next problem to be solved was how to throw a projectile -with sufficient force to penetrate the iron and steel armour-plates -then being generally applied to war-ships. "Build larger guns" was the -conclusion arrived at, and presently the arsenals of the Powers were -turning out mammoth weapons up to 100 tons, and even 110 tons in -weight with a calibre of 16 inches and more for their huge shells. -Then was the mighty 35-ton "Woolwich Infant" born (1872), and its -younger but still bigger brothers, 81 tons, 16-inch bore, followed by -the Elswick 100-ton giants, some of which were mounted on our defences -in the Mediterranean. But the fearful concussion of such enormous guns -when fixed in action on board ship injured the superstruction, and -even destroyed the boats, and the great improvements made in steel -both for guns and armour soon led to a fresh revolution. Henceforward -instead of mounting a few very heavy guns we have preferred to trust -to the weight of metal projected by an increased number of smaller -size, but much higher velocity. And these guns are the quick-firing -breech-loaders. - -The heaviest of our up-to-date ordnance is of moderate calibre, the -largest breech-loaders being 12-inch, 10-inch, and 9.2-inch guns. But -the elaborateness of its manufacture is such that one big gun takes -nearly as long to "build up" as the ship for which it is destined. -Each weapon has to pass through about sixteen different processes:-- - - (1) The solid (or hollow) ingot is _forged_. - - (2) _Annealed_, to get rid of strains. - - (3) It is placed horizontally on a lathe and _rough-turned_. - - (4) _Rough-bored_ in a lathe. - - (5) _Hardened._ Heated to a high temperature and plunged, while - hot, into a bath of rape oil kept cold by a water-bath. It - cools slowly for seven to eight hours, being moved about at - intervals by a crane. This makes the steel more elastic and - tenacious. - - (6) _Annealed_, _i.e._ reheated to 900 deg. Fahr. and slowly - cooled. Siemens' pyrometer is used in these operations. - - (7) _Tested_ by pieces cut off. - - (8) _Turned_ and _bored_ for the second time. - - (9) Carefully turned again for _shrinkage_. Outer coil expanded - till large enough to fit easily over inner. Inside, set up - vertically in a pit, has outside lowered on to it, water and - gas being applied to make all shrink evenly. Other projections, - hoops, rings, &c., also shrunk on. - - (10) Finish--_bored_ and _chambered_. - - (11) _Broached_, or very fine bored, perhaps _lapped_ with lead - and emery. - - (12) _Rifled_ horizontally in a machine. - - (13) Prepared for breech fittings. - - (14) Taken to the Proof Butts for trial. - - (15) Drilled for sockets, sights, &c. Lined and engraved. - Breech fittings, locks, electric firing gear, &c., added. Small - adjustments made by filing. - - (16) _Browned_ or _painted_. - -When worn the bore can be lined with a new steel tube. - -These lengthy operations completed, our gun has still to be _mounted_ -upon its field-carriage, naval cone, or disappearing mounting, any of -which are complicated and delicately-adjusted pieces of mechanism, the -product of much time and labour, which we have no space here to -describe. - -Some account of the principal parts of these guns has already been -given, but the method by which the breech is closed remains to be -dealt with. - -It will be noticed that though guns now barely reach half the weight -of the monster muzzle-loaders, they are even more effective. Thus the -46-ton (12-inch) gun hurls an 850-lb. projectile with a velocity of -2750 foot-seconds, and uses a comparatively small charge. The famous -"81-ton" needed a very big charge for its 1700-lb. shell, and had -little more than half the velocity and no such power of penetration. -This change has been brought about by using a slower-burning explosive -very powerful in its effects; enlarging the chamber to give it -sufficient air space, and lengthening the chase of the gun so that -every particle of the powder-gas may be brought into action before -the shot leaves the muzzle. This system and the substitution of steel -for the many layers of welded iron, makes our modern guns long and -slim in comparison with the older ones. - -To resist the pressure of the explosion against the breech end, a -tightly-fitting breech-plug must be employed. The most modern and -ingenious is the Welin plug, invented by a Swedish engineer. The -ordinary interrupted screw breech-plug has three parts of its -circumference plane and the other three parts "threaded," or grooved, -to screw into corresponding grooves in the breech; thus only half of -the circumference is engaged by the screw. Mr. Welin has cut steps on -the plug, three of which would be threaded to one plane segment, each -locking with its counterpart in the breech. In this case there are -three segments engaged to each one left plane, and the strength of the -screw is almost irresistible. The plug, which is hinged at the side, -has therefore been shortened by one-third, and is light enough to -swing clear with one touch of the handwheel that first rotates and -unlocks it. - -The method of firing is this: The projectile lifted (by hydraulic -power on a ship) into the loading tray is swung to the mouth of the -breech and pushed into the bore. A driving-band attached near its base -is so notched at the edges that it jams the shell closely and prevents -it slipping back if loaded at a high angle of elevation. The powder -charge being placed in the chamber the breech-plug is now swung-to and -turned till it locks close. The vent-axial or inner part of this -breech-plug (next to the charge), which is called from its shape the -"mushroom-head," encloses between its head and the screw-plug the de -Bange obturator, a flat canvas pad of many layers soaked with mutton -fat tightly packed between discs of tin. When the charge explodes, the -mushroom-head--forced back upon the pad--compresses it till its edges -bulge against the tube and prevent any escape of gas breechwards. - -The electric spark which fires the charge is passed in from outside by -means of a minute and ingenious apparatus fitted into a little vent or -tube in the mushroom-head. As the electric circuit cannot be completed -till the breech-plug is screwed quite home there is now no more fear -of a premature explosion than of double loading. If the electric gear -is disordered the gun can be fired equally well and safely by a -percussion tube. - -This description is of a typical large gun, and may be applied to all -calibres and also to the larger quick-firers. The mechanism as the -breech is swung open again withdraws the empty cartridge. So valuable -has de Bange's obturator proved, however, that guns up to the 6-inch -calibre now have the powder charge thrown into the chamber in bags, -thus saving the weight of the metal tubes hitherto necessary. - -Of course several types of breech-loading guns are used in the -Service, but the above are the most modern. - -The favourite mode of construction at the present time is the -wire-wound barrel, the building up of which is completed by covering -the many layers of wire with an outer tube or jacket expanded by heat -before it is slipped on in order that it may fit closely when cold. A -previous make, without wire, is strengthened by rings or hoops also -shrunk on hot. - -The quick-firers proper are of many sizes, 8-inch, 7.5-inch, 6-inch, -4.7-inch, 4-inch, and 3-inch (12-pounders). The naval type is as a -rule longer and lighter than those made for the rough usage of field -campaigning and have a much greater range. There are also smaller -quick-firers, 3-pounders and 6-pounders with bore something over -1-inch and 2-inch (Nordenfelt, Hotchkiss, Vickers-Maxim). Some of the -high velocity 12-pounders being employed as garrison guns along with -6-inch and 4.7-inch, and the large calibre howitzers. - -We still use howitzer batteries of 5-inch bore in the field and in the -siege-train, all being short, rifled, breech-loading weapons, as they -throw a heavy shell with smallish charges at a high angle of -elevation, but cover a relatively short distance. A new pattern of -8-inch calibre is now under consideration. - -It is interesting to contrast the potencies of some of these guns, all -of which use cordite charges. - - +----------+---------------+-----------+----------------+-----------+ - |Calibre. | Charge. |Weight of |Muzzle Velocity |Number of | - | | | Shot. | in |Rounds per | - | | | | Foot Seconds. | Minute. | - +----------+---------------+-----------+----------------+-----------+ - | 12 inch |207 lbs. | 850 lbs. | 2750 | 1 | - | 8 " | 52 " | 210 " | 2750 | 5 | - | 6 " | 25 " | 100 " | 2775 | 8 | - |4.7 " | 9 " | 45 " | 2600 | 12 | - | 3 " | 2 lbs. 9 oz. |12.5 " | 2600 | 20 | - +----------+---------------+-----------+----------------+-----------+ - -[Illustration: _The Simms armour-clad motor-car for coast defence. -Maxim guns and Pom-pom in action._] - -In the armament of our fine Navy guns are roughly distributed as -follows:--81-ton, 13-1/2-inch, and superseded patterns of machine-guns -such as Gatling's, Gardner's, and Nordenfelt's, besides a few -surviving muzzle-loaders, &c., are carried only by the oldest -battleships. - -The first-class battleships are chiefly supplied with four 12-inch -guns in barbettes, twelve 6-inch as secondary batteries, and a number -of smaller quick-firers on the upper decks and in the fighting tops, -also for use in the boats, to which are added several Maxims. - -The first-class cruisers have 9.2 as their largest calibre, with a -lessened proportion of 6-inch, &c. Some of the newest bear only 7-1/2 -or 6-inch guns as their heaviest ordnance; like the second-class -cruisers which, however, add several 4.7's between these and their -small quick-firers. - -Vessels of inferior size usually carry nothing more powerful than the -4.7. - -All are now armed with torpedo tubes. - -These same useful little quick-firers and machine-guns have been the -lethal weapons which made the armoured trains so formidable. Indeed, -there seems no limit to their value both for offence and defence, for -the battle chariot of the ancient Briton has its modern successor in -the Simms' motor war car lately exhibited at the Crystal Palace. This -armour-plated movable fort is intended primarily for coast defence, -but can work off beaten tracks over almost any sort of country. It is -propelled at the rate of nine miles an hour by a 16-horse-power -motor, carrying all its own fuel, two pom-poms, two small Maxims, and -10,000 rounds of ammunition, besides the necessary complement of men -and searchlights for night use, &c., &c. - -The searchlight, by the way, has taken the place of all former -inventions thrown from guns, such as ground-light balls, or parachute -lights with a time-fuse which burst in the air and remained suspended, -betraying the enemy's proceedings. - -In like manner the linked chain and "double-headed" shot, the -"canister"--iron balls packed in thin iron or tin cylinders which -would travel about 350 yards--the "carcasses" filled with inflammable -composition for firing ships and villages, are as much out of date as -the solid round shot or cannon-ball. Young Shrapnell's invention a -century ago of the form of shell that bears his name, a number of -balls arranged in a case containing also a small bursting-charge fired -either by percussion or by a time-fuse, has practically replaced them -all. Thrown with great precision of aim its effective range is now up -to 5000 yards. A 15-pounder shrapnell shell, for instance, contains -192 bullets, and covers several hundred yards with the scattered -missiles flying with extreme velocity. - -Common shell, from 2-1/2 to 3 calibres long, contains an explosive -only. Another variety is segment shell, made of pieces built up in a -ring with a bursting charge in the centre which presently shatters -it. - -The Palliser shell has a marvellous penetrating power when used -against iron plates. But, _mirabile dictu!_ experiments tried within -the past few months prove that a soft cap added externally enables a -projectile to pierce with ease armour which had previously defied -every attack. - - -EXPLOSIVES. - -Half a century ago gunpowder was still the one driving power which -started the projectile on its flight. It is composed of some 75 parts -of saltpetre or nitrate of potash, 15 parts of carefully prepared -charcoal, and 10 parts of sulphur. This composition imprisons a large -amount of oxygen for combustion and is found to act most successfully -when formed into rather large prismatic grains. - -On the abolition of the old flint-lock its place was taken by a -detonating substance enclosed in a copper cap, and some time later -inventors came forward with new and more powerful explosives to -supersede the use of gunpowder. - -By treating cotton with nitric and sulphuric acid reaction -_gun-cotton_ was produced; and a year later glycerine treated in the -same manner became known to commerce as _nitro-glycerine_. This liquid -form being inconvenient to handle, some inert granular substance such -as infusorial earth was used to absorb the nitro-glycerine, and -_dynamite_ was the result. - -The explosion of gun-cotton was found to be too sudden and rapid for -rifles or cannon; it was liable to burst the piece instead of blowing -out the charge. In order to lessen the rapidity of its ignition -ordinary cotton was mixed with it, or its threads were twisted round -some inert substance. - -When repeating-rifles and machine-guns came into general use a -smokeless powder became necessary. Such powders as a rule contain -nitro-cellulose (gun-cotton) or nitro-glycerine, or both. These are -combined into a plastic, gluey composition, which is then made up into -sticks or pellets of various shapes, and usually of large size to -lessen the extreme rapidity of their combustion. Substances such as -tan, paraffin, starch, bran, peat, &c., &c., and many mineral salts, -are used in forming low explosives from high ones. - -To secure complete combustion some of the larger pellets are made with -a central hole, or even pierced by many holes, so that the fire -penetrates the entire mass and carries off all its explosive -qualities. - -Our _cordite_ consists of nitro-glycerine dissolving di-nitro -cellulose by the acid of a volatile solvent and a mineral jelly or -oil. This compound is semi-fluid, and being passed like macaroni -through round holes in a metal plate it forms strings or cords of -varying size according to the diameter of the holes. Hence the name, -cordite. - -Many experiments in search of more powerful explosives resulted in an -almost universal adoption of picric acid as the base. This acid is -itself produced by the action of nitric acid upon carbolic acid, and -each nation has its own fashion of preparing it for artillery. - -The French began with _melinite_ in 1885, this being a mixture of -picric acid and gun-cotton. - -The composition of _lyddite_ (named from its place of manufacture, -Lydd, in Kent) is a jealously-guarded British secret. This substance -was first used in 5-inch howitzers during the late Soudan campaign, -playing a part in the bombardment of Omdurman. The effect of the -50-lb. lyddite shells upon the South African kopjes is described as -astounding. When the yellow cloud had cleared away trees were seen -uprooted, rocks pulverised, the very face of the earth had changed. - -Several attempts have been made to utilise dynamite for shells, some -of the guns employing compressed air as their motive power. The United -States some years ago went to great expense in setting up for this -purpose heavy pneumatic plant, which has recently been disposed of as -too cumbrous. Dudley's "Aerial Torpedo" gun discharged a 13-lb. shell -containing explosive gelatine, gun-cotton, and fulminate of mercury by -igniting the small cordite charge in a parallel tube, through a vent -in which the partially cooled gases acted on the projectile in the -barrel. This was rotated in the air by inclined blades on a tailpiece, -as the barrel could not be rifled for fear of the heat set up by -friction. Some guns actuated on much the same principle are said to -have been used with effect in the Hispano-American war. Mr. Hudson -Maxim with his explosive "maximite" claims to throw half a ton of -dynamite about a mile, and a one-ton shell to half that distance. - -But even these inventors are outstripped by Professor Birkeland, who -undertakes to hurl a projectile weighing two tons from an iron tube -coiled with copper wire down which an electric current is passed; thus -doing away entirely with the need of a firing-charge. - - -IN THE GUN FACTORY. - -Let us pay a visit to one of our gun factories and get some idea of -the multiform activities necessary to the turning out complete of a -single piece of ordnance or a complicated machine-gun. We enter the -enormous workshop, glazed as to roof and sides, full of the varied -buzz and whirr and clank of the machinery. Up and down the long bays -stand row upon row of lathes, turning, milling, polishing, boring, -rifling--all moving automatically, and with a precision which leaves -nothing to be desired. The silent attendants seem to have nothing in -their own hands, they simply watch that the cutting does not go too -far, and with a touch of the guiding handles regulate the pace or -occasionally insert a fresh tool. The bits used in these processes are -self-cleaning, so the machinery is never clogged; and on the ground -lie little heaps of brass chips cut away by the minute milling tools; -or in other places it is bestrewn with shavings of brass and steel -which great chisels peel off as easily as a carpenter shaves a deal -board. - -Here an enormous steel ingot, forged solid, heated again and again in -a huge furnace and beaten by steam-hammers, or pressed by hydraulic -power between each heating till it is brought to the desired size and -shape, is having its centre bored through by a special drill which -takes out a solid core. This operation is termed "trepanning," and is -applied to guns not exceeding eight inches; those of larger calibre -being rough-bored on a lathe, and mandrils placed in them during the -subsequent forgings. The tremendous heat generated during the boring -processes--we may recall how Benjamin Thompson made water boil by the -experimental boring of a cannon--is kept down by streams of soapy -water continually pumped through and over the metal. We notice this -flow of lubricating fluid in all directions, from oil dropping slowly -on to the small brass-milling machines to this fountain-play of water -which makes a pleasant undertone amidst the jangle of the machines. -But these machines are less noisy than we anticipated; in their actual -working they emit scarcely the slightest sound. What strikes us more -than the supreme exactness with which each does its portion of the -work, is the great deliberateness of its proceeding. All the hurry and -bustle is above us, caused by the driving-bands from the engine, which -keeps the whole machinery of the shed in motion. Suddenly, with harsh -creakings, a great overhead crane comes jarring along the bay, drops a -chain, grips up a gun-barrel, and, handling this mass of many tons' -weight as easily as we should lift a walking-stick, swings it off to -undergo another process of manufacture. - -We pass on to the next lathe where a still larger forging is being -turned externally, supported on specially devised running gear, many -different cutters acting upon it at the same time, so that it is -gradually assuming the tapering, banded appearance familiar to us in -the completed state. - -We turn, fairly bewildered, from one stage of manufacture to another. -Here is a gun whose bore is being "chambered" to the size necessary -for containing the firing charge. Further along we examine a more -finished weapon in process of preparation to receive the breech-plug -and other fittings. Still another we notice which has been -"fine-bored" to a beautifully smooth surface but is being improved yet -more by "lapping" with lead and emery powder. - -In the next shed a marvellous machine is rifling the interior of a -barrel with a dexterity absolutely uncanny, for the tool which does -the rifling has to be rotated in order to give the proper "twist" at -the same moment as it is advancing lengthwise down the bore. The -grooves are not made simultaneously but as a rule one at a time, the -distance between them being kept by measurements on a prepared disc. - -Now we have reached the apparatus for the wire-wound guns, a principle -representing the _ne plus ultra_ of strength and durability hitherto -evolved. The rough-bored gun is placed upon a lathe which revolves -slowly, drawing on to it from a reel mounted at one side a continuous -layer of steel ribbon about a quarter of an inch wide. On a 12-inch -gun there is wound some 117 miles of this wire! fourteen layers of it -at the muzzle end and seventy-five at the breech end. Heavy weights -regulate the tension of the wire, which varies for each layer, the -outermost being at the lowest tension, which will resist a pressure of -over 100 tons to the square inch. - -We next enter the division in which the gun cradles and mounts are -prepared, where we see some of the heaviest work carried out by -electric dynamos, the workman sitting on a raised platform to keep -careful watch over his business. - -Passing through this with interested but cursory inspection of the -cone mountings for quick-firing naval guns, some ingenious elevating -and training gear and a field carriage whose hydraulic buffers merit -closer examination, we come to the shell department where all kinds of -projectiles are manufactured. Shrapnel in its various forms, -armour-piercing shells, forged steel or cast-iron, and small brass -cartridges for the machine-guns may be found here; and the beautifully -delicate workmanship of the fuse arrangements attracts our admiration. -But we may not linger; the plant for the machine-guns themselves claim -our attention. - -Owing to the complexity and minute mechanism of these weapons almost a -hundred different machines are needed, some of the milling machines -taking a large selection of cutters upon one spindle. Indeed, in many -parts of the works one notices the men changing their tools for others -of different size or application. Some of the boring machines work two -barrels at the same time, others can drill three barrels or polish a -couple simultaneously. But there are hundreds of minute operations -which need to be done separately, down to the boring of screw holes -and cutting the groove on a screw-head. Many labourers are employed -upon the lock alone. And every portion is gauged correctly to the most -infinitesimal fraction, being turned out by the thousand, that every -separate item may be interchangeable among weapons of the same make. - -Look at the barrel which came grey and dull from its first turning now -as it is dealt with changing into bright silver. Here it is adjusted -upon the hydraulic rifling machine which will prepare it to carry the -small-arm bullet (.303 inch). That one of larger calibre is rifled to -fire a small shell. Further on, the barrels and their jackets are -being fitted together and the different parts assembled and screwed -up. We have not time to follow the perfect implement to its mounting, -nor to do more than glance at those howitzers and the breech mechanism -of the 6-inch quick-firers near which our guide indicates piles of -flat cases to keep the de Bange obturators from warping while out of -use. For the afternoon is waning and the foundry still unvisited. - -To reach it we pass through the smith's shop and pause awhile to watch -a supply of spanners being roughly stamped by an immense machine out -of metal plates and having their edges tidied off before they can be -further perfected. A steam-hammer is busily engaged in driving -mandrils of increasing size through the centre of a red-hot forging. -The heat from the forges is tremendous, and though it is tempered by a -spray of falling water we are glad to escape into the next shed. - -Here we find skilled workmen carefully preparing moulds by taking in -sand the exact impression of a wooden dummy. Fortunately we arrive -just as a series of casts deeply sunk in the ground are about to be -made. Two brawny labourers bear forward an enormous iron crucible, -red-hot from the furnace, filled with seething liquid--manganese -bronze, we are told--which, when an iron bar is dipped into it, throws -up tongues of beautiful greenish-golden flame. The smith stirs and -clears off the scum as coolly as a cook skims her broth! Now it is -ready, the crucible is again lifted and its contents poured into a -large funnel from which it flows into the moulds beneath and fills -them to the level of the floor. At each one a helper armed with an -iron bar takes his stand and stirs again to work up all dross and -air-bubbles to the surface before the metal sets--a scene worthy of a -painter's brush. - -And so we leave them. - - - - -DIRIGIBLE TORPEDOES. - - -The history of warlike inventions is the history of a continual -see-saw between the discovery of a new means of defence and the -discovery of a fresh means of attack. At one time a shield is devised -to repel a javelin; at another a machine to hurl the javelin with -increased violence against the shield; then the shield is reinforced -by complete coats of mail, and so on. The ball of invention has rolled -steadily on into our own times, gathering size as it rolls, and -bringing more and more startling revolutions in the art of war. To-day -it is a battle between the forces of nature, controllable by man in -the shape of "high explosives," and the resisting power of metals -tempered to extreme toughness. - -At present it looks as if, on the sea at least, the attack were -stronger than the defence. Our warships may be cased in the hardest -metal several inches thick until they become floating forts, almost -impregnable to the heaviest shells. They may be provided with terrible -engines able to give blow for blow, and be manned with the stoutest -hearts in the world. And yet, were a sea-fight in progress, a blow, -crushing and resistless, might at any time come upon the vessel from a -quarter whence, even though suspected, its coming might escape -notice--below the waterline. Were it possible to case an ironclad from -deck to keel in foot-thick plating, the metal would crumple like a -biscuit-box under the terrible impact of the torpedo. - -This destructive weapon is an object of awe not so much from what it -has done as from what it can do. The instances of a torpedo shivering -a vessel in actual warfare are but few. Yet its moral effect must be -immense. Even though it may miss its mark, the very fact of its -possible presence will, especially at night-time, tend to keep the -commanding minds of a fleet very much on the stretch, and to destroy -their efficiency. A torpedo knows no half measures. It is either -entirely successful or utterly useless. Its construction entails great -expense, but inasmuch as it can, if directed aright, send a million of -the enemy's money and a regiment of men to the bottom, the discharge -of a torpedo is, after all, but the setting of a sprat to catch a -whale. - -The aim of inventors has been to endow the dirigible torpedo, fit for -use in the open sea, with such qualities that when once launched on -its murderous course it can pursue its course in the required -direction without external help. The difficulties to be overcome in -arriving at a serviceable weapon have been very great owing to the -complexity of the problem. A torpedo cannot be fired through water -like a cannon shell through air. Water, though yielding, is -incompressible, and offers to a moving body a resistance increasing -with the speed of that body. Therefore the torpedo must contain its -own motive power and its own steering apparatus, and be in effect a -miniature submarine vessel complete in itself. To be out of sight and -danger it must travel beneath the surface and yet not sink to the -bottom; to be effective it must possess great speed, a considerable -sphere of action, and be able to counteract any chance currents it may -meet on its way. - -Among purely automobile torpedoes the Whitehead is easily first. After -thirty years it still holds the lead for open sea work. It is a very -marvel of ingenious adaptation of means to an end, and as it has -fulfilled most successfully the conditions set forth above for an -effective projectile it will be interesting to examine in some detail -this most valuable weapon. - -In 1873 one Captain Lupuis of the Austrian navy experimented with a -small fireship which he directed along the surface of the sea by means -of ropes and guiding lines. This fireship was to be loaded with -explosives which should ignite immediately on coming into collision -with the vessel aimed at. The Austrian Government declared his scheme -unworkable in its crude form, and the Captain looked about for some -one to help him throw what he felt to be a sound idea into a practical -shape. He found the man he wanted in Mr. Whitehead, who was at that -time manager of an engineering establishment at Fiume. Mr. Whitehead -fell in enthusiastically with his proposition, at once discarded the -complicated system of guiding ropes, and set to work to solve the -problem on his own lines. At the end of two years, during which he -worked in secret, aided only by a trusted mechanic and a boy, his son, -he constructed the first torpedo of the type that bears his name. It -was made of steel, was fourteen inches in diameter, weighed 300 lbs., -and carried eighteen pounds of dynamite as explosive charge. But its -powers were limited. It could attain a rate of but six knots an hour -under favourable conditions, and then for a short distance only. Its -conduct was uncertain. Sometimes it would run along the surface, at -others make plunges for the bottom. However, the British Government, -recognising the importance of Mr. Whitehead's work, encouraged him to -perfect his instrument, and paid him a large sum for the patent -rights. Pattern succeeded pattern, until comparative perfection was -reached. - -Described briefly, the Whitehead torpedo is cigar-shaped, blunt-nosed -and tapering gradually towards the tail, so following the lines of a -fish. Its length is twelve times its diameter, which varies in -different patterns from fourteen to nineteen inches. At the fore end -is the striker, and at the tail are a couple of three-bladed screws -working on one shaft in opposite directions, to economise power and -obviate any tendency of the torpedo to travel in a curve; and two sets -of rudders, the one horizontal, the other vertical. The latest form of -the torpedo has a speed of twenty-nine knots and a range of over a -thousand yards. - -The torpedo is divided into five compartments by watertight steel -bulkheads. At the front is the _explosive head_, containing wet -gun-cotton, or some other explosive. The "war head," as it is called, -is detachable, and for practice purposes its place is taken by a -dummy-head filled with wood to make the balance correct. - -Next comes the _air chamber_, filled with highly-compressed air to -drive the engines; after it the _balance chamber_, containing the -apparatus for keeping the torpedo at its proper depth; then the -_engine-room_; and, last of all, the _buoyancy chamber_, which is -air-tight and prevents the torpedo from sinking at the end of its run. - -To examine the compartments in order:-- - -In the very front of the torpedo is the pistol and primer-charge for -igniting the gun-cotton. Especial care has been taken over this part -of the mechanism, to prevent the torpedo being as dangerous to friends -as to foes. The pistol consists of a steel plug sliding in a metal -tube, at the back end of which is the fulminating charge. Until the -plug is driven right in against this charge there can be no explosion. -Three precautions are taken against this happening prematurely. In the -first place, there is on the forward end of the plug a thread cut, up -which a screw-fan travels as soon as it strikes the water. Until the -torpedo has run forty-five feet the fan has not reached the end of its -travel, and the plug consequently cannot be driven home. Even when the -plug is quite free only a heavy blow will drive it in, as a little -copper pin has to be sheared through by the impact. And before the -screw can unwind at all, a safety-pin must be withdrawn at the moment -of firing. So that a torpedo is harmless until it has passed outside -the zone of danger to the discharging vessel. - -The detonating charge is thirty-eight grains of fulminate of mercury, -and the primer-charge consists of six one-ounce discs of dry -gun-cotton contained in a copper cylinder, the front end of which is -connected with the striker-tube of the pistol. The fulminate, on -receiving a blow, expands 2500 times, giving a violent shock to the -gun-cotton discs, which in turn explode and impart a shock to the main -charge, 200 lbs. of gun-cotton. - -The _air chamber_ is made of the finest compressed steel, or of -phosphor-bronze, a third of an inch thick. When ready for action this -chamber has to bear a pressure of 1350 lbs. to the square inch. So -severe is the compression that in the largest-sized torpedoes the air -in this chamber weighs no less than 63 lbs. The air is forced in by -very powerful pumps of a special design. Aft of this chamber is that -containing the stop-valve and steering-gear. The stop-valve is a -species of air-tap sealing the air chamber until the torpedo is to be -discharged. The valve is so arranged that it is impossible to insert -the torpedo into the firing-tube before the valve has been opened, -and so brought the air chamber into communication with the -starting-valve, which does not admit air to the engines till after the -projectile has left the tube. - -The _steering apparatus_ is undoubtedly the most ingenious of the many -clever contrivances packed into a Whitehead torpedo. Its function is -to keep the torpedo on an even keel at a depth determined before the -discharge. This is effected by means of two agencies, a swinging -weight, and a valve which is driven in by water pressure as the -torpedo sinks. When the torpedo points head downwards the weight -swings forward, and by means of connecting levers brings the -horizontal rudders up. As the torpedo rises the weight becomes -vertical and the rudder horizontal. This device only insures that the -torpedo shall travel horizontally. The valve makes it keep its proper -depth by working in conjunction with the pendulum. The principle, -which is too complicated for full description, is, put briefly, a -tendency of the valve to correct the pendulum whenever the latter -swings too far. Lest the pendulum should be violently shaken by the -discharge there is a special controlling gear which keeps the rudders -fixed until the torpedo has proceeded a certain distance, when the -steering mechanism is released. The steering-gear does not work -directly on the rudder. Mr. Whitehead found in his earlier experiments -that the pull exerted by the weight and valve was not sufficient to -move the rudders against the pressure of the screws. He therefore -introduced a beautiful little auxiliary engine, called the -servo-motor, which is to the torpedo what the steam steering-gear is -to a ship. The servo-motor, situated in the _engine-room_, is only -four inches long, but the power it exerts by means of compressed air -is so great that a pressure of half an ounce exerted by the -steering-gear produces a pull of 160 lbs. on the rudders. - -The engines consist of three single-action cylinders, their cranks -working at an angle of 120 deg. to one another, so that there is no "dead" -or stopping point in their action. They are very small, but, thanks to -the huge pressure in the air chamber, develop nearly thirty-one -horse-power. Lest they should "race," or revolve too quickly, while -passing from the tube to the water and do themselves serious damage, -they are provided with a "delay action valve," which is opened by the -impact of the torpedo against the water. Further, lest the air should -be admitted to the cylinders at a very high pressure gradually -decreasing to zero, a "reducing valve" or governor is added to keep -the engines running at a constant speed. - -Whitehead torpedoes are fired from tubes above or below the waterline. -Deck tubes have the advantage of being more easily aimed, but when -loaded they are a source of danger, as any stray bullet or shell from -an enemy's ship might explode the torpedo with dire results. There is -therefore an increasing preference for submerged tubes. An ingenious -device is used for aiming the torpedo, which makes allowances for the -speed of the ship from which it is fired, the speed of the ship aimed -at, and the speed of the torpedo itself. When the moment for firing -arrives, the officer in charge presses an electric button, which sets -in motion an electric magnet fixed to the side of the tube. The magnet -releases a heavy ball which falls and turns the "firing rod." -Compressed air or a powder discharge is brought to bear on the rear -end of the torpedo, which, if submerged, darts out from the vessel's -side along a guiding bar, from which it is released at both ends -simultaneously, thus avoiding the great deflection towards the stern -which would occur were a broadside torpedo not held at the nose till -the tail is clear. This guiding apparatus enables a torpedo to leave -the side of a vessel travelling at high speed almost at right angles -to the vessel's path. - -It will be easily understood that a Whitehead torpedo is a costly -projectile, and that its value--L500 or more--makes the authorities -very careful of its welfare. During practice with "blank" torpedoes a -"Holmes light" is attached. This light is a canister full of calcium -phosphide to which water penetrates through numerous holes, causing -gas to be thrown off and rise to the surface, where, on meeting with -the oxygen of the air, it bursts into flame and gives off dense -volumes of heavy smoke, disclosing the position of the torpedo by -night or day. - -At Portsmouth are storehouses containing upwards of a thousand -torpedoes. Every torpedo is at intervals taken to pieces, examined, -tested, and put together again after full particulars have been taken -down on paper. Each steel "baby" is kept bright and clean, coated -with a thin layer of oil, lest a single spot of rust should mar its -beauty. An interesting passage from Lieutenant G. E. Armstrong's book -on "Torpedoes and Torpedo Vessels" will illustrate the scrupulous -exactness observed in all things relating to the torpedo depots: "As -an example of the care with which the stores are kept it may be -mentioned that a particular tiny pattern of brass screw which forms -part of the torpedo's mechanism and which is valued at about -twopence-halfpenny per gross, is never allowed to be a single number -wrong. On one occasion, when the stocktaking took place, it was found -that instead of 5000 little screws being accounted for by the man who -was told off to count them, there were only 4997. Several foolscap -letters were written and exchanged over these three small screws, -though their value was not more than a small fraction of a farthing." - -The classic instance of the effectiveness of this type of torpedo is -the battle of the Yalu, fought between the Japanese and Chinese fleets -in 1894. The Japanese had been pounding their adversaries for hours -with their big guns without producing decisive results. So they -determined upon a torpedo attack, which was delivered early in the -morning under cover of darkness, and resulted in the destruction of a -cruiser, the _Ting Yuen_. The next night a second incursion of the -Japanese destroyers wrecked another cruiser, the _Lai Yuen_, which -sunk within five minutes of being struck; sank the _Wei Yuen_, an old -wooden vessel used as a training-school; and blew a large steam -launch out of the water on to an adjacent wharf. These hits "below the -belt" were too much for the Chinese, who soon afterwards surrendered -to their more scientific and better equipped foes. - -If a general naval war broke out to-day most nations would undoubtedly -pin their faith to the Whitehead torpedo for use in the open sea, now -that its accuracy has been largely increased by the gyroscope, a heavy -flywheel attachment revolving rapidly at right angles to the path of -the torpedo, and rendering a change of direction almost impossible. - -For harbour defence the Brennan or its American rival, the -Sims-Edison, might be employed. They are both torpedoes dirigible from -a fixed base by means of connecting wires. The presence of these wires -constitutes an obstacle to their being of service in a fleet action. - -The Brennan is used by our naval authorities. It is the invention of a -Melbourne watchmaker. Being a comparatively poor man, Mr. Brennan -applied to the Colonial Government for grants to aid him in the -manufacture and development of his torpedo, and he was supplied with -sufficient money to perfect it. In 1881 he was requested by our -Admiralty to bring his invention to England, where it was experimented -upon, and pronounced so efficient for harbour and creek defence that -at the advice of the Royal Engineers Mr. Brennan was paid large sums -for his patents and services. - -The Brennan torpedo derives its motive power from a very powerful -engine on shore, capable of developing 100 horse-power, with which it -is connected by stout piano wires. One end of these wires is wound on -two reels inside the torpedo, each working a screw; the other end is -attached to two winding drums driven at high velocity by the engine on -shore. As the drums wind in the wire the reels in the torpedo revolve; -consequently, the harder the torpedo is pulled back the faster it -moves forward, liked a trained trotting mare. The steering of the -torpedo is effected by alterations in the relative speeds of the -drums, and consequently of the screws. The drums run loose on the -engine axle, and are thrown in or out of gear by means of a -friction-brake, so that their speed can be regulated without altering -the pace of the engines. Any increase in the speed of one drum causes -a corresponding decrease in the speed of the other. The torpedo can be -steered easily to right or left within an arc of forty degrees on each -side of straight ahead; but when once launched it cannot be retrieved -except by means of a boat. Its path is marked by a Holmes light, -described above. It has a 200-lb. gun-cotton charge, and is fitted -with an apparatus for maintaining a proper depth very similar to that -used in the Whitehead torpedo. - -The Sims-Edison torpedo differs from the Brennan in its greater -obedience to orders and in its motive power being electrically -transmitted through a single connecting cable. It is over thirty feet -in length and two feet in diameter. Attached to the torpedo proper by -rods is a large copper float, furnished with balls to show the -operator the path of the torpedo. The torpedo itself is in four parts: -the explosive head; the magazine of electric cables, which is paid out -as the torpedo travels; the motor room; and the compartment containing -the steering-gear. The projectile has a high speed and long -range--over four thousand yards. It can twist and turn in any -direction, and, if need be, be called to heel. Like the Brennan, it -has the disadvantage of a long trailing wire, which could easily -become entangled; and it might be put out of action by any damage -inflicted on its float by the enemy's guns. But it is likely to prove -a very effective harbour-guard if brought to the test. - -In passing to the Orling-Armstrong torpedo we enter the latest phase -of torpedo construction. Seeing the disadvantages arising from wires, -electricians have sought a means of controlling torpedoes without any -tangible connection. Wireless telegraphy showed that such a means was -not beyond the bounds of possibility. Mr. Axel Orling, a Swede, -working in concert with Mr. J. T. Armstrong, has lately proved that a -torpedo can be steered by waves of energy transmitted along rays of -light, or perhaps it would be more correct to say along shafts of a -form of X-rays. - -Mr. Orling claims for his torpedo that it is capable of a speed of -twenty-two knots or more an hour; that it can be called to heel, and -steered to right or left at will; that as long as it is in sight it is -controllable by rays invisible to the enemy; that not merely one, but -a number of torpedoes can be directed by the same beams of light; -that, as it is submerged, it would, even if detected, be a bad mark -for the enemy's guns. - -The torpedo carries a shaft which projects above the water, and bears -on its upper end a white disc to receive the rays and transmit them to -internal motors to be transmuted into driving power. The rod also -carries at night an electric light, shaded on the enemy's side, but -rendering the whereabouts of the torpedo very visible to the steerer. - -Mr. Orling's torpedo acts throughout in a cruelly calculating manner. -Before its attack a ship would derive small advantage from a crinoline -of steel netting; for the large torpedo conceals in its head a smaller -torpedo, which, as soon as the netting is struck, darts out and blasts -an opening through which its longer brother, after a momentary delay, -can easily follow. The netting penetrated, the torpedo has yet to -strike twice before exploding. On the first impact, a pin, projecting -from the nose, is driven in to reverse the engines, and at the same -time a certain nut commences to travel along a screw. The nut having -worked its way to the end of the thread, the head of the torpedo fills -slowly through a valve, giving it a downward slant in front. The -engines are again reversed and the nut again travels, this time -bringing the head of the torpedo up, so as to strike the vessel at a -very effective angle from below. - -This torpedo has passed beyond the experimental stage. It is reported -that by command of the Swedish Government, to whom Mr. Orling offered -his invention, and of the King, who takes a keen interest in the ideas -of his young countryman, a number of experiments were some time ago -carried out in the Swedish rivers. Torpedoes were sent 2-1/2 miles, -directed as desired, and made to rise or sink--all this without any -tangible connection. The Government was sufficiently satisfied with -the result to take up the patents, as furnishing a cheap means of -defending their coasts. - -Mr. Orling has described what he imagines would happen in case of an -attack on a position protected by his ingenious creations. "Suppose -that I had twelve torpedoes hidden away under ten feet of water in a -convenient little cove, and that I was directed to annihilate a -hostile fleet just appearing above the horizon. Before me, on a little -table perhaps, I should have my apparatus; twelve buttons would be -under my fingers. Against each button there would be a description of -the torpedo to which it was connected; it would tell me its power of -destruction, and the power of its machinery, and for what distance it -would go. On each button, also, would be indicated the time that I -must press it to release the torpedoes. Well now, I perceive a large -vessel in the van of the approaching fleet. I put my fingers on the -button which is connected with my largest and most formidable weapon. -I press the button--perhaps for twelve seconds. The torpedo is pushed -forward from its fastenings by a special spring, a small pin is -extracted from it, and immediately the motive machinery is set in -motion, and underneath the water goes my little agent of destruction, -and there is nothing to tell the ship of its doom. I place my hand on -another button, and according to the time I press it I steer the -torpedo; the rudder answers to the rays, and the rays answer to the -will of my mind."