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diff --git a/16792-8.txt b/16792-8.txt new file mode 100644 index 0000000..f7b5cb6 --- /dev/null +++ b/16792-8.txt @@ -0,0 +1,4504 @@ +The Project Gutenberg EBook of Scientific American Supplement, No. 508, +September 26, 1885, by Various + +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: Scientific American Supplement, No. 508, September 26, 1885 + +Author: Various + +Release Date: October 3, 2005 [EBook #16792] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN *** + + + + +Produced by Juliet Sutherland, Josephine Paolucci and the +Online Distributed Proofreading Team at www.pgdp.net + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 508 + + + + +NEW YORK, SEPTEMBER 26, 1885 + +Scientific American Supplement. Vol. XX., No. 508. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + * * * * * + + + + +TABLE OF CONTENTS + + PAGE +I. CHEMISTRY AND METALLURGY.--The Cowles Electric Smelting + Process. 5 figures. 8113 + + On the Electrical Furnace and the Reduction of the Oxides of + Boron, Silicon, Aluminum, and other Metals by Carbon.--By + EUGENE H. COWLES, ALFRED H. COWLES, and CHARLES F. MABERY. 8112 + + Chemical Action of Light. 8117 + + Eutexia.--Cryohydrates.--Eutectic salt alloys and metal + alloys. 8117 + + Chinoline. 8118 + + Method of Rapid Estimation of Urea. 1 figure. 8118 + + Assay of Earthenware Glaze. 8112 + +II. ENGINEERING AND MECHANICS.--Deep Shafts and Deep Mining. 8104 + + Sinking of the Quievrechain Working Shaft.--Numerous + figures. 8108 + + On the Elementary Principles of the Gas Engine.--An + interesting paper read before the Gas Institute by Mr. + DENNY LANE, of Cork, and discussion following. 8109 + + M. MEIZEL'S Reciprocating Exhauster. 8112 + + Automatic Siphon for Irrigation. 1 figure. 8113 + +III. ELECTRICITY, TELEGRAPHY, ETC.--Optical Telegraphy.-- + Cryptography.--Preservation of Telegrams.--The projector in + optical telegraphy.--Use of balloons. 4 figures. 8114 + + A New Style of Submarine Telegraph. 4 figures. 8115 + + A New Circuit Cutter. 2 figures. 8115 + + New Micro Telephonic Apparatus. 5 figures. 8116 + + Messrs. Kapp and Crompton's Measuring Instruments. + 5 figures. 8116 + +IV. GEOLOGY, ETC.--Permeability of Sand Rock.--By F.H. NEWELL. 8103 + + The Grotto of Gargas, in the Pyrenees.--Paleontological + remains found therein. 2 engravings. 8103 + + Remarkable Wells and Caverns in Yucatan.--By ALICE D. LE + PLONGEON. 8105 + +V. NATURAL HISTORY.--The Cabbage Butterfly and the Peacock + Butterfly. 8105 + +VI. BOTANY AND HORTICULTURE.--The Bhotan Cypress (Cupressus + torulosa).--With engraving. 8106 + + The Pitcher Plant. 8106 + + What is a Plant? 8106 + + Camellias.--Culture of the same. 8106 + + Arisæma Fimbriatum.--Leaf, spathe, and floral details.--With + engraving. 8107 + +VII. MISCELLANEOUS.--Striking a Light with Bamboo. 8107 + + Experiments in Memory. 8107 + + * * * * * + + + + +PERMEABILITY OF SAND ROCK. + +By FREDERICK H. NEWELL, M.E. + + +Among oil producers, there has been much discussion as to whether the +sand rock in which petroleum occurs is of necessity fissured or is +still in its original unbroken condition. + +The earliest and most natural theory, which for years was indisputed, +and is still given by some textbooks, was, that oil wells reached a +cavity filled with petroleum. + +Within the past few years, however, the opinion has been gaining +ground that the oil is stored in the sandrock itself in the minute +spaces between the small grains of sand, not entirely filled by +cementing material, and that crevices holding and conducting oil are +rare, all fissures as a rule being confined to the upper fresh-water +bearing rocks of the well. Mr. Carll, in III. Pennsylvania Second +Geological Survey, has discussed this subject very fully, and has made +estimates of the quantity of oil that the sand rock can hold and +deliver into a well; also, T. Sterry Hunt, in his _Chemical and +Geological Essays_, has made deductions as to the petroleum contained +in the Niagara limestone that outcrops about Chicago. + +While the experiments and conclusions of these geologists go to prove +that these rocks are capable of holding the oil, there are on record +no facts as to the phenomena of its flow, other than by capillarity, +through the rock. To obtain some data of the flow of liquids under +pressure through certain oil-bearing stones, series of tests on small +pieces were made. These tests were carried on during this spring, and +many results quite unlooked for were obtained. When crude oil, +kerosene, or water (river or distilled) was forced through the +specimens, the pressure being constant, the rate of flow was variable. +At first, the amount flowing through was large, then fell off rapidly, +and when the flow had diminished to about one-quarter of its original +rate, the decrease was very