[2] - - [2] _Pearson's Magazine._ - -If this torpedo acts fully up to its author's expectations, naval -warfare, at least as at present conducted, will be impossible. There -appears to be no reason why this torpedo should not be worked from -shipboard; and we cannot imagine that hostile ships possessing such -truly infernal machines would care to approach within miles of one -another, especially if the submarine be reinforced by the aerial -torpedo, different patterns of which are in course of construction by -Mr. Orling and Major Unge, a brother Swede. The Orling type will be -worked by the new rays, strong enough to project it through space. -Major Unge's will depend for its motive power upon a succession of -impulses obtained by the ignition of a slow-burning gas, passing -through a turbine in the rear of the torpedo. The inventor hopes for a -range of at least six miles. - -What defence would be possible against such missiles? Liable to be -shattered from below, or shivered from above, the warship will be -placed at an ever-increasing disadvantage. Its size will only render -it an easier mark; its strength, bought at the expense of weight, will -be but the means of insuring a quicker descent to the sea's bottom. Is -it not probable that sea-fights will become more and more matters of a -few terrible, quickly-delivered blows? Human inventions will hold the -balance more and more evenly between nations of unequal size, first on -sea, then on land, until at last, as we may hope, even the hottest -heads and bravest hearts will shrink from courting what will be less -war than sheer annihilation, and war, man's worst enemy, will be -itself annihilated. - - - - -SUBMARINE BOATS. - - -The introduction of torpedoes for use against an enemy's ships below -the waterline has led by natural stages to the evolution of a vessel -which may approach unsuspected close enough to the object of attack to -discharge its missile effectively. Before the searchlight was adopted -a night surprise gave due concealment to small craft; but now that the -gloom of midnight can be in an instant flooded with the brilliance of -day a more subtle mode of attack becomes necessary. - -Hence the genesis of the submarine or submersible boat, so constructed -as to disappear beneath the sea at a safe distance from the doomed -ship, and when its torpedo has been sped to retrace its invisible -course until outside the radius of destruction. - -To this end many so-called submarine boats have been invented and -experimented with during recent years. The idea is an ancient one -revived, as indeed are the large proportion of our boasted modern -discoveries. - -Aristotle describes a vessel of this kind (a diving-bell rather than a -boat, however), used in the siege of Tyre more than two thousand years -ago; and also refers to the divers being provided with an air-tube, -"like the trunk of an elephant," by means of which they drew a fresh -supply of air from above the surface--a contrivance adopted in more -than one of our modern submarines. Alexander the Great is said to have -employed divers in warfare; Pliny speaks of an ingenious diving -apparatus, and Bacon refers to air-tubes used by divers. We even find -traces of weapons of offence being employed. Calluvius is credited -with the invention of a submarine gun for projecting Greek fire. - -The Bishop of Upsala in the sixteenth century gives a somewhat -elaborate description of certain leather skiffs or boats used to -scuttle ships by attacking them from beneath, two of which he claims -to have personally examined. In 1629 we read that the Barbary corsairs -fixed submarine torpedoes to the enemy's keel by means of divers. - -As early as 1579 an English gunner named William Bourne patented a -submarine boat of his own invention fitted with leather joints, so -contrived as to be made smaller or larger by the action of screws, -ballasted with water, and having an air-pipe as mast. The Campbell-Ash -submarine tried in 1885 was on much the same principle. - -Cornelius van Drebbel, an ingenious Dutchman who settled in England -before 1600, produced certain submersible vessels and obtained for -them the patronage of two kings. He claims to have discovered a means -of re-oxygenating the foul air and so enabling his craft to remain a -long time below water; whether this was done by chemical treatment, -compressed air, or by surface tubes no record remains. Drebbel's -success was such that he was allowed to experiment in the Thames, and -James I. accompanied him on one of his sub-aquatic journeys. In 1626 -Charles I. gave him an order to make "boates to go under water," as -well as "water mines, water petards," &c., presumably for the campaign -against France, but we do not hear of these weapons of destruction -being actually used upon this occasion. - -[Illustration: _The "Holland" Submarine Boat._] - -These early craft seem to have been generally moved by oars working in -air-tight leather sockets; but one constructed at Rotterdam about 1654 -was furnished with a paddle-wheel. - -Coming now nearer to our own times, we find that an American called -Bushnell had a like inspiration in 1773, when he invented his famous -"Turtles," small, upright boats in which one man could sit, submerge -himself by means of leather bottles with the mouths projecting -outside, propel himself with a small set of oars and steer with an -elementary rudder. An unsuccessful attempt was made to blow up the -English fleet with one of these "Turtles" carrying a torpedo, but the -current proved too strong, and the missile exploded at a harmless -distance, the operator being finally rescued from an unpremeditated -sea-trip! Bushnell was the author of the removable safety-keel now -uniformly adopted. - -Soon afterwards another New Englander took up the running, Fulton--one -of the cleverest and least appreciated engineers of the early years -of the nineteenth century. His _Nautilus_, built in the French -dockyards, was in many respects the pattern for our own modern -submarines. The cigar-shaped copper hull, supported by iron ribs, was -twenty-four feet four inches long, with a greatest diameter of seven -feet. Propulsion came from a wheel, rotated by a hand winch, in the -centre of the stern; forward was a small conning-tower, and the boat -was steered by a rudder. There was a detachable keel below; and fitted -into groves on the top were a collapsible mast and sail for use on the -surface of the water. An anchor was also carried externally. In spite -of the imperfect materials at his disposal Fulton had much success. At -Brest he took a crew of three men twenty-five feet down, and on -another day blew up an old hulk. In the Seine two men went down for -twenty minutes and steered back to their starting-point under water. -He also put in air at high pressure and remained submerged for hours. -But France, England, and his own country in turn rejected his -invention; and, completely discouraged, he bent his energies to -designing boat engines instead. - -In 1821 Captain Johnson, also an American, made a submersible vessel -100 feet long, designed to fetch Napoleon from St. Helena, travelling -for the most part upon the surface. This expedition never came off. - -Two later inventions, by Castera and Payerne, in 1827 and 1846 -respectively, were intended for more peaceful objects. Being -furnished with diving-chambers, the occupants could retrieve things -from the bottom of the sea; Castera providing his boat with an -air-tube to the surface. - -Bauer, another inventor, lived for some years in England under the -patronage of Prince Albert, who supplied him with funds for his -experiments. With Brunel's help he built a vessel which was -indiscreetly modified by the naval authorities, and finally sank and -drowned its crew. Going then to Russia he constructed sundry -submarines for the navy; but was in the end thrown over, and, like -Fulton, had to turn himself to other employment. - -The fact is that up to this period the cry for a practical submarine -to use in warfare had not yet arisen, or these inventions would have -met with a far different reception. Within the last half century all -has changed. America and France now rival each other in construction, -while the other nations of Europe look on with intelligent interest, -and in turn make their contributions towards solving the problem of -under-wave propulsion. - -America led the way during the Civil War blockades in 1864, when the -_Housatonic_ was sunk in Charleston harbour, and damage done to other -ships. But these experimental torpedo-boats were clumsy contrivances -compared with their modern successors, for they could only carry their -destructive weapon at the end of a spar projecting from the bows--to -be exploded upon contact with the obstacle, and probably involve the -aggressor in a common ruin. So nothing more was done till the -perfecting of the Whitehead torpedo (see Dirigible Torpedoes) gave the -required impetus to fresh enterprise. - -France, experimenting in the same direction, produced in 1889 Goubet's -submarine, patent of a private inventor, who has also been patronised -by other navies. These are very small boats, the first, 16-1/2 feet -long, carrying a crew of two or three men. _Goubet No. 2_, built in -1899, is 26-1/4 feet long, composed of several layers of gun-metal -united by strong screw-bolts, and so able to resist very great -pressure. They are egg-or spindle-shaped, supplied with compressed -air, able to sink and rise by rearrangement of water-ballast. -Reservoirs in the hull are gradually filled for submersion with water, -which is easily expelled when it is desired to rise again. If this -system goes wrong a false keel of thirty-six hundredweight can be -detached and the boat springs up to the surface. The propulsive force -is electricity, which works the driving-screw at the rear, and the -automobile torpedo is discharged from its tube by compressed air. - -"By the aid of an optical tube, which a pneumatic telescopic apparatus -enables the operator to thrust above the surface and pull down in a -moment, the captain of the _Goubet_ can, when near the surface, see -what is going on all round him. This telescope has a system of prisms -and lenses which cause the image of the sea-surface to be deflected -down to the eye of the observer below. - -"Fresh air for the crew is provided by reservoirs of oxygen, and -accumulations of foul air can be expelled by means of a small pump. -Enough fresh air can be compressed into the reservoirs to last the -crew for a week or more." - -The _Gymnote_, laid down in 1898, is more than double the size of the -_Goubet_; it is cigar-shaped, 29 feet long by 6 feet diameter, with a -displacement of thirty tons. The motive power is also electricity -stored in accumulators for use during submersion, and the speed -expected--but not realised--was to be ten knots. - -Five years later this type was improved upon in the _Gustave Zede_, -the largest submarine ever yet designed. This boat, built of -phosphor-bronze, with a single screw, measures 131 feet in length and -has a displacement of 266 tons; she can contain a crew of nine -officers and men, carries three torpedoes--though with one torpedo -tube instead of two--has a lightly armoured conning-tower, and is said -to give a surface speed of thirteen knots and to make eight knots when -submerged. At a trial of her powers made in the presence of M. -Lockroy, Minister of Marine, she affixed an unloaded torpedo to the -battleship _Magenta_ and got away unobserved. The whole performance of -the boat on that occasion was declared to be most successful. But its -cost proved excessive considering the small radius of action -obtainable, and a smaller vessel of the same type, the _Morse_ (118 x -9 feet), is now the official size for that particular class. - -In 1896 a competition was held and won by the submersible _Narval_ of -M. Laubeuf, a craft shaped much like the ordinary torpedo-boat. On the -surface or awash the _Narval_ works by means of a Brule engine burning -oil fuel to heat its boilers; but when submerged for attack with -funnel shut down is driven by electric accumulators. She displaces 100 -odd tons and is provided with four Dzewiecki torpedo tubes. Her radius -of action, steaming awash, is calculated at some 250 miles, or seventy -miles when proceeding under water at five knots an hour. This is the -parent of another class of boats designed for offensive tactics, while -the _Morse_ type is adapted chiefly for coast and harbour defence. The -French navy includes altogether thirty submarine craft, though several -of these are only projected at present, and none have yet been put to -the practical tests of actual warfare--the torpedoes used in -experimenting being, of course, blank. - -Meanwhile in America experiments have also been proceeding since 1887, -when Mr. Holland of New York produced the vessel that bears his name. -This, considerably modified, has now been adopted as model by our Navy -Department, which is building some half-dozen on very similar lines. -Though it is not easy to get any definite particulars concerning -French submarines Americans are less reticent, and we have graphic -accounts of the _Holland_ and her offspring from those who have -visited her. - -These vessels, though cigar-shaped liked most others, in some respects -resemble the _Narval_, being intended for long runs on the surface, -when they burn oil in a four-cylinder gasolene engine of 160 -horse-power. Under water they are propelled by an electric waterproof -motor of seventy horse-power, and proceed at a pace of seven knots per -hour. There is a superstructure for deck, with a funnel for the engine -and a small conning-tower protected by 4-inch armour. The armament -carried comprises five 18-inch Whitehead torpedoes, 11 feet 8 inches -long. One hundred and twenty tons is the displacement, including tank -capacity for 850 gallons of gasolene; the full length is 63 feet 4 -inches, with a beam of 11 feet 9 inches. - -[Illustration: _An interior view of the "Holland." The large pendulum -on the right actuates mechanism to keep the Submarine at the required -depth below the surface._] - -The original Holland boat is thus described by an adventurous -correspondent who took a trip in her[3]: "The _Holland_ is fifty-three -feet long, and in its widest part it is 10-1/4 feet in diameter. It -has a displacement of seventy-four tons, and what is called a reserve -buoyancy of 2-1/2 tons which tends to make it come to the surface. - - [3] _Pearson's Magazine._ - -"The frames of the boat are exact circles of steel. They are set a -little more than a foot apart. They diminish gradually in diameter -from the centre of the boat to the bow and stern. On the top of the -boat a flat superstructure is built to afford a walking platform, and -under this are spaces for exhaust pipes and for the external outfit of -the boat, such as ropes and a small anchor. The steel plates which -cover the frame are from one-half to three-eighths of an inch in -thickness. - -"From what may be called the centre of the boat a turret extends -upwards through the superstructure for about eighteen inches. It is -two feet in diameter, and is the only means of entrance to the boat. -It is the place from which the boat is operated. At the stern is an -ordinary three-bladed propeller and an ordinary rudder, and in -addition there are two horizontal rudders--"diving-rudders" they are -called--which look like the feet of a duck spread out behind as it -swims along the water. - -"From the bow two-thirds of the way to the stern there is a flooring, -beneath which are the storage batteries, the tank for the gasolene, -and the tanks which are filled with water for submerging; in the last -one-third of the boat the flooring drops away, and the space is -occupied by the propelling machinery. - -"There are about a dozen openings in the boat, the chief being three -Kingston valves, by means of which the submerging tanks are filled or -emptied. Others admit water to pressure gauges, which regulate or show -the depth of the vessel under water. There are twelve deadlights in -the top and sides of the craft. To remain under water the boat must be -kept in motion, unless an anchor is used. - -"It can be steered to the surface by the diving rudders, or sent -flying to the top through emptying the storage tanks. If it strikes -bottom, or gets stuck in the mud, it can blow itself loose by means of -its compressed air. It cannot be sunk unless pierced above the -flooring. It has a speed capacity of from eight to ten knots either -on the surface or under water. - -"It can go 1500 miles on the surface without renewing its supply of -gasolene. It can go fully forty knots under water without coming to -the surface, and there is enough compressed air in the tanks to supply -a crew with fresh air for thirty hours, if the air is not used for any -other purpose, such as emptying the submerging tanks. It can dive to a -depth of twenty feet in eight seconds. - -"The interior is simply packed with machinery. As you climb down the -turret you are confronted with it at once. There is a diminutive -compass which must be avoided carefully by the feet. A pressure gauge -is directly in front of the operator's eye as he stands in position. -There are speaking-tubes to various parts of the boat, and a -signal-bell to the engine-room. - -"As the operator's hands hang by his sides, he touches a wheel on the -port side, by turning which he steers the little vessel, and one on -the starboard side, by turning which he controls the diving machinery. -After the top is clamped down the operator can look out through -plate-glass windows, about one inch wide and three inches long, which -encircle the turret. - -"So long as the boat is running on the surface these are valuable, -giving a complete view of the surroundings if the water is smooth. -After the boat goes beneath the surface, these windows are useless; it -is impossible to see through the water. Steering must be done by -compass; until recently considered an impossible task in a submarine -boat. A tiny electric light in the turret shows the operator the -direction in which he is going, and reveals the markings on the depth -gauges. If the boat should pass under an object, such as a ship, a -perceptible shadow would be noticed through the deadlights, but that -is all. The ability to see fishes swimming about in the water is a -pleasant fiction. - -"The only clear space in the body of the boat is directly in front of -the bench on which the man in the turret is standing. It is where the -eighteen-inch torpedo-tube, and the eight and five-eighths inch aerial -gun are loaded. - -"Along the sides of this open space are six compressed-air tanks, -containing thirty cubic feet of air at a pressure of 2000 lbs. to a -square inch. Near by is a smaller tank, containing three cubic feet of -air at a fifty pounds pressure. A still smaller tank contains two -cubic feet of air at a ten pounds pressure. These smaller tanks supply -the compressed air which, with the smokeless powder, is used in -discharging the projectiles from the boat. - -"Directly behind the turret, up against the roof on the port side, is -the little engine by which the vessel is steered; it is worked by -compressed air. Fastened to the roof on the starboard side is the -diving-engine, with discs that look as large as dinner-plates stood on -end. These discs are diaphragms on which the water-pressure exerts an -influence, counteracting certain springs which are set to keep the -diving rudders at a given pitch, and thus insuring an immersion of an -exact depth during a run. - -"At one side is a cubic steel box--the air compressor; and directly in -the centre of this part of the boat is a long pendulum, just as there -is in the ordinary torpedo, which, by swinging backwards and forwards -as the boat dives and rises, checks a tendency to go too far down, or -to come up at too sharp an angle. On the floor are the levers which, -when raised and moved in certain directions, fill or empty the -submerging tanks. On every hand are valves and wheels and pipes in -such apparent confusion as to turn a layman's head. - -"There are also pumps in the boat, a ventilating apparatus, and a -sounding contrivance, by means of which the channel is picked out when -running under water. This sounding contrivance consists of a heavy -weight attached to a piano wire passing from a reel out through a -stuffing-box in the bottom. There are also valves which release fresh -air to the crew, although in ordinary runs of from one-half to one -hour this is not necessary, the fresh air received from the various -exhausts in the boat being sufficient to supply all necessities in -that length of time." - -Another submersible of somewhat different design is the production of -the Swedish inventor, Mr. Nordenfelt. This boat is 9-1/2 metres in -length, and has a displacement of sixty tons. Like the _Goubet_ it -sinks only in a horizontal position, while the _Holland_ plunges -downward at a slight angle. On the surface a steam-engine of 100 -horse-power propels it, and when the funnel is closed down and the -vessel submerges itself, the screws are still driven by superheated -steam from the large reservoir of water boiling at high pressure which -maintains a constant supply, three circulation pumps keeping this in -touch with the boiler. The plunge is accomplished by means of two -protected screws, and when they cease to move the reserve buoyancy of -the boat brings it back to the surface. It is steered by a rudder -which a pendulum regulates. The most modern of these boats is of -English manufacture, built at Barrow, and tried in Southampton Water. - -The vessels hitherto described should be termed submersible rather -than submarine, as they are designed to usually proceed on the -surface, and submerge themselves only for action when in sight of the -enemy. - -American ingenuity has produced an absolutely unique craft to which -the name submarine may with real appropriateness be applied, for, -sinking in water 100 feet deep, it can remain below and run upon three -wheels along the bottom of the sea. This is the _Argonaut_, invented -by Mr. Simon Lake of Baltimore, and its main portion consists of a -steel framework of cylindrical form which is surmounted by a flat, -hollow steel deck. During submersion the deck is filled with water and -thus saved from being crushed by outside pressure as well as helping -to sink the craft. - -When moving on the surface it has the appearance of an ordinary ship, -with its two light masts, a small conning-tower on which is the -steering-wheel, bowsprit, ventilators, a derrick, suction-pump, and -two anchors. A gasolene engine of special design is used for both -surface and submerged cruising under ordinary circumstances, but in -time of war storage batteries are available. An electric dynamo -supplies light to the whole interior, including a 4000 candle-power -searchlight in the extreme bow which illuminates the pathway while -under water. - -On the boat being stopped and the order given to submerge, the crew -first throw out sounding lines to make sure of the depth. They then -close down external openings, and retreat into the boat through the -conning-tower, within which the helmsman takes his stand, continuing -to steer as easily as when outside. The valves which fill the deck and -submersion tanks are opened, and the _Argonaut_ drops gently to the -floor of the ocean. The two apparent masts are in reality 3-inch iron -pipes which rise thirty feet or more above the deck, and so long as no -greater depth is attained, they supply the occupants with fresh air -and let exhausted gases escape, but close automatically when the water -reaches their top. - -Once upon the bottom of the sea this versatile submarine begins its -journey as a tricycle. It is furnished with a driving-wheel on either -side, each of which is 6-1/2 feet in diameter and weighs 5000 lbs.; -and is guided by a third wheel weighing 2000 lbs. journalled in the -rudder. On a hard bottom or against a strong tide the wheels are most -effective owing to their weight, but in passing through soft sand or -mud the screw propeller pushes the boat along, the driving-wheels -running "loose." In this way she can travel through even waist-deep -mud, the screw working more strongly than on the surface, because it -has such a weight of water to help it, and she moves more easily -uphill. - -In construction the _Argonaut_ is shaped something like a huge cigar, -her strong steel frames, spaced twenty inches apart, being clad with -steel plates 3/8-inch thick double riveted over them. Great strength -is necessary to resist the pressure of superincumbent water, which at -a depth of 100 feet amounts to 44 lbs. per square inch. - -Originally she was built 36 feet long, but was subsequently lengthened -by some 20 odd feet, and has 9 feet beam. She weighs fifty-seven tons -when submerged. A false section of keel, 4000 lbs. in weight, can on -emergency be instantly released from inside; and two downhaul weights, -each of 1000 lbs., are used as an extra precaution for safety when -sinking in deep water. - -The interior is divided into various compartments, the living quarters -consisting of the cabin, galley, operating chamber and engine-room. -There are also a division containing stores and telephone, the -intermediate, and the divers' room. The "operating" room contains the -levers, handwheels, and other mechanism by which the boat's movements -are governed. A water gauge shows her exact depth below the surface; a -dial on either side indicates any inclination from the horizontal. -Certain levers open the valves which admit water to the ballast-tanks -in the hold; another releases the false keel; there is a cyclometer to -register the wheel travelling, and other gauges mark the pressure of -steam, speed of engines, &c. - -A compass in the conning-tower enables the navigator to steer a true -course whether above or below the surface. This conning-tower, only -six feet high, rises above the centre of the living quarters, and is -of steel with small windows in the upper part. Encircling it to about -three-quarters of its height is a reservoir for gasolene, which feeds -into a smaller tank within the boat for consumption. The compressed -air is stored in two Mannesmann steel reservoirs which have been -tested to a pressure of 4000 lbs. per square inch. This renews the -air-supply for the crew when the _Argonaut_ is long below, and also -enables the diving operations to be carried on. - -The maximum speed at which the _Argonaut_ travels submerged is five -knots an hour, and when she has arrived at her destination--say a -sunken coal steamer--the working party pass into the "intermediate" -chamber, whose air-tight doors are then closed. A current of -compressed air is then turned on until the air is equal in pressure to -that in the divers' room. The doors of this close over india rubber to -be air and water-tight; one communicates with the "intermediate," the -other is a trap which opens downwards into the sea. Through three -windows in the prow those remaining in the room can watch operations -outside within a radius varying according to the clearness of the -water. The divers assume their suits, to the helmets of which a -telephone is attached, so arranged that they are able to talk to each -other as well as to those in the boat. They are also provided with -electric lamps, and a brilliant flood of light streams upon them from -the bows of the vessel. The derrick can be used with ease under water, -and the powerful suction-pump will "retrieve" coal from a submerged -vessel into a barge above at the rate of sixty tons per hour. - -It will thus be seen how valuable a boat of this kind may be for -salvage operations, as well as for surveying the bottom of harbours, -river mouths, sea coasts, and so on. In war time it can lay or examine -submarine mines for harbour defence, or, if employed offensively, can -enter the enemy's harbour with no chance of detection, and there -destroy his mines or blow up his ships with perfect impunity. - -To return the _Argonaut_ to the surface it is only necessary to force -compressed air into the space below the deck and the four tanks in the -hold. Her buoyancy being thus gradually restored she rises slowly and -steadily till she is again afloat upon the water, and steams for land. - -We have now glanced briefly at some of the most interesting -attempts--out of many dozens--to produce a practicable submarine -vessel in bygone days; and have inquired more closely into the -construction of several modern designs; among these the _Holland_ has -received especial attention, as that is the model adopted by our -Admiralty, and our own new boats only differ in detail from their -American prototype. But before quitting this subject it will be well -to consider what is required from the navigating engineer, and how far -present invention has supplied the demand. - -[Illustration: _The "Holland" Submarine in the last stages of -submersion._] - -The perfect submarine of fiction was introduced by Jules Verne, whose -_Nautilus_ remains a masterpiece of scientific imagination. This -marvellous vessel ploughed the seas with equal power and safety, -whether on the surface or deeply sunk beneath the waves, bearing the -pressure of many atmospheres. It would rest upon the ocean floor while -its inmates, clad in diving suits, issued forth to stroll amid aquatic -forests and scale marine mountains. It gathered fabulous treasures -from pearl beds and sunken galleons; and could ram and sink an -offending ship a thousand times its size without dinting or loosening -a plate on its own hull. No weather deflected its compass, no movement -disturbed its equilibrium. Its crew followed peacefully and cheerfully -in their spacious cabins a daily round of duties which electric power -and automatic gear reduced to a minimum. Save for the misadventure of -a shortened air-supply when exploring the Polar pack, and the clash of -human passions, Captain Nemo's guests would have voyaged in a -floating paradise. - -Compare with this entrancing creation the most practical vessels of -actual experiment. They are small, blind craft, groping their way -perilously when below the surface, the steel and electrical machinery -sadly interfering with any trustworthy working of their compass, and -the best form of periscope hitherto introduced forming a very -imperfect substitute for ordinary vision. - -Their speed, never very fast upon the surface, is reduced by -submersion to that of the oldest and slowest gunboats. Their radius of -action is also circumscribed--that is, they cannot carry supplies -sufficient to go a long distance, deal with a hostile fleet, and then -return to headquarters without replenishment. - -Furthermore, there arise the nice questions of buoyancy combined with -stability when afloat, of sinking quickly out of sight, and of keeping -a correct balance under water. The equilibrium of such small vessels -navigating between the surface and the bottom is extremely sensitive; -even the movements to and fro of the crew are enough to imperil them. -To meet this difficulty the big water-ballast tanks, engines and -accumulators are necessarily arranged at the bottom of the hull, and a -pendulum working a helm automatically is introduced to keep it -longitudinally stable. - -To sink the boat, which is done by changing the angle of the -propeller in the _Goubet_ and some others, and by means of horizontal -rudders and vanes in the _Nordenfelt_ and _Holland_, it must first be -most accurately balanced, bow and stern exactly in trim. Then the boat -must be put into precise equilibrium with the water--_i.e._ must weigh -just the amount of water displaced. For this its specific gravity must -be nearly the same as that of the water (whether salt or fresh), and a -small accident might upset all calculations. Collision, even with a -large fish, could destroy the steering-gear, and a dent in the side -would also tend to plunge it at once to destruction. - -Did it escape these dangers and succeed in steering an accurate course -to its goal, we have up to now little practical proof that the mere -act of discharging its torpedo--though the weight of the missile is -intended to be automatically replaced immediately it drops from the -tube--may not suffice to send the vessel either to bottom or top of -the sea. In the latter case it would be within the danger zone of its -alarmed enemy and at his mercy, its slow speed (even if uninjured) -leaving it little chance of successful flight. - -But whatever the final result, one thing is certain, that--untried as -it is--the possible contingency of a submarine attack is likely to -shake the _morale_ of an aggressive fleet. - -"When the first submarine torpedo-boat goes into action," says Mr. -Holland, "she will bring us face to face with the most perplexing -problem ever met in warfare. She will present the unique spectacle, -when used in attack, of a weapon against which there is no defence.... -You can send nothing against the submarine boat, not even itself.... -You cannot see under water, hence you cannot fight under water. Hence -you cannot defend yourself against an attack under water except by -running away." - -This inventor is, however, an enthusiast about the future awaiting the -submarine as a social factor. His boat has been tested by long voyages -on and below water with complete success. The _Argonaut_ also upon one -occasion travelled a thousand miles with five persons, and proved -herself "habitable, seaworthy, and under perfect control." - -Mr. Holland confidently anticipates in the near future a Channel -service of submerged boats run by automatic steering-gear upon cables -stretched from coast to coast, and eloquently sums up its advantages. - -The passage would be always practicable, for ordinary interruptions -such as fog and storms cannot affect the sea depths. - -An even temperature would prevail summer and winter, the well-warmed -and lighted boats being also free from smoke and spray. - -No nauseating smells would proceed from the evenly-working electric -engines. No motion cause sea-sickness, no collision be apprehended--as -each line would run on its own cable, and at its own specified depth, -a telephone keeping it in communication with shore. - -In like manner a service might be plied over lake bottoms, or across -the bed of wide rivers whose surface is bound in ice. Such is the -submarine boat as hitherto conceived for peace or war--a daring -project for the coming generation to justify. - - - - -ANIMATED PICTURES. - - -Has it ever occurred to the reader to ask himself why rain appears to -fall in streaks though it arrives at earth in drops? Or why the -glowing end of a charred stick produces fiery lines if waved about in -the darkness? Common sense tells us the drop and the burning point -cannot _be_ in two places at one and the same time. And yet apparently -we are able to see both in many positions simultaneously. - -This seeming paradox is due to "persistence of vision," a phenomenon -that has attracted the notice of scientific men for many centuries. -Persistence may be briefly explained thus:-- - -The eye is extremely sensitive to light, and will, as is proved by the -visibility of the electric spark, lasting for less than the millionth -part of a second, _receive_ impressions with marvellous rapidity. - -But it cannot get rid of these impressions at the same speed. The -duration of a visual impression has been calculated as one-tenth to -one-twenty-first of a second. The electric spark, therefore, appears -to last much longer than it really does. - -Hence it is obvious that if a series of impressions follow one another -more rapidly than the eye can free itself of them, the impressions -will overlap, and one of four results will follow. - - (_a_) _Apparently uninterrupted presence_ of an image if the - same image be repeatedly represented. - - (_b_) _Confusion_, if the images be all different and - disconnected. - - (_c_) _Combination_, if the images of two or a very few objects - be presented in regular rotation. - - (_d_) _Motion_, if the objects be similar in all but one part, - which occupies a slightly different portion in each - presentation. - -In connection with (_c_) an interesting story is told of Sir J. -Herschel by Charles Babbage:--[4] - - [4] Quoted from Mr. Henry V. Hopwood's "Living Pictures," to - which book the author is indebted for much of his information - in this chapter. - -"One day Herschel, sitting with me after dinner, amusing himself by -spinning a pear upon the table, suddenly asked whether I could show -him the two sides of a shilling at the same moment. I took out of my -pocket a shilling, and holding it up before the looking-glass, pointed -out my method. 'No,' said my friend, 'that won't do;' then spinning my -shilling upon the table, he pointed out his method of seeing both -sides at once. The next day I mentioned the anecdote to the late Dr. -Fitton, who a few days after brought me a beautiful illustration of -the principle. It consisted of a round disc of card suspended between -two pieces of sewing silk. These threads being held between the finger -and thumb of each hand, were then made to turn quickly, when the disc -of card, of course, revolved also. Upon one side of this disc of card -was painted a bird, upon the other side an empty bird-cage. On turning -the thread rapidly the bird appeared to have got inside the cage. We -soon made numerous applications, as a rat on one side and a trap on -the other, &c. It was shown to Captain Kater, Dr. Wollaston, and many -of our friends, and was, after the lapse of a short time, forgotten. -Some months after, during dinner at the Royal Society Club, Sir Joseph -Banks being in the chair, I heard Mr. Barrow, then secretary to the -Admiralty, talking very loudly about a wonderful invention of Dr. -Paris, the object of which I could not quite understand. It was called -the Thaumatrope, and was said to be sold at the Royal Institution, in -Albemarle Street. Suspecting that it had some connection with our -unnamed toy I went next morning and purchased for seven shillings and -sixpence a thaumatrope, which I afterwards sent down to Slough to the -late Lady Herschel. It was precisely the thing which her son and Dr. -Fitton had contributed to invent, which amused all their friends for a -time, and had then been forgotten." - -The _thaumatrope_, then, did nothing more than illustrate the power of -the eye to weld together a couple of alternating impressions. The toys -to which we shall next pass represent the same principle working in a -different direction towards the production of the living picture. - -Now, when we see a man running (to take an instance) we see the _same_ -body and the same legs continuously, but in different positions, which -merge insensibly the one into the other. No method of reproducing that -impression of motion is possible if only _one_ drawing, diagram, or -photograph be employed. - -A man represented with as many legs as a centipede would not give us -any impression of running or movement; and a blur showing the -positions taken successively by his legs would be equally futile. -Therefore we are driven back to a _series_ of pictures, slightly -different from one another; and in order that the pictures may not be -blurred a screen must be interposed before the eye while the change -from picture to picture is made. The shorter the period of change, and -the greater the number of pictures presented to illustrate a single -motion, the more realistic is the effect. These are the general -principles which have to be observed in all mechanism for the -production of an illusory effect of motion. The persistence of vision -has led to the invention of many optical toys, the names of which, in -common with the names of most apparatus connected with the living -picture, are remarkable for their length. Of these toys we will select -three for special notice. - -In 1833 Plateau of Ghent invented the _phenakistoscope_, "the thing -that gives one a false impression of reality"--to interpret this -formidable word. The phenakistoscope is a disc of card or metal round -the edge of which are drawn a succession of pictures showing a man or -animal in progressive positions. Between every two pictures a narrow -slit is cut. The disc is mounted on an axle and revolved before a -mirror, so that a person looking through the slits see one picture -after another reflected in the mirror. - -The _zoetrope_, or Wheel of Life, which appeared first in 1860, is a -modification of the same idea. In this instrument the pictures are -arranged on the inner side of a hollow cylinder revolving on a -vertical axis, its sides being perforated with slits above the -pictures. As the slit in both cases caused distortion M. Reynaud, a -Frenchman, produced in 1877 the _praxinoscope_, which differed from -the zoetrope in that the pictures were not seen directly through -slits, but were reflected by mirrors set half-way between the pictures -and the axis of the cylinder, a mirror for every picture. Only at the -moment when the mirror is at right angles to the line of sight would -the picture be visible. M. Reynaud also devised a special lantern for -projecting praxinoscope pictures on to a screen. - -These and other somewhat similar contrivances, though ingenious, had -very distinct limitations. They depended for their success upon the -inventiveness and accuracy of the artist, who was confined in his -choice of subject; and could, owing to the construction of the -apparatus, only represent a small series of actions, indefinitely -repeated by the machine. And as a complete action had to be crowded -into a few pictures, the changes of position were necessarily abrupt. - -To make the living picture a success two things were needed; some -method of securing a very rapid series of many pictures, and a machine -for reproducing the series, whatever its length. The method was found -in photography, with the advance of which the living picture's -progress is so closely related, that it will be worth while to notice -briefly the various improvements of photographic processes. The -old-fashioned Daguerreotype process, discovered in 1839, required an -exposure of half-an-hour. The introduction of wet collodion reduced -this tax on a sitter's patience to ten seconds. In 1878 the dry plate -process had still further shortened the exposure to one second; and -since that date the silver-salt emulsions used in photography have had -their sensitiveness to light so much increased, that clear pictures -can now be made in one-thousandth of a second, a period minute enough -to arrest the most rapid movements of animals. - -By 1878, therefore, instantaneous photography was ready to aid the -living picture. Previously to that year series of photographs had been -taken from posed models, without however extending the choice of -subjects to any great extent. But between 1870 and 1880 two men, Marey -and Muybridge, began work with the camera on the movements of horses. -Marey endeavoured to produce a series of pictures round the edge of -one plate with a single lens and repeated exposures.[5] Muybridge, on -the other hand, used a series of cameras. He erected a long white -background parallel to which were stationed the cameras at equal -distances. The shutters of the cameras were connected to threads laid -across the interval between the background and the cameras in such a -manner that a horse driven along the track snapped them at regular -intervals, and brought about successive exposures. Muybridge's method -was carried on by Anschuetz, a German, who in 1899 brought out his -electrical Tachyscope, or "quick-seer." Having secured his negatives -he printed off transparent positives on glass, and arranged these last -round the circumference of a large disc rotating in front of a screen, -having in it a hole the size of the transparencies. As each picture -came opposite the hole a Geissler tube was momentarily lit up behind -it by electrical contact, giving a fleeting view of one phase of a -horse's motion. - - [5] A very interesting article in the May, 1902, issue of - _Pearson's Magazine_ deals with the latest work of Professor - Marey in the field of the photographic representation of the - movements of men, birds, and quadrupeds. - -The introduction of the ribbon film in or about 1888 opened much -greater possibilities to the living picture than would ever have -existed had the glass plate been retained. It was now comparatively -easy to take a long series of pictures; and accordingly we find -Messrs. Friese-Greene and Evans exhibiting in 1890 a camera capable of -securing three hundred exposures in half a minute, or ten per second. - - -The next apparatus to be specially mentioned is Edison's Kinetoscope, -which he first exhibited in England in 1894. As early as 1887 Mr. -Edison had tried to produce animated pictures in a manner analogous to -the making of a sound-record on a phonograph (see p. 56). He wrapped -round a cylinder a sheet of sensitized celluloid which was covered, -after numerous exposures, by a spiral line of tiny negatives. The -positives made from these were illuminated in turn by flashes of -electric light. This method was, however, entirely abandoned in the -perfected kinetoscope, an instrument for viewing pictures the size of -a postage stamp, carried on a continuously moving celluloid film -between the eye of the observer and a small electric lamp. The -pictures passed the point of inspection at the rate of forty-six per -second (a rate hitherto never approached), and as each picture was -properly centred a slit in a rapidly revolving shutter made it visible -for a very small fraction of a second. Holes punched at regular -intervals along each side of the film engaged with studs on a wheel, -and insured a regular motion of the pictures. This principle of a -perforated film has been used by nearly all subsequent manufacturers -of animatographs. - -To secure forty-six negatives per second Edison invented a special -exposure device. Each negative would have but one-forty-sixth of a -second to itself, and that must include the time during which the -fresh surface of film was being brought into position before the lens. -He therefore introduced an intermittent gearing, which jerked the -film forwards forty-six times per second, but allowed it to remain -stationary for nine-tenths of the period allotted to each picture. -During the time of movement the lens was covered by the shutter. This -principle of exposure has also been largely adopted by other -inventors. By its means weak negatives are avoided, while pictures -projected on to a screen gain greatly in brilliancy and steadiness. - -The capabilities of a long flexible film-band having been shown by -Edison, he was not long without imitators. Phantoscopes, Bioscopes, -Photoscopes, and many other instruments followed in quick succession. -In 1895 Messrs. Lumiere scored a great success with their -Cinematograph, which they exhibited at Marseilles and Paris; throwing -the living picture as we now know it on to a screen for a large -company to see. This camera-lantern opens the era of commercial -animated-photography. The number of patents taken out since 1895 in -connection with living-picture machines is sufficient proof that -inventors have either found in this particular branch of photography a -peculiar fascination, or have anticipated from it a substantial -profit. - -A company known as the Mutoscope and Biograph Company has been formed -for the sole object of working the manufacture and exhibition of the -living picture on a great commercial scale. The present company is -American, but there are subsidiary allied companies in many parts of -the world, including the British Isles, France, Italy, Belgium, -Germany, Austria, India, Australia, South Africa. The part that the -company has played in the development of animated photography will be -easily understood from the short account that follows. - -The company controls three machines, the Mutograph, or camera for -making negatives; the Biograph, or lantern for throwing pictures on to -the screen; and the Mutoscope, a familiar apparatus in which the same -pictures may be seen in a different fashion on the payment of a penny. - -Externally the Mutograph is remarkable for its size, which makes it a -giant of its kind. The complete apparatus weighs, with its -accumulators, several hundreds of pounds. It takes a very large -picture, as animatograph pictures go--two by two-and-a-half inches, -which, besides giving increased detail, require less severe -magnification than is usual with other films. The camera can make up -to a hundred exposures per second, in which time _twenty-two_ feet of -film will have passed before the lens. - -The film is so heavy that were it arrested bodily during each exposure -and then jerked forward again, it might be injured. The mechanism of -the mutograph, driven at regular speed, by an electric motor, has been -so arranged as to halt only that part of the film which is being -exposed, the rest moving forward continuously. The exposed portion, -together with the next surface, which has accumulated in a loop -behind it, is dragged on by two rollers that are in contact with the -film during part only of their revolutions. Thus the jerky motion is -confined to but a few inches of the film, and even at the highest -speeds the camera is peculiarly free from vibration. - -An exposed mutograph film is wound for development round a skeleton -reel, three feet in diameter and seven long, which rotates in a -shallow trough containing the developing solution. Development -complete, the reel is lifted from its supports and suspended over a -succession of other troughs for washing, fixing, and final washing. -When dry the negative film is passed through a special printing frame -in contact with another film, which receives the positive image for -the biograph. The difficulty of handling such films will be -appreciated to a certain extent even by those whose experience is -confined to the snaky behaviour of a short Kodak reel during -development. - -The Mutoscope Company's organisation is as perfect as its machinery. -It has representatives in all parts of the world. Wherever stirring -events are taking place, whether in peace or war, a mutograph operator -will soon be on the spot with his heavy apparatus to secure pictures -for world-wide exhibition. It need hardly be said that great -obstacles, human and physical, have often to be overcome before a film -can be exposed; and considerable personal danger encountered. We read -that an operator, despatched to Cuba during the Spanish-American War -was left three days and nights without food or water to guard his -precious instruments, the party that had landed him having suddenly -put to sea on sighting a Spanish cruiser. Another is reported to have -had a narrow escape from being captured at sea by the Spaniards after -a hot chase. It is also on record that a mutograph set up in Atlantic -City to take a procession of fire-engines was charged and shattered by -one of the engines; that the operators were flung into the crowd: and -that nevertheless the box containing the exposed films was uninjured, -and on development yielded a very sensational series of pictures -lasting to the moment of collision. - -The Mutoscope Company owns several thousand series of views, none -probably more valuable than those of his Holiness the Pope, who -graciously gave Mr. W. K. Dickson five special sittings, during which -no less than 17,000 negatives were made, each one of great interest to -millions of people throughout the world. - -The company spares neither time nor money in its endeavour to supply -the public with what will prove acceptable. A year's output runs into -a couple of hundred miles of film. As much as 700 feet is sometimes -expended on a single series, which may be worth anything up to L1000. - -The energy displayed by the operators is often marvellous. To take -instances. The Derby of 1898 was run at 3.20 P.M. At ten o'clock the -race was run again by Biograph on the great sheet at the Palace -Theatre. On the home-coming of Lord Kitchener from the Soudan -Campaign, a series of photographs was taken at Dover in the afternoon -and exhibited the same evening! Or again, to consider a wider sphere -of action, the Jubilee Procession of 1897 was watched in New York ten -days after the event; two days later in Chicago; and in three more the -films were attracting large audiences in San Francisco, 5000 miles -from the actual scene of the procession! - -One may easily weary of a series of single views passed slowly through -a magic-lantern at a lecture or entertainment. But when the Biograph -is flashing its records at lightning speed there is no cause for -dullness. It is impossible to escape from the fascination of -_movement_. A single photograph gives the impression of mere -resemblance to the original; but a series, each reinforcing the -signification of the last, breathes life into the dead image, and -deludes us into the belief that we see, not the representation of a -thing, but the thing itself. The bill of fare provided by the Biograph -Company is varied enough to suit the most fastidious taste. Now it is -the great Naval Review off Spithead, or President Faure shooting -pheasants on his preserves near Paris. A moment's pause and then the -magnificent Falls of Niagara foam across the sheet; Maxim guns fire -harmlessly; panoramic scenes taken from locomotives running at high -velocity unfold themselves to the delighted spectators, who feel as if -they really were speeding over open country, among towering rocks, or -plunging into the darkness of a tunnel. Here is an express approaching -with all the quiver and fuss of real motion, so faithfully rendered -that it seems as if a catastrophe were imminent; when, snap! we are -transported a hundred miles to watch it glide into a station. The -doors open, passengers step out and shake hands with friends, porters -bustle about after luggage, doors are slammed again, the guard waves -his flag, and the carriages move slowly out of the picture. Then our -attention is switched away to the 10-inch disappearing gun, landing -and firing at Sandy Hook. And next, as though to show that nothing is -beneath the notice of the biograph, we are perhaps introduced to a -family of small pigs feeding from a trough with porcine earnestness -and want of manners. - -It must not be thought that the Living Picture caters for mere -entertainment only. It serves some very practical and useful ends. By -its aid the movements of machinery and the human muscles may be -studied in detail, to aid a mechanical or medical education. It -furnishes art schools with all the poses of a living model. Less -serious pursuits, such as dancing, boxing, wrestling and all athletic -sports and exercise, will find a use for it. As an advertising medium -it stands unrivalled, and we shall owe it a deep debt of gratitude if -it ultimately supplants the flaring posters that disfigure our towns -and desecrate our landscapes. Not so long since, the directors of the -Norddeutscher-Lloyd Steamship Company hired the biograph at the -Palace Theatre, London, to demonstrate to anybody who cared to witness -a very interesting exhibition that their line of vessels should always -be used for a journey between England and America. - -The Living Picture has even been impressed into the service of the -British Empire to promote emigration to the Colonies. Three years ago -Mr. Freer exhibited at the Imperial Institute and in other places in -England a series of films representing the 1897 harvest in Manitoba. -Would-be emigrants were able to satisfy themselves that the great -Canadian plains were fruitful not only on paper. For could they not -see with their own eyes the stately procession of automatic "binders" -reaping, binding, and delivering sheaves of wheat, and puffing engines -threshing out the grain ready for market? A far preferable method this -to the bogus descriptions of land companies such as lured poor -Chuzzlewit and Mark Tapley into the deadly swamps of "Eden." - -Again, what more calculated to recruit boys for our warships than the -fine Polytechnic exhibition known as "Our Navy"? What words, spoken or -printed, could have the effect of a series of vivid scenes truthfully -rendered, of drills on board ship, the manning and firing of big guns, -the limbering-up of smaller guns, the discharge of torpedoes, the -headlong rush of the "destroyers"? - -The Mutoscope, to which reference has been made above, may be found in -most places of public entertainment, in refreshment bars, on piers, -in exhibitions, on promenades. A penny dropped into a slot releases a -handle, the turning of which brings a series of pictures under -inspection. The pictures, enlarged from mutograph films, are mounted -in consecutive order round a cylinder, standing out like the leaves of -a book. When the cylinder is revolved by means of the handle the -picture cards are snapped past the eye, giving an effect similar to -the lifelike projections on a biograph screen. From 900 to 1000 -pictures are mounted on a cylinder. - -The advantages of the mutoscope--its convenient size, its simplicity, -and the ease with which its contents may be changed to illustrate the -topics and events of the day--have made the animated photograph -extremely popular. It does for vision what the phonograph does for -sound. In a short time we shall doubtless be provided with handy -machines combining the two functions and giving us double value for -our penny. - -The real importance and value of animated photography will be more -easily estimated a few years hence than to-day, when it is still more -or less of a novelty. The multiplication of illustrated newspapers and -magazines points to a general desire for pictorial matter to help down -the daily, weekly, or monthly budget of news, even if the -illustrations be imaginative products of Fleet Street rather than -faithful to fact. The reliable living picture (we expect the -"set-scene") which "holds up a mirror to nature," will be a companion -rather than a rival of journalism, following hard on the description -in print of an event that has taken place under the eye of the -recording camera. The zest with which we have watched during the last -two years biographic views of the embarkation and disembarkation of -troops, of the transport of big guns through drifts and difficult -country, and of the other circumstances of war, is largely due to the -descriptions we have already read of the things that we see on the -screen. And, on the other hand, the impression left by a series of -animated views will dwell in our memories long after the contents of -the newspaper columns have become confused and jumbled. It is -therefore especially to be hoped that photographic records will be -kept of historic events, such as the Jubilee, the Queen's Funeral, -King Edward's Coronation, so that future generations may, by the -turning of a handle, be brought face to face with the great doings of -a bygone age. - - - - -THE GREAT PARIS TELESCOPE - - -A telescope so powerful that it brings the moon apparently to within -thirty-five miles of the earth; so long that many a cricketer could -not throw a ball from one end of it to the other; so heavy that it -would by itself make a respectable load for a goods train; so -expensive that astronomically-inclined millionaires might well -hesitate to order a similar one for their private use. - -Such is the huge Paris telescope that in 1900 delighted thousands of -visitors in the French Exposition, where, among the many wonderful -sights to be seen on all sides, it probably attracted more notice than -any other exhibit. This triumph of scientific engineering and dogged -perseverance in the face of great difficulties owes its being to a -suggestion made in 1894 to a group of French astronomers by M. -Deloncle. He proposed to bring astronomy to the front at the coming -Exposition, and to effect this by building a refracting telescope that -in size and power should completely eclipse all existing instruments -and add a new chapter to the "story of the heavens." - -To the mind unversed in astronomy the telescope appeals by the -magnitude of its dimensions, in the same way as do the Forth Bridge, -the Eiffel Tower, the Big Wheel, the statue of Liberty near New York -harbour, the Pyramids, and most human-made "biggest on records." - -At the time of M. Deloncle's proposal the largest refracting telescope -was the Yerkes' at William's Bay, Wisconsin, with an object-glass -forty inches in diameter; and next to it the 36-inch Lick instrument -on Mount Hamilton, California, built by Messrs. Alvan Clark of -Cambridgeport, Massachusetts. Among reflecting telescopes the prior -place is still held by Lord Rosse's, set up on the lawn of Birr Castle -half a century ago. Its speculum, or mirror, weighing three tons, lies -at the lower end of a tube six feet across and sixty feet long. This -huge reflector, being mounted in meridian, moves only in a vertical -direction. A refracting telescope is one of the ordinary pocket type, -having an object-lens at one end and an eyepiece at the other. A -reflector, on the other hand, has no object-lens, its place being -taken by a mirror that gathers the rays entering the tube and reflects -them back into the eyepiece, which is situated nearer the mouth end of -the tube than the mirror itself. - -Each system has its peculiar disadvantages. In reflectors the image is -more or less distorted by "spherical aberration." In refractors the -image is approximately perfect in shape, but liable to "chromatic -aberration," a phenomenon especially noticeable in cheap telescopes -and field-glasses, which often show objects fringed with some of the -colours of the spectrum. This defect arises from the different -refrangibility of different light rays. Thus, violet rays come to a -focus at a shorter distance from the lens than red rays, and when one -set is in focus to the eye the other must be out of focus. In -carefully-made and expensive instruments compound lenses are used, -which by the employment of different kinds of glass bring all the -colours to practically the same focus, and so do away with chromatic -aberration. - -To reduce colour troubles to a _minimum_ M. Deloncle proposed that the -object-lens should have a focal distance of about two hundred feet, -since a long focus is more easily corrected than a short one, and a -diameter of over fifty-nine inches. The need for so huge a lens arises -out of the optical principles of a refractor. The rays from an -object--a star, for instance--strike the object-glass at the near end, -and are bent by it into a converging beam, till they all meet at the -focus. Behind the focus they again separate, and are caught by the -eyepiece, which reduces them to a parallel beam small enough to enter -the pupil. We thus see that though the unaided eye gathers only the -few rays that fall directly from the object on to the pupil, when -helped by the telescope it receives the concentrated rays falling on -the whole area of the object-glass; and it would be sensible of a -greatly increased brightness had not this light to be redistributed -over the image, which is the object magnified by the eyepiece. -Assuming the aperture of the pupil to be one-tenth of an inch, and -the object to be magnified a hundred times, the object-lens should -have a hundred times the diameter of the pupil to render the image as -bright as the object itself. If the lens be five instead of ten inches -across, a great loss of light results, as in the high powers of a -microscope, and the image loses in distinctness what it gains in size. - -As M. Deloncle meant his telescope to beat all records in respect of -magnification, he had no choice but to make a lens that should give -proportionate illumination, and itself be of unprecedented size. - -At first M. Deloncle met with considerable opposition and ridicule. -Such a scheme as his was declared to be beyond accomplishment. But in -spite of many prophecies of ultimate failure he set to work, -entrusting the construction of the various portions of his colossal -telescope to well-tried experts. To M. Gautier was given the task of -making all the mechanical parts of the apparatus; to M. Mantois the -casting of the giant lenses; to M. Despret the casting of the huge -mirror, to which reference will be made immediately. - -The first difficulty to be encountered arose from the sheer size of -the instrument. It was evidently impossible to mount such a leviathan -in the ordinary way. A tube, 180 feet long, could not be made rigid -enough to move about and yet permit careful observation of the stars. -Even supposing that it were satisfactorily mounted on an "equatorial -foot" like smaller glasses, how could it be protected from wind and -weather? To cover it, a mighty dome, two hundred feet or more in -diameter, would be required; a dome exceeding by over seventy feet the -cupola of St. Peter's, Rome; and this dome must revolve easily on its -base at a pace of about fifty feet an hour, so that the telescope -might follow the motion of the heavenly bodies. - -The constructors therefore decided to abandon any idea of making a -telescope that could be moved about and pointed in any desired -direction. The alternative course open to them was to fix the -telescope itself rigidly in position, and to bring the stars within -its field by means of a mirror mounted on a massive iron frame--the -two together technically called a siderostat. The mirror and its -support would be driven by clockwork at the proper sidereal rate. The -siderostat principle had been employed as early as the eighteenth -century, and perfected in recent years by Leon Foucault, so that in -having recourse to it the builders of the telescope were not -committing themselves to any untried device. - -In days when the handling of masses of iron, and the erection of huge -metal constructions have become matters of everyday engineering life, -no peculiar difficulty presented itself in connection with the -metal-work of the telescope. The greatest possible care was of course -observed in every particular. All joints and bearings were adjusted -with an extraordinary accuracy; and all the cylindrical moving parts -of the siderostat verified till they did not vary from perfect -cylindricity by so much as one twenty-five-thousandth of an inch! - -The tube of the telescope, 180 feet long, consisted of twenty-four -sections, fifty-nine inches in diameter, bolted together and supported -on seven massive iron pillars. It weighed twenty-one tons. The -siderostat, twenty-seven feet high, and as many in length, weighed -forty-five tons. The lower portion, which was fixed firmly on a bed of -concrete, had on the top a tank filled with quicksilver, in which the -mirror and its frame floated. The quicksilver supported nine-tenths of -the weight, the rest being taken by the levers used to move the -mirror. Though the total weight of the mirror and frame was thirteen -tons, the quicksilver offered so little resistance that a pull of a -few pounds sufficed to rotate the entire mass. - -The real romance of the construction of this huge telescope centres on -the making of the lenses and mirror. First-class lenses for all -photographic and optical purposes command a very high price on account -of the care and labour that has to be expended on their production; -the value of the glass being trifling by comparison. Few, if any, -trades require greater mechanical skill than that of lensmaking; the -larger the lens the greater the difficulties it presents, first in the -casting, then in the grinding, last of all in the polishing. The -presence of a single air-bubble in the molten glass, the slightest -irregularity of surface in the polishing may utterly destroy the -value of a lens otherwise worth several thousands of pounds. - -[Illustration: _Reproduced by the permission of Proprietors of -"Knowledge."_ - -_General view, of the Great Paris Telescope, showing the eye-end. The -tube is 180 feet long, and 59 inches in diameter. It weighs 21 tons._] - -The object-glass of the great telescope was cast by M. Mantois, famous -as the manufacturer of large lenses. The glass used was boiled and -reboiled many times to get rid of all bubbles. Then it was run into a -mould and allowed to cool very gradually. A whole month elapsed before -the breaking of a mould, when the lens often proved to be cracked on -the surface, owing to the exterior having cooled faster than the -interior and parted company with it. At last, however, a perfect cast -resulted. - -M. Despret undertook the even more formidable task of casting the -mirror at his works at Jeumont, North France. A special furnace and -oven, capable of containing over fifteen tons of molten glass, had to -be constructed. The mirror, 6-1/2 feet in diameter and eleven inches -thick, absorbed 3-3/4 tons of liquid glass; and so great was the -difficulty of cooling it gradually, that out of the twenty casts -eighteen were failures. - -The rough lenses and mirror having been ground to approximate -correctness in the ordinary way, there arose the question of -polishing, which is generally done by one of the most sensitive and -perfect instruments existing-the human hand. In this case, owing to -the enormous size of the objects to be treated, hand work would not -do. The mere hot touch of a workman would raise on the glass a tiny -protuberance, which would be worn level with the rest of the surface -by the polisher, and on the cooling of the part would leave a -depression, only 1-75,000 of an inch deep, perhaps, but sufficient to -produce distortion, and require that the lens should be ground down -again, and the whole surface polished afresh. - -M. Gautier therefore polished by machinery. It proved a very difficult -process altogether, on account of frictional heating, the rise of -temperature in the polishing room, and the presence of dust. To insure -success it was found necessary to warm all the polishing machinery, -and to keep it at a fixed temperature. - -At the end of almost a year the polishing was finished, after the -lenses and mirror had been subjected to the most searching tests, able -to detect irregularities not exceeding 1-250,000 of an inch. M. -Gautier applied to the mirror M. Foucault's test, which is worth -mentioning. A point of light thrown by the mirror is focused through a -telescope. The eyepiece is then moved inwards and outwards so as to -throw the point out of focus. If the point becomes a luminous circle -surrounded by concentric rings, the surface throwing the light point -is perfectly plane or smooth. If, however, a pushing-in shows a -vertical flattening of the point, and a pulling-out a horizontal -flattening, that part is concave; if the reverse happens, convexity is -the cause. - -For the removal of the mirror from Jeumont to Paris a special train -was engaged, and precautions were taken rivalling those by which -travelling Royalty is guarded. The train ran at night without -stopping, and at a constant pace, so that the vibration of the glass -atoms might not vary. On arriving at Paris, the mirror was transferred -to a ponderous waggon, and escorted by a body of men to the Exposition -buildings. The huge object-lens received equally careful treatment. - -The telescope was housed at the Exhibition in a long gallery pointing -due north and south, the siderostat at the north end. At the other, -the eyepiece, end, a large amphitheatre accommodated the public -assembled to watch the projection of stellar or lunar images on to a -screen thirty feet high, while a lecturer explained what was visible -from time to time. The images of the sun and moon as they appeared at -the primary focus in the eyepiece measured from twenty-one to -twenty-two inches in diameter, and the screen projections were -magnified from these about thirty times superficially. - -The eyepiece section consisted of a short tube, of the same breadth as -the main tube, resting on four wheels that travelled along rails. -Special gearing moved this truck-like construction backwards and -forwards to bring a sharp focus into the eyepiece or on to a -photographic plate. Focusing was thus easy enough when once the -desired object came in view; but the observer being unable to control -the siderostat, 250 feet distant, had to telephone directions to an -assistant stationed near the mirror whenever he wished to examine an -object not in the field of vision. - -By the courtesy of the proprietors of the _Strand_ _Magazine_ we are -allowed to quote M. Deloncle's own words describing his emotions on -his first view through the giant telescope:-- - -"As is invariably the case, whenever an innovation that sets at nought -old-established theories is brought forward, the prophecies of failure -were many and loud, and I had more than a suspicion that my success -would cause less satisfaction to others than to myself. Better than -any one else I myself was cognisant of the unpropitious conditions in -which my instrument had to work. The proximity of the river, the dust -raised by hundreds of thousands of trampling feet, the trepidation of -the soil, the working of the machinery, the changes of temperature, -the glare from the thousands of electric lamps in close -proximity--each of these circumstances, and many others of a more -technical nature, which it would be tedious to enumerate, but which -were no less important, would have been more than sufficient to make -any astronomer despair of success even in observatories where all the -surroundings are chosen with the utmost care. - -"In regions pure of calm and serene air large new instruments take -months, more often years, to regulate properly. - -"In spite of everything, however, I still felt confident. Our -calculations had been gone over again and again, and I could see -nothing that in my opinion warranted the worst apprehensions of my -kind critics. - -"It was with ill-restrained impatience that I waited for the first -night when the moon should show herself in a suitable position for -being observed; but the night arrived in due course. - -"Everything was in readiness. The movable portion of the roof of the -building had been slid back, and the mirror of the siderostat stood -bared to the sky. - -"In the dark, square chamber at the other end of the instrument, 200 -feet away, into which the eyepiece of the instrument opened, I had -taken my station with two or three friends. An attendant at the -telephone stood waiting at my elbow to transmit my orders to his -colleague in charge of the levers that regulated the siderostat and -its mirror. - -"The moon had risen now, and her silvery glory shone and sparkled in -the mirror. - -"'A right declension,' I ordered. - -"The telephone bell rang in reply. 'Slowly, still slower; now to the -left--enough; again a right declension--slower; stop now--very, very -slowly.' - -"On the ground-glass before our eyes the moon's image crept up from -one corner until it had overspread the glass completely. And there we -stood in the centre of Paris, examining the surface of our satellite -with all its craters and valleys and bleak desolation. - -"I had won the day." - - - - -PHOTOGRAPHING THE INVISIBLE. - - -Most of us are able to recognise when we see them shadowgraphs taken -by the aid of the now famous X-rays. They generally represent some -part of the structure of men, beasts, birds, or fishes. Very dark -patches show the position of the bones, large and small; lighter -patches the more solid muscles clinging to the bony framework; and -outside these again are shadowy tracts corresponding to the thinnest -and most transparent portions of the fleshy envelope. - -In an age fruitful as this in scientific marvels, it often takes some -considerable time for the public to grasp the full importance of a -fresh discovery. But when, in 1896, it was announced that Professor -Roentgen of Wuerzburg had actually taken photographs of the internal -organs of still living creatures, and penetrated metal and other -opaque substances with a new kind of ray, great interest was -manifested throughout the civilised world. On the one hand the "new -photography" seemed to upset popular ideas of opacity; on the other it -savoured strongly of the black art, and, by its easy excursions -through the human body, seemed likely to revolutionise medical and -surgical methods. At first many strange ideas about the X-rays got -afloat, attributing to them powers which would have surprised even -their modest discoverer. It was also thought that the records were -made in a camera after the ordinary manner of photography, but as a -matter of fact Roentgen used neither lens nor camera, the operation -being similar to that of casting a shadow on a wall by means of a -lamp. In X-radiography a specially constructed electrically-lit glass -tube takes the place of the lamp, and for the wall is substituted a -sensitised plate. The object to be radiographed is merely inserted -between them, its various parts offering varying resistance to the -rays, so that the plate is affected unequally, and after exposure may -be developed and printed from it the usual way. Photographs obtained -by using X-rays are therefore properly called shadowgraphs or -skiagraphs. - -The discovery that has made Professor Roentgen famous is, like many -great discoveries, based upon the labours of other men in the same -field. Geissler, whose vacuum tubes are so well known for their -striking colour effects, had already noticed that electric discharges -sent through very much rarefied air or gases produced beautiful glows. -Sir William Crookes, following the same line of research, and reducing -with a Sprengel air-pump the internal pressure of the tubes to -1/100000 of an atmosphere, found that a luminous glow streamed from -the cathode, or negative pole, in a straight line, heating and -rendering phosphorescent anything that it met. Crookes regarded the -glow as composed of "radiant matter," and explained its existence as -follows. The airy particles inside the tube, being few in number, are -able to move about with far greater freedom than in the tightly packed -atmosphere outside the tube. A particle, on reaching the cathode, is -repelled violently by it in a straight line, to "bombard" another -particle, the walls of the tube, or any object set up in its path, the -sudden arrest of motion being converted into light and heat. - -By means of special tubes he proved that the "radiant matter" could -turn little vanes, and that the flow continued even when the terminals -of the shocking-coil were _outside_ the glass, thus meeting the -contention of Puluj that the radiant matter was nothing more than -small particles of platinum torn from the terminals. He also showed -that, when intercepted, radiant matter cast a shadow, the intercepting -object receiving the energy of the bombardment; but that when the -obstruction was removed the hitherto sheltered part of the glass wall -of the tube glowed with a brighter phosphorescence than the part which -had become "tired" by prolonged bombardment. Experiments further -revealed the fact that the shaft of "Cathode rays" could be deflected -by a magnet from their course, and that they affected an ordinary -photographic plate exposed to them. - -In 1894 Lenard, a Hungarian, and pupil of the famous Hertz, fitted a -Crookes' tube with a "window" of aluminium in its side replacing a -part of the glass, and saw that the course of the rays could be -traced through the outside air. From this it was evident that -something else than matter must be present in the shaft of energy sent -from the negative terminal of the tube, as there was no direct -communication between the interior and the exterior of the tube to -account for the external phosphorescence. Whatever was the nature of -the rays he succeeded in making them penetrate and impress themselves -on a sensitised plate enclosed in a metal box. - -Then in 1896 came Roentgen's great discovery that the rays from a -Crookes' tube, after traversing the _glass_, could pierce opaque -matter. He covered the tube with thick cardboard, but found that it -would still cast the shadows of books, cards, wood, metals, the human -hand, &c., on to a photographic plate even at the distance of some -feet. The rays would also pass through the wood, metal, or bones in -course of time; but certain bodies, notably metals, offered a much -greater resistance than others, such as wood, leather, and paper. -Professor Roentgen crowned his efforts by showing that a skeleton could -be "shadow-graphed" while its owner was still alive. - -Naturally everybody wished to know not only what the rays could do, -but what they were. Roentgen, not being able to identify them with any -known rays, took refuge in the algebraical symbol of the unknown -quantity and dubbed them X-rays. He discovered this much, however, -that they were invisible to the eye under ordinary conditions; that -they travelled in straight lines only, passing through a prism, water, -or other refracting bodies without turning aside from their path; and -that a magnet exerted no power over them. This last fact was -sufficient of itself to prevent their confusion with the radiant -matter "cathode rays" of the tube. Roentgen thought, nevertheless, that -they might be the cathode rays transmuted in some manner by their -passage through the glass, so as to resemble in their motion -sound-waves, _i.e._ moving straight forward and not swaying from side -to side in a series of zig-zags. The existence of such ether waves had -for some time before been suspected by Lord Kelvin. - -Other authorities have other theories. We may mention the view that X -represents the ultra-violet rays of the spectrum, caused by vibrations -of such extreme rapidity as to be imperceptible to the human eye, just -as sounds of extremely high pitch are inaudible to the ear. This -theory is to a certain extent upheld by the behaviour of the -photographic plate, which is least affected by the colours of the -spectrum at the red end and most by those at the violet end. A -photographer is able to use red or orange light in his dark room -because his plates cannot "see" them, though he can; whereas the -reverse would be the case with X-rays. This ultra-violet theory claims -for X-rays a rate of ether vibration of trillions of waves per -second. - -An alternative theory is to relegate the rays to the gap in the scale -of ether-waves between heatwaves and light-waves. But this does not -explain any more satisfactorily than the other the peculiar phenomenon -of non-refraction. - -The apparatus employed in X-photography consists of a Crookes' tube of -a special type, a powerful shocking or induction coil, a fluorescent -screen and photographic plates and appliances for developing, &c., -besides a supply of high-pressure electricity derived from the main, a -small dynamo or batteries. - -A Crookes' tube is four to five inches in diameter, globular in its -middle portion, but tapering away towards each end. Through one -extremity is led a platinum wire, terminating in a saucer-shaped -platinum plate an inch or so across. At the focus of this, the -negative terminal, is fixed a platinum plate at an angle to the path -of the rays so as to deflect them through the side of the tube. The -positive terminal penetrates the glass at one side. The tube contains, -as we have seen, a very tiny residue of air. If this were entirely -exhausted the action of the tube would cease; so that some tubes are -so arranged that when rarefaction becomes too high the passage of an -electrical current through small bars of chemicals, whose ends project -through the sides of the tube, liberates gas from the bars in -sufficient quantity to render the tube active again. - -When the Ruhmkorff induction coil is joined to the electric circuit a -series of violent discharges of great rapidity occur between the tube -terminals, resembling in their power the discharge of a Leyden jar, -though for want of a dense atmosphere the brilliant spark has been -replaced by a glow and brush-light in the tube. The coil is of large -dimensions, capable of passing a spark across an air-gap of ten to -twelve inches. It will perhaps increase the reader's respect for -X-rays to learn that a coil of proper size contains upwards of -thirteen miles of wire; though indeed this quantity is nothing in -comparison with the 150 miles wound on the huge inductorium formerly -exhibited at the London Polytechnic. - -If we were invited to an X-ray demonstration we should find the -operator and his apparatus in a darkened room. He turns on the current -and the darkness is broken by a velvety glow surrounding the negative -terminal, which gradually extends until the whole tube becomes clothed -in a green phosphorescence. A sharply-defined line athwart the tube -separates the shadowed part behind the receiving plate at the negative -focus--now intensely hot--from that on which the reflected rays fall -directly. - -One of us is now invited to extend a hand close to the tube. The -operator then holds on the near side of the hand his fluorescent -screen, which is nothing more than a framework supporting a paper -smeared on one side with platino-cyanide of barium, a chemical that, -in common with several others, was discovered by Salvioni of Perugia -to be sensitive to the rays and able to make them visible to the human -eye. The value of the screen to the X-radiographer is that of the -ground-glass plate to the ordinary photographer, as it allows him to -see exactly what things are before the sensitised plate is brought -into position, and in fact largely obviates the necessity for making a -permanent record. - -The screen shows clearly and in full detail all the bones of the -hand--so clearly that one is almost irresistibly drawn to peep behind -to see if a real hand is there. One of us now extends an arm and the -screen shows us the _ulna_ and the _radius_ working round each other, -now both visible, now one obscuring the other. On presenting the body -to the course of the rays a remarkable shadow is cast on to the -screen. The spinal column and the ribs; the action of the heart and -lungs are seen quite distinctly. A deep breath causes the movement of -a dark mass--the liver. There is no privacy in presence of the rays. -The enlarged heart, the diseased lung, the ulcerated liver betrays -itself at once. In a second of time the phosphorescent screen reveals -what might baulk medical examination for months. - -If a photographic slide containing a dry-plate be substituted for the -focusing-screen, the rays soon penetrate any covering in which the -plate may be wrapped to protect it from ordinary light rays. The -process of taking a shadowgraph may therefore be conducted in broad -daylight, which is under certain conditions a great advantage, though -the sensitiveness of plates exposed to Roentgen rays entails special -care being taken of them when they are not in use. In the early days -of X-radiography an exposure of some minutes was necessary to secure a -negative, but now, thanks to the improvements in the tubes, a few -seconds is often sufficient. - -The discovery of the X-rays is a great discovery, because it has done -much to promote the noblest possible cause, the alleviation of human -suffering. Not everybody will appreciate a more rapid mode of -telegraphy, or a new method of spinning yarn, but the dullest -intellect will give due credit to a scientific process that helps to -save life and limb. Who among us is not liable to break an arm or leg, -or suffer from internal injuries invisible to the eye? Who among us -therefore should not be thankful on reflecting that, in event of such -a mishap, the X-rays will be at hand to show just what the trouble is, -how to deal with it, and how far the healing advances day by day? The -X-ray apparatus is now as necessary for the proper equipment of a -hospital as a camera for that of a photographic studio. - -It is especially welcome in the hospitals which accompany an army into -the field. Since May 1896 many a wounded soldier has had reason to -bless the patient work that led to the discovery at Wuerzburg. The -Greek war, the war in Cuba, the Tirah campaign, the Egyptian campaign, -and the war in South Africa, have given a quick succession of fine -opportunities for putting the new photography to the test. There is -now small excuse for the useless and agonising probings that once -added to the dangers and horrors of the military hospital. Even if the -X-ray equipment, by reason of its weight, cannot conveniently be kept -at the front of a rapidly moving army, it can be set up in the -"advanced" or "base" hospitals, whither the wounded are sent after a -first rough dressing of their injuries. The medical staff there -subject their patients to the searching rays, are able to record the -exact position of a bullet or shell-fragment, and the damage it has -done; and by promptly removing the intruder to greatly lessen its -power to harm. - -The Roentgen ray has added to the surgeon's armoury a powerful weapon. -Its possibilities are not yet fully known, but there can be no doubt -that it marks a new epoch in surgical work. And for this reason -Professor Roentgen deserves to rank with Harvey, the discoverer of the -blood's circulation; with Jenner, the father of vaccination; and with -Sir James Young Simpson, the first doctor to use chloroform as an -anaesthetic. - - -PHOTOGRAPHY IN THE DARK. - -Strange as it seems to take photographs with invisible rays, it is -still stranger to be able to affect sensitised plates without -apparently the presence of any kind of rays. - -Professor W. J. Russell, Vice-President of the Royal Society of -London, has discovered that many substances have the power of -impressing their outlines automatically on a sensitive film, if the -substance be placed in a dark cupboard in contact with, or very close -to a dry-plate. - -After some hours, or it may be days, development of the plate will -reveal a distinct impression of the body in question. Dr. Russell -experimented with wood, metal, leaves, drawings, printed matter, lace. -Zinc proved to be an unusually active agent. A plate of the metal, -highly polished and then ruled with patterns, had at the end of a few -days imparted a record of every scratch and mark to the plate. And not -only will zinc impress itself, but it affects substances which are not -themselves active, throwing shadowgraphs on to the plate. This was -demonstrated with samples of lace, laid between a plate and a small -sheet of bright zinc; also with a skeleton leaf. It is curious that -while the interposition of thin films of celluloid, gutta-percha, -vegetable parchment, and gold-beater's skin--all inactive--between the -zinc and the plate has no obstructive effect, a plate of thin glass -counteracts the action of the zinc. Besides zinc, nickel, aluminium, -pewter, lead, and tin among the metals influence a sensitised plate. -Another totally different substance, printer's ink, has a similar -power; or at least some printer's ink, for Professor Russell found -that different samples varied greatly in their effects. What is -especially curious, the printed matter on _both sides_ of a piece of -newspaper appeared on the plate, and that the effect proceeded from -the ink and not from any rays passing from beyond it is proved by the -fact that the type came out _dark_ in the development, whereas if it -had been a case of shadowgraphy, the ink by intercepting rays would -have produced _white_ letters. Professor Russell has also shown that -modern writing ink is incapable of producing an impression unaided, -but that on the other hand paper written on a hundred years ago or a -printed book centuries old will, with the help of zinc, yield a -picture in which even faded and uncertain characters appear quite -distinctly. This opens the way to a practical use of the discovery, in -the deciphering of old and partly obliterated manuscripts. - -A very interesting experiment may be made with that useful -possession--a five-pound note. Place the note printed side next to the -plate, and the printing appears dark; but insert the note between a -zinc sheet and the plate, its back being this time towards the -sensitised surface, and the printing appears _white_; and the zinc, -after contact with the printed side, will itself yield a picture of -the inscription as though it had absorbed some virtue from the note! - -As explanation of this paradoxical dark photography--or whatever it -is--two theories may be advanced. The one--favoured by Professor -Russell--is that all "active" substances give off _vapours_ able to -act on a photographic plate. In support of this may be urged the fact -that the interposition of glass prevents the making of dark pictures. -But on the other hand it must be remembered that celluloid and -sheet-gelatine, also air-tight substances, are able to store up light -and to give it out again. It is well known among photographers that to -allow sunlight to fall on the inside of a camera is apt to have a -"fogging" effect on a plate that is exposed in the camera afterwards, -though the greatest care be taken to keep all external light from the -plate. But here the glass again presents a difficulty, for if this -were a case of reflected light, glass would evidently be _less_ -obstructive than opaque vegetable parchment or gutta-percha. - - - - -SOLAR MOTORS. - - -One day George Stephenson and a friend stood watching a train drawn by -one of his locomotives. - -"What moves that train?" asked Stephenson. - -"The engine," replied his friend. - -"And what moves the engine?" - -"The steam." - -"And what produces the steam?" - -"Coal." - -"And what produces coal?" - -This last query nonplussed his friend, and Stephenson himself replied, -"The sun." - -The "bottled sunshine" that drove the locomotive was stored up -millions of years ago in the dense forests then covering the face of -the globe. Every day vegetation was built by the sunbeams, and in the -course of ages this growth was crushed into fossil form by the -pressure of high-piled rock and debris. To-day we cast "black -diamonds" into our grates and furnaces, to call out the warmth and -power that is a legacy from a period long prior to the advent of -fire-loving man, often forgetful of its real source. - -We see the influence of the sun more directly in the motions of wind -and water. Had not the sun's action deposited snow and rain on the -uplands of the world, there would be no roaring waterfall, no rushing -torrent, no smooth-flowing stream. But for the sun heating the -atmosphere unequally, there would not be that rushing of cool air to -replace hot which we know as wind. - -We press Sol into our service when we burn fuel; our wind-mills and -water-mills make him our slave. Of late years many prophets have -arisen to warn us that we must not be too lavish of our coal; that the -time is not so far distant, reckoning by centuries, when the -coal-seams of the world will be worked out and leave our descendants -destitute of what plays so important a part in modern life. Now, -though waste is unpardonable, and the care for posterity praiseworthy, -there really seems to be no good reason why we should alarm ourselves -about the welfare of the people of the far future. Even if coal fails, -the winds and the rivers will be there, and the huge unharnessed -energy of the tides, and the sun himself is ready to answer appeals -for help, if rightly shaped. He does not demand the prayers of Persian -fire-worshippers, but rather the scientific gathering of his good -gifts. - -Place your hand on a roof lying square to the summer sun, and you will -find it too hot for the touch. Concentrate a beam of sunshine through -a small burning-glass. How fierce is the small glowing focal spot that -makes us draw our hands suddenly away! Suppose now a large glass many -feet across bending several square yards of sun rays to a point, and -at that point a boiler. The boiler would develop steam, and the steam -might be led into cylinders and forced to drudge for us. - -Do many of us realise the enormous energy of a hot summer's day? The -heat falling in the tropics on a single square foot of the earth's -surface has been estimated as the equivalent of one-third of a -horse-power. The force of Niagara itself would on this basis be -matched by the sunshine streaming on to a square mile or so. A -steamship might be propelled by the heat that scorches its decks. - -For many centuries inventors have tried to utilise this huge waste -power. We all know how, according to the story, Archimedes burnt up -the Roman ships besieging his native town, Syracuse, by concentrating -on them the sun heat cast from hundreds of mirrors. This story is less -probable than interesting as a proof that the ancients were aware of -the sun's power. The first genuine solar machine was the work of -Ericsson, the builder of the _Monitor_. He focused sun heat on a -boiler, which gave the equivalent of one horse-power for every hundred -square feet of mirrors employed. This was not what engineers would -call a "high efficiency," a great deal of heat being wasted, but it -led the way to further improvements. - -In America, especially in the dry, arid regions, where fuel is scarce -and the sun shines pitilessly day after day, all the year round, -sun-catchers of various types have been erected and worked -successfully. Dr. William Calver, of Washington, has built in the -barren wastes of Arizona huge frames of mirrors, travelling on -circular rails, so that they may be brought to face the sun at all -hours between sunrise and sunset. Dr. Calver employs no less than 1600 -mirrors. As each of these mirrors develops 10-15 degrees of heat it is -obvious, after an appeal to simple arithmetic, that the united efforts -of these reflectors should produce the tremendous temperature -16,000-24,000 degrees, which, expressed comparatively, means the -paltry 90 degrees in the shade beneath which we grow restive -multiplied hundreds of times. Hitherto the greatest known heat had -been that of the arc of the electric lamp, in which the incandescent -particles between pole and pole attain 6000 degrees Fahrenheit. - -The combined effect of the burning mirrors is irresistible. They can, -we are told, in a few moments reduce Russian iron to the consistency -of warmed wax, though it mocks the heat of many blast-furnaces. They -will bake bricks twenty times as rapidly as any kiln, and the bricks -produced are not the friable blocks which a mason chips easily with -his trowel, but bodies so hard as to scratch case-hardened steel. - -There are at work in California sun-motors of another design. The -reader must imagine a huge conical lamp-shade turned over on to its -smaller end, its inner surface lined with nearly 1800 mirrors 2 feet -long and 3 inches broad, the whole supported on a light iron -framework, and he will have a good idea of the apparatus used on the -Pasadena ostrich farm. The machine is arranged _in meridian_, that is, -at right angles to the path of the sun, which it follows all day long -by the agency of clockwork. In the focus of the mirrors is a boiler, -13 feet 6 inches long, coated with black, heat-absorbing substances. -This boiler holds over 100 gallons of water, and being fed -automatically will raise steam untended all the day through. The steam -is led by pipes to an engine working a pump, capable of delivering -1400 gallons per minute. - -The cheapness of the apparatus in proportion to its utility is so -marked that, in regions where sunshine is almost perpetual, the solar -motor will in time become as common as are windmills and factory -chimneys elsewhere. If the heat falling on a few square yards of -mirror lifts nearly 100,000 gallons of water an hour, there is indeed -hope for the Sahara, the Persian Desert, Arabia, Mongolia, Mexico, -Australia. That is to say, if the water under the earth be in these -parts as plentiful as the sunshine above it. The effect of water on -the most unpromising soil is marvellous. Already in Algeria the French -have reclaimed thousands of square miles by scientific irrigation. In -Australia huge artesian wells have made habitable for man and beast -millions of acres that were before desert. - -It is only a just retribution that the sun should be harnessed and -compelled to draw water for tracts to which he has so long denied it. -The sun-motor is only just entering on its useful career, and at -present we can but dream of the great effects it may have on future -civilisation. Yet its principle is so simple, so scientific, and so -obvious, that it is easy to imagine it at no far distant date a -dangerous rival to King Coal himself. To quarry coal from the bowels -of the earth and transform it into heat, is to traverse two sides of a -triangle, the third being to use the sunshine of the passing hour. - - - - -LIQUID AIR. - - -Among common phenomena few are more interesting than the changes -undergone by the substance called water. Its usual form is a liquid. -Under the influence of frost it becomes hard as iron, brittle as -glass. At the touch of fire it passes into unsubstantial vapour. - -This transformation illustrates the great principle that the form of -every substance in the universe is a question of heat. A metal -transported from the earth to the sun would first melt and then -vaporise; while what we here know only as vapours would in the moon -turn into liquids. - -We notice that, as regards bulk, the most striking change is from -liquid to gaseous form. In steam the atoms and molecules of water are -endowed with enormous repulsive vigour. Each atom suddenly shows a -huge distaste for the company of its neighbours, drives them off, and -endeavours to occupy the largest possible amount of private space. - -Now, though we are accustomed to see water-atoms thus stirred into an -activity which gives us the giant steam as servant, it has probably -fallen to the lot of but few of us to encounter certain gaseous -substances so utterly deprived of their self-assertiveness as to -collapse into a liquid mass, in which shape they are quite strangers -to us. What gaseous body do we know better than the air we breathe? -and what should we less expect to be reducible to the consistency of -water? Yet science has lately brought prominently into notice that -strange child of pressure and cold, Liquid Air; of which great things -are prophesied, and about which many strange facts may be told. - -Very likely our readers have sometimes noticed a porter uncoupling the -air-tube between two railway carriages. He first turns off the tap at -each end of the tube, and then by a twist disconnects a joint in the -centre. At the moment of disconnection what appears to be a small -cloud of steam issues from the joint. This is, however, the result of -cold, not heat, the tube being full of highly-compressed air, which by -its sudden expansion develops cold sufficient to freeze any particles -of moisture in the surrounding air. - -Keep this in mind, and also what happens when you inflate your -cycle-tyre. The air-pump grows hotter and hotter as inflation -proceeds: until at last, if of metal, it becomes uncomfortably warm. -The heat is caused by the forcing together of air-molecules, and -inasmuch as all force produces heat, your strength is transformed into -warmth. - -In these two operations, compression and expansion, we have the key to -the creation of liquid air--the great power, as some say, of -to-morrow. - -[Illustration: _By kind permission of The Liquid Air Co._ - -_A view of the Liquid Air Co.'s factory at Pimlico. On the left are -the three compressors, squeezing the air at pressures of 90, 500 and -2,200 lbs. to the square inch respectively. On the right is the -reservoir in which the liquid is stored._] - -Suppose we take a volume of air and squeeze it into 1/100 of its -original space. The combativeness of the air-atoms is immensely -increased. They pound each other frantically, and become very hot in -the process. Now, by cooling the vessel in which they are, we rob them -of their energy. They become quiet, but they are much closer than -before. Then imagine that all of a sudden we let them loose again. The -life is gone out of them, their heat has departed, and on separating -they shiver grievously. In other words, the heat contained by the -1/100 volume is suddenly compelled to "spread itself thin" over the -whole volume: result--intense cold. And if this air be brought to bear -upon a second vessel filled likewise with compressed air, the cold -will be even more intense, until at last the air-atoms lose all their -strength and collapse into a liquid. - -Liquid air is no new thing. Who first made it is uncertain. The credit -has been claimed for several people, among them Olzewski, a Pole, and -Pictet, a Swiss. As a mere laboratory experiment the manufacture of -liquid air in small quantities has been known for twenty years or -more. The earlier process was one of terrific compression alone, -actually forcing the air molecules by sheer strength into such close -contact that their antagonism to one another was temporarily overcome. -So expensive was the process that the first ounce of liquid air is -estimated to have cost over L600! - -In order to make liquid air an article of commerce the most important -condition was a wholesale decrease in cost of production. In 1857 C. -W. Siemens took out a patent for making the liquid on what is known as -the regenerative principle, whereby the compressed air is chilled by -expanding a part of it. Professor Dewar--a scientist well known for -his researches in the field of liquid gases--had in 1892 produced -liquid air by a modification of the principle at comparatively small -cost; and other inventors have since then still further reduced the -expense, until at the present day there appears to be a prospect of -liquid air becoming cheap enough to prove a dangerous rival to steam -and electricity. - -A company, known as the Liquid Air, Power and Automobile Company, has -established large plants in America and England for the manufacture of -the liquid on a commercial scale. The writer paid a visit to their -depot in Gillingham Street, London, where he was shown the process by -Mr. Hans Knudsen, the inventor of much of the machinery there used. -The reader will doubtless like to learn the "plain, unvarnished truth" -about the creation of this peculiar liquid, and to hear of the freaks -in which it indulges--if indeed those may be called freaks which are -but obedience to the unchanging laws of Nature. - -On entering the factory the first thing that strikes the eye and ear -is the monstrous fifty horse-power gas-engine, pounding away with an -energy that shakes the whole building. From its ponderous flywheels -great leather belts pass to the compressors, three in number, by which -the air, drawn from outside the building through special purifiers, is -subjected to an increasing pressure. Three dials on the wall show -exactly what is going on inside the compressors. The first stands at -90 lbs. to the square inch, the second at 500, and the third at 2200, -or rather less than a ton pressure on the area of a penny! The pistons -of the low-pressure compressor is ten inches in diameter, but that of -the high pressure only two inches, or 1/25 of the area, so great is -the resistance to be overcome in the last stage of compression. - -Now, if the cycle-pump heats our hands, it will be easily understood -that the temperature of the compressors is very high. They are -water-jacketed like the cylinders of a gas-engine, so that a -circulating stream of cold water may absorb some of the heat. The -compressed air is passed through spiral tubes winding through large -tanks of water which fairly boils from the fierceness of the heat of -compression. - -When the air has been sufficiently cooled it is allowed to pass into a -small chamber, expanding as it goes, and from the small into a larger -chamber, where the cold of expansion becomes so acute that the -air-molecules collapse into liquid, which collects in a special -receptacle. Arrangements are made whereby any vapour rising from the -liquid passes through a space outside the expansion chambers, so that -it helps to cool the incoming air and is not wasted. - -The liquid-air tank is inside a great wooden case, carefully protected -from the heat of the atmosphere by non-conducting substances. A tap -being turned, a rush of vapour shoots out, soon followed by a clear, -bluish liquid, which is the air we breathe in a fresh guise. - -A quantity of it is collected in a saucepan. It simmers at first, and -presently boils like water on a fire. The air-heat is _by comparison_ -so great that the liquid cannot resist it, and strives to regain its -former condition. - -You may dip your finger into the saucepan--if you withdraw it again -quickly--without hurt. The cushion of air that your finger takes in -with it protects you against harm--for a moment. But if you held it in -the liquid for a couple of seconds you would be minus a digit. Pour a -little over your coat sleeve. It flows harmlessly to the ground, where -it suddenly expands into a cloud of chilly vapour. - -Put some in a test tube and cork it up. The cork soon flies out with a -report--the pressure of the boiling air drives it. Now watch the -boiling process. The nitrogen being more volatile--as it boils at a -lower temperature than oxygen--passes off first, leaving the pure, -blue oxygen. The temperature of this liquid is over 312 degrees below -zero (as far below the temperature of the air we breathe as the -temperature of molten lead is above it!). A tumbler of liquid oxygen -dipped into water is soon covered with a coating of ice, which can be -detached from the tumbler and itself used as a cup to hold the liquid. -If a bit of steel wire be now twisted round a lighted match and the -whole dipped into the cup, the steel flares fiercely and fuses into -small pellets; which means that an operation requiring 3000 degrees -Fahrenheit has been accomplished in a liquid 300 degrees below zero! - -Liquid air has curious effects upon certain substances. It makes iron -so brittle that a ladle immersed for a few moments may be crushed in -the hands; but, curiously enough, it has a toughening effect on copper -and brass. Meat, eggs, fruit, and all bodies containing water become -hard as steel and as breakable as glass. Mercury is by it congealed to -the consistency of iron; even alcohol, that can brave the utmost -Arctic cold, succumbs to it. The writer was present when some -thermometers, manufactured by Messrs. Negretti and Zambra, were tested -with liquid air. The spirit in the tubes rapidly descended to 250 -degrees below zero, then sank slowly, and at about 260 degrees froze -and burst the bulb. The measuring of such extreme temperatures is a -very difficult matter in consequence of the inability of spirit to -withstand them, and special apparatus, registering cold by the -shrinkage of metal, must be used for testing some liquid gases, -notably liquid hydrogen, which is so much colder than liquid air that -it actually freezes it into a solid ice form! - -For handling and transporting liquid gases glass receptacles with a -double skin from which all air has been exhausted are employed. The -surrounding vacuum is so perfect an insulator that a "Dewar bulb" full -of liquid air scarcely cools the hand, though the intervening space is -less than an inch. This fact is hard to square with the assertion of -scientific men that our atmosphere extends but a hundred or two miles -from the earth's surface, and that the recesses of space are a vacuum. -If it were so, how would heat reach us from the sun, ninety-two -millions of miles away? - -One use at least for liquid air is sufficiently obvious. As a -refrigerating agent it is unequalled. Bulk for bulk its effect is of -course far greater than that of ice; and it has this advantage over -other freezing compounds, that whereas slow freezing has a destructive -effect upon the tissues of meat and fruit, the instantaneous action of -liquid air has no bad results when the thing frozen is thawed out -again. The Liquid Air Company therefore proposes erecting depots at -large ports for supplying ships, to preserve the food, cool the cabins -in the tropics, and, we hope, to alleviate some of the horrors of the -stokehold. - -Liquid air is already used in medical and surgical science. In surgery -it is substituted for anaesthetics, deadening any part of the body on -which an operation has to be performed. In fever hospitals, too, its -cooling influence will be welcomed; and liquid oxygen takes the places -of compressed oxygen for reviving the flickering flame of life. It -will also prove invaluable for divers and submarine boats. - -In combination with oil and charcoal liquid air, under the name of -"oxyliquit," becomes a powerful blasting agent. Cartridges of paper -filled with the oil and charcoal are provided with a firing primer. -When everything is ready for the blasting the cartridges are dropped -into a vessel full of liquid air, saturated, placed in position, and -exploded. Mr. Knudsen assured the writer that oxyliquit is twice as -powerful as nitro-glycerine, and its cost but one-third of that of the -other explosive. It is also safer to handle, for in case of a misfire -the cartridge becomes harmless in a few minutes, after the liquid air -has evaporated. - -But the greatest use will be found for liquid air when it exerts its -force less violently. It is the result of power; its condition is -abnormal; and its return to its ordinary state is accompanied by a -great development of energy. If it be placed in a closed vessel it is -capable of exerting a pressure of 12,000 lbs. to the square inch. Its -return to atmospheric condition may be regulated by exposing it more -or less to the heat of the atmosphere. So long as it remains liquid -it represents so much _stored force_, like the electricity stored in -accumulators. The Liquid Air Company have at their Gillingham Street -depot a neat little motor car worked by liquid air. A copper -reservoir, carefully protected, is filled with the liquid, which is by -mechanical means squirted into coils, in which it rapidly expands, and -from them passes to the cylinders. A charge of eighteen gallons will -move the car forty miles at an average pace of twelve miles an hour, -without any of the noise, dirt, smell, or vapour inseparable from the -employment of steam or petroleum. The speed of the car is regulated by -the amount of liquid injected into the expansion coils. - -We now come to the question of cost--the unromantic balance in which -new discoveries are weighed and many found wanting. The storage of -liquid air is feasible for long periods. (A large vacuum bulb filled -and exposed to the atmosphere had some of the liquid still -unevaporated at the end of twenty-two days.) But will it be too costly -for ordinary practical purposes now served by steam and electricity? -The managers of the Liquid Air Company, while deprecating extravagant -prophecies about the future of their commodity, are nevertheless -confident that it has "come to stay." With the small 50 horse-power -plant its production costs upwards of one shilling a gallon, but with -much larger plant of 1000 horse-power they calculate that the expenses -will be covered and a profit left if they retail it at but one penny -the gallon. This great reduction in cost arises from the economising -of "waste energy." In the first place the power of expansion previous -to the liquefaction of the compressed air will be utilised to work -motors. Secondly, the heat of the cooling tanks will be turned to -account, and even the "exhaust" of a motor would be cold enough for -ordinary refrigerating. It is, of course, impossible to get more out -of a thing than has been put into it; and liquid air will therefore -not develop even as much power as was required to form it. But its -handiness and cleanliness strongly recommend it for many purposes, as -we have seen; and as soon as it is turned out in large quantities new -uses will be found for it. Perhaps the day will come when liquid-air -motors will replace the petrol car, and in every village we shall see -hung out the sign, "Liquid air sold here." As the French say, "_Qui -vivra verra_." - - - - -HORSELESS CARRIAGES. - - -A body of enterprising Manchester merchants, in the year 1754, put on -the road a "flying coach," which, according to their special -advertisement, would, "however incredible it may appear, actually, -barring accidents, arrive in London in four and a half days after -leaving Manchester." According to the Lord Chancellor of the time such -swift travelling was considered dangerous as well as wonderful--the -condition of the roads might well make it so--and also injurious to -health. "I was gravely advised," he says, "to stay a day in York on my -journey between Edinburgh and London, as several passengers who had -gone through without stopping had died of apoplexy from the rapidity -of the motion." - -As the coach took a fortnight to pass from the Scotch to the English -capital, at an average pace of between three and four miles an hour, -it is probable that the Chancellor's advisers would be very seriously -indisposed by the mere sight of a motor-car whirling along in its -attendant cloud of dust, could they be resuscitated for the purpose. -And we, on the other hand, should prefer to get out and walk to -"flying" at the safe speed of their mail coaches. - -[Illustration: _By kind permission of The Speedwell Motor Co._ - -_M. Serpollet on the "Easter Egg," which at Nice covered a kilometre -in the record time of 29-4/5 secs. (over 75 miles per hour). This car -is run with steam._] - -The improvement of highroads, and road-making generally, accelerated -the rate of posting. In the first quarter of the nineteenth century an -average of ten or even twelve miles an hour was maintained on the Bath -Road. But that pace was considered inadequate when the era of the -"iron horse" commenced, and the decay of stage-driving followed hard -upon the growth of railways. What should have been the natural -successor of the stage-coach was driven from the road by ill-advised -legislation, which gave the railroads a monopoly of swift transport, -which has but lately been removed. - -The history of the steam-coach, steam-carriage, automobile, -motor-car--to give it its successive names--is in a manner unique, -showing as it does, instead of steady development of a practical means -of locomotion, a sudden and decisive check to an invention worthy of -far better treatment than it received. The compiler of even a short -survey of the automobile's career is obliged to divide his account -into two main portions, linked together by a few solitary engineering -achievements. - -The first period (1800-1836), will, without any desire to arrogate for -England more than her due or to belittle the efforts of any other -nations, be termed the English period, since in it England took the -lead, and produced by far the greatest number of steam-carriages. The -second (1870 to the present day) may, with equal justice, be styled -the Continental period, as witnessing the great developments made in -automobilism by French, German, Belgian, and American engineers: -England, for reasons that will be presently noticed, being until quite -recently too heavily handicapped to take a part in the advance. - -_Historical._--It is impossible to discover who made the first -self-moving carriage. In the sixteenth century one Johann Haustach, a -Nuremberg watchmaker, produced a vehicle that derived its motive power -from coiled springs, and was in fact a large edition of our modern -clockwork toys. About the same time the Dutch, and among them -especially one Simon Stevin, fitted carriages with sails, and there -are records of a steam-carriage as early as the same century. - -But the first practical, and at least semi-successful, automobile -driven by internal force was undoubtedly that of a Frenchman, Nicholas -Joseph Cugnot, who justly merits the title of father of automobilism. -His machine, which is to-day one of the most treasured exhibits in the -Paris Museum of Arts and Crafts, consisted of a large carriage, having -in front a pivoted platform bearing the machinery, and resting on a -solid wheel, which propelled as well as steered the vehicle. The -boiler, of stout riveted copper plates, had below it an enclosed -furnace, from which the flames passed upwards through the water -through a funnel. A couple of cylinders, provided with a simple -reversing gear, worked a ratchet that communicated motion to the -driving-wheel. This carriage did not travel beyond a very slow walking -pace, and Cugnot therefore added certain improvements, after which -(1770) it reached the still very moderate speed of four miles an hour, -and distinguished itself by charging and knocking down a wall, a feat -that is said to have for a time deterred engineers from developing a -seemingly dangerous mode of progression. - -Ten years later Dallery built a steam car, and ran it in the streets -of Amiens--we are not told with what success; and before any further -advance had been made with the automobile the French Revolution put a -stop to all inventions of a peaceful character among our neighbours. - -In England, however, steam had already been recognised as the coming -power. Richard Trevethick, afterwards to become famous as a railroad -engineer, built a steam motor in 1802, and actually drove it from -Cambourne to Plymouth, a distance of ninety miles. But instead of -following up this success, he forsook steam-carriages for the -construction of locomotives, leaving his idea to be expanded by other -men, who were convinced that a vehicle which could be driven over -existing roads was preferable to one that was helpless when separated -from smooth metal rails. Between the years 1800 and 1836 many steam -vehicles for road traffic appeared from time to time, some, such as -David Gordon's (propelled by metal legs pressing upon the ground), -strangely unpractical, but the majority showing a steady improvement -in mechanical design. - -As it will be impossible, without writing a small book, to name all -the English constructors of this period, we must rest content with the -mention of the leading pioneers of the new locomotion. - -Sir Goldsworthy Gurney, an eminent chemist, did for mechanical road -propulsion what George Stephenson was doing for railway development. -He boldly spent large sums on experimental vehicles, which took the -form of six-wheeled coaches. The earliest of these were fitted with -legs as well as driving-wheels, since he thought that in difficult -country wheels alone would not have sufficient grip. (A similar -fallacy was responsible for the cogged wheels on the first railways.) -But in the later types legs were abandoned as unnecessary. His coaches -easily climbed the steepest hills round London, including Highgate -Hill, though a thoughtful mathematician had proved by calculations -that a steam-carriage, so far from mounting a gradient, could not, -without violating all natural laws, so much as move itself on the -level! - -Having satisfied himself of their power, Gurney took his coaches -further afield. In 1829 was published the first account of a motor -trip made by him and three companions through Reading, Devizes, and -Melksham. The pace was, we read, at first only about six miles an -hour, including stoppages. They drove very carefully to avoid injury -to the persons or feelings of the country folk; but at Melksham, where -a fair was in progress, they had to face a shower of stones, hurled by -a crowd of roughs at the instigation of some coaching postilions, who -feared losing their livelihood if the new method of locomotion became -general. Two of the tourists were severely hurt, and Gurney was -obliged to take shelter in a brewery, where constables guarded his -coach. On the return journey the party timed their movements so as to -pass through Melksham while the inhabitants were all safely in bed. - -The coach ran most satisfactorily, improving every mile. "Our pace was -so rapid," wrote one of the company, "that the horses of the mail-cart -which accompanied us were hard put to it to keep up with us. At the -foot of Devizes Hill we met a coach and another vehicle, which stopped -to see us mount this hill, an extremely steep one. We ascended it at a -rapid rate. The coach and passengers, delighted at this unexpected -sight, honoured us with shouts of applause." - -In 1830 Messrs. Ogle and Summers completely beat the road record on a -vehicle fitted with a tubular boiler. This car, put through its trials -before a Special Commission of the House of Commons, attained the -astonishing speed of 35 miles an hour on the level, and mounted a hill -near Southampton at 24-1/2 miles an hour. It worked at a boiler -pressure of 250 lbs. to the square inch, and though not hung on -springs, ran 800 miles without a breakdown. This performance appears -all the more extraordinary when we remember the roads of that day were -not generally as good as they are now, and that in the previous year -Stephenson's "Rocket," running on rails, had not reached a higher -velocity. - -The report of the Parliamentary Commission on horseless carriages was -most favourable. It urged that the steam-driven car was swifter and -lighter than the mail-coaches; better able to climb and descend hills; -safer; more economical; and less injurious to the roads; and, in -conclusion, that the heavy charges levied at the toll-gates (often -twenty times those on horse vehicles) were nothing short of -iniquitous. - -As a result of this report, motor services, inaugurated by Walter -Hancock, Braithwayte, and others, commenced between Paddington and the -Bank, London and Greenwich, London and Windsor, London and Stratford. -Already, in 1829, Sir Charles Dance had a steam-coach running between -Cheltenham and Gloucester. In four months it ran 3500 miles and -carried 3000 passengers, traversing the nine miles in three-quarters -of an hour; although narrow-minded landowners placed ridges of stone -eighteen inches deep on the road by way of protest. - -The most ambitious service of all was that between London and -Birmingham, established in 1833 by Dr. Church. The rolling-stock -consisted of a single very much decorated coach. - -The success of the road-steamer seemed now assured, when a cloud -appeared on the horizon. It had already been too successful. The -railway companies were up in arms. They saw plainly that if once the -roads were covered with vehicles able to transport the public at low -fares quickly from door to door on existing thoroughfares, the -construction of expensive railroads would be seriously hindered, if -not altogether stopped. So, taking advantage of two motor accidents, -the companies appealed to Parliament--full of horse-loving squires and -manufacturers, who scented profit in the railways--and though -scientific opinion ran strongly in favour of the steam-coach, a law -was passed in 1836 which rendered the steamers harmless by robbing -them of their speed. The fiat went forth that in future _every road -locomotive should be preceded at a distance of a hundred yards by a -man on foot carrying a red flag to warn passengers of its approach_. -This law marks the end of the first period of automobilism as far as -England is concerned. At one blow it crippled a great industry, -deprived the community of a very valuable means of transport, and -crushed the energies of many clever inventors who would soon, if we -may judge by the rapid advances already made in construction, have -brought the steam-carriage to a high pitch of perfection. In the very -year in which they were suppressed the steam services had proved their -efficiency and safety. Hancock's London service alone traversed 4200 -miles without serious accident, and was so popular that the coaches -were generally crowded. It is therefore hard to believe that these -vehicles did not supply a public want, or that they were regarded by -those who used them as in any way inferior to horse-drawn coaches. -Yet ignorant prejudice drove them off the road for sixty years; and -to-day it surprises many Englishmen to learn that what is generally -considered a novel method of travelling was already fairly well -developed in the time of their grandfathers. - -_Second Period_ (1870 onwards).--To follow the further development of -the automobile we must cross the Channel once again. French invention -had not been idle while Gurney and Hancock were building their -coaches. In 1835 M. Dietz established a service between Versailles and -Paris, and the same year M. D'Asda carried out some successful trials -of his steam "diligence" under the eyes of Royalty. But we find that -for the next thirty-five years the steam-carriage was not much -improved, owing to want of capital among its French admirers. No -Gurney appeared, ready to spend his thousands in experimenting; also, -though the law left road locomotion unrestricted, the railways offered -a determined opposition to a possibly dangerous rival. So that, on the -whole, road transport by steam fared badly till after the terrible -Franco-Prussian war, when inventors again took courage. M. Bollee, of -Mans, built in 1873 a car, "l'Obeissante," which ran from Mans to -Paris; and became the subject of allusions in popular songs and plays, -while its name was held up as an example to the Paris ladies. Three -years later he constructed a steam omnibus to carry fifty persons, and -in 1878 exhibited a car that journeyed at the rate of eighteen miles -an hour from Paris to Vienna, where it aroused great admiration. - -After the year 1880 French engineers divided their attention between -the heavy motor omnibus and light vehicles for pleasure parties. In -1884 MM. Bouton and Trepardoux, working conjointly with the Comte de -Dion, produced a steam-driven tricycle, and in 1887 M. Serpollet -followed suit with another, fitted with the peculiar form of steam -generator that bears his name. Then came in 1890 a very important -innovation, which has made automobilism what it now is. Gottlieb -Daimler, a German engineer, introduced the _petrol gas-motor_. Its -comparative lightness and simplicity at once stamped it as the thing -for which makers were waiting. Petrol-driven vehicles were soon abroad -in considerable numbers and varieties, but they did not attract public -attention to any great extent until, in 1894, M. Pierre Giffard, an -editor of the _Petit Journal_, organised a motor race from Paris to -Rouen. The proprietors of the paper offered handsome prizes to the -successful competitors. There were ten starters, some on steam, others -on petrol cars. The race showed that, so far as stability went, -Daimler's engine was the equal of the steam cylinder. The next year -another race of a more ambitious character was held, the course being -from Paris to Bordeaux and back. Subscriptions for prizes flowed in -freely. Serpollet, de Dion, and Bollee prepared steam cars that should -win back for steam its lost supremacy, while the petrol faction -secretly built motors of a strength to relegate steam once and for all -to a back place. Electricity, too, made a bid unsuccessfully for the -prize in the Jeantaud car, a special train being engaged in advance to -distribute charged accumulators over the route. The steamers broke -down soon after the start, so that the petrol cars "walked over" and -won a most decisive victory. - -The interest roused in the race led the Comte de Dion to found the -Automobile Club of France, which drew together all the enthusiastic -admirers of the new locomotion. Automobilism now became a sport, a -craze. The French, with their fine straight roads, and a not too -deeply ingrained love of horseflesh, gladly welcomed the flying car, -despite its noisy and malodorous properties. - -Orders flowed in so freely that the motor makers could not keep pace -with the demand, or promise delivery within eighteen months. Rich men -were therefore obliged to pay double prices if they could find any one -willing to sell--a state of things that remains unto this day with -certain makes of French cars. Poorer folks contented themselves with -De Dion motor tricycles, which showed up so well in the 1896 -Paris-Marseilles race; or with the neat little three-wheeled cars of -M. Bollee. Motor racing became the topic of the hour. Journals were -started for the sole purpose of recording the doings of motorists; and -few newspapers of any popularity omitted a special column of motor -news. Successive contests on the highroads at increasing speeds -attracted increased interest. The black-goggled, fur-clad _chauffeur_ -who carried off the prizes found himself a hero. - -In short, the hold which automobilism has over our neighbours may be -gauged from the fact that in 1901 it was estimated that nearly a -thousand motor cars assembled to see the sport on the Longchamps -Course (the scene of that ultra-"horsey" event, the Grand Prix), and -the real interest of the meet did not centre round horses of flesh and -blood. - -The French have not a monopoly of devotion to automobilism. The speedy -motor car is too much in accord with the bustling spirit of the age; -its delights too easily appreciated to be confined to one country. -Allowing France the first place, America, Germany, and Belgium are not -far behind in their addiction to the "sport," and even in Britain, -partially freed since 1896 from the red-flag tyranny, thanks to the -efforts of Sir David Salomons, there are most visible signs that the -era of the horse is beginning its end. - - -TYPES OF CAR. - -Automobiles may be classified according to the purpose they serve, -according to their size and weight, or according to their motive -power. We will first review them under the latter head. - -_A. Petrol._--The petrol motor, suitable alike for large cars of 40 -to 60 horse-power and for the small bicycle weighing 70 lbs. or so, at -present undoubtedly occupies the first place in popular estimation on -account of its comparative simplicity, which more than compensates -certain defects that affect persons off the vehicle more than those on -it--smell and noise. - -The chief feature of the internal explosion motor is that at one -operation it converts fuel directly into energy, by exploding it -inside a cylinder. It is herein more economical than steam, which -loses power while passing from the boiler to the driving-gear. - -Petrol cycles and small cars have usually only one cylinder, but large -vehicles carry two, three, and sometimes four cylinders. Four and more -avoid that bugbear of rotary motion, "dead points," during which the -momentum of the machinery alone is doing work; and for that reason the -engines of racing cars are often quadrupled. - -For the sake of simplicity we will describe the working of a single -cylinder, leaving the reader to imagine it acting alone or in concert -with others as he pleases. - -In the first place the fuel, petrol, is a very inflammable -distillation of petroleum: so ready to ignite that it must be most -rigorously guarded from naked lights; so quick to evaporate that the -receptacles containing it, if not quite airtight, will soon render it -"stale" and unprofitable for motor driving. - -The engine, to mention its most important parts, consists of a -single-action cylinder (giving a thrust one way only); a heavy -flywheel revolving in an airtight circular case, and connected to the -piston by a hinged rod which converts the reciprocating movement of -the piston into a rotary movement of the crank-shaft built in with the -wheel; inlet and outlet valves; a carburettor for generating petrol -gas, and a device to ignite the gas-and-air mixture in the cylinder. - -The action of the engine is as follows: as the piston moves outwards -in its first stroke it sucks through the inlet valve a quantity of -mixed air and gas, the proportions of which are regulated by special -taps. The stroke ended, the piston returns, compressing the mixture -and rendering it more combustible. Just as the piston commences its -second outward stroke an electric spark passed through the mixture -mechanically ignites it, and creates an explosion, which drives the -piston violently forwards. The second return forces the burnt gas -through the exhaust-valve, which is lifted by cog-gear once in every -two revolutions of the crank, into the "silencer." The cycle of -operations is then repeated. - -We see that during three-quarters of the "cycle"--the suction, -compression, and expulsion--the work is performed entirely by the -flywheel. It follows that a single-cylinder motor, to work at all, -must rotate the wheel at a high rate. Once stopped, it can be -restarted only by the action of the handle or pedals; a task often so -unpleasant and laborious that the driver of a car, when he comes to -rest for a short time only, disconnects his motor from the -driving-gear and lets it throb away idly beneath him. - -The means of igniting the gas in the cylinders may be either a Bunsen -burner or an electric spark. Tube ignition is generally considered -inferior to electrical because it does not permit "timing" of the -explosion. Large cars are often fitted with both systems, so as to -have one in reserve should the other break down. - -Electrical ignition is most commonly produced by the aid of an -intensity coil, which consists of an inner core of coarse insulated -wire, called the primary coil; and an outer, or secondary coil, of -very fine wire. A current passes at intervals, timed by a cam on the -exhaust-valve gear working a make-and-break contact blade, from an -accumulator through the primary coil, exciting by induction a current -of much greater intensity in the secondary. The secondary is connected -to a "sparking plug," which screws into the end of the cylinder, and -carries two platinum points about 1/32 of an inch apart. The secondary -current leaps this little gap in the circuit, and the spark, being -intensely hot, fires the compressed gas. Instead of accumulators a -small dynamo, driven by the motor, is sometimes used to produce the -primary current. - -By moving a small lever, known as the "advancing lever," the driver -can control the time of explosion relatively to the compression of the -gas, and raise or lower the speed of the motor. - -The strokes of the petrol-driven cylinder are very rapid, varying from -1000 to 3000 a minute. The heat of very frequent explosions would soon -make the cylinder too hot to work were not measures adopted to keep it -cool. Small cylinders, such as are carried on motor cycles, are -sufficiently cooled by a number of radiating ribs cast in a piece with -the cylinder itself; but for large machines a water jacket or tank -surrounding the cylinder is a necessity. Water is circulated through -the jacket by means of a small centrifugal pump working off the -driving gear, and through a coil of pipes fixed in the front of the -car to catch the draught of progression. So long as the jacket and -tubes are full of water the temperature of the cylinder cannot rise -above boiling point. - -Motion is transmitted from the motor to the driving-wheels by -intermediate gear, which in cycles may be only a leather band or -couple of cogs, but in cars is more or less complicated. Under the -body of the car, running usually across it, is the countershaft, -fitted at each end with a small cog which drives a chain passing also -over much larger cogs fixed to the driving-wheels. The countershaft -engages with the cylinder mechanism by a "friction-clutch," a couple -of circular faces which can be pressed against one another by a lever. -To start his car the driver allows the motor to obtain a considerable -momentum, and then, using the friction lever, brings more and more -stress on to the countershaft until the friction-clutch overcomes the -inertia of the car and produces movement. - -Gearing suitable for level stretches would not be sufficiently -powerful for hills: the motor would slow and probably stop from want -of momentum. A car is therefore fitted with changing gears, which give -two or three speeds, the lower for ascents, the higher for the level: -and on declines the friction-clutch can be released, allowing the car -to "coast." - -_B. Steam Cars._--Though the petrol car has come to the front of late -years it still has a powerful rival in the steam car. Inventors have -made strenuous efforts to provide steam-engines light enough to be -suitable for small pleasure cars. At present the Locomobile (American) -and Serpollet (French) systems are increasing their popularity. The -Locomobile, the cost of which (about L120) contrasts favourably with -that of even the cheaper petrol cars, has a small multitubular boiler -wound on the outside with two or three layers of piano wire, to render -it safe at high pressures. As the boiler is placed under the seat it -is only fit and proper that it should have a large margin of safety. -The fuel, petrol, is passed through a specially designed burner, -pierced with hundreds of fine holes arranged in circles round air -inlets. The feed-supply to the burner is governed by a spring valve, -which cuts off the petrol automatically as soon as the steam in the -boiler reaches a certain pressure. The locomobile runs very evenly and -smoothly, and with very little noise, a welcome change after the very -audible explosion motor. - -The Serpollet system is a peculiar method of generating steam. The -boiler is merely a long coil of tubing, into which a small jet of -water is squirted by a pump at every stroke of the cylinders. The -steam is generated and used in a moment, and the speed of the machine -is regulated by the amount of water thrown by the pumps. By an -ingenious device the fuel supply is controlled in combination with the -water supply, so that there may not be any undue waste in the burner. - -_C. Electricity._--Of electric cars there are many patterns, but at -present they are not commercially so practical as the other two types. -The great drawbacks to electrically-driven cars are the weight of the -accumulators (which often scale nearly as much as all the rest of the -vehicle), and the difficulty of getting them recharged when exhausted. -We might add to these the rapidity with which the accumulators become -worn out, and the consequent expense of renewal. T. A. Edison is -reported at work on an accumulator which will surpass all hitherto -constructed, having a much longer life, and weighing very much less, -power for power. The longest continuous run ever made with -electricity, 187 miles at Chicago, compares badly with the feat of a -petrol car which on November 23, 1900, travelled a thousand miles on -the Crystal Palace track in 48 hours 24 minutes, without a single -stop. Successful attempts have been made by MM. Pieper and Jenatsky to -combine the petrol and electric systems, by an arrangement which -instead of wasting power in the cylinders when less speed is required, -throws into action electric dynamos to store up energy, convertible, -when needed, into motive power by reversing the dynamo into a motor. -But the simple electric car will not be a universal favourite until -either accumulators are so light that a very large store of -electricity can be carried without inconvenient addition of weight, or -until charging stations are erected all over the country at distances -of fifty miles or so apart. - -Whether steam will eventually get the upper hand of the petrol engine -is at present uncertain. The steam car has the advantage over the -gas-engine car in ease of starting, the delicate regulation of power, -facility of reversing, absence of vibration, noise and smell, and -freedom from complicated gears. On the other hand the petrol car has -no boiler to get out of order or burst, no troublesome gauges -requiring constant attention, and there is small difficulty about a -supply of fuel. Petrol sufficient to give motive power for hundreds of -miles can be carried if need be; and as long as there is petrol on -board the car is ready for work at a moment's notice. Judging by the -number of the various types of vehicles actually at work we should -say that while steam is best for heavy traction, the gas-engine is -most often employed on pleasure cars. - -[Illustration: _By kind permission of The Liquid Air Co._ - -_This graceful little motor-car is driven by Liquid Air. It makes -absolutely no smell or noise._] - -_D. Liquid Air_ will also have to be reckoned with as a motive power. -At present it is only on its probation; but the writer has good -authority for stating that before these words appear in print there -will be on the roads a car driven by liquid air, and able to turn off -eighty miles in the hour. - -_Manufacture._--As the English were the pioneers of the steam car, so -are the Germans and French the chief manufacturers of the petrol car. -While the hands of English manufacturers were tied by shortsighted -legislation, continental nations were inventing and controlling -valuable patents, so that even now our manufacturers are greatly -handicapped. Large numbers of petrol cars are imported annually from -France, Germany, and Belgium. Steam cars come chiefly from America and -France. The former country sent us nearly 2000 vehicles in 1901. There -are signs, however, that English engineers mean to make a determined -effort to recover lost ground; and it is satisfactory to learn that in -heavy steam vehicles, such as are turned out by Thorneycroft and Co., -this country holds the lead. We will hope that in a few years we shall -be exporters in turn. - -Having glanced at the history and nature of the various types of car, -it will be interesting to turn to a consideration of their travelling -capacities. As we have seen, a steam omnibus attained, in 1830, a -speed of no less than thirty-five miles an hour on what we should call -bad roads. It is therefore to be expected that on good modern roads -the latest types of car would be able to eclipse the records of -seventy years ago. That such has indeed been the case is evident when -we examine the performances of cars in races organised as tests of -speed. France, with its straight, beautifully-kept, military roads, is -the country _par excellence_ for the _chauffeur_. One has only to -glance at the map to see how the main highways conform to Euclid's -dictum that a straight line is the shortest distance between any two -points, _e.g._ between Rouen and Dieppe, where a park of artillery, -well posted, could rake the road either way for miles. - -The growth of speed in the French races is remarkable. In 1894 the -winning car ran at a mean velocity of thirteen miles an hour; in 1895, -of fifteen. The year 1898 witnessed a great advance to twenty-three -miles, and the next year to thirty miles. But all these speeds paled -before that of the Paris to Bordeaux race of 1901, in which the -winner, M. Fournier, traversed the distance of 327-1/2 miles at a rate -of 53-3/4 miles per hour! The famous Sud express, running between the -same cities, and considered the fastest long-distance express in the -world, was beaten by a full hour. It is interesting to note that in -the same races a motor bicycle, a Werner, weighing 80 lbs. or less, -successfully accomplished the course at an average rate of nearly -thirty miles an hour. The motor-car, after waiting seventy years, had -had its revenge on the railways. - -This was not the only occasion on which an express service showed up -badly against its nimble rival of the roads. In June, 1901, the French -and German authorities forgot old animosities in a common enthusiasm -for the automobile, and organised a race between Paris and Berlin. It -was to be a big affair, in which the cars of all nations should fight -for the speed championship. Every possible precaution was taken to -insure the safety of the competitors and the spectators. Flags of -various colours and placards marked out the course, which lay through -Rheims, Luxembourg, Coblentz, Frankfurt, Eisenach, Leipsic, and -Potsdam to the German capital. About fifty towns and large villages -were "neutralised"--that is to say, the competitors had to consume a -certain time in traversing them. At the entrance to each neutralised -zone a "control" was established. As soon as a competitor arrived, he -must slow down, and a card on which was written the time of his -arrival was handed to a "pilot," who cycled in front of the car to the -other "control" at the farther end of the zone, from which, when the -proper time had elapsed, the car was dismissed. Among other rules -were: that no car should be pushed or pulled during the race by any -one else than the passengers; that at the end of the day only a -certain time should be allowed for cleaning and repairs; and that a -limited number of persons, varying with the size of the car, should -be permitted to handle it during that period. - -A small army of automobile club representatives, besides thousands of -police and soldiers, were distributed along the course to restrain the -crowds of spectators. It was absolutely imperative that for vehicles -propelled at a rate of from 50 to 60 miles an hour a clear path should -be kept. - -At dawn, on July 27th, 109 racing machines assembled at the Fort de -Champigny, outside Paris, in readiness to start for Berlin. Just -before half-past three, the first competitor received the signal; two -minutes later the second; and then at short intervals for three hours -the remaining 107, among whom was one lady, Mme. de Gast. At least -20,000 persons were present, even at that early hour, to give the -racers a hearty farewell, and demonstrate the interest attaching in -France to all things connected with automobilism. - -Great excitement prevailed in Paris during the three days of the race. -Every few minutes telegrams arrived from posts on the route telling -how the competitors fared. The news showed that during the first stage -at least a hard fight for the leading place was in progress. The -French cracks, Fournier, Charron, De Knyff, Farman, and Girardot -pressed hard on Hourgieres, No. 2 at the starting-point. Fournier soon -secured the lead, and those who remembered his remarkable driving in -the Paris-Bordeaux race at once selected him as the winner. -Aix-la-Chapelle, 283 miles from Paris and the end of the first -stage, was reached in 6 hours 28 minutes. Fournier first, De Knyff -second by six minutes. - -[Illustration: _By kind permission of The Liquid Air Co._ - -_Diagram of the Liquid Air Motor-Car, showing A, reservoir of liquid -air; B, pipes in which the liquid is transformed into atmospheric air -under great pressure; C, cylinders for driving the rear wheels by -means of chain-gear._] - -On the 28th the racing became furious. Several accidents occurred. -Edge, driving the only English car, wrecked his machine on a culvert, -the sharp curve of which flung the car into the air and broke its -springs. Another ruined his chances by running over and killing a boy. -But Fournier, Antony, De Knyff, and Girardot managed to avoid mishaps -for that day, and covered the ground at a tremendous pace. At -Duesseldorf Girardot won the lead from Fournier, to lose it again -shortly. Antony, driving at a reckless speed, gained ground all day, -and arrived a close second at Hanover, the halting-place, after a run -averaging, in spite of bad roads and dangerous corners, no less than -54 miles an hour! - -The _chauffeur_ in such a race must indeed be a man of iron nerves. -Through the great black goggles which shelter his face from the -dust-laden hurricane set up by the speed he travels at he must keep a -perpetual, piercingly keen watch. Though travelling at express speed, -there are no signals to help him; he must be his own signalman as well -as driver. He must mark every loose stone on the road, every -inequality, every sudden rise or depression; he must calculate the -curves at the corners and judge whether his mechanician, hanging out -on the inward side, will enable a car to round a turn without -slackening speed. His calculations and decisions must be made in the -fraction of a second, for a moment's hesitation might be disaster. His -driving must be furious and not reckless; the timid _chauffeur_ will -never win, the careless one will probably lose. His head must be cool -although the car leaps beneath him like a wild thing, and the wind -lashes his face. At least one well-tried driver found the mere mental -strain too great to bear, and retired from the contest; and we may be -sure that few of the competitors slept much during the nights of the -race. - -At four o'clock on the 29th Fournier started on the third stage, which -witnessed another bout of fast travelling. It was now a struggle -between him and Antony for first place. The pace rose at times to -eighty miles an hour, a speed at which our fastest expresses seldom -travel. Such a speed means huge risks, for stopping, even with the -powerful brakes fitted to the large cars, would be a matter of a -hundred yards or more. Not far from Hanover Antony met with an -accident--Girardot now held second place; and Fournier finished an -easy first. All along the route crowds had cheered him, and hurled -bouquets into the car, and wished him good speed; but in Berlin the -assembled populace went nearly frantic at his appearance. Fournier was -overwhelmed with flowers, laurel wreaths, and other offerings; dukes, -duchesses, and the great people of the land pressed for presentations; -he was the hero of the hour. - -Thus ended what may be termed a peaceful invasion of Germany by the -French. Among other things it had shown that over an immense stretch -of country, over roads in places bad as only German roads can be, the -automobile was able to maintain an average speed superior to that of -the express trains running between Paris and Berlin; also that, in -spite of the large number of cars employed in the race, the accidents -to the public were a negligible quantity. It should be mentioned that -the actual time occupied by Fournier was 16 hours 5 minutes; that out -of the 109 starters 47 reached Berlin; and that Osmont on a motor -cycle finished only 3 hours and 10 minutes behind the winner. - -In England such racing would be undesirable and impossible, owing to -the crookedness of our roads. It would certainly not be permissible so -long as the 12 miles an hour limit is observed. At the present time an -agitation is on foot against this restriction, which, though -reasonable enough among traffic and in towns, appears unjustifiable in -open country. To help to convince the magisterial mind of the ease -with which a car can be stopped, and therefore of its safety even at -comparatively high speeds, trials were held on January 2, 1902, in -Welbeck Park. The results showed that a car travelling at 13 miles an -hour could be stopped dead in 4 yards; at 18 miles in 7 yards; at 20 -miles in 13 yards; or in less than half the distance required to pull -up a horse-vehicle driven at similar speeds. - -_Uses._--Ninety-five per cent of motors, at least in England, are -attached to pleasure vehicles, cycles, voiturettes, and large cars. On -account of the costliness of cars motorists are far less numerous than -cyclists; but those people whose means enable them to indulge in -automobilism find it extremely fascinating. Caricaturists have -presented to us in plenty the gloomier incidents of motoring--the -broken chain, the burst tyre, the "something gone wrong." It requires -personal experience to understand how lightly these mishaps weigh -against the exhilaration of movement, the rapid change of scene, the -sensation of control over power which can whirl one along tirelessly -at a pace altogether beyond the capacities of horseflesh. If proof -were wanted of the motor car's popularity it will be seen in the -unconventional dress of the _chauffeur_. The breeze set up by his -rapid rush is such as would penetrate ordinary clothing; he dons -cumbrous fur cloaks. The dust is all-pervading at times; he swathes -himself in dust-proof overalls, and mounts large goggles edged with -velvet, while a cap of semi-nautical cut tightly drawn down over neck -and ears serves to protect those portions of his anatomy. The -general effect is peculiarly unpicturesque; but even the most -artistically-minded driver is ready to sacrifice appearances to -comfort and the proper enjoyment of his car. - -In England the great grievance of motorists arises from the speed -limit imposed by law. To restrict a powerful car to twelve miles an -hour is like confining a thoroughbred to the paces of a broken-down -cab horse. Careless driving is unpardonable, but its occasional -existence scarcely justifies the intolerant attitude of the law -towards motorists in general. It must, however, be granted in justice -to the police that the _chauffeur_, from constant transgression of the -law, becomes a bad judge of speed, and often travels at a far greater -velocity than he is willing to admit. - -The convenience of the motor car for many purposes is immense, -especially for cross-country journeys, which may be made from door to -door without the monotony or indirectness of railway travel. It bears -the doctor swiftly on his rounds. It carries the business man from his -country house to his office. It delivers goods for the merchant; -parcels for the post office. - -In the warfare of the future, too, it will play its part, whether to -drag heavy ordnance and stores, or to move commanding officers from -point to point, or perform errands of mercy among the wounded. By the -courtesy of the Locomobile Company we are permitted to append the -testimony of Captain R. S. Walker, R.E., to the usefulness of a car -during the great Boer War. - -"Several months ago I noticed a locomobile car at Cape Town, and being -struck with its simplicity and neatness, bought it and took it up -country with me, with a view to making some tests with it over bad -roads, &c. Its first trip was over a rough course round Pretoria, -especially chosen to find out defects before taking it into regular -use. Naturally, as the machine was not designed for this class of -work, there were several. In about a month these had all been found -out and remedied, and the car was in constant use, taking stores, &c., -round the towns and forts. It also performed some very useful work in -visiting out-stations, where searchlights were either installed or -wanted, and in this way visited nearly all the bigger towns in the -Transvaal. It was possible to go round all the likely positions for a -searchlight in one day at every station, which frequently meant -considerably over fifty miles of most indifferent roads--more than a -single horse could have been expected to do--and the car generally -carried two persons on these occasions. The car was also used as a -tender to a searchlight plant, on a gun-carriage and limber, being -utilised to fetch gasolene, carbons, water, &c., &c., and also to run -the dynamo for charging the accumulators used for sparking, thus -saving running the gasolene motor for this purpose. To do this the -trail of the carriage, on which was the dynamo, was lowered on to the -ground, the back of the car was pulled up, one wheel being supported -on the dynamo pulley and the other clear of the ground, and two bolts -were passed through the balance-gear to join it. On one occasion the -car ran a 30 c.m. searchlight for an hour, driving a dynamo in this -way. In consequence of this a trailer has been made to carry a dynamo -and projector for searchlighting in the field, but so far this has -not been so used. The trailer hooks into an eye, passing just behind -the balance-gear. A Maxim, Colt, or small ammunition cart, &c., could -be attached to this same eye. - -"Undoubtedly the best piece of work done by the car so far was its -trial trip with the trailer, when it blew up the mines at Klein Nek. -These mines were laid some eight months previously, and had never been -looked to in the interval. There had been several bad storms, the -Boers and cattle had been frequently through the Nek, it had been on -fire, and finally it was shelled with lyddite. The mines, eighteen in -number, were found to be intact except two, which presumably had been -fired off by the heat of the veldt fire. All the insulation was burnt -off the wires, and the battery was useless. It had been anticipated -that a dynamo exploder would be inadequate to fire these mines, so a -250 volt two h.p. motor, which happened to be in Pretoria, weighing -about three or four hundredweight, was placed on the trailer; a -quarter of a mile of insulated cable, some testing gear, the kits of -three men and their rations for three days, with a case of gasolene -for the car, were also carried on the car and trailer, and the whole -left Pretoria one morning and trekked to Rietfontein. Two of us were -mounted, the third drove the car. At Rietfontein we halted for the -night, and started next morning with an escort through Commando Nek, -round the north of the Magaliesburg, to near Klein Nek, where the road -had to be left, and the car taken across country through bush veldt. -At the bottom the going was pretty easy; only a few bushes had to be -charged down, and the grass, &c., rather wound itself around the -wheels and chain. As the rise became steeper the stones became very -large, and the car had to be taken along very gingerly to prevent -breaking the wheels. A halt was made about a quarter of a mile from -the top of the Nek, where the mines were. These were reconnoitered, -and the wire, &c., was picked up; that portion which was useless was -placed on top of the charges, and the remainder taken to the car. The -dynamo was slid off the trailer, the car backed against it; one wheel -was raised slightly and placed against the dynamo pulley, which was -held up to it by a man using his rifle as a lever; the other wheel was -on the ground with a stone under it. The balance gear being free, the -dynamo was excited without the other wheel moving, and the load being -on for a very short time (that is, from the time of touching lead on -dynamo terminal to firing of the mine) no harm could come to the car. -When all the leads had been joined to the dynamo the car was started, -and after a short time, when it was judged to have excited, the second -terminal was touched, a bang and clouds of dust resulted, and the -Klein Nek Minefield had ceased to exist. The day was extremely hot, -and the work had not been light, so the tea, made with water drawn -direct from the boiler, which we were able to serve round to the main -body of our escort was much appreciated, and washed down the surplus -rations we dispensed with to accommodate the battery and wire, which -we could not leave behind for the enemy. - -"On the return journey we found this extra load too much for the car, -and had great difficulty getting up to Commando Nek, frequently having -to stop to get up steam, so these materials were left at the first -blockhouse, and the journey home continued in comfort. - -"A second night at Rietfontein gave us a rest after our labour, and -the third afternoon saw us on our way back to Pretoria. As luck would -have it, a sandstorm overtook the car, which had a lively time of it. -The storm began by blowing the sole occupant's hat off, so, the two -mounted men being a long way behind, he shut off steam and chased his -hat. In the meantime the wind increased, and the car sailed off 'on -its own,' and was only just caught in time to save a smash. Luckily -the gale was in the right direction, for the fire was blown out, and -it was impossible to light a match in the open. The car sailed into a -poort on the outskirts of Pretoria, got a tow from a friendly cart -through it, and then steamed home after the fire had been relit. - -"The load carried on this occasion (without the battery, &c.) must -have been at least five hundredweight besides the driver, which, -considering the car is designed to carry two on ordinary roads, and -that these roads were by no means ordinary, was no mean feat. The car, -as ordinarily equipped for trekking, carries the following: Blankets, -waterproof sheets, &c., for two men; four planks for crossing ditches, -bogs, stones, &c.; all necessary tools and spare parts, a day's supply -of gasolene, a couple of telephones, and one mile of wire. In -addition, on the trailer, if used for searchlighting: One 30 c.m. -projector, one automatic lamp for projector, one dynamo (100 volts 20 -amperes), two short lengths of wire, two pairs of carbons, tools, &c. -This trailer would normally be carried with the baggage, and only -picked up by the car when wanted as a light; that is, as a rule, after -arriving in camp, when a good many other things could be left behind." - -Perhaps the most useful work in store for the motor is to help relieve -the congestion of our large towns and to restore to the country some -of its lost prosperity. There is no stronger inducement to make people -live in the country than rapid and safe means of locomotion, whether -public or private. At present the slow and congested suburban train -services on some sides of London consume as much time as would suffice -a motor car to cover twice or three times the distance. We must -welcome any form of travel which will tend to restore the balance -between country and town by enabling the worker to live far from his -work. The gain to the health of the nation arising from more even -distribution of population would be inestimable. - -A world's tour is among the latest projects in automobilism. On April -29, 1902, Dr. Lehwess and nine friends started from Hyde Park Corner -for a nine months' tour on three vehicles, the largest of them a -luxuriously appointed 24 horse-power caravan, built to accommodate -four persons. Their route lies through France, Germany, Russia, -Siberia, China, Japan, and the United States. - - - - -HIGH-SPEED RAILWAYS. - - -A century ago a long journey was considered an exploit, and an exploit -to be carried through as quickly as possible on account of the dangers -of the road and the generally uncomfortable conditions of travel. -To-day, though our express speed is many times greater than that of -the lumbering coaches, our carriages comparatively luxurious, the risk -practically nil, the same wish lurks in the breast of ninety-nine out -of a hundred railway passengers--to spend the shortest time in the -train that the time-table permits of. Time differences that to our -grandfathers would have appeared trifling are now matters of -sufficient importance to make rival railway companies anxious to clip -a few minutes off a 100-mile "run" simply because their passengers -appreciate a few minutes' less confinement to the cars. - -During the last fifty years the highest express speeds have not -materially altered. The Great Western Company in its early days ran -trains from Paddington to Slough, 18 miles, in 15-1/2 minutes, or at -an average pace of 69-1/2 miles an hour. - -On turning to the present regular express services of the world we -find America heading the list with a 50-mile run between Atlantic City -and Camden, covered at the average speed of 68 miles an hour; Britain -second with a 33-mile run between Forfar and Perth at 59 miles; and -France a good third with an hourly average of rather more than 58 -miles between Les Aubrais and S. Pierre des Corps. These runs are -longer than that on the Great Western Railway referred to above (which -now occupies twenty-four minutes), but their average velocity is less. -What is the cause of this decrease of speed? Not want of power in -modern engines; at times our trains attain a rate of 80 miles an hour, -and in America a mile has been turned off in the astonishing time of -thirty-two seconds. We should rather seek it in the need for economy -and in the physical limitations imposed by the present system of -plate-laying and railroad engineering. An average speed of ninety -miles an hour would, as things now stand, be too wasteful of coal and -too injurious to the rolling-stock to yield profit to the proprietors -of a line; and, except in certain districts, would prove perilous for -the passengers. Before our services can be much improved the steam -locomotive must be supplanted by some other application of motive -power, and the metals be laid in a manner which will make special -provision for extreme speed. - -Since rapid transit is as much a matter of commercial importance as of -mere personal convenience it must not be supposed that an average of -50 miles an hour will continue to meet the needs of travellers. -Already practical experiments have been made with two systems that -promise us an ordinary speed of 100 miles an hour and an express speed -considerably higher. - -One of these, the monorail or single-rail system, will be employed on -a railroad projected between Manchester and Liverpool. At present -passengers between these two cities--the first to be connected by a -railroad of any kind--enjoy the choice of three rival services -covering 34-1/2 miles in three-quarters of an hour. An eminent -engineer, Mr. F. B. Behr, now wishes to add a fourth of unprecedented -swiftness. Parliamentary powers have been secured for a line starting -from Deansgate, Manchester, and terminating behind the pro-Cathedral -in Liverpool, on which single cars will run every ten minutes at a -velocity of 110 miles an hour. - -A monorail track presents a rather curious appearance. The ordinary -parallel metals are replaced by a single rail carried on the summit of -A-shaped trestles, the legs of which are firmly bolted to sleepers. A -monorail car is divided lengthwise by a gap that allows it to hang -half on either side of the trestles and clear them as it moves. The -double flanged wheels to carry and drive the car are placed at the -apex of the gap. As the "centre of gravity" is below the rail the car -cannot turn over, even when travelling round a sharp curve. - -The first railway built on this system was constructed by M. Charles -Lartigue, a French engineer, in Algeria, a district where an ordinary -two-rail track is often blocked by severe sand-storms. He derived the -idea of balancing trucks over an elevated rail from caravans of camels -laden on each flank with large bags. The camel, or rather its legs, -was transformed by the engineer's eye into iron trestles, while its -burden became a car. A line built as a result of this observation, and -supplied with mules as tractive power, has for many years played an -important part in the esparto-grass trade of Algeria. - -In 1886 Mr. Behr decided that by applying steam to M. Lartigue's -system he could make it successful as a means of transporting -passengers and goods. He accordingly set up in Tothill Fields, -Westminster, on the site of the new Roman Catholic Cathedral, a -miniature railway which during nine months of use showed that the -monorail would be practical for heavy traffic, safe, and more cheaply -maintained than the ordinary double-metal railway. The train travelled -easily round very sharp curves and climbed unusually steep gradients -without slipping. - -Mr. Behr was encouraged to construct a monorail in Kerry, between -Listowel, a country town famous for its butter, and Ballybunion, a -seaside resort of increasing popularity. The line, opened on the 28th -of February 1888, has worked most satisfactorily ever since, without -injury to a single employe or passenger. - -On each side of the trestles, two feet below the apex, run two -guide-rails, against which press small wheels attached to the -carriages to prevent undue oscillation and "tipping" round curves. At -the three stations there are, instead of points, turn-tables or -switches on to which the train runs for transference to sidings. - -Road traffic crosses the rail on drawbridges, which are very easily -worked, and which automatically set signals against the train. The -bridges are in two portions and act on the principle of the Tower -Bridge, each half falling from a perpendicular position towards the -centre, where the ends rest on the rail, specially strengthened at -that spot to carry the extra weight. The locomotive is a twin affair; -has two boilers, two funnels, two fireboxes; can draw 240 tons on the -level at fifteen miles an hour, and when running light travels a mile -in two minutes. The carriages, 18 feet long and carrying twelve -passengers on each side, are divided longitudinally into two parts. -Trucks too are used, mainly for the transport of sand--of which each -carries three tons--from Ballybunion to Listowel: and in the centre of -each train is a queer-looking vehicle serving as a bridge for any one -who may wish to cross from one side of the rail to the other. - -Several lines on the pattern of the Ballybunion-Listowel have been -erected in different countries. Mr. Behr was not satisfied with his -first success, however, and determined to develop the monorail in the -direction of fast travelling, which he thought would be most easily -attained on a trestle-track. In 1893 he startled engineers by -proposing a Lightning-Express service, to transport passengers at a -velocity of 120 miles an hour. But the project seemed too ideal to -tempt money from the pockets of financiers, and Mr. Behr soon saw that -if a high-speed railway after his own heart were constructed it must -be at his own expense. He had sufficient faith in his scheme to spend -L40,000 on an experimental track at the Brussels Exhibition of 1897. -The exhibition was in two parts, connected by an electric railway, the -one at the capital, the other at Tervueren, seven miles away. Mr. Behr -built his line at Tervueren. - -The greatest difficulty he encountered in its construction arose from -the opposition of landowners, mostly small peasant proprietors, who -were anxious to make advantageous terms before they would hear of the -rail passing through their lands. Until he had concluded two hundred -separate contracts, by most of which the peasants benefited, his -platelayers could not get to work. Apart from this opposition the -conditions were not favourable. He was obliged to bridge no less than -ten roads; and the contour of the country necessitated steep -gradients, sharp curves, long cuttings and embankments, the last of -which, owing to a wet summer, could not be trusted to stand quite -firm. The track was doubled for three miles, passing at each end round -a curve of 1600 feet radius. - -The rail ran about four feet above the track on trestles bolted down -to steel sleepers resting on ordinary ballast. The carriage--Mr. Behr -used but one on this line--weighed 68 tons, was 59 feet long and 11 -feet wide, and could accommodate one hundred persons. It was -handsomely fitted up, and had specially-shaped seats which neutralised -the effect of rounding curves, and ended fore and aft in a point, to -overcome the wind-resistance in front and the air-suction behind. -Sixteen pairs of wheels on the under side of the carriage engaged with -the two pairs of guide rails flanking the trestles, and eight large -double-flanged wheels, 4-1/2 feet in diameter, carried the weight of -the vehicle. The inner four of these wheels were driven by as many -powerful electric motors contained, along with the guiding mechanism, -in the lower part of the car. The motors picked up current from the -centre rail and from another steel rail laid along the sleepers on -porcelain insulators. - -The top speed attained was about ninety miles an hour. On the close of -the Exhibition special experiments were made at the request of the -Belgian, French, and Russian Governments, with results that proved -that the Behr system deserved a trial on a much larger scale. - -The engineer accordingly approached the British Government with a Bill -for the construction of a high-speed line between Liverpool and -Manchester. A Committee of the House of Commons rejected the Bill on -representations of the Salford Corporation. The Committee had to -admit, nevertheless, that the evidence called was mainly in favour of -the system; and, the plans of the rail having been altered to meet -certain objections, Parliamentary consent was obtained to commence -operations when the necessary capital had been subscribed. In a few -years the great seaport and the great cotton town will probably be -within a few minutes' run of each other. - -A question that naturally arises in the mind of the reader is this: -could the cars, when travelling at 110 miles an hour, be arrested -quickly enough to avoid an accident if anything got on the line? - -The Westinghouse air-brake has a retarding force of three miles a -second. It would therefore arrest a train travelling at 110 miles per -hour in 37 seconds, or 995 yards. Mr. Behr proposes to reinforce the -Westinghouse with an electric brake, composed of magnets 18 inches -long, exerting on the guide rails by means of current generated by the -reversed motors an attractive force of 200 lbs. per square inch. One -great advantage of this brake is that its efficiency is greatest when -the speed of the train is highest and when it is most needed. The -united brakes are expected to stop the car in half the distance of the -Westinghouse alone; but they would not both be applied except in -emergencies. Under ordinary conditions the slowing of a car would take -place only at the termini, where the line ascends gradients into the -stations. There would, however, be small chance of collisions, the -railway being securely fenced off throughout its entire length, and -free from level crossings, drawbridges and points. Furthermore, each -train would be its own signalman. Suppose the total 34-1/2 miles -divided into "block" lengths of 7 miles. On leaving a terminus the -train sets a danger signal behind it; at 7 miles it sets another, and -at 14 miles releases the first signal. So that the driver of a car -would have at least 7 miles to slow down in after seeing the signals -against him. In case of fog he would consult a miniature signal in his -cabin working electrically in unison with the large semaphores. - -The Manchester-Liverpool rail will be reserved for express traffic -only. Mr. Behr does not believe in mixing speeds, and considers it one -of the advantages of his system that slow cars and waggons of the -ordinary two-rail type cannot be run on the monorail; because if they -could managers might be tempted to place them there. - -A train will consist of a single vehicle for forty, fifty, or seventy -passengers, as the occasion requires. It is calculated that an average -of twelve passengers at one penny per mile would pay all the expenses -of running a car. - -Mr. Behr maintains that monorails can be constructed far more cheaply -than the two-rail, because they permit sharper curves, and thereby -save a lot of cutting and embankment; and also because the monorail -itself, when trestles and rail are specially strengthened, can serve -as its own bridge across roads, valleys and rivers. - -Though the single-rail has come to the front of late, it must not be -supposed that the two-rail track is for ever doomed to moderate speeds -only. German engineers have built an electric two-rail military line -between Berlin and Zossen, seventeen miles long, over which cars have -been run at a hundred miles an hour. The line has very gradual curves, -and in this respect is inferior to the more sinuous monorail. Its -chief virtue is the method of applying motive power--a method common -to both systems. - -The steam locomotive creates its own motive force, and as long as it -has fuel and water can act independently. The electric locomotive, on -the other hand, receives its power through metallic conductors from -some central station. Should the current fail all the traffic on the -line is suspended. So far the advantage rests with the steamer. But -as regards economy the superiority of the current is obvious. In -the electric systems under consideration--the monorail and -Berlin-Zossen--there is less weight per passenger to be shifted, since -a comparatively light motor supersedes the heavy locomotive. The cars -running singly, bridges and track are subjected to less strain, and -cost less to keep in repair. But the greatest saving of all is made in -fuel. A steam locomotive uses coal wastefully, sending a lot of latent -power up the funnel in the shape of half-expanded steam. Want of space -prevents the designer from fitting to a moving engine the more -economical machinery to be found in the central power-station of an -electric railway, which may be so situated--by the water-side or near -a pit's mouth--that fuel can be brought to it at a trifling cost. Not -only is the expense of distributing coal over the system avoided, but -the coal itself, by the help of triple and quadruple expansion engines -should yield two or three times as much energy per ton as is developed -in a locomotive furnace. - -Many schemes are afoot for the construction of high-speed railways. -The South-Eastern plans a monorail between Cannon Street and Charing -Cross to avoid the delay that at present occurs in passing from one -station to the other. We hear also of a projected railway from London -to Brighton, which will reduce the journey to half-an-hour; and of -another to connect Dover and London. It has even been suggested to -establish monorails on existing tracks for fast passenger traffic, the -expresses passing overhead, the slow and goods trains plodding along -the double metals below. - -But the most ambitious programme of all comes from the land of the -Czar. M. Hippolyte Romanoff, a Russian engineer, proposes to unite St. -Petersburg and Moscow by a line that shall cover the intervening 600 -miles in three hours--an improvement of ten hours on the present -time-tables. He will use T-shaped supports to carry two rails, one on -each arm, from which the cars are to hang. The line being thus double -will permit the cars--some four hundred in number--to run to and fro -continuously, urged on their way by current picked up from overhead -wires. Each car is to have twelve wheels, four drivers arranged -vertically and eight horizontally, to prevent derailment by gripping -the rail on either side. The stoppage or breakdown of any car will -automatically stop those following by cutting off the current. - -In the early days of railway history lines were projected in all -directions, regardless of the fact whether they would be of any use or -not. Many of these lines began, where they ended, on paper. And now -that the high-speed question has cropped up, we must not believe that -every projected electric railway will be built, though of the ultimate -prevalence of far higher speeds than we now enjoy there can be no -doubt. - -The following is a time-table drawn up on the two-mile-per-minute -basis. - -A man leaving London at 10 A.M. would reach-- - - Brighton 50 miles away, at 10.25 A.M. - Portsmouth 60 " " 10.30 A.M. - Birmingham 113 " " 10.57 A.M. - Leeds 188 " " 11.34 A.M. - Liverpool 202 " " 11.41 A.M. - Holyhead 262 " " 12.11 P.M. - Edinburgh 400 " " 1.20 P.M. - Aberdeen 540 " " 2.30 P.M. - -What would become of the records established in the "Race to the -North" and by American "fliers"? - -And what about continental travel? - -Assuming that the Channel Tunnel is built--perhaps a rather large -assumption--Paris will be at our very doors. A commercial traveller -will step into the lightning express at London, sleep for two hours -and twenty-four minutes and wake, refreshed, to find the blue-smocked -Paris porters bawling in his ear. Or even if we prefer to keep the -"little silver streak" free from subterranean burrows, he will be able -to catch the swift turbine steamers--of which more anon--at Dover, -slip across to Calais in half-an-hour, and be at the French capital -within four hours of quitting London. And if M. Romanoff's standard be -reached, the latest thing in hats despatched from Paris at noon may -be worn in Regent Street before two o'clock. - -Such speeds would indeed produce a revolution in travelling comparable -to the substitution of the steam locomotive for the stage coach. As -has been pithily said, the effect of steam was to make the bulk of -population travel, whereas they had never travelled before, but the -effect of the electric railway will be to make those who travel travel -much further and much oftener. - - - - -SEA EXPRESSES. - - -In the year 1836 the _Sirius_, a paddle-wheel vessel, crossed the -Atlantic from Cork Harbour to New York in nineteen days. Contrast with -the first steam-passage from the Old World to the New a return journey -of the _Deutschland_, a North German liner, which in 1900 averaged -over twenty-seven miles an hour between Sandy Hook and Plymouth, -accomplishing the whole distance in the record time of five days seven -hours thirty-eight minutes. - -This growth of speed is even more remarkable than might appear from -the mere comparison of figures. A body moving through water is so -retarded by the inertia and friction of the fluid that to quicken its -pace a force quite out of proportion to the increase of velocity must -be exerted. The proportion cannot be reduced to an exact formula, but -under certain conditions the speed and the power required advance in -the ratio of their cubes; that is, to double a given rate of progress -eight times the driving-power is needed; to treble it, twenty-seven -times. - -The mechanism of our fast modern vessels is in every way as superior -to that which moved the _Sirius_, as the beautifully-adjusted safety -cycle is to the clumsy "boneshaker" which passed for a wonder among -our grandfathers. A great improvement has also taken place in the art -of building ships on lines calculated to offer least resistance to the -water, and at the same time afford a good carrying capacity. The big -liner, with its knife-edged bow and tapering hull, is by its shape -alone eloquent of the high speed which has earned it the title -of Ocean Greyhound; and as for the fastest craft of all, -torpedo-destroyers, their designers seem to have kept in mind Euclid's -definition of a line--length without breadth. But whatever its shape, -boat or ship may not shake itself free of Nature's laws. Her -restraining hand lies heavy upon it. A single man paddles his -weight-carrying dinghy along easily at four miles an hour; eight men -in the pink of condition, after arduous training, cannot urge their -light, slender, racing shell more than twelve miles in the same time. - -To understand how mail boats and "destroyers" attain, despite the -enormous resistance of water, velocities that would shame many a -train-service, we have only to visit the stokeholds and engine-rooms -of our sea expresses and note the many devices of marine engineers by -which fuel is converted into speed. - -We enter the stokehold through air-locks, closing one door before we -can open the other, and find ourselves among sweating, grimy men, -stripped to the waist. As though life itself depended upon it they -shovel coal into the rapacious maws of furnaces glowing with a -dazzling glare under the "forced-draught" sent down into the hold by -the fans whirling overhead. The ignited furnace gases on their way to -the outer air surrender a portion of their heat to the water from -which they are separated by a skin of steel. Two kinds of marine -boiler are used--the fire-tube and the water-tube. In fire-tube -boilers the fire passes inside the tubes and the water outside; in -water-tube boilers the reverse is the case, the crown and sides of the -furnace being composed of sheaves of small parallel pipes through -which water circulates. The latter type, as generating steam very -quickly, and being able to bear very high pressures, is most often -found in war vessels of all kinds. The quality sought in boiler -construction is that the heating surface should be very large in -proportion to the quantity of water to be heated. Special coal, -anthracite or Welsh, is used in the navy on account of its great -heating power and freedom from smoke; experiments have also been made -with crude petroleum, or liquid fuel, which can be more quickly put on -board than coal, requires the services of fewer stokers, and may be -stored in odd corners unavailable as coal bunkers. - -From the boiler the steam passes to the engine-room, whither we will -follow it. We are now in a bewildering maze of clanking, whirling -machinery; our noses offended by the reek of oil, our ears deafened -by the uproar of the moving metal, our eyes wearied by the efforts to -follow the motions of the cranks and rods. - -On either side of us is ranged a series of three or perhaps even four -cylinders, of increasing size. The smallest, known as the -high-pressure cylinder, receives steam direct from the boiler. It -takes in through a slide-valve a supply for a stroke; its piston is -driven from end to end; the piston-rod flies through the cylinder-end -and transmits a rotary motion to a crank by means of a connecting-rod. -The half-expanded steam is then ejected, not into the air as would -happen on a locomotive, but into the next cylinder, which has a larger -piston to compensate the reduction of pressure. Number two served, the -steam does duty a third time in number three, and perhaps yet a fourth -time before it reaches the condensers, where its sudden conversion -into water by cold produces a vacuum suction in the last cylinder of -the series. The secret of a marine engine's strength and economy lies -then in its treatment of the steam, which, like clothes in a numerous -family, is not thought to have served its purpose till it has been -used over and over again. - -Reciprocating (_i.e._ cylinder) engines, though brought to a high -pitch of efficiency, have grave disadvantages, the greatest among -which is the annoyance caused by their intense vibration to all -persons in the vessel. A revolving body that is not exactly balanced -runs unequally, and transmits a tremor to anything with which it may -be in contact. Turn a cycle upside down and revolve the driving-wheel -rapidly by means of the pedal. The whole machine soon begins to -tremble violently, and dance up and down on the saddle springs, -because one part of the wheel is heavier than the rest, the mere -weight of the air-valve being sufficient to disturb the balance. Now -consider what happens in the engine-room of high-powered vessels. On -destroyers the screws make 400 revolutions a minute. That is to say, -all the momentum of the pistons, cranks, rods, and valves (weighing -tons), has to be arrested thirteen or fourteen times every second. -However well the moving parts may be balanced, the vibration is felt -from stem to stern of the vessel. Even on luxuriously-appointed -liners, with engines running at a far slower speed, the throbbing of -the screw (_i.e._ engines) is only too noticeable and productive of -discomfort. - -We shall be told, perhaps, that vibration is a necessary consequence -of speed. This is true enough of all vehicles, such as railway trains, -motor-cars, cycles, which are shaken by the irregularities of the -unyielding surface over which they run, but does not apply universally -to ships and boats. A sail or oar-propelled craft may be entirely free -from vibration, whatever its speed, as the motions arising from water -are usually slow and deliberate. In fact, water in its calmer moods is -an ideal medium to travel on, and the trouble begins only with the -introduction of steam as motive force. - -But even steam may be robbed of its power to annoy us. The -steam-turbine has arrived. It works a screw propeller as smoothly as a -dynamo, and at a speed that no cylinder engine could maintain for a -minute without shaking itself to pieces. - -The steam-turbine is most closely connected with the name of the Hon. -Charles Parsons, son of Lord Rosse, the famous astronomer. He was the -first to show, in his speedy little _Turbinia_, the possibilities of -the turbine when applied to steam navigation. The results have been -such as to attract the attention of the whole shipbuilding world. - -The principle of the turbine is seen in the ordinary windmill. To an -axle revolving in a stationary bearing are attached vanes which oppose -a current of air, water, or steam, at an angle to its course, and by -it are moved sideways through a circular path. Mr. Parsons' turbine -has of course been specially adapted for the action of steam. It -consists of a cylindrical, air-tight chest, inside which rotates a -drum, fitted round its circumference with rows of curved vanes. The -chest itself has fixed immovably to its inner side a corresponding -number of vane rings, alternating with those on the drum, and so -arranged as to deflect the steam on to the latter at the most -efficient angle. The diameter of the chest and drum is not constant, -but increases towards the exhaust end, in order to give the expanding -and weakening steam a larger leverage as it proceeds. - -The steam entering the chest from the boiler at a pressure of some -hundreds of pounds to the square inch strikes the first set of vanes -on the drum, passes them and meets the first set of chest-vanes, is -turned from its course on to the second set of drum-vanes, and so on -to the other end of the chest. Its power arises entirely from its -expansive velocity, which, rather than turn a number of sharp corners, -will, if possible, compel the obstruction to move out of its way. If -that obstruction be from any cause difficult to stir, the steam must -pass round it until its pressure overcomes the inertia. Consequently -the turbine differs from the cylinder engine in this respect, that -steam _can_ pass through and be wasted without doing any work at all, -whereas, unless the gear of a cylinder moves, and power is exerted, -all steam ways are closed, and there is no waste. In practice, -therefore, it is found that a turbine is most effective when running -at high speed. - -The first steam-turbines were used to drive dynamos. In 1884 Mr. -Parsons made a turbine in which fifteen wheels of increasing size -moved at the astonishing rate of 300 revolutions per second, and -developed 10 horse-power. In 1888 followed a 120 horse-power turbine, -and in 1892 one of 2000 horse-power, provided with a condenser to -produce suction. So successful were these steam fans for electrical -work, pumping water and ventilating mines, that Mr. Parsons determined -to test them as a means of propelling ships. A small vessel 100 feet -long and 9 feet in beam was fitted with three turbines--high, medium, -and low pressure, of a total 2000 horse-power--a proportion of motive -force to tonnage hitherto not approached. Yet when tried over the test -course the _Turbinia_, as the boat was fitly named, ran in a most -disappointing fashion. The screws revolved _too fast_, producing what -is known as _cavitation_, or the scooping out of the water by the -screws, so that they moved in a partial vacuum and utilised only a -fraction of their force, from lack of anything to "bite" on. This -defect was remedied by employing screws of coarser pitch and larger -blade area, three of which were attached to each of the three -propeller shafts. On a second trial the _Turbinia_ attained 32-3/4 -knots over the "measured mile," and later the astonishing speed of -forty miles an hour, or double that of the fast Channel packets. At -the Spithead Review in 1897 one of the most interesting sights was the -little nimble _Turbinia_ rushing up and down the rows of majestic -warships at the rate of an express train. - -[Illustration: _H.M.S. Torpedo Destroyer "Viper." This vessel was the -fastest afloat, attaining the enormous speed of 41 miles an hour. The -screws were worked by turbines, giving 11,000 horse-power. She was -wrecked on Alderney during the Naval Manoeuvres of 1901._] - -After this success Mr. Parsons erected works at Wallsend-on-Tyne for -the special manufacture of turbines. The Admiralty soon placed with -him an order for a torpedo-destroyer--the _Viper_--of 350 tons; which -on its trial trip exceeded forty-one miles an hour at an estimated -horse-power (11,000) equalling that of our largest battleships. A -sister vessel, the _Cobra_, of like size, proved as speedy. -Misfortune, however, overtook both destroyers. The _Viper_ was wrecked -August 3, 1901, on the coast of Alderney during the autumn naval -manoeuvres, and the _Cobra_ foundered in a severe storm on September -12 of the same year in the North Sea. This double disaster casts no -reflections on the turbine engines; being attributed to fog in the one -case and to structural weakness in the other. The Admiralty has since -ordered another turbine destroyer, and before many years are past we -shall probably see all the great naval powers providing themselves -with like craft to act as the "eyes of the fleet," and travel at even -higher speeds than those of the _Viper_ and _Cobra_. - -The turbine has been applied to mercantile as well as warlike -purposes. There is at the present time a turbine-propelled steamer, -the _King Edward_, running in the Clyde on the Fairlie-Campbelltown -route. This vessel, 250 feet long, 30 broad, 18 deep, contains three -turbines. In each the steam is expanded fivefold, so that by the time -it passes into the condensers it occupies 125 times its boiler volume. -(On the _Viper_ the steam entered the turbine through an inlet eight -inches in diameter, and left them by an outlet four feet square.) In -cylinder engines thirty-fold expansion is considered a high ratio; -hence the turbine extracts a great deal more power in proportion from -its steam. As a turbine cannot be reversed, special turbines are -attached to the two outside of the three propeller shafts to drive the -vessel astern. The steamer attained 20-1/2 knots over the "Skelmorlie -mile" in fair and calm weather, with 3500 horse-power produced at the -turbines. The _King Edward_ is thus the fastest by two or three knots -of all the Clyde steamers, as she is the most comfortable. We are -assured that as far as the turbines are concerned it is impossible by -placing the hand upon the steam-chest to tell whether the drum inside -is revolving or not! - -Every marine engine is judged by its economy in the consumption of -coal. Except in times of national peril extra speed produced by an -extravagant use of fuel would be severely avoided by all owners and -captains of ships. At low speeds the turbine develops less power than -cylinders from the same amount of steam, but when working at high -velocity it gives at least equal results. A careful record kept by the -managers of the Caledonian Steamship Company compares the _King -Edward_ with the _Duchess of Hamilton_, a paddle steamer of equal -tonnage used on the same route and built by the same firm. The record -shows that though the paddle-boat ran a fraction of a mile further -for every ton of coal burnt in the furnaces, the _King Edward_ -averaged two knots an hour faster, a superiority of speed quite out of -proportion to the slight excess of fuel. Were the _Duchess_ driven at -18-1/2 knots instead of 16-1/2 her coal bill would far exceed that of -the turbine. - -As an outcome of these first trials the Caledonian Company are -launching a second turbine vessel. Three high-speed turbine yachts are -also on the stocks; one of 700 tons, another of 1500 tons, and a third -of 170 tons. The last, the property of Colonel M'Calmont, is designed -for a speed of twenty-four knots. - -Mr. Parsons claims for his system the following advantages: Greatly -increased speed; increased carrying power of coal; economy in coal -consumption; increased facilities for navigating shallow waters; -greater stability of vessels; reduced weight of machinery (the -turbines of the _King Edward_ weigh but one-half of cylinders required -to give the same power); cheapness of attending the machinery; absence -of vibration, lessening wear and tear of the ship's hull and assisting -the accurate training of guns; lowered centre of gravity in the -vessel, and consequent greater safety during times of war. - -The inventor has suggested a cruiser of 2800 tons, engined up to -80,000 horse-power, to yield a speed of forty-four knots (about fifty -miles) an hour. Figures such as these suggest that we may be on the -eve of a revolution of ocean travel comparable to that made by the -substitution of steam for wind power. Whether the steam-turbine will -make for increased speed all round, or for greater economy, remains to -be seen; but we may be assured of a higher degree of comfort. We can -easily believe that improvements will follow in this as in other -mechanical contrivances, and that the turbine's efficiency has not yet -reached a maximum; and even if our ocean expresses, naval and -mercantile, do not attain the one-mile-a-minute standard, which is -still regarded as creditable to the fastest methods of land -locomotion, we look forward to a time in the near future when much -higher speeds will prevail, and the tedium of long voyages be greatly -shortened. Already there is talk of a service which shall reduce the -trans-Atlantic journey to three-and-a-half days. The means are at hand -to make it a fact. - - _Note._--In the recently-launched turbine destroyer _Velox_ a - novel feature is the introduction of ordinary reciprocating - engines fitted in conjunction with the steam turbines. These - engines are of triple-compound type, and are coupled direct to - the main turbines. They take steam from the boilers direct and - exhaust into the high-pressure turbine. These reciprocating - engines are for use at cruising speeds. When higher power is - needed the steam will be admitted to the turbines direct from - the boilers, and the cylinders be thrown out of gear. - - - - -MECHANICAL FLIGHT. - - -Few, if any, problems have so strongly influenced the imagination and -exercised the ingenuity of mankind as that of aerial navigation. There -is something in our nature that rebels against being condemned to the -condition of "featherless bipeds" when birds, bats, and even minute -insects have the whole realm of air and the wide heavens open to them. -Who has not, like Solomon, pondered upon "the way of a bird in the -air" with feelings of envy and regret that he is chained to earth by -his gross body; contrasting our laboured movements from point to point -of the earth's surface with the easy gliding of the feathered -traveller? The unrealised wish has found expression in legends of -Daedalus, Pegasus, in the "flying carpet" of the fairy tale, and in the -pages of Jules Verne, in which last the adventurous Robur on his -"Clipper of the Clouds" anticipates the future in a most startling -fashion. - -Aeromobilism--to use its most modern title--is regarded by the crowd -as the mechanical counterpart of the Philosopher's Stone or the Elixir -of Life; a highly desirable but unattainable thing. At times this -incredulity is transformed by highly-coloured press reports into an -equally unreasonable readiness to believe that the conquest of the air -is completed, followed by a feeling of irritation that facts are not -as they were represented in print. - -The proper attitude is of course half-way between these extremes. -Reflection will show us that money, time, and life itself would not -have been freely and ungrudgingly given or risked by many -men--hard-headed, practical men among them--in pursuit of a -Will-o'-the-Wisp, especially in a century when scientific calculation -tends always to calm down any too imaginative scheme. The existing -state of the aerial problem may be compared to that of a railway truck -which an insufficient number of men are trying to move. Ten men may -make no impression on it, though they are putting out all their -strength. Yet the arrival of an eleventh may enable them to overcome -the truck's inertia and move it at an increasing pace. - -Every new discovery of the scientific application of power brings us -nearer to the day when the truck will move. We have metals of -wonderful strength in proportion to their weight; pigmy motors -containing the force of giants; a huge fund of mechanical experience -to draw upon; in fact, to paraphrase the Jingo song, "We've got the -things, we've got the men, we've got the money too"--but we haven't -as yet got the machine that can mock the bird like the flying express -mocks the strength and speed of horses. - -The reason of this is not far to seek. The difficulties attending the -creation of a successful flying-machine are immense, some unique, not -being found in aquatic and terrestrial locomotion. - -In the first place, the airship, flying-machine, aerostat, or whatever -we please to call it, must not merely move, but also lift itself. -Neither a ship nor a locomotive is called upon to do this. Its ability -to lift itself must depend upon either the employment of large -balloons or upon sheer power. In the first case the balloon will, by -reason of its size, be unmanageable in a high wind; in the second -case, a breakdown in the machinery would probably prove fatal. - -Even supposing that our aerostat can lift itself successfully, we -encounter the difficulties connected with steering in a medium -traversed by ever-shifting currents of air, which demands of the -helmsman a caution and capacity seldom required on land or water. Add -to these the difficulties of leaving the ground and alighting safely -upon it; and, what is more serious than all, the fact that though -success can be attained only by experiment, experiment is in this case -extremely expensive and risky, any failure often resulting in total -ruin of the machine, and sometimes in loss of life. The list of those -who have perished in the search for the power of flight is a very long -one. - -Yet in spite of these obstacles determined attempts have been and are -being made to conquer the air. Men in a position to judge are -confident that the day of conquest is not very far distant, and that -the next generation may be as familiar with aerostats as we with -motor-cars. Speculation as to the future is, however, here less -profitable than a consideration of what has been already done in the -direction of collecting forces for the final victory. - -To begin at the beginning, we see that experimenters must be divided -into two great classes: those who pin their faith to airships lighter -than air, _e.g._ Santos Dumont, Zeppelin, Roze; and those who have -small respect for balloons, and see the ideal air-craft in a _machine_ -lifted entirely by means of power and surfaces pressing the air after -the manner of a kite. Sir Hiram Maxim and Professor S. P. Langley, Mr. -Lawrence Hargrave, and Mr. Sydney Hollands are eminent members of the -latter cult. - -As soon as we get on the topic of steerable balloons the name of Mr. -Santos Dumont looms large. But before dealing with his exploits we may -notice the airship of Count Zeppelin, an ingenious and costly -structure that was tested over Lake Constance in 1900. - -The balloon was built in a large wooden shed, 450 by 78 by 66 feet, -that floated on the lake on ninety pontoons. The shed alone cost over -L10,000. - -The balloon itself was nearly 400 feet long, with a cylindrical -diameter of 39 feet, except at its ends, which were conical, to offer -as little resistance as possible to the air. Externally it afforded -the appearance of a single-compartment bag, but in reality it was -divided into seventeen parts, each gas-tight, so that an accident to -one part of the fabric should not imperil the whole. - -A framework of aluminium rods and rings gave the bag a partial -rigidity. - -Its capacity was 12,000 cubic yards of hydrogen gas, which, as our -readers doubtless know, is much lighter though more expensive than -ordinary coal-gas; each inflation costing several hundreds of pounds. - -Under the balloon hung two cars of aluminium, the motors and the -screws; and also a great sliding weight of 600 lbs. for altering the -"tip" of the airship; and rudders to steer its course. - -On June 30 a great number of scientific men and experts assembled to -witness the behaviour of a balloon which had cost L20,000. For two -days wind prevented a start, but on July 2, at 7.30 P.M., the balloon -emerged from its shed, and at eight o'clock commenced its first -journey, with and against a light easterly wind for a distance of -three and a half miles. A mishap to the steering-gear occurred early -in the trip, and prevented the airship appearing to advantage, but a -landing was effected easily and safely. In the following October the -Count made a second attempt, returning against a wind blowing at three -yards a second, or rather more than six miles an hour. - -[Illustration: _The air-ship of M. Santos-Dumont rounding the Eiffel -Tower during its successful run for the Henri Deutsch Prize._] - -Owing to lack of funds the fate of the "Great Eastern" has overtaken -the Zeppelin airship--to be broken up, and the parts sold. - -The aged Count had demonstrated that a petroleum motor could be used -in the neighbourhood of gas without danger. It was, however, reserved -for a younger man to give a more decided proof of the steerableness of -a balloon. - -In 1900 M. Henri Deutsch, a member of the French Aero Club, founded a -prize of L4000, to win which a competitor must start from the Aero -Club Park, near the Seine in Paris, sail to and round the Eiffel -Tower, and be back at the starting-point within a time-limit of -half-an-hour. - -M. Santos Dumont, a wealthy and plucky young Brazilian, had, -previously to this offer, made several successful journeys in motor -balloons in the neighbourhood of the Eiffel Tower. He therefore -determined to make a bid for the prize with a specially constructed -balloon "Santos Dumont V." The third unsuccessful attempt ended in -disaster to the airship, which fell on to the houses, but fortunately -without injuring its occupant. - -Another balloon--"Santos Dumont VI."--was then built. On Saturday, -October 19th, M. Dumont reached the Tower in nine minutes and -recrossed the starting line in 20-1/2 more minutes, thus complying -with the conditions of the prize with half-a-minute to spare. A -dispute, however, arose as to whether the prize had been actually won, -some of the committee contending that the balloon should have come to -earth within the half-hour, instead of merely passing overhead; but -finally the well-merited prize was awarded to the determined young -aeronaut. - -The successful airship was of moderate proportions as compared with -that of Count Zeppelin. The cigar-shaped bag was 112 feet long and 20 -feet in diameter, holding 715 cubic yards of gas. M. Dumont showed -originality in furnishing it with a smaller balloon inside, which -could be pumped full of air so as to counteract any leakage in the -external bag and keep it taut. The motor, on which everything -depended, was a four-cylinder petrol-driven engine, furnished with -"water-jackets" to prevent over-heating. The motor turned a large -screw--made of silk and stretched over light frames--200 times a -minute, giving a driving force of 175 lbs. Behind, a rudder directed -the airship, and in front hung down a long rope suspended by one end -that could be drawn towards the centre of the frame to alter the trim -of the ship. The aeronaut stood in a large wicker basket flanked on -either side by bags of sand ballast. The fact that the motor, once -stopped, could only be restarted by coming to earth again added an -element of great uncertainty to all his trips; and on one occasion the -mis-firing of one of the cylinders almost brought about a collision -with the Eiffel Tower. - -From Paris M. Dumont went to Monaco at the invitation of the prince of -that principality, and cruised about over the bay in his balloon. His -fresh scheme was to cross to Corsica, but it was brought to an abrupt -conclusion by a leakage of gas, which precipitated balloon and -balloonist into the sea. Dumont was rescued, and at once set about new -projects, including a visit to the Crystal Palace, where he would have -made a series of ascents this summer (1902) but for damage done to the -silk of the gas-bag by its immersion in salt water and the other -vicissitudes it had passed through. Dumont's most important -achievement has been, like that of Count Zeppelin, the application of -the gasolene motor to aeromobilism. In proportion to its size this -form of motor develops a large amount of energy, and its mechanism is -comparatively simple--a matter of great moment to the aeronaut. He has -also shown that under favourable conditions a balloon may be steered -against a head-wind, though not with the certainty that is desirable -before air travel can be pronounced an even moderately simple -undertaking. The fact that many inventors, such as Dr. Barton, M. -Roze, Henri Deutsch, are fitting motors to balloons in the hopes of -solving the aerial problem shows that the airship has still a strong -hold on the minds of men. But on reviewing the successes of such -combinations of lifting and driving power it must be confessed, with -all due respect to M. Dumont, that they are somewhat meagre, and do -not show any great advance. - -The question is whether these men are not working on wrong lines, and -whether their utmost endeavours and those of their successors will -ever produce anything more than a very semi-successful craft. Their -efforts appear foredoomed to failure. As Sir Hiram Maxim has observed, -a balloon by its very nature is light and fragile, it is a mere -bubble. If it were possible to construct a motor to develop 100 -horse-power for every pound of its weight, it would still be -impossible to navigate a balloon against a wind of more than a certain -strength. The mere energy of the motor would crush the gas-bag against -the pressure of the wind, deform it, and render it unmanageable. -Balloons therefore must be at the mercy of the wind, and obliged to -submit to it under conditions not always in accordance with the wish -of the aeronaut. - -Sir Hiram in condemning the airship was ready with a substitute. On -looking round on the patterns of Nature, he concluded that, inasmuch -as all things that fly are heavier than air, the problem of aerial -navigation must be solved by a machine whose natural tendency is to -fall to the ground, and which can be sustained only by the exertion of -great force. Its very weight would enable it to withstand, at least to -a far greater extent than the airship, the varying currents of the -air. - -The lifting principle must be analogous to that by which a kite is -suspended. A kite is prevented from rising beyond a certain height by -a string, and the pressure of the wind working against it at an angle -tends to lift it, like a soft wedge continuously driven under it. In -practice it makes no difference whether the kite be stationary in a -wind or towed rapidly through a dead calm; the wedge-like action of -the air remains the same. - -Maxim decided upon constructing what was practically a huge compound -kite driven by very powerful motors. - -But before setting to work on the machine itself he made some useful -experiments to determine the necessary size of his kites or -aeroplanes, and the force requisite to move them. - -He accordingly built a "whirling-table," consisting of a long arm -mounted on a strong pivot at one end, and driven by a 10 horse-power -engine. To the free end, which described a circle of 200 feet in -circumference, he attached small aeroplanes, and by means of delicate -balances discovered that at 40 miles an hour the aeroplane would lift -133 lbs. per horse-power, and at 60 miles per hour every square foot -of surface sustained 8 lbs. weight. He, in common with other -experimenters on the same lines, became aware of the fact that if it -took a certain strain to suspend a stationary weight in the air, _to -advance it rapidly as well as to suspend it took a smaller strain_. -Now, as on sea and land, increased speed means a very rapid increase -in the force required, this is a point in favour of the -flying-machine. Professor Langley found that a brass plate weighing a -pound, when whirled at great speed, was supported in the air by a -pulling pressure of less than one ounce. And, of course, as the speed -increased the plate became more nearly horizontal, offering less -resistance to the air. - -It is on this behaviour of the aeroplane that the hopes of Maxim and -others have been based. The swiftly moving aeroplane, coming -constantly on to fresh air, the inertia of which had not been -disturbed, would resemble the skater who can at high speed traverse -ice that would not bear him at rest. - -Maxim next turned his attention to the construction of the aeroplanes -and engines. He made a special machine for testing fabrics, to decide -which would be most suitable for stretching over strong frames to form -the planes. The fabric must be light, very strong, and offer small -frictional resistance to the air. The testing-machine was fitted with -a nozzle, through which air was forced at a known pace on to the -substance under trial, which met the air current at a certain angle -and by means of indicators showed the strength of its "lift" or -tendency to rise, and that of its "drift" or tendency to move -horizontally in the direction of the air-current. A piece of tin, -mounted at an angle of one in ten to the air-current, showed a "lift" -of ten times its "drift." This proportion was made the standard. -Experiments conducted on velvet, plush, silk, cotton and woollen goods -proved that the drift of crape was several times that of its lift, but -that fine linen had a lift equal to nine times its drift; while a -sample of Spencer's balloon fabric was as good as tin. - -Accordingly he selected this balloon fabric to stretch over light but -strong frames. The stretching of the material was no easy matter, as -uneven tension distorted it; but eventually the aeroplanes were -completed, tight as drumheads. - -The large or central plane was 50 feet wide and 40 long; on either -side were auxiliary planes, five pairs; giving a total area of 5400 -square feet. - -The steam-engine built to give the motive power was perhaps the most -interesting feature of the whole construction. Maxim employed steam in -preference to any other power as being one with which he was most -familiar, and yielding most force in proportion to the weight of the -apparatus. He designed and constructed a pair of high-pressure -compound engines, the high-pressure cylinders 5 inches in diameter, -the low-pressure 8 inches, and both 1 foot stroke. Steam was supplied -to the high-pressure cylinders at 320 lbs. per square inch from a -tubular boiler heated by a gasolene burner so powerful in its action -as to raise the pressure from 100 to 200 lbs. in a minute. The total -weight of the boiler, burner, and engines developing 350 horse-power -was 2000 lbs., or about 6 lbs. per horse-power. - -The two screw-propellers driven by the engine measured 17 feet 11 -inches in diameter. - -The completed flying-machine, weighing 7500 lbs., was mounted on a -railway-truck of 9-foot gauge, in Baldwyn's Park, Kent, not far from -the gun-factories for which Sir Hiram is famous. Outside and parallel -to the 9-foot track was a second track, 35 feet across, with a -reversed rail, so that as soon as the machine should rise from the -inner track long spars furnished with flanged wheels at their -extremities should press against the under side of the outer track and -prevent the machine from rising too far. Dynamometers, or instruments -for measuring strains, were fitted to decide the driving and lifting -power of the screws. Experiments proved that with the engines working -at full power the screw-thrust against the air was 2200 lbs., and the -lifting force of the aeroplanes 10,000 lbs., or 1500 in excess of the -machine's weight. - -Everything being ready the machine was fastened to a dynamometer and -steam run up until it strained at its tether with maximum power; when -the moorings were suddenly released and it bounded forward at a -terrific pace, so suddenly that some of the crew were flung violently -down on to the platform. When a speed of 42 miles was reached the -inner wheels left their track, and the outer wheels came into play. -Unfortunately, the long 35-foot axletrees were too weak to bear the -strain, and one of them broke. The upper track gave way, and for the -first time in the history of the world a flying-machine actually left -the ground fully equipped with engines, boiler, fuel, and a crew. The -journey, however, was a short one, for part of the broken track fouled -the screws, snapped a propeller blade and necessitated the shutting -off of the steam, which done, the machine settled to earth, the wheels -sinking into the sward and showing by the absence of any marks that it -had come directly downwards and not run along the surface. - -The inventor was prevented by other business, and by the want of a -sufficiently large open space, from continuing his experiments, which -had demonstrated that a large machine heavier than air could be made -to lift itself and move at high speed. Misfortune alone prevented its -true capacities being shown. - -Another experimenter on similar lines, but on a less heroic scale than -Sir Hiram Maxim, is Professor S. P. Langley, the secretary of the -Smithsonian Institution, Washington. For sixteen years he has devoted -himself to a persevering course of study of the flying-machine, and -after oft-repeated failures has scored a decided success in his -Aerodrome, which, though only a model, has made considerable flights. -His researches have proved beyond doubt that the amount of energy -required for flight is but one-fiftieth of what was formerly regarded -as a minimum. A French mathematician had proved by figures that a -swallow must develop the power of a horse to maintain its rapid -flight! Professor Langley's aerodrome has told a very different tale, -affording another instance of the truth of the saying that an ounce of -practice is worth a pound of theory. - -A bird is nearly one thousand times heavier than the air it displaces. -As a motor it develops huge power for its weight, and consumes a very -large amount of fuel in doing so. An observant naturalist has -calculated that the homely robin devours per diem, in proportion to -its size, what would be to a man a sausage two hundred feet long and -three inches thick! Any one who has watched birds pulling worms out of -the garden lawn and swallowing them wholesale can readily credit this. - -Professor Langley therefore concentrated himself on the production of -an extremely light and at the same time powerful machine. Like Maxim, -he turned to steam for motive-power, and by rigid economy of weight -constructed an engine with boilers weighing 5 lbs., cylinders of 26 -ozs., and an energy of 1 to 1-1/2 horse-power! Surely a masterpiece of -mechanical workmanship! This he enclosed in a boat-shaped cover which -hung from two pairs of aeroplanes 12-1/2 feet from tip to tip. The -whole apparatus weighed nearly 30 lbs., of which one quarter -represented the machinery. Experiments with smaller aerodromes warned -the Professor that rigidity and balance were the two most difficult -things to attain; also that the starting of the machine on its aerial -course was far from an easy matter. - -A soaring bird does not rise straight from the ground, but opens its -wings and runs along the ground until the pressure of the air raises -it sufficiently to give a full stroke of its pinions. Also it rises -_against_ the wind to get the full benefit of its lifting force. -Professor Langley hired a houseboat on the Potomac River, and on the -top of it built an apparatus from which the aerodrome could be -launched into space at high velocity. - -On May 6, 1896, after a long wait for propitious weather, the -aerodrome was despatched on a trial trip. It rose in the face of the -wind and travelled for over half a mile at the rate of twenty-five -miles an hour. The water and fuel being then exhausted it settled -lightly on the water and was again launched. Its flight on both -occasions was steady, and limited only by the rapid consumption of its -power-producing elements. The Professor believes that larger machines -would remain in the air for a long period and travel at speeds -hitherto unknown to us. - -In both the machines that we have considered the propulsive power was -a screw. No counterpart of it is seen in Nature. This is not a valid -argument against its employment, since no animal is furnished with -driving-wheels, nor does any fish carry a revolving propeller in its -tail. But some inventors are strongly in favour of copying Nature as -regards the employment of wings. Mr. Sydney H. Hollands, an -enthusiastic aeromobilist, has devised an ingenious cylinder-motor so -arranged as to flap a pair of long wings, giving them a much stronger -impulse on the down than on the up stroke. The pectoral muscles of a -bird are reproduced by two strong springs which are extended by the -upward motion of the wings and store up energy for the down-stroke. -Close attention is also being paid to the actual shape of a bird's -wing, which is not flat but hollow on its under side, and at the front -has a slightly downward dip. "Aerocurves" are therefore likely to -supersede the "aeroplane," for Nature would not have built bird's -wings as they are without an object. The theory of the aerocurve's -action is this: that the front of the wing, on striking the air, gives -it a downwards motion, and if the wing were quite flat its rear -portion would strike air already in motion, and therefore less -buoyant. The curvature of a floating bird's wings, which becomes more -and more pronounced towards the rear, counteracts this yielding of the -air by pressing harder upon it as it passes towards their hinder edge. - -[Illustration: _M. Santos Dumont's Airship returning to Longchamps -after doubling the Eiffel Tower, October 19, 1901._] - -The aerocurve has been used by a very interesting group of -experimenters, those who, putting motors entirely aside, have floated -on wings, and learnt some of the secrets of balancing in the air. For -a man to propel himself by flapping wings moved by legs or arms is -impossible. Sir Hiram Maxim, in addressing the Aeronautical Society, -once said that for a man to successfully imitate a bird his lungs must -weigh 40 lbs., to consume sufficient oxygen, his breast muscles 75 -lbs., and his breast bone be extended in front 21 inches. And unless -his total weight were increased his legs must dwindle to the size of -broomsticks, his head to that of an apple! So that for the present we -shall be content to remain as we are! - -Dr. Lilienthal, a German, was the first to try scientific -wing-sailing. He became a regular air gymnast, running down the sides -of an artificial mound until the wings lifted him up and enabled him -to float a considerable distance before reaching earth again. His -wings had an area of 160 square feet, or about a foot to every pound -weight. He was killed by the wings collapsing in mid-air. A similar -fate also overtook Mr. Percy Pilcher, who abandoned the initial run -down a sloping surface in favour of being towed on a rope attached to -a fast-moving vehicle. At present Mr. Octave Chanute, of Chicago, is -the most distinguished member of the "gliding" school. He employs, -instead of wings, a species of kite made up of a number of small -aerocurves placed one on the top of another a small distance apart. -These box kites are said to give a great lifting force for their -weight. - -These and many other experimenters have had the same object in -view--to learn the laws of equilibrium in the air. Until these are -fully understood the construction of large flying-machines must be -regarded as somewhat premature. Man must walk before he can run, and -balance himself before he can fly. - -There is no falling off in the number of aerial machines and schemes -brought from time to time into public notice. We may assure ourselves -that if patient work and experiment can do it the problem of "how to -fly" is not very far from solution at the present moment. - -As a sign of the times, the War Office, not usually very ready to -take up a new idea, has interested itself in the airship, and -commissioned Dr. F. A. Barton to construct a dirigible balloon which -combines the two systems of aerostation. Propulsion is effected by six -sets of triple propellers, three on each side. Ascent is brought about -partly by a balloon 180 feet long, containing 156,000 cubic feet of -hydrogen, partly by nine aeroplanes having a total superficial area of -nearly 2000 square feet. The utilisation of these aeroplanes obviates -the necessity to throw out ballast to rise, or to let out gas for a -descent. The airship, being just heavier than air, is raised by the -135 horse-power motors pressing the aeroplanes against the air at the -proper angle. In descent they act as parachutes. - -The most original feature of this war balloon is the automatic -water-balance. At each end of the "deck" is a tank holding forty -gallons of water. Two pumps circulate water through these tanks, the -amount sent into a tank being regulated by a heavy pendulum which -turns on the cock leading to the end which may be highest in -proportion as it turns off that leading to the lower end. The idea is -very ingenious, and should work successfully when the time of trial -comes. - -Valuable money prizes will be competed for by aeronauts at the coming -World's Fair at St. Louis in 1903. Sir Hiram Maxim has expressed an -intention of spending L20,000 in further experiments and prizes. In -this country, too, certain journals have offered large rewards to any -aeronaut who shall make prescribed journeys in a given time. It has -also been suggested that aeronautical research should be endowed by -the state, since England has nothing to fear more than the flying -machine and the submarine boat, each of which tends to rob her of the -advantages of being an island by exposing her to unexpected and unseen -attacks. - -Tennyson, in a fine passage in "Locksley Hall," turns a poetical eye -towards the future. This is what he sees-- - - "For I dipt into the future, far as human eye could see, - Saw the vision of the world and all the wonder that would be, - Saw the heavens fill with commerce, argosies of magic sail, - Pilots of the purple twilight dropping down with costly bales, - Heard the heavens fill with shouting, then there rained a ghostly dew, - From the nations' airy navies, grappling in the central blue." - -Expressed in more prosaic language, the flying-machine will primarily -be used for military purposes. A country cannot spread a metal -umbrella over itself to protect its towns from explosives dropped from -the clouds. - -Mail services will be revolutionised. The pleasure aerodrome will take -the place of the yacht and motor-car, affording grand opportunities -for the mountaineer and explorer (if the latter could find anything -new to explore). Then there will also be a direct route to the North -Pole over the top of those terrible icefields that have cost -civilisation so many gallant lives. And possibly the ease of transit -will bring the nations closer together, and produce good-fellowship -and concord among them. It is pleasanter to regard the flying-machine -of the future as a bringer of peace than as a novel means of spreading -death and destruction. - - - - -TYPE-SETTING BY MACHINERY. - - -To the Assyrian brickmakers who, thousands of years ago, used blocks -wherewith to impress on their unbaked bricks hieroglyphics and -symbolical characters, must be attributed the first hesitating step -towards that most marvellous and revolutionary of human -discoveries--the art of printing. Not, however, till the early part of -the fifteenth century did Gutenberg and Coster conceive the brilliant -but simple idea of printing from separate types, which could be set in -different orders and combinations to represent different ideas. For -Englishmen, 1474 deserves to rank with 1815, as in that year a very -Waterloo was won on English soil against the forces of ignorance and -oppression, though the effects of the victory were not at once -evident. Considering the stir made at the time by the appearance of -Caxton's first book at Westminster, it seems strange that an invention -of such importance as the printing-press should have been frowned upon -by those in power, and so discouraged that for nearly two centuries -printing remained an ill-used and unprogressive art, a giant half -strangled in his cradle. Yet as soon as prejudice gave it an open -field, improved methods followed close on one another's heels. To-day -we have in the place of Caxton's rude hand-made press great cylinder -machines capable of absorbing paper by the mile, and grinding out -20,000 impressions an hour as easily as a child can unwind a reel of -cotton. - -Side by side with the problem how to produce the greatest possible -number of copies in a given time from one machine, has arisen -another:--how to set up type with a proportionate rapidity. A press -without type is as useless as a chaff-cutter without hay or straw. The -type once assembled, as many casts or stereotypes can be made from it -as there are machines to be worked. But to arrange a large body of -type in a short time brings the printer face to face with the -need of employing the expensive services of a small army of -compositors--unless he can attain his end by some equally efficient -and less costly means. For the last century a struggle has been in -progress between the machine compositor and the human compositor, -mechanical ingenuity against eye and brains. In the last five years -the battle has turned most decidedly in favour of the machine. To-day -there are in existence two wonderful contrivances which enable a man -to set up type six times as fast as he could by hand from a box of -type, with an ease that reminds one of the mythical machine for the -conversion of live pigs into strings of sausages by an uninterrupted -series of movements. - -These machines are called respectively the Linotype and Monotype. -Roughly described, they are to the compositor what a typewriter is to -a clerk--forming words in obedience to the depression of keys on a -keyboard. But whereas the typewriter merely imprints a single -character on paper, the linotype and monotype cast, deliver, and set -up type from which an indefinite number of impressions can be taken. -They meet the compositor more than half-way, and simplify his labour -while hugely increasing his productiveness. - -As far back as 1842 periodicals were mechanically composed by a -machine which is now practically forgotten. Since that time hundreds -of other inventions have been patented, and some scores of different -machines tried, though with small success in most cases; as it was -found that quality of composition was sacrificed to quantity, and that -what at first appeared a short cut to the printing-press was after all -the longest way round, when corrections had all been attended to. A -really economical type-setter must be accurate as well as prolific. -Slipshod work will not pay in the long run. - -Such a machine was perfected a few years ago by Ottmar Mergenthaler of -Baltimore, who devised the plan of casting a whole _line of type_. The -Linotype Composing Machine, to give it its full title, produces type -all ready for the presses in "slugs" or lines--hence the name, Lin' o' -type. It deserves at least a short description. - -The Linotype occupies about six square feet of floor space, weighs one -ton, and is entirely operated by one man. Its most prominent features -are a sloping magazine at the top to hold the brass matrices, or -dies from which the type is cast, a keyboard controlling the machinery -to drop and collect the dies, and a long lever which restores the dies -to the magazine when done with. - -[Illustration: _By kind permission of The Linotype Co._ - -_The Linotype Machine. By pressing keys on the key-board the operator -causes lines of type to be set up, cast, and arranged on the "galley" -ready for the printers._] - -The operator sits facing the keyboard, in which are ninety keys, -variously coloured to distinguish the different kinds of letters. His -hands twinkle over the keys, and the brass dies fly into place. When a -key is depressed a die shoots from the magazine on to a travelling -belt and is whirled off to the assembling-box. Each die is a flat, -oblong brass plate, of a thickness varying with the letter, having a -large V-shaped notch in the top, and the letter cut half-way down on -one of the longer sides. A corresponding letter is stamped on the side -nearest to the operator so that he may see what he is doing and make -needful corrections. - -As soon as a word is complete, he touches the "spacing" lever at the -side of the keyboard. The action causes a "space" to be placed against -the last die to separate it from the following word. The operations -are repeated until the tinkle of a bell warns him that, though there -may be room for one or two more letters, the line will not admit -another whole syllable. The line must therefore be "justified," that -is, the spaces between the words increased till the vacant room is -filled in. In hand composition this takes a considerable time, and is -irksome; but at the linotype the operator merely twists a handle and -the wedge-shaped "spaces," placed thin end upwards, are driven up -simultaneously, giving the lateral expansion required to make the line -of the right measure. - -A word about the "spaces," or space-bands. Were each a single wedge -the pressure would be on the bottom only of the dies, and their tops, -being able to move slightly, would admit lead between them. To obviate -this a small second wedge, thin end _downwards_, is arranged to slide -on the larger wedge, so that in all positions parallelism is secured. -This smaller wedge is of the same shape as the dies and remains -stationary in line with them, the larger one only moving. - -The line of dies being now complete, it is automatically borne off and -pressed into contact with the casting wheel. This wheel, revolving on -its centre, has a slit in it corresponding in length and width to the -size of line required. At first the slit is horizontal, and the dies -fit against it so that the row of sunk letters on the faces are in the -exact position to receive the molten lead, which is squirted through -the slit from behind by an automatic pump, supplied from a metal-pot. -The pot is kept at a proper heat of 550 deg. Fahrenheit by the flames of a -Bunsen burner. - -The lead solidifies in an instant, and the "slug" of type is ready for -removal, after its back has been carefully trimmed by a knife. The -wheel revolves for a quarter-turn, bringing the slit into a vertical -position; a punch drives out the "slug," which is slid into the galley -to join its predecessors. The wheel then resumes its former horizontal -position in readiness for another cast. - -The assembled dies have for the time done their work and must be -returned to the magazine. The mechanism used to effect this is -peculiarly ingenious. - -An arm carrying a ribbed bar descends. The dies are pushed up, leaving -the "spaces" behind to be restored to their proper compartment, till -on a level with the ribbed bar, on to which they are slid by a lateral -movement, the notches of the V-shaped opening in the top side of each -die engaging with the ribs on the bar. The bar then ascends till it is -in line with a longer bar of like section passing over the open top of -the entire magazine. A set of horizontal screw-bars, rotating at high -speed, transfer the dies from the short to the long bar, along which -they move till, as a die comes above its proper division of the -magazine, the arrangement of the teeth allows it to drop. While all -this has been going on, the operator has composed another line of -moulds, which will in turn be transferred to the casting wheel, and -then back to the magazine. So that the three operations of composing, -casting, and sorting moulds are in progress simultaneously in -different parts of the machine; with the result that as many as 20,000 -letters can be formed by an expert in the space of an hour, against -the 1500 letters of a skilled hand compositor. - -How about corrections? Even a comma too few or too many needs the -whole line cast over again. It is a convincing proof of the difference -in speed between the two methods that a column of type can be -corrected much faster by the machine, handicapped as it is by its -solid "slugs," than by hand. No wonder then that more than 1000 -linotypes are to be found in the printing offices of Great Britain. - -The Monotype, like the Linotype, aims at speed in composition, but in -its mechanism it differs essentially from the linotype. In the first -place, the apparatus is constructed in two quite separate parts. There -is a keyboard, which may be on the third floor of the printing -offices, and the casting machine, which ceaselessly casts and sets -type in the basement. Yet they are but one whole. The connecting link -is the long strip of paper punched by the keyboard mechanism, and then -transferred to the casting machine to bring about the formation of -type. The keyboard is the servant of man; the casting machine is the -slave of the keyboard. - -Secondly, the Monotype casts type, not in blocks or a whole line, but -in separate letters. It is thus a complete type-foundry. Order it to -cast G's and it will turn them out by the thousand till another letter -is required. - -Thirdly, by means of the punched paper roll, the same type can be set -up time after time without a second recourse to the keyboard, just as -a tune is ground repeatedly out of a barrel organ. - -The keyboard has a formidable appearance. It contains 225 keys, -providing as many characters; also thirty keys to regulate the spacing -of the words. At the back of the machine a roll of paper runs over -rollers and above a row of thirty little punches worked by the keys. -A key being depressed, an opened valve admits air into two cylinders, -each driving a punch. The punches fly up and cut two neat little holes -in the paper. The roll then moves forward for the next letter. At the -end of the word a special lever is used to register a space, and so on -to the end of the line. The operator then consults an automatic -indicator which tells him exactly how much space is left, and how much -too long or too short the line would be if the spaces were of the -normal size. Supposing, for instance, that there are ten spaces, and -that there is one-tenth of an inch to spare. It is obvious that by -extending each space one-hundredth of an inch the vacant room will be -exactly filled. Similarly, if the ten normal spaces would make the -line one-tenth of an inch too _long_, by _decreasing_ the spaces each -one-hundredth inch the line will also be "justified." - -[Illustration: _By kind permission of_] [_The Monotype Co._ - -_The Monotype Casting Machine. A punched paper roll fed through the -top of the machine automatically casts and sets up type in separate -letters._] - -But the operator need not trouble his head about calculations of this -kind. His indicator, a vertical cylinder covered with tiny squares, in -each of which are printed two figures, tell him exactly what he has to -do. On pressing a certain key the cylinder revolves and comes to rest -with the tip of a pointer over a square. The operator at once presses -down the keys bearing the numbers printed on that square, confident -that the line will be of the proper length. - -As soon as the roll is finished, it is detached from the keyboard and -introduced to the casting machine. Hitherto passive, it now becomes -active. Having been placed in position on the rollers it is slowly -unwound by the machinery. The paper passes over a hollow bar in which -there are as many holes as there were punches in the keyboard, and in -precisely the same position. When a hole in the paper comes over a -hole in the hollow bar air rushes in, and passing through a tube -actuates the type-setting machinery in a certain manner, so as to -bring the desired die into contact with molten lead. The dies are, in -the monotype, all carried in a magazine about three inches square, -which moves backwards or forwards, to right or left, in obedience to -orders from the perforated roll. The dies are arranged in exactly the -same way as the keys on the keyboard. So that, supposing A to have -been stamped on the roll, one of the perforations causes the magazine -to slide one way, while the other shoves it another, until the -combined motions bring the matrix engraved with the A underneath the -small hole through which molten lead is forced. The letter is ejected -and moves sideways through a narrow channel, pushing preceding letters -before it, and the magazine is free for other movements. - -At the end of each word a "space" or blank lead is cast, its size -exactly determined by the "justifying" hole belonging to that line. -Word follows word till the line is complete; then a knife-like lever -rises, and the type is propelled into the "galley." Though a slave the -casting machine will not tolerate injustice. Should the compositor -have made a mistake, so that the line is too long or too short, -automatic machinery at once comes into play, and slips the driving -belt from the fixed to the loose pulley, thus stopping the machine -till some one can attend to it. But if the punching has been correctly -done, the machine will work away unattended till, a whole column of -type having been set up, it comes to a standstill. - -The advantages of the Monotype are easily seen. In order to save money -a man need not possess the complete apparatus. If he has the keyboard -only he becomes to a certain extent his own compositor, able to set up -the type, as it were by proxy, at any convenient time. He can give his -undivided attention to the keyboard, stop work whenever he likes -without keeping a casting-machine idle, and as soon as his roll is -complete forward it to a central establishment where type is set. -There a single man can superintend the completion of half-a-dozen -men's labours at the keyboard. That means a great reduction of -expense. - -In due time he receives back his copy in the shape of set-up type, all -ready to be corrected and transferred to the printing machines. The -type done with, he can melt it down without fear of future regret, for -he knows that the paper roll locked up in his cupboard will do its -work a second time as well as it did the first. Should he need the -same matter re-setting, he has only to send the roll through the post -to the central establishment. - -Thanks to Mr. Lanston's invention we may hope for the day when every -parish will be able to do its own printing, or at least set up its own -magazine. The only thing needful will be a monotype keyboard supplied -by an enlightened Parish Council--as soon as the expense appears -justifiable--and kept in the Post Office or Village Institute. The -payment of a small fee will entitle the Squire to punch out his speech -on behalf of the Conservative Candidate, the Schoolmaster to compose -special information for his pupils, the Rector to reduce to print -pamphlets and appeals to charity. And if those of humbler degree think -they can strike eloquence from the keys, they too will of course be -allowed to turn out their ideas literally by the yard. - - - - -PHOTOGRAPHY IN COLOURS. - - -While photography was still in its infancy many people believed that, -a means having been found of impressing the representation of an -object on a sensitised surface, a short time only would have to elapse -before the discovery of some method of registering the colours as well -as the forms of nature. - -Photography has during the last forty years passed through some -startling developments, especially as regards speed. Experts, such as -M. Marey, have proved the superiority of the camera over the human eye -in its power to grasp the various phases of animal motion. Even rifle -bullets have been arrested in their lightning flight by the sensitised -plate. But while the camera is a valuable aid to the eye in the matter -of form, the eye still has the advantage so far as colour is -concerned. It is still impossible for a photographer by a simple -process similar to that of making an ordinary black-and-white -negative, to affect a plate in such a manner that from it prints may -be made by a single operation showing objects in their natural -colours. Nor, for the matter of that, does colour photography direct -from nature seem any nearer attainment now than it was in the time of -Daguerre. - -There are, however, extant several methods of making colour -photographs in an indirect or roundabout way. These various "dodges" -are, apart from their beautiful results, so extremely ingenious and -interesting that we propose to here examine three of the best known. - -The reader must be careful to banish from his mind those _coloured_ -photographs so often to be seen in railway carriages and shop windows, -which are purely the result of hand-work and mechanical printing, and -therefore not _colour_ photographs at all. - -Before embarking on an explanation of these three methods it will be -necessary to examine briefly the nature of those phenomena on which -all are based--light and colour. The two are really identical, light -is colour and colour is light. - -Scientists now agree that the sensation of light arises from the -wave-like movements of that mysterious fluid, the omnipresent ether. -In a beam of white light several rates of wave vibrations exist side -by side. Pass the beam through a prism and the various rapidities are -sorted out into violet, indigo, blue, green, yellow, orange and red, -which are called the pure colours, since if any of them be passed -again through a prism the result is still that colour. Crimson, brown, -&c., the composite colours, would, if subjected to the prism, at once -split up into their component pure colours. - -There are several points to be noticed about the relationship of the -seven pure colours. In the first place, though they are all allies in -the task of making white light, there is hostility among them, each -being jealous of the others, and only waiting a chance to show it. -Thus, suppose that we have on a strip of paper squares of the seven -colours, and look at the strip through a piece of red glass we see -only one square--the red--in its natural colour, since that square is -in harmony only with red rays. (Compare the sympathy of a piano with a -note struck on another instrument; if C is struck, say on a violin, -the piano strings producing the corresponding note will sound, but the -other strings will be silent.) The orange square suggests orange, but -the green and blue and violet appear black. Red glass has arrested -their ether vibrations and said "no way here." Green and violet would -serve just the same trick on red or on each other. It is from this -readiness to absorb or stop dissimilar rays that we have the different -colours in a landscape flooded by a common white sunlight. The trees -and grass absorb all but the green rays, which they reflect. The -dandelions and buttercups capture and hold fast all but the yellow -rays. The poppies in the corn send us back red only, and the -cornflowers only blue; but the daisy is more generous and gives up all -the seven. Colour therefore is not a thing that can be touched, any -more than sound, but merely the capacity to affect the retina of the -eye with a certain number of ether vibrations per second, and it makes -no difference whether light is reflected from a substance or refracted -through a substance; a red brick and a piece of red glass have similar -effects on the eye. - -This then is the first thing to be clearly grasped, that whenever a -colour has a chance to make prisoners of other colours it will do so. - -The second point is rather more intricate, viz. that this imprisonment -is going on even when friendly concord appears to be the order of the -day. Let us endeavour to present this clearly to the reader. Of the -pure colours, violet, green and red--the extremes and the centre--are -sufficient to produce white, because each contains an element of its -neighbours. Violet has a certain amount of indigo, green some yellow, -red some orange; in fact every colour of the spectrum contains a -greater or less degree of several of the others, but not enough to -destroy its own identity. Now, suppose that we have three lanterns -projecting their rays on to the same portion of a white sheet, and -that in front of the first is placed a violet glass, in front of the -second a green glass, in front of the third a red glass. What is the -result? A white light. Why? Because they meet _on equal terms_, and as -no one of them is in a point of advantage no prisoners can be made and -they must work in harmony. Next, turn down the violet lantern, and -green and red produce a yellow, half-way between them; turn down red -and turn up violet, indigo-blue results. All the way through a -compromise is effected. - -But supposing that the red and green glasses are put in front of the -_same_ lantern and the white light sent through them--where has the -yellow gone to? only a brownish-black light reaches the screen. The -same thing happens with red and violet or green and violet. - -Prisoners have been taken, because one colour has had to _demand -passage_ from the other. Red says to green, "You want your rays to -pass through me, but they shall not." Green retorts, "Very well; but I -myself have already cut off all but green rays, and if they don't pass -you, nothing shall." And the consequence of the quarrel is practical -darkness. - -The same phenomenon may be illustrated with blue and yellow. Lights of -these two colours projected simultaneously on to a sheet yield white; -but white light sent through blue and yellow glass _in succession_ -produces a green light. Also, blue paint mixed with yellow gives -green. In neither case is there darkness or entire cutting-off of -colour, as in the case of Red + Violet or Green + Red. - -The reason is easy to see. - -Blue light is a compromise of violet and green; yellow of green and -red. Hence the two coloured lights falling on the screen make a -combination which can be expressed as an addition sum. - - Blue = green + violet. - Yellow = green + red. - -------------------- - green + violet + red = white. - -But when light is passed _through_ two coloured glasses in succession, -or reflected from two layers of coloured paints, there are prisoners -to be made. - -Blue passes green and violet only. - -Yellow passes green and red only. - -So violet is captured by yellow, and red by blue, green being free to -pass on its way. - -There is, then, a great difference between the _mixing_ of colours, -which evokes any tendency to antagonism, and the _adding_ of colours -under such conditions that they meet on equal terms. The first process -happens, as we have seen, when a ray of light is passed through -colours _in succession_; the second, when lights stream simultaneously -on to an object. A white screen, being capable of reflecting any -colour that falls on to it, will with equal readiness show green, red, -violet, or a combination; but a substance that is in white light red, -or green, or violet will capture any other colour. So that if for the -white screen we substituted a red one, violet or green falling -simultaneously, would yield blackness, because red takes _both_ -prisoners; if it were violet, green would be captured, and so on. - -From this follows another phenomenon: that whereas projection of two -or more lights may yield white, white cannot result from any mixture -of pigments. A person with a whole boxful of paints could not get -white were he to mix them in an infinitude of different ways; but with -the aid of his lanterns and as many differently coloured glasses the -feat is easy enough. - -Any two colours which meet on equal terms to make white are called -_complementary_ colours. - - Thus yellow (= red + green lights) is complementary of violet. - - Thus pink (= red + violet lights) is complementary of green. - - Thus blue (= violet + green lights) is complementary of red. - -This does not of course apply to mixture of paints, for complementary -colours must act together, not in antagonism. - -If the reader has mastered these preliminary considerations he will -have no difficulty in following out the following processes. - -(_a_) _The Joly Process_, invented by Professor Joly of Dublin. A -glass plate is ruled across with fine parallel lines--350 to the inch, -we believe. These lines are filled in alternately with violet, green, -and red matter, every third being violet, green or red as the case may -be. The colour-screen is placed in the camera in front of the -sensitised plate. Upon an exposure being made, all light reflected -from a red object (to select a colour) is allowed to pass through the -red lines, but blocked by all the green and violet lines. So that on -development that part of the negative corresponding to the position of -the red object will be covered with dark lines separated by -transparent belts of twice the breadth. From the negative a positive -is printed, which of course shows transparent lines separated by -opaque belts of twice their breadth. Now, suppose that we take the -colour-screen and place it again in front of the plate in the position -it occupied when the negative was taken, the red lines being opposite -the transparent parts of the positive will be visible, but the green -and violet being blocked by the black deposit behind them will not be -noticeable. So that the object is represented by a number of red -lines, which at a small distance appear to blend into a continuous -whole. - -The violet and green affect the plate in a corresponding manner; and -composite colours will affect two sets of lines in varying degrees, -the lights from the two sets blending in the eye. Thus yellow will -obtain passage from both green and red, and when the screen is held up -against the positive, the light streaming through the green and red -lines will blend into yellow in the same manner as they would make -yellow if projected by lanterns on to a screen. The same applies to -all the colours. - -The advantage of the Joly process is that in it only one negative has -to be made. - -(_b_) _The Ives Process._--Mr. Frederic Eugene Ives, of Philadelphia, -arrives at the same result as Professor Joly, but by an entirely -different means. He takes three negatives of the same object, one -through a violet-blue, another through a green, and a third through a -red screen placed in front of the lens. The red negative is affected -by red rays only; the green by green rays only, and the violet-blue by -violet-blue rays only, in the proper gradations. That is to say, each -negative will have opaque patches wherever the rays of a certain kind -strike it; and the positive printed off will be by consequence -transparent at the same places. By holding the positive made from the -red-screen negative against a piece of red glass, we should see light -only in those parts of the positive which were transparent. Similarly -with the green and violet positives if viewed through glasses of -proper colour. The most ingenious part of Mr. Ives' method is the -apparatus for presenting all three positives (lighted through their -coloured glasses) to the eye simultaneously. When properly adjusted, -so that their various parts exactly coincide, the eye blends the three -together, seeing green, red, or violet separately, or blended in -correct proportions. The Kromoscope, as the viewing apparatus is -termed, contains three mirrors, projecting the reflections from the -positives in a single line. As the three slides are taken -stereoscopically the result gives the impression of solidity as well -as of colour, and is most realistic. - -(_c_) _The Sanger Shepherd Process._--This is employed mostly for -lantern transparencies. As in the Ives process, three negatives and -three transparent positives are made. But instead of coloured glasses -being used to give effect to the positives the positives themselves -are dyed, and placed one on the top of another in close contact, so -that the light from the lantern passes through them in succession. We -have therefore now quitted the realms of harmony for that of discord, -in which prisoners are made; and Mr. Shepherd has had to so arrange -matters that in every case the capture of prisoners does not interfere -with the final result, but conduces to it. - -In the first place, three negatives are secured through violet, green, -and red screens. Positives are printed by the carbon process on thin -celluloid films. The carbon film contains gelatine and bichromate of -potassium. The light acts on the bichromate in such a way as to render -the gelatine insoluble. The result is that, though in the positives -there is at first no colour, patches of gelatine are left which will -absorb dyes of various colours. The dyeing process requires a large -amount of care and patience. - -Now, it would be a mistake to suppose that each positive is dyed in -the colour of the screen through which its negative was taken. A -moment's consideration will show us why. - -Let us assume that we are photographing a red object, a flower-pot for -instance. The red negative represents the pot by a dark deposit. The -positive printed off will consequently show clear glass at that spot, -the unaffected gelatine being soluble. So that to dye the plate would -be to make all red _except_ the very part which we require red; and on -holding it up to the light the flower-pot would appear as a white -transparent patch. - -How then is the problem to be solved? - -Mr. Shepherd's process is based upon an ordered system of -prisoner-taking. Thus, as red in this particular case is wanted it -will be attained by the _other two_ positives (which are placed in -contact with the red positive, so that all three coincide exactly), -robbing white light of all _but_ its red rays. - -Now if the other positives were dyed green and violet, what would -happen? They would not produce red, but by robbing white light between -them of red, green, and violet, would produce blackness, and we should -be as far as ever from our object. - -The positives are therefore dyed, not in the same colours as the -screens used when the negatives were made, but in their -_complementary_ colours, _i.e._ as explained above, those colours -which added to the colour of the screen would make white. - -The red screen negative is therefore dyed (violet + green) = blue. The -green negative (red + violet) = pink. The violet negative (red + -green) = yellow. - -To return to our flower-pot. The red-screen positive (dyed blue) is, -as we saw, quite transparent where the pot should be. But behind the -transparent gap are the pink and yellow positives. - -White light (= violet + green + red) passes through pink (= violet + -red), and has to surrender all its green rays. The violet and red pass -on and encounter yellow (= green + red), and violet falls a victim to -green, leaving red unmolested. - -If the flower-pot had been white all three positives would have -contained clear patches unaffected by the three dyes, and the white -light would have been unobstructed. The gradations and mixtures of -colours are obtained by two of the screens being influenced by the -colour of the object. Thus, if it were crimson, both violet and -red-screen negatives would be affected by the rays reflected by it, -and the green screen negative not at all. Hence the pink positive -would be pink, the yellow clear, and the blue clear. - -White light passing through is robbed by pink of green, leaving red + -violet = crimson. - - -COLOUR PRINTING. - -Printing in ink colours is done in a manner very similar to the Sanger -Shepherd lantern slide process. Three blocks are made, by the help of -photography, through violet, green and red screens, and etched away -with acid, like ordinary half-tone black-and-white blocks. The three -blocks have applied to them ink of a complementary colour to the -screen they represent, just as in the Sanger Shepherd process the -positives were dyed. The three inks are laid over one another on the -paper by the blocks, the relieved parts of which (corresponding to the -undissolved gelatine of the Shepherd positives) only take the ink. -White light being reflected through layers of coloured inks is treated -in just the same way as it would be were it transmitted through -coloured glasses, yielding all the colours in approximately correct -gradations. - - - - -LIGHTING. - - -The production of fire by artificial means has been reasonably -regarded as the greatest invention in the history of the human race. -Prior to the day when a man was first able to call heat from the -substances about him the condition of our ancestors must have been -wretched indeed. Raw food was their portion; metals mingled with other -matter mocked their efforts to separate them; the cold of winter drove -them to the recesses of gloomy caverns, where night reigned perpetual. - -The production of fire also, of course, entailed the creation of -light, which in its developments has been of an importance second only -to the improved methods of heating. So accustomed are we to our -candles, our lamps, our gas-jets, our electric lights, that it is hard -for us to imagine what an immense effect their sudden and complete -removal would have on our existence. At times, when floods, -explosions, or other accidents cause a temporary stoppage of the gas -or current supply, a town may for a time be plunged into darkness; but -this only for a short period, the distress of which can be alleviated -by recourse to paraffin lamps, or the more homely candle. - -The earliest method of illumination was the rough-and-ready one of -kindling a pile of brushwood or logs. The light produced was very -uncertain and feeble, but possibly sufficient for the needs of the -cave-dweller. With the advance of civilisation arose an increasing -necessity for a more steady illuminant, discovered in vegetable oils, -burned in lamps of various designs. Lamps have been found in old -Egyptian and Etruscan tombs constructed thousands of years ago. These -lamps do not differ essentially from those in use to-day, being -reservoirs fitted with a channel to carry a wick. - -But probably from the difficulty of procuring oil, lamps fell into -comparative disuse, or rather were almost unknown, in many countries -of Europe as late as the fifteenth century; when the cottage and -baronial hall were alike lit by the blazing torch fixed into an iron -sconce or bracket on the wall. - -The rushlight, consisting of a peeled rush, coated by repeated dipping -into a vessel of melted fat, made a feeble effort to dispel the gloom -of long winter evenings. This was succeeded by the tallow and more -scientifically made wax candle, which last still maintains a certain -popularity. - -How our grandmothers managed to "keep their eyes" as they worked at -stitching by the light of a couple of candles, whose advent was the -event of the evening, is now a mystery. To-day we feel aggrieved if -our lamps are not of many candle-power, and protest that our sight -will be ruined by what one hundred and fifty years ago would have -seemed a marvel of illumination. In the case of lighting necessity has -been the mother of invention. The tendency of modern life is to turn -night into day. We go to bed late and we get up late; this is perhaps -foolish, but still we do it. And, what is more, we make increasing use -of places, such as basements, underground tunnels, and "tubes," to -which the light of heaven cannot penetrate during any of the daily -twenty-four hours. - -The nineteenth century saw a wonderful advance in the science of -illumination. As early as 1804 the famous scientist, Sir Humphrey -Davy, discovered the electric arc, presently to be put to such -universal use. About the same time gas was first manufactured and led -about in pipes. But before electricity for lighting purposes had been -rendered sufficiently cheap the discovery of the huge oil deposits in -Pennsylvania flooded the world with an inexpensive illuminant. As -early as the thirteenth century Marco Polo, the explorer, wrote of a -natural petroleum spring at Baku, on the Caspian Sea: "There is a -fountain of great abundance, inasmuch as a thousand shiploads might be -taken from it at one time. This oil is not good to use with food, but -it is _good to burn_; and is also used to anoint camels that have the -mange. People come from vast distances to fetch it, for in all other -countries there is no oil." His last words have been confuted by the -American oil-fields, yielding many thousands of barrels a day--often -in such quantities that the oil runs to waste for lack of a buyer. - -The rivals for pre-eminence in lighting to-day are electricity, coal -gas, petroleum, and acetylene gas. The two former have the advantage -of being easily turned on at will, like water; the third is more -generally available. - -The invention of the dynamo by Gramme in 1870 marks the beginning of -an epoch in the history of illumination. With its aid current of such -intensity as to constantly bridge an air-gap between carbon points -could be generated for a fraction of the cost entailed by other -previous methods. Paul Jablochkoff devised in 1876 his "electric -candle"--a couple of parallel carbon rods separated by an insulating -medium that wasted away under the influence of heat at the same rate -as the rods. The "candles" were used with rapidly-alternating -currents, as the positive "pole" wasted twice as quickly as the -negative. During the Paris Exhibition of 1878 visitors to Paris were -delighted by the new method of illumination installed in some of the -principal streets and theatres. - -The arc-lamp of to-day, such as we see in our streets, factories, and -railway stations, is a modification of M. Jablochkoff's principle. -Carbon rods are used, but they are pointed towards each other, the -distance between their extremities being kept constant by ingenious -mechanical contrivances. Arc-lamps of all types labour under the -disadvantage of being, by necessity, very powerful; and were they only -available the employment of electric lighting would be greatly -restricted. As it is, we have, thanks to the genius of Mr. Edison, a -means of utilising current in but small quantities to yield a gentler -light. The glow-lamp, as it is called, is so familiar to us that we -ought to know something of its antecedents. - -In the arc-lamp the electric circuit is _broken_ at the point where -light is required. In glow or incandescent lamps the current is only -_hindered_ by the interposition of a bad conductor of electricity, -which must also be incombustible. Just as a current of water flows in -less volume as the bore of a pipe is reduced, and requires that -greater pressure shall be exerted to force a constant amount through -the pipe, so is an electric current _choked_ by its conductor being -reduced in size or altered in nature. Edison in 1878 employed as the -current-choker a very fine platinum wire, which, having a melting -temperature of 3450 degrees Fahrenheit, allowed a very white heat to -be generated in it. The wire was enclosed in a glass bulb almost -entirely exhausted of air by a mercury-pump before being sealed. But -it was found that even platinum could not always withstand the heating -effect of a strong current; and accordingly Edison looked about for -some less combustible material. Mr. J. W. Swan of Newcastle-on-Tyne -had already experimented with carbon filaments made from cotton -threads steeped in sulphuric acid. Edison and Swan joined hands to -produce the present well-known lamp, "The Ediswan," the filament of -which is a bamboo fibre, carbonised during the exhaustion of air in -the bulb to one-millionth of an atmosphere pressure by passing the -electric current through it. These bamboo filaments are very elastic -and capable of standing almost any heat. - -Glow-lamps are made in all sizes--from tiny globes small enough to top -a tie-pin to powerful lamps of 1000 candle-power. Their independence -of atmospheric air renders them most convenient in places where other -forms of illumination would be dangerous or impossible; _e.g._ in coal -mines, and under water during diving operations. By their aid great -improvements have been effected in the lighting of theatres, which -require a quick switching on and off of light. They have also been -used in connection with minute cameras to explore the recesses of the -human body. In libraries they illuminate without injuring the books. -In living rooms they do not foul the air or blacken the ceiling like -oil or gas burners. The advantages of the "Edison lamp" are, in short, -multitudinous. - -Cheapness of current to work them is, of course, a very important -condition of their economy. In some small country villages the -cottages are lit by electricity even in England, but these are -generally within easy reach of water power. Mountainous districts, -such as Norway and Switzerland, with their rushing streams and high -water-falls, are peculiarly suited for electric lighting: the cost of -which is mainly represented by the expense of the generating apparatus -and the motive power. - -One of the greatest engineering undertakings in the world is connected -with the manufacture of electric current. Niagara, the "Thunder of the -Waters" as the Indians called it, has been harnessed to produce -electrical energy, convertible at will into motion, heat, or light. -The falls pass all the water overflowing from nearly 100,000 square -miles of lakes, which in turn drain a far larger area of territory. -Upwards of 10,000 cubic yards of water leap over the falls every -second, and are hurled downwards for more than 200 feet, with an -energy of eight or nine million horse-power! In 1886 a company -determined to turn some of this huge force to account. They bought up -land on the American bank, and cut a tunnel 6700 yards long, beginning -a mile and a half above the falls, and terminating below them. Water -drawn from the river thunders into the tunnel through a number of -wheel pits, at the bottom of each of which is a water-turbine -developing 5000 horse-power. The united force of the turbines is said -to approximate 100,000 horse-power; and as if this were but a small -thing, the same Company has obtained concessions to erect plant on the -Canadian bank to double or treble the total power. - -So cheaply is current thus produced that the Company is in a position -to supply it at rates which appear small compared with those that -prevail in this country. A farthing will there purchase what would -here cost from ninepence to a shilling. Under such conditions the -electric lamp need fear no competitor. - -But in less favoured districts gas and petroleum are again holding up -their heads. - -Both coal and oil-gas develop a great amount of heat in proportion to -the light they yield. The hydrogen they contain in large quantities -burns, when pure, with an almost invisible flame, but more hotly than -any other known gas. The particles of carbon also present in the flame -are heated to whiteness by the hydrogen, but they are not sufficient -in number to convert more than a fraction of the heat into light. - -A German, Auer von Welsbach, conceived the idea of suspending round -the flame a circular "mantle" of woven cotton steeped in a solution of -certain rare earths (_e.g._ lanthanum, yttrium, zirconium), to arrest -the heat and compel it to produce bright incandescence in the -arresting substance. - -With the same gas consumption a Welsbach burner yields seven or more -times the light of an ordinary batswing burner. The light itself is -also of a more pleasant description, being well supplied with the blue -rays of the spectrum. - -The mantle is used with other systems than the ordinary gas-jet. -Recently two methods of illumination have been introduced in which the -source of illumination is supplied under pressure. - -The high-pressure incandescent gas installations of Mr. William Sugg -supply gas to burners at five or six times the ordinary pressure of -the mains. The effect is to pulverise the gas as it issues from the -nozzle of the burners, and, by rendering it more inflammable, to -increase its heating power until the surrounding mantle glows with a -very brilliant and white light of great penetration. Gas is forced -through the pipes connected with the lamps by hydraulic rams working -gas-pumps, which alternately suck in and expel the gas under a -pressure of twelve inches (_i.e._ a pressure sufficient to maintain a -column of water twelve inches high). The gas under this pressure -passes into a cylinder of a capacity considerably greater than the -capacity of the pumps. This cylinder neutralises the shock of the -rams, when the stroke changes from up-to downstroke, and _vice versa_. -On the top of the cylinder is fixed a governor consisting of a strong -leathern gas-holder, which has a stroke of about three inches, and -actuates a lever which opens and closes the valve through which the -supply of water to the rams flows, and reduces the flow of the water -when it exceeds ten or twelve inches pressure, according to -circumstances. The gas-holder of the governor is lifted by the -pressure of the gas in the cylinder, which passes through a small -opening from the cylinder to the governor so as not to cause any -sudden rise or fall of the gas-holder. By this means a nearly constant -pressure is maintained; and from the outlet of the cylinder the gas -passes to another governor sufficient to supply the number of lights -the apparatus is designed for, and to maintain the pressure without -variation whether all or a few lamps are in action. For very large -installations steam is used. - -Each burner develops 300 candle-power. A double-cylinder steam-engine -working a double pump supplies 300 of these burners, giving a total -lighting-power of 90,000 candles. As compared with the cost of -low-pressure incandescent lighting the high-pressure system is very -economical, being but half as expensive for the same amount of light. - -It is largely used in factories and railway stations. It may be seen -on the Tower Bridge, Blackfriars Bridge, Euston Station, and in the -terminus of the Great Central Railway, St. John's Wood. - -Perhaps the most formidable rival to the electric arc-lamp for the -lighting of large spaces and buildings is the Kitson Oil Lamp, now so -largely used in America and this country. - -The lamp is usually placed on the top of an iron post similar to an -ordinary gas-light standard. At the bottom of the post is a chamber -containing a steel reservoir capable of holding from five to forty -gallons of petroleum. Above the oil is an air-space into which air has -been forced at a pressure of fifty lbs. to the square inch, to act as -an elastic cushion to press the oil into the burners. The oil passes -upwards through an extremely fine tube scarcely thicker than electric -incandescent wires to a pair of cross tubes above the burners. The top -one of these acts as a filter to arrest any foreign matter that finds -its way into the oil; the lower one, in diameter about the size of a -lead-pencil and eight inches long, is immediately above the mantles, -the heat from which vaporises the small quantity of oil in the tube. -The oil-gas then passes through a tiny hole no larger than a -needle-point into an open mixing-tube where sufficient air is drawn in -for supporting combustion. The mixture then travels down to the -mantle, inside which it burns. - -An ingenious device has lately been added to the system for -facilitating the lighting of the lamp. At the base of the lamp-post a -small hermetically-closed can containing petroleum ether is placed, -and connected by very fine copper-tubing with a burner under the -vaporising tube. When the lamp is to be lit a small rubber bulb is -squeezed, forcing a quantity of the ether vapour into the burner, -where it is ignited by a platinum wire rendered incandescent by a -current passing from a small accumulator also placed in the lamp-post. -The burner rapidly heats the vaporising tube, and in a few moments -oil-gas is passing into the mantles, where it is ignited by the -burner. - -So economical is the system that a light of 1000 candle-power is -produced by the combustion of about half-a-pint of petroleum per hour! -Comparisons are proverbially odious, but in many cases very -instructive. Professor V. B. Lewes thus tabulates the results of -experiments with various illuminants:-- - -_Cost of 1000 candles per hour._ - - _s. d._ - Electricity Per unit, 3-1/2d. - " Incandescent, 1 2 - " Arc, 0 3-3/4 - Coal-gas Flat flame, 1 6 - " Incandescent, 0 2-1/4 - " " high pressure, 0 1-3/4 - Oil Lamp (oil at 8d. per gall.), 0 7-1/4 - " Incandescent lamp, 0 2-1/4 - " Kitson lamp, 0 1 - -Petroleum, therefore, at present comes in a very good first in -England. - -The system that we have noticed at some length has been adapted for -lighthouse use, as it gives a light peculiarly fog-piercing. It is -said to approximate most closely to ordinary sunlight, and on that -account has been found very useful for the taking of photographs at -night-time. The portability of the apparatus makes it popular with -contractors; and the fact that its installation requires no tearing up -of the streets is a great recommendation with the long-suffering -public of some of our large towns. - -Another very powerful light is produced by burning the gas given off -by carbide of calcium when immersed in water. _Acetylene_ gas, as it -is called, is now widely used in cycle and motor lamps, which emit a -shaft of light sometimes painfully dazzling to those who have to face -it. In Germany the gas is largely employed in village streets; and in -this country it is gaining ground as an illuminant of country houses, -being easy to manufacture--in small gasometers of a few cubic yards -capacity--and economical to burn. - -Well supplied as we are with lights, we find, nevertheless, that -savants are constantly in pursuit of an _ideal_ illuminant. - -From the sun are borne to us through the ether light waves, heat -waves, magnetic waves, and other waves of which we have as yet but a -dim perception. The waves are commingled, and we are unable to -separate them absolutely. And as soon as we try to copy the sun's -effects as a source of heat or light we find the same difficulty. The -fire that cooks our food gives off a quantity of useless light-waves; -the oil-lamp that brightens one's rooms gives off a quantity of -useless, often obnoxious, heat. - -The ideal illuminant and the ideal heating agent must be one in which -the required waves are in a great majority. Unfortunately, even with -our most perfected methods, the production of light is accompanied by -the exertion of a disproportionate amount of wasted energy. In the -ordinary incandescent lamp, to take an instance, only 5 or 6 per cent. -of the energy put into it as electricity results in light. The rest is -dispelled in overcoming the resistance of the filament and agitating -the few air-molecules in the bulb. To this we must add the fact that -the current itself represents but a fraction of the power exerted to -produce it. The following words of Professor Lodge are to the point on -this subject:-- - -"Look at the furnaces and boilers of a steam-engine driving a group of -dynamos, and estimate the energy expended; and then look at the -incandescent filaments of the lamps excited by them, and estimate how -much of their radiated energy is of real service to the eye. It will -be as the energy of a pitch-pipe to an entire orchestra. - -"It is not too much to say that a boy turning a handle could, if his -energy were properly directed, produce quite as much real light as is -produced by all this mass of mechanism and consumption of -material."[6] - - [6] Professor Oliver Lodge, in a lecture to the Ashmolean - Society, 3rd June 1889. - -The most perfect light in nature is probably that of the glow-worm and -firefly--a phosphorescent or "cold" light, illuminating without -combustion owing to the absence of all waves but those of the -requisite frequency. The task before mankind is to imitate the -glow-worm in the production of isolated light-waves. - -The nearest approach to its achievement has occurred in the -laboratories of Mr. Nikola Tesla, the famous electrician. By means of -a special oscillator, invented by himself, he has succeeded in -throwing the ether particles into such an intense state of vibration -that they become luminous. In other words, he has created vibrations -of the enormous rapidity of light, and this without the creation of -heat waves to any appreciable extent. - -An incandescent lamp, mounted on a powerful coil, is lit _without_ -contact by ether waves transmitted from a cable running round the -laboratory, or bulbs and tubes containing highly rarefied gases are -placed between two large plate-terminals arranged on the end walls. As -soon as the bulbs are held in the path of the currents passing through -the ether from plate to plate they become incandescent, shining with a -light which, though weak, is sufficiently strong to take photographs -by with a long exposure. Tesla has also invented what he calls a -"sanitary" light, as he claims for it the germ-killing properties of -sunshine. The lamps are glass tubes several feet long, bent into -spirals or other convolutions, and filled before sealing with a -certain gas. The ends of the glass tube are coated with metal and -provided with hooks to connect the lamp with an electric current. The -gas becomes _luminous_ under the influence of current, but not -strictly incandescent, as there is very little heat engendered. This -means economy in use. The lamps are said to be cheaply manufactured, -but as yet they are not "on the market." We shall hear more of them in -the near future, which will probably witness no more interesting -development than that of lighting. - -Before closing this chapter a few words may be said about new heating -methods. Gas stoves are becoming increasingly popular by reason of the -ease with which they can be put in action and made to maintain an even -temperature. But the most up-to-date heating apparatus is undoubtedly -electrical. Utensils of all sorts are fitted with very thin heating -strips (formed by the deposition of precious metals, such as gold, -platinum, &c., on exceedingly thin mica sheets), through which are -passed powerful currents from the mains. The resistance of the strip -converts the electromotive energy of the current into heat, which is -either radiated into the air or into water for cookery, &c. - -In all parts of the house the electric current may be made to do work -besides that of lighting. It warms the passages by means of special -radiators--replacing the clumsy coal and "stuffy" gas stove; in the -kitchen it boils, stews, and fries, heats the flat-irons and ovens; in -the breakfast room boils the kettle, keeps the dishes, teapots, and -coffee-pots warm; in the bathroom heats the water; in the smoking-room -replaces matches; in the bedroom electrifies footwarmers, and--last -wonder of all--even makes possible an artificially warm bed-quilt to -heat the chilled limbs of invalids! - -The great advantage of electric heating is the freedom from all smell -and smoke that accompanies it. But until current can be provided at -cheaper rates than prevail at present, its employment will be chiefly -restricted to the houses of the wealthy or to large establishments, -such as hotels, where it can be used on a sufficient scale to be -comparatively economical. - - THE END - - - Printed by BALLANTYNE, HANSON & CO. - Edinburgh & London - - - * * * * * - - - The Romance of Modern Invention - - - _BY THE SAME AUTHOR_ - - _Uniform with this Volume_ - - - THE ROMANCE OF MODERN ENGINEERING - - Containing Interesting Descriptions in Non-Technical Language - of the Nile Dam, the Panama Canal, the Tower Bridge, the - Brooklyn Bridge, the Trans-Siberian Railway, the Niagara Falls - Power Co., Bermuda Floating Dock, etc. etc. - - "A series of descriptions which rival one another in - lucidity of explanation and in interest, both of subject and - treatment."--_Manchester Courier._ - - "Men of any age will be interested in this volume; - boys will be fascinated by it."--_Spectator._ - - "If there lives a boy who is fond of engineering and - speaks the English tongue, this is the book for him."--_The - Bookman._ - - - _With 24 Illustrations. Gilt edges. Price 5s._ - - - - THE ROMANCE OF MODERN LOCOMOTION - - Containing Interesting Descriptions in Non-Technical Language - of the Rise and Development of the Railroad Systems in all - Parts of the World. - - - "The book is crisply written, is brimful of incident not - less than instruction, and should be as welcome to an intelligent - lad as a Ballantyne story or a Mayne Reid romance."--_Glasgow - Herald._ - - - _With 25 Illustrations. Crown 8vo, cloth Gilt, Gilt edges. Price 5s._ - - - * * * * * - - _UNIFORM WITH THIS VOLUME_ - - THE LIBRARY OF ROMANCE - - _Extra Crown 8vo. With many illustrations, 5s. each_ - - - "Messrs. Seeley's well-known series of gift books, finely - illustrated and in most attractive bindings." - - _The Northern Whig._ - - "These popular natural history books are written by competent - authorities, and besides being entertaining are instructive and - educative."--_The Liverpool Courier._ - - - By Prof. G. F. SCOTT ELLIOT, M.A., B.Sc. - - THE ROMANCE OF PLANT LIFE - - - By H. COUPIN, D.Sc., & JOHN LEA, B.A. - - THE ROMANCE OF ANIMAL ARTS AND CRAFTS - - - By the Rev. J. C. LAMBERT, M.A., D.D. - - THE ROMANCE OF MISSIONARY HEROISM - - - By G. FIRTH SCOTT - - THE ROMANCE OF POLAR EXPLORATION - - - By ARCHIBALD WILLIAMS, F.R.G.S. - - THE ROMANCE OF EARLY EXPLORATION - THE ROMANCE OF MODERN EXPLORATION - THE ROMANCE OF MODERN MECHANISM - THE ROMANCE OF MODERN INVENTION - THE ROMANCE OF MODERN ENGINEERING - THE ROMANCE OF MODERN LOCOMOTION - THE ROMANCE OF MODERN MINING - - - By CHARLES R. GIBSON, A.I.E.E. - - THE ROMANCE OF MODERN ELECTRICITY - - - By EDMUND SELOUS - - THE ROMANCE OF THE ANIMAL WORLD - THE ROMANCE OF INSECT LIFE - - - By AGNES GIBERNE - - THE ROMANCE OF THE MIGHTY DEEP - - - SEELEY & Co., LIMITED - - - - - -End of the Project Gutenberg EBook of The Romance of Modern Invention, by -Archibald Williams - -*** END OF THIS PROJECT GUTENBERG EBOOK THE ROMANCE OF MODERN INVENTION *** - -***** This file should be named 41160.txt or 41160.zip ***** -This and all associated files of various formats will be found in: - http://www.gutenberg.org/4/1/1/6/41160/ - -Produced by Chris Curnow, Matthew Wheaton and the Online -Distributed Proofreading Team at http://www.pgdp.net (This -file was produced from images generously made available -by The Internet Archive) - - -Updated editions will replace the previous one--the old editions -will be renamed. - -Creating the works from public domain print editions means that no -one owns a United States copyright in these works, so the Foundation -(and you!) can copy and distribute it in the United States without -permission and without paying copyright royalties. Special rules, -set forth in the General Terms of Use part of this license, apply to -copying and distributing Project Gutenberg-tm electronic works to -protect the PROJECT GUTENBERG-tm concept and trademark. Project -Gutenberg is a registered trademark, and may not be used if you -charge for the eBooks, unless you receive specific permission. If you -do not charge anything for copies of this eBook, complying with the -rules is very easy. You may use this eBook for nearly any purpose -such as creation of derivative works, reports, performances and -research. They may be modified and printed and given away--you may do -practically ANYTHING with public domain eBooks. Redistribution is -subject to the trademark license, especially commercial -redistribution. - - - -*** START: FULL LICENSE *** - -THE FULL PROJECT GUTENBERG LICENSE -PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK - -To protect the Project Gutenberg-tm mission of promoting the free -distribution of electronic works, by using or distributing this work -(or any other work associated in any way with the phrase "Project -Gutenberg"), you agree to comply with all the terms of the Full Project -Gutenberg-tm License available with this file or online at - www.gutenberg.org/license. - - -Section 1. General Terms of Use and Redistributing Project Gutenberg-tm -electronic works - -1.A. By reading or using any part of this Project Gutenberg-tm -electronic work, you indicate that you have read, understand, agree to -and accept all the terms of this license and intellectual property -(trademark/copyright) agreement. If you do not agree to abide by all -the terms of this agreement, you must cease using and return or destroy -all copies of Project Gutenberg-tm electronic works in your possession. -If you paid a fee for obtaining a copy of or access to a Project -Gutenberg-tm electronic work and you do not agree to be bound by the -terms of this agreement, you may obtain a refund from the person or -entity to whom you paid the fee as set forth in paragraph 1.E.8. - -1.B. "Project Gutenberg" is a registered trademark. It may only be -used on or associated in any way with an electronic work by people who -agree to be bound by the terms of this agreement. There are a few -things that you can do with most Project Gutenberg-tm electronic works -even without complying with the full terms of this agreement. See -paragraph 1.C below. There are a lot of things you can do with Project -Gutenberg-tm electronic works if you follow the terms of this agreement -and help preserve free future access to Project Gutenberg-tm electronic -works. See paragraph 1.E below. - -1.C. The Project Gutenberg Literary Archive Foundation ("the Foundation" -or PGLAF), owns a compilation copyright in the collection of Project -Gutenberg-tm electronic works. Nearly all the individual works in the -collection are in the public domain in the United States. If an -individual work is in the public domain in the United States and you are -located in the United States, we do not claim a right to prevent you from -copying, distributing, performing, displaying or creating derivative -works based on the work as long as all references to Project Gutenberg -are removed. Of course, we hope that you will support the Project -Gutenberg-tm mission of promoting free access to electronic works by -freely sharing Project Gutenberg-tm works in compliance with the terms of -this agreement for keeping the Project Gutenberg-tm name associated with -the work. You can easily comply with the terms of this agreement by -keeping this work in the same format with its attached full Project -Gutenberg-tm License when you share it without charge with others. - -1.D. The copyright laws of the place where you are located also govern -what you can do with this work. Copyright laws in most countries are in -a constant state of change. If you are outside the United States, check -the laws of your country in addition to the terms of this agreement -before downloading, copying, displaying, performing, distributing or -creating derivative works based on this work or any other Project -Gutenberg-tm work. The Foundation makes no representations concerning -the copyright status of any work in any country outside the United -States. - -1.E. Unless you have removed all references to Project Gutenberg: - -1.E.1. The following sentence, with active links to, or other immediate -access to, the full Project Gutenberg-tm License must appear prominently -whenever any copy of a Project Gutenberg-tm work (any work on which the -phrase "Project Gutenberg" appears, or with which the phrase "Project -Gutenberg" is associated) is accessed, displayed, performed, viewed, -copied or distributed: - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org - -1.E.2. If an individual Project Gutenberg-tm electronic work is derived -from the public domain (does not contain a notice indicating that it is -posted with permission of the copyright holder), the work can be copied -and distributed to anyone in the United States without paying any fees -or charges. If you are redistributing or providing access to a work -with the phrase "Project Gutenberg" associated with or appearing on the -work, you must comply either with the requirements of paragraphs 1.E.1 -through 1.E.7 or obtain permission for the use of the work and the -Project Gutenberg-tm trademark as set forth in paragraphs 1.E.8 or -1.E.9. - -1.E.3. If an individual Project Gutenberg-tm electronic work is posted -with the permission of the copyright holder, your use and distribution -must comply with both paragraphs 1.E.1 through 1.E.7 and any additional -terms imposed by the copyright holder. Additional terms will be linked -to the Project Gutenberg-tm License for all works posted with the -permission of the copyright holder found at the beginning of this work. - -1.E.4. Do not unlink or detach or remove the full Project Gutenberg-tm -License terms from this work, or any files containing a part of this -work or any other work associated with Project Gutenberg-tm. - -1.E.5. Do not copy, display, perform, distribute or redistribute this -electronic work, or any part of this electronic work, without -prominently displaying the sentence set forth in paragraph 1.E.1 with -active links or immediate access to the full terms of the Project -Gutenberg-tm License. - -1.E.6. You may convert to and distribute this work in any binary, -compressed, marked up, nonproprietary or proprietary form, including any -word processing or hypertext form. However, if you provide access to or -distribute copies of a Project Gutenberg-tm work in a format other than -"Plain Vanilla ASCII" or other format used in the official version -posted on the official Project Gutenberg-tm web site (www.gutenberg.org), -you must, at no additional cost, fee or expense to the user, provide a -copy, a means of exporting a copy, or a means of obtaining a copy upon -request, of the work in its original "Plain Vanilla ASCII" or other -form. Any alternate format must include the full Project Gutenberg-tm -License as specified in paragraph 1.E.1. - -1.E.7. Do not charge a fee for access to, viewing, displaying, -performing, copying or distributing any Project Gutenberg-tm works -unless you comply with paragraph 1.E.8 or 1.E.9. - -1.E.8. You may charge a reasonable fee for copies of or providing -access to or distributing Project Gutenberg-tm electronic works provided -that - -- You pay a royalty fee of 20% of the gross profits you derive from - the use of Project Gutenberg-tm works calculated using the method - you already use to calculate your applicable taxes. The fee is - owed to the owner of the Project Gutenberg-tm trademark, but he - has agreed to donate royalties under this paragraph to the - Project Gutenberg Literary Archive Foundation. Royalty payments - must be paid within 60 days following each date on which you - prepare (or are legally required to prepare) your periodic tax - returns. Royalty payments should be clearly marked as such and - sent to the Project Gutenberg Literary Archive Foundation at the - address specified in Section 4, "Information about donations to - the Project Gutenberg Literary Archive Foundation." - -- You provide a full refund of any money paid by a user who notifies - you in writing (or by e-mail) within 30 days of receipt that s/he - does not agree to the terms of the full Project Gutenberg-tm - License. You must require such a user to return or - destroy all copies of the works possessed in a physical medium - and discontinue all use of and all access to other copies of - Project Gutenberg-tm works. - -- You provide, in accordance with paragraph 1.F.3, a full refund of any - money paid for a work or a replacement copy, if a defect in the - electronic work is discovered and reported to you within 90 days - of receipt of the work. - -- You comply with all other terms of this agreement for free - distribution of Project Gutenberg-tm works. - -1.E.9. If you wish to charge a fee or distribute a Project Gutenberg-tm -electronic work or group of works on different terms than are set -forth in this agreement, you must obtain permission in writing from -both the Project Gutenberg Literary Archive Foundation and Michael -Hart, the owner of the Project Gutenberg-tm trademark. Contact the -Foundation as set forth in Section 3 below. - -1.F. - -1.F.1. Project Gutenberg volunteers and employees expend considerable -effort to identify, do copyright research on, transcribe and proofread -public domain works in creating the Project Gutenberg-tm -collection. Despite these efforts, Project Gutenberg-tm electronic -works, and the medium on which they may be stored, may contain -"Defects," such as, but not limited to, incomplete, inaccurate or -corrupt data, transcription errors, a copyright or other intellectual -property infringement, a defective or damaged disk or other medium, a -computer virus, or computer codes that damage or cannot be read by -your equipment. - -1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the "Right -of Replacement or Refund" described in paragraph 1.F.3, the Project -Gutenberg Literary Archive Foundation, the owner of the Project -Gutenberg-tm trademark, and any other party distributing a Project -Gutenberg-tm electronic work under this agreement, disclaim all -liability to you for damages, costs and expenses, including legal -fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT -LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE -PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE FOUNDATION, THE -TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE -LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR -INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH -DAMAGE. - -1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a -defect in this electronic work within 90 days of receiving it, you can -receive a refund of the money (if any) you paid for it by sending a -written explanation to the person you received the work from. If you -received the work on a physical medium, you must return the medium with -your written explanation. The person or entity that provided you with -the defective work may elect to provide a replacement copy in lieu of a -refund. If you received the work electronically, the person or entity -providing it to you may choose to give you a second opportunity to -receive the work electronically in lieu of a refund. If the second copy -is also defective, you may demand a refund in writing without further -opportunities to fix the problem. - -1.F.4. Except for the limited right of replacement or refund set forth -in paragraph 1.F.3, this work is provided to you 'AS-IS', WITH NO OTHER -WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO -WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PURPOSE. - -1.F.5. Some states do not allow disclaimers of certain implied -warranties or the exclusion or limitation of certain types of damages. -If any disclaimer or limitation set forth in this agreement violates the -law of the state applicable to this agreement, the agreement shall be -interpreted to make the maximum disclaimer or limitation permitted by -the applicable state law. The invalidity or unenforceability of any -provision of this agreement shall not void the remaining provisions. - -1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the -trademark owner, any agent or employee of the Foundation, anyone -providing copies of Project Gutenberg-tm electronic works in accordance -with this agreement, and any volunteers associated with the production, -promotion and distribution of Project Gutenberg-tm electronic works, -harmless from all liability, costs and expenses, including legal fees, -that arise directly or indirectly from any of the following which you do -or cause to occur: (a) distribution of this or any Project Gutenberg-tm -work, (b) alteration, modification, or additions or deletions to any -Project Gutenberg-tm work, and (c) any Defect you cause. - - -Section 2. Information about the Mission of Project Gutenberg-tm - -Project Gutenberg-tm is synonymous with the free distribution of -electronic works in formats readable by the widest variety of computers -including obsolete, old, middle-aged and new computers. It exists -because of the efforts of hundreds of volunteers and donations from -people in all walks of life. - -Volunteers and financial support to provide volunteers with the -assistance they need are critical to reaching Project Gutenberg-tm's -goals and ensuring that the Project Gutenberg-tm collection will -remain freely available for generations to come. In 2001, the Project -Gutenberg Literary Archive Foundation was created to provide a secure -and permanent future for Project Gutenberg-tm and future generations. -To learn more about the Project Gutenberg Literary Archive Foundation -and how your efforts and donations can help, see Sections 3 and 4 -and the Foundation information page at www.gutenberg.org - - -Section 3. Information about the Project Gutenberg Literary Archive -Foundation - -The Project Gutenberg Literary Archive Foundation is a non profit -501(c)(3) educational corporation organized under the laws of the -state of Mississippi and granted tax exempt status by the Internal -Revenue Service. The Foundation's EIN or federal tax identification -number is 64-6221541. Contributions to the Project Gutenberg -Literary Archive Foundation are tax deductible to the full extent -permitted by U.S. federal laws and your state's laws. - -The Foundation's principal office is located at 4557 Melan Dr. S. -Fairbanks, AK, 99712., but its volunteers and employees are scattered -throughout numerous locations. Its business office is located at 809 -North 1500 West, Salt Lake City, UT 84116, (801) 596-1887. Email -contact links and up to date contact information can be found at the -Foundation's web site and official page at www.gutenberg.org/contact - -For additional contact information: - Dr. Gregory B. Newby - Chief Executive and Director - gbnewby@pglaf.org - -Section 4. Information about Donations to the Project Gutenberg -Literary Archive Foundation - -Project Gutenberg-tm depends upon and cannot survive without wide -spread public support and donations to carry out its mission of -increasing the number of public domain and licensed works that can be -freely distributed in machine readable form accessible by the widest -array of equipment including outdated equipment. Many small donations -($1 to $5,000) are particularly important to maintaining tax exempt -status with the IRS. - -The Foundation is committed to complying with the laws regulating -charities and charitable donations in all 50 states of the United -States. Compliance requirements are not uniform and it takes a -considerable effort, much paperwork and many fees to meet and keep up -with these requirements. We do not solicit donations in locations -where we have not received written confirmation of compliance. To -SEND DONATIONS or determine the status of compliance for any -particular state visit www.gutenberg.org/donate - -While we cannot and do not solicit contributions from states where we -have not met the solicitation requirements, we know of no prohibition -against accepting unsolicited donations from donors in such states who -approach us with offers to donate. - -International donations are gratefully accepted, but we cannot make -any statements concerning tax treatment of donations received from -outside the United States. U.S. laws alone swamp our small staff. - -Please check the Project Gutenberg Web pages for current donation -methods and addresses. Donations are accepted in a number of other -ways including checks, online payments and credit card donations. -To donate, please visit: www.gutenberg.org/donate - - -Section 5. General Information About Project Gutenberg-tm electronic -works. - -Professor Michael S. Hart was the originator of the Project Gutenberg-tm -concept of a library of electronic works that could be freely shared -with anyone. For forty years, he produced and distributed Project -Gutenberg-tm eBooks with only a loose network of volunteer support. - -Project Gutenberg-tm eBooks are often created from several printed -editions, all of which are confirmed as Public Domain in the U.S. -unless a copyright notice is included. Thus, we do not necessarily -keep eBooks in compliance with any particular paper edition. - -Most people start at our Web site which has the main PG search facility: - - www.gutenberg.org - -This Web site includes information about Project Gutenberg-tm, -including how to make donations to the Project Gutenberg Literary -Archive Foundation, how to help produce our new eBooks, and how to -subscribe to our email newsletter to hear about new eBooks. diff --git a/41160.zip b/41160.zip Binary files differdeleted file mode 100644 index 36d8a02..0000000 --- a/41160.zip +++ /dev/null |