slight, but still continued as long as +measurements were made, in some cases for three weeks. + +When using crude oil, this result was not surprising, for, as the oil +men say, crude oil "paraffines up" a rock, that is, clogs the minute +pores by depositing solid paraffine (?); but this so-called +paraffining took place, not only with crude oil, but with refined oil, +and even with distilled water. + +The only explanation as yet is, that liquids flowing under pressure +through rock on which they exert little or no dissolving effect, +instead of washing out fine particles, tend to dislodge any minute +grains of the stone that may not be firmly held by cement, and these +block up extremely fine and crooked pores in which the fluid is +passing. + +Several tests indicated that this blocking up was largely near the +surface into which the fluid was passing. When this surface was ground +off, even 1/50 of an inch, the flow increased immediately nearly to +the original rate. + +Reversing the flow also had the effect of increasing the rate, even +above that of any time previous. + +With the moderate pressures used--from 2" to 80" of mercury--the +results show that the rate of flow, other things being equal, is +directly proportional to the pressure. + +The porosity of rock is not always a criterion of its permeability; a +very fine grained marble, containing about 0.6 per cent. cell space, +transmitted water and oil more freely than a shale that would hold 4 +per cent. of its bulk of water. + +If the above conclusions hold on a large scale as on the small, they +may aid in explaining the diminished flow of oil wells. Not only will +the flow lessen from reduced gas pressure, but the passages in the +rock become less able to allow the oil to flow through. + +The increase in flow following the explosion of large shots in a sand +rock may be due not only to fissuring of the rock, but to temporary +reversal of the pressure, the force of the explosive tending to drive +the oil back for an instant. + +The large shots now used (up to 200 quarts, or say 660 pounds of +nitroglycerine) must exert some influence of this kind, especially +when held down by 500± feet of liquid tamping. In the course of these +tests, it was noticed that fresh water has a more energetic +disintegrating action on the shales and clay than on salt water. + +This may furnish a reason for the fact, noticed by the oil men, that +fresh water has a much more injurious effect than salt in clogging a +well. No oil-bearing sand rock is free from laminæ of shale, and when +fresh water gets down into the sand, the water must, as the +experiments show, rapidly break up the shale, setting free fine +particles, which soon are driven along into the minute interstices of +the sand rock, plastering it up and injuring the well.--_Engineering +and Mining Journal._ + + * * * * * + + + + +THE GROTTO OF GARGAS. + + +The grotto of Gargas is located in Mount Tibiran about three hundred +yards above the level of the valley, and about two miles southeast of +the village of Aventignan. Access to it is easy, since a road made by +Mr. Borderes in 1884 allows carriages to reach its entrance. + +This grotto is one of the most beautiful in the Pyrenees, and presents +to the visitor a succession of vast halls with roofs that are curved +like a dome, or are in the form of an ogive, or are as flat as a +ceiling. It is easy to explore these halls, for the floor is covered +with a thick stalagmitic stratum, and is not irregular as in the +majority of large caves. + +[Illustration: FIG. 1.--SECTION OF THE GROTTO OF GARGAS.] + +Upon entering through the iron gate at the mouth of the grotto, one +finds himself in Bear Hall, wherein a strange calcareous concretion +offers the form of the carnivorous animal after which the room is +named. This chamber is about 80 feet in width by 98 in length. We +first descend a slope formed of earth and debris mostly derived from +the outside. This slope, in which are cut several steps, rests upon a +hard, compact, and crystalline stalagmitic floor. Upon turning to the +right, we come to the Hall of Columns, the most beautiful of all. Here +the floor bristles with stalagmites, which in several places are +connected with the stalactites that depend from the ceiling. This room +is about 50 feet square. After this we reach the Hall of Crevices, 80 +feet square, and this leads to the great Hall of Gargas, which is +about 328 feet in length by 80, 98, and 105 in width. In certain +places enormous fissures in the vault rise to a great height. Some of +these, shaped like great inverted funnels, are more than 60 yards in +length. The grotto terminates in the Creeping Hall. As its name +indicates, this part of the cave can only be traversed by lying flat +upon the belly. It gives access to the upper grotto through a narrow +and difficult passage that it would be possible to widen, and which +would then allow visitors to make their exit by traversing the +beautiful upper grotto, whose natural entrance is situated 150 yards +above the present one. This latter was blasted out about thirty years +ago. + +Upon following the direction of the great crevices, we reach a small +chamber, wherein are found the Oubliettes of Gargas--a vertical well +65 feet feet in depth. The aperture that gives access to this strange +well (rendered important through the paleontological remains collected +in it) is no more than two feet in diameter. Such is the general +configuration of the grotto. + +In 1865 Dr. Garrigou and Mr. De Chastaignier visited the grotto, and +were the first to make excavations therein. These latter allowed these +scientists to ascertain that the great chamber contained the remains +of a quaternary fauna, and, near the declivity, a deposit of the +reindeer age. + +As soon as it was possible to obtain a permit from the Municipal +Council of Aventignan to do so, I began the work of excavation, and +the persistence with which I continued my explorations led me to +discover one of the most important deposits that we possess in the +chain of the Pyrenees. My first excavations in Bear Hall were made in +1873, and were particularly fruitful in an opening 29 feet long by 10 +wide that terminates the hall, to the left. I have remarked that these +sorts of retreats in grottoes are generally rich in bones. Currents of +water rushing through the entrance to the grotto carry along the +bones--entire, broken, or gnawed--that lie upon the ground. These +remains are transported to the depths of the cave, and are often +stopped along the walls, and lie buried in the chambers in +argillaceous mud. Rounded flint stones are constantly associated with +the bones, and the latter are always in great disorder. The species +that I met with were as follows: the great cave bear, the little bear, +the hyena, the great cat, the rhinoceros, the ox, the horse, and the +stag. + +The stalagmitic floor is 1½, 2, and 2¼ inches thick. The bones were +either scattered or accumulated at certain points. They were generally +broken, and often worn and rounded. They appeared to have been rolled +with violence by the waters. The clay that contained them was from 3 +to 6 feet in thickness, and rested upon a stratum of water-worn +pebbles whose dimensions varied from the size of the fist to a grain +of sand. A thick layer of very hard, crystalline stalagmite covers the +Hall of Columns, and it was very difficult to excavate without +destroying this part of the grotto. + +I found that there anciently existed several apertures that are now +sealed up, either by calcareous concretions or by earthy rubbish from +the mountain. One of these was situated in the vicinity of the present +mouth, and permitted of the access to Bear Hall of a host of carnivora +that found therein a vast and convenient place of shelter. + +[Illustration: FIG. 2.--SKELETON OF THE CAVE HYENA.] + +These excavations revealed to me at this entrance, at the bottom of +the declivity, a thick stratum of remains brought thither by primitive +man. This deposit, which was formed of black earth mixed with charcoal +and numerous remains of bones, calcined and broken longitudinally for +the most part, contained rudely worked flint stones. I collected a few +implements, one surface of which offered a clean fracture, while the +other represented the cutting edge. According to Mr. De Mortillet, +such instruments were not intended to have a handle. They were capable +of serving as paring knives and saws, but they were especially +designed for scraping bones and skins. The deposit was from 26 to 32 +feet square and from 2 inches to 5 feet deep, and rested upon a bed of +broken stones above the stalagmite. The animals found in it were the +modern bear (rare), the aurochs, the ox, the horse, and the stag--the +last four in abundance. + +At the extremity of the grotto there is a well with vertical sides +which is no less than 65 feet in depth. It is called the Gargas +Oubilettes. Its mouth is from 15 to 24 inches in diameter, and +scarcely gives passage to a man (Fig. 1). Mr. Borderes, in the hope of +discovering a new grotto, was the first to descend into this well, +which he did by means of a rope ladder, and collected a few bones that +were a revelation to me. Despite the great difficulty and danger of +excavating at this point, I proceeded, and found at the first blow of +the pick that there was here a deposit of the highest importance, +since all the bones that I met with were intact. The first thing +collected was an entire skull of the great cave bear, with its +maxillaries in place. From this moment I began a series of excavations +that lasted two years. + +The descent is effected through a narrow vertical passage 6½ feet in +length. The cavity afterward imperceptibly widens, and, at a depth of +12 yards, reaches 6½ feet in diameter, and at 15 yards 10 feet. +Finally, in the widest part (at a depth of 62 feet) it measures about +16 feet (Fig. 1). + +A glance at the section of the well, which I have drawn as accurately +as possible (not an easy thing to do when one is standing upon a rope +ladder), will give an idea of the form of this strange pocket formed +in the limestone of the mountain through the most complex dislocations +and erosions. Two lateral pockets attracted my attention because of +the enormous quantity of clay and bones that obstructed them. The +first, to the left, was about 15 feet from the orifice. When we had +entirely emptied it, we found that it communicated with the bottom of +the well by a narrow passage. An entire skeleton of the great cave +bear had stopped up this narrow passage, and of this, by the aid of a +small ladder, we gathered the greater part of the skeleton, the state +of preservation of which was remarkable. + +The second pocket, which was almost completely filled with clay, and +situated a little lower than the other, likewise communicated with a +third cavity that reached the bottom of the well. The clay of these +different pockets contained so large a quantity of bones that we could +hardly use our picks, and the excavation had to be performed with very +short hooks, and often by hand. In this way I was enabled to remove +the bones without accident. The lower pocket was dug out first, and +with extreme care, the bones being hoisted out by means of a basket +attached to a rope. Three or four candles sufficed to give us light. +The air was heavy and very warm, and, after staying in it for two +hours, it was necessary to come to the surface to breathe. After +extracting the bones from the lower pocket, and when no more clay +remained, we successively dug out the upper ones and threw the earth +to the bottom of the well. + +On the 20th of December, 1884, my excavating was finished. To-day the +Oubliettes of Gargas are obstructed with the clay that it was +impossible to carry elsewhere. The animals that I thus collected in +the well were the following: The great bear (in abundance), the little +bear (a variety of the preceding), the hyena, and the wolf. The +pockets contained nearly entire skeletons of these species. How had +the animals been able to penetrate this well? It is difficult to admit +that it was through the aperture that I have mentioned. I endeavored +to ascertain whether there was not another communication with the +Gargas grotto, and had the satisfaction of finding a fissure that +ended in the cave, and that probably was wider at the epoch at which +the place served as a lair for the bear and hyena. + +Very old individuals and other adults, and very young animals, were +living in the grotto, and, being surprised, without power to save +themselves, by a sudden inundation, reached the bottom of the well +that we have described. The entire remains of these animals were +carried along by the water and deposited in the pockets in the rock. +Once buried in the argillaceous mud, the bones no longer underwent the +action of the running water, and their preservation was thence +secured.--_F. Regnault, in La Nature._ + + * * * * * + + + + +DEEP SHAFTS AND DEEP MINING. + + +A correspondent of the New York _Sun_, writing from Virginia City, +Nevada, describes the progress of the work there on the Combination +shaft of the Comstock lode, the deepest vertical shaft in America, and +the second deepest in the world. It is being sunk by the Chollar +Potosi, Hale & Norcross, and Savage mining companies; hence its name +of the Combination shaft. This shaft has now reached a perpendicular +depth of a little over 3,100 feet. There is only one deeper vertical +shaft in the world--the Adalbent shaft of the silver-lead mines of +Przibram, Bohemia, which at last accounts had reached a depth of 3,280 +feet. The attainment of that depth was made the occasion of a +festival, which continued three days, and was still further honored by +the striking off of commemorative medals of the value of a florin +each. There is no record of the beginning of work on this mine at +Przibram, although its written history goes back to 1527. + +Twenty years ago very few mining shafts in the world had reached a +depth of 2,000 feet. The very deepest at that time was in a +metalliferous mine in Hanover, which had been carried down 2,900 feet; +but this was probably not a single perpendicular shaft. Two vertical +shafts near Gilly, in Belgium, are sunk to the depth of 2,847 feet. At +this point they are connected by a drift, from which an exploring +shaft or winze is sunk to a further depth of 666 feet, and from that +again was put down a bore hole 49 feet in depth, making the total +depth reached 3,562 feet. As the bore hole did not reach the seam of +coal sought for, they returned and resumed operations at the 2,847 +level. In Europe it is thought worthy of particular note that there +are vertical shafts of the following depths: + + Feet. + Eimkert's shaft of the Luganer Coal Mining + Company, Saxony 2,653 + + Sampson shaft of the Oberhartz silver mine, + near St. Andreasberg, Hanover. 2,437 + + The hoisting shaft of the Rosebridge Colliery, + near Wigan, Lancashire, England. 2,458 + + Shaft of the coal mines of St. Luke, near + St. Chaumont, France. 2,253 + + Amelia shaft, Shemnitz, Hungary. 1,782 + + The No. 1 Camphausen shaft, near Fishbach, + in the department of the Saarbruck + Collieries, Prussia. 1,650 + + +Now, taking the mines of the Comstock for a distance of over a +mile--from the Utah on the north to the Alto on the south--there is +hardly a mine that is not down over 2,500 feet, and most of the shafts +are deeper than those mentioned above; while the Union Consolidated +shaft has a vertical depth of 2,900 feet, and the Yellow Jacket a +depth of 3,030 feet. In his closing argument before the Congressional +Committee on Mines and Mining in 1872, Adolph Sutro of the Sutro +tunnel said: "The deepest hole dug by man since the world has existed +is only 2,700 feet deep, and it remains for the youngest nation on +earth to contribute more to science and geology by giving +opportunities of studying the formation of mineral veins at a greater +depth than has ever been accomplished by any other nation in the +world." Mr. Sutro was of the opinion that the completion of his tunnel +would enable our leading mining companies to reach a vertical depth of +5,000 feet. + +This great depth has never yet been attained except in a bore hole or +artesian well. The deepest points to which the crust of the earth has +ever been penetrated have been by means of such borings in quest of +salt, coal, or water. A bore hole for salt at Probst Jesar, near +Lubtheen, for the Government of Mecklenberg-Schwerin, is down 3,315 +feet, the size of which bore is twelve inches at the top and three +inches at the bottom. A bore hole was put down for the Prussian +Government to the depth of 4,183 feet. But in these bore holes the +United States leads the world, as there is one near St. Louis, Mo., +that is 5,500 feet in depth. Here on the Comstock, in the Union +Consolidated mine, a depth of 3,300 feet has been attained, but not by +means of a single vertical shaft. The vertical depth of the shaft is +2,900 feet; the remainder of the depth has been attained by means of +winzes sunk from drifts. Several long drifts were run at this great +depth without difficulty as regards ventilation or heat. + +The combination shaft is situated much further east (in which +direction the lode dips) than any other on the Comstock. It is 3,000 +feet east of the point where the great vein crops out on the side of +Mount Davidson; 2,200 feet east of the old Chollar-Potosi shaft, 1,800 +ft. east of the old Hale & Norcross (or Fair) shaft, and 2,000 ft. +east of the Savage shaft. Thus, it will be seen it is far out to the +front in the country toward which the vein is going. The shaft is sunk +in a very hard rock (andesite), every foot of which requires to be +blasted. The opening is about thirty feet in length by ten feet in +width. In timbering up this is divided into four different +compartments, some for the hoisting and some for the pumping +machinery, thus presenting the appearance at the top of four small +shafts set in a row. Over the shaft stand several large buildings, all +filled with ponderous machinery. + +The Sutro drain tunnel (nearly four miles in length) connects with the +shaft at a depth of 1,600 ft., up to which point all the water +encountered below is pumped. The shaft was sunk to the depth of 2,200 +ft. before more water was encountered than could be hoisted out in the +"skips" with the dirt. At the 2,200 level two Cornish pumps, each with +columns fifteen inches in diameter, were put in. At the 2,400 level +the same pumps were used. On this level a drift was run that connected +with the old Hale & Norcross and Savage shafts, producing a good +circulation of air both in the shaft and in the mines mentioned. At +this point, on account of the inflow from the mines consequent upon +connecting with them by means of the drift, they had more water than +the Cornish pumps could handle, and introduced the hydraulic pumps, +which pumps are run by the pressure of water from the surface through +a pipe running down from the top of the shaft, whereas the Cornish +pumps are run by huge steam engines. + +By means of the hydraulic pumps they were enabled to sink the shaft to +the 2,600 level, and extended the Cornish pumps to that point, where +another set of hydraulic pumps was put in. They then sunk the shaft to +the 2,800 level, when they ran another drift westward, and tapped the +vein. The prospects at this depth in the Hale & Norcross and Chollar +mines were so encouraging that the management decided to sink the +shaft to the depth of 3,000 ft. On reaching the 3,000 level, they ran +a third drift through to the vein. The distance from the shaft to the +east wall of the vein was found to be only 250 ft. At the depth of +3,000 ft. they put in one of the pair of hydraulic pumps that is to be +set up there. The second pump is now arriving from San Francisco, and +as soon as the several parts are on the ground, it will be at once put +in place alongside its fellow on the 3,000 level. This additional pump +will increase the capacity from 600,000 to 700,000 gallons in +twenty-four hours, or about forty-five miners' inches. + +Owing to the excellent showing of ore obtained on the 3,000 level by +the Hale & Norcross Company, and to the continuation of the ore below +that level (as shown by a winze sunk in the vein), the management +determined to sink the shaft to the vertical depth of 3,200 ft. It is +now 3,120 ft. deep, and it is safe to say that it will reach the depth +of 3,200 ft. early in September, when it will lack but eighty feet of +being as deep as the shaft at Przibram was at the time of the great +festival. Although the shaft is of great size--about thirty feet by +ten feet before the timbers are put in--the workmen lower it at the +rate of about three feet a day, in rock as hard as flint. + +The hydraulic pump now working at the 3,000 foot level of the shaft is +the deepest in the world. In Europe the deepest is in a mine in the +Hartz Mountains, Germany, which is working at the depth of 2,700 feet. +It is, however, a small pump not half the size of the one in the +Combination shaft. Although these pumps were first used in Europe, +those in operation here are far superior in size, and in every other +respect, to those of the Old World, several valuable improvements +having been made in them by the machinists of the Pacific coast. + +The capacity of the two Cornish pumps, which lift the water from the +2,900 foot level to the Sutro drain tunnel (at the 1,600 level), is +about 1,000,000 gallons in twenty-four hours, and the capacity of the +present hydraulic pumps is 3,500,000 gallons in the same time. They +are now daily pumping, with both hydraulic and Cornish pumps, about +4,000,000 gallons, but could pump at least 500,000 gallons more in +twenty-four hours than they are now doing. The daily capacity with the +hydraulic pump now coming, and which will be set up as mate to that +now in operation at the 3,000 foot level, will be 5,200,000 gallons. + +The water which feeds the pressure pipe of the three sets of hydraulic +pumps is brought from near Lake Tahoe, in the Sierra Nevada Mountains. +The distance is about thirty miles, and the greater part of the way +the water flows through iron pipes, which at one point cross a +depression 1,720 feet in depth. The pressure pipe takes this water +from a tank situated on the eastern slope of Mount Davidson, 3,500 +feet west of the shaft. At the tank this pipe is twelve inches in +diameter, but is only eight inches where it enters the top of the +shaft. The tank whence the water is taken is 426 feet higher than the +top of the shaft, therefore the vertical pressure upon the hydraulic +pump at the 3,000 foot level is 3,426 feet. The pressure pipe is of +ordinary galvanized iron where it receives the water at the tank, but +gradually grows thicker and stronger, and at the 3,000 level it is +constructed of cast iron, and is 2½ inches in thickness. The pressure +at this point is 1,500 pounds to the square inch. + +In the early days of hydraulic mining in California the miners thought +that with a vertical pressure of 300 feet they could almost tear the +world to pieces, and not a man among them could have been made to +believe that any pipe could be constructed that would withstand a +vertical pressure of 1,000 feet; but we now see that a thickness of +two and a half inches of cast iron will sustain a vertical pressure of +over 3,400 feet. + +There is only one pressure pipe for all the hydraulic pumps. This +extends from the tank on the side of the mountain to the 3,000 foot +level. It is tapped at the points where are situated the several sets +of hydraulic pumps. The water from the pressure pipe enters one part +of the pump, where it moves a piston-back and forth, just as the +piston of a steam engine is moved by steam. This water engine moves a +pump which not only raises to the surface the water which has been +used as driving power, but also a vast quantity of water from the +shaft, all of which is forced up to the Sutro drain tunnel through +what is called a return pipe. Each set of hydraulic pumps has its +return pipe; therefore there are three return pipes--one from the +2,400, one from the 2,600, and another from the 3,000 level. + +Some idea may be formed of the great size of these hydraulic engines +when it is known that the stations excavated for them at the several +levels where they are placed are 85 feet long, 28 feet wide, and 12 +feet high. All this space is so filled with machinery that only +sufficient room is left to allow of the workmen moving about it. One +of these stations would, on the surface, form a hall large enough for +a ball room, and to those who are unacquainted with the skill of our +miners it must seem wonderful that such great openings can be made and +securely supported far down in the bowels of the earth; yet it is very +effectually done. These great subterranean halls are supported by +timbers 14×16 inches square set along the walls three feet apart, from +center to center, and the caps or joists passing overhead are timbers +of the same size. The timber used is mountain spruce. Not one of these +huge stations has thus far cost one dollar for repairs. The station at +the 2,400 level has been in use five years, that at the 2,600 three +years, and the one at the 3,000 level eight months. Room for +ventilation is left behind the timbers, and all are still sound. +Timbers of the same kind are used in the shaft, and all are sound. The +shaft has cost nothing for repairs. Being in hard andesite rock from +top to bottom, the ground does not swell and crowd upon the timbers. + +If it shall be thought advisable to go to a greater depth than 3,200 +feet, a station of large size will be made on the east side of the +present shaft, and in this station will be sunk a shaft of smaller +size. The reason why the work will be continued in this way is that in +a single hoist of 3,200 feet the weight of a steel wire cable of that +length is very great--so great that the loaded cage it brings up is a +mere trifle in comparison. In this secondary shaft the hoisting +apparatus and pumps will be run by means of compressed air. As it is +very expensive to make compressed air by steam power, the pressure +pipe will be tapped at the level of the Sutro tunnel, and a stream of +water taken out that will be used in running a turbine wheel of +sufficient capacity to drive three air compressors. As there will be a +vertical pressure upon the turbine at this depth of over 2,000 feet, a +large stream of water will not be required. The water used in driving +the wheel will flow out through the Sutro tunnel, and give no trouble +in the shaft. + +By means of this great shaft and its powerful hydraulic and Cornish +pumps the crust of the earth will probably yet be penetrated to far +greater depth than in any other place in the world. It has been only a +little over ten years since the work of sinking it was begun, whereas +in the mines of the Old World they have been delving since "time +whereof the memory of man runneth not to the contrary." The work on +the Combination shaft has been by no means continuous. There have been +long stoppages aside from those required at such times as they were +engaged in running long drifts to the westward to tap the vein, and at +times for many months, when the several companies interested in the +shaft were engaged in prospecting the various levels it had opened up. + + * * * * * + + + + +REMARKABLE WELLS AND CAVERNS. + + +Yucatan is one of the most interesting States of Mexico, owing to the +splendid ancient palaces and temples of once grand cities, now hidden +in the forests. That country also presents great attractions for +geologists and botanists, as well as naturalists, who there find rare +and beautiful birds, insects, and reptiles. + +There are no rivers on the surface of the land, but in many parts it +is entirely undermined by extensive caverns, in which are basins of +water fed by subterranean currents. The caverns are delightfully cool +even at midday, and the fantastic forms of some of the stalactites and +stalagmites are a never-ending source of interest. There are long +winding passages and roomy chambers following one after another for +great distances, with here and there some chink in the stony vault +above, through which a sunbeam penetrates, enabling us to see to the +right and left openings leading to untrodden places in the bowels of +the earth. As few of these caves have been explored, the wildest +accounts are given by the natives concerning the dark recesses where +only wild beasts seek shelter. Before venturing far in, it is +advisable to secure one end of a ball of twine at the entrance, and +keep the ball in hand; nor is it safe to go without lanterns or +torches, lest we step into some yawning chasm or deep water. The +leader of one party suddenly saw a very dark spot just before him; he +jumped over, instead of stepping on it, and told the others to halt. +Examination proved the dark patch to be a pit that seemed bottomless. + +Awe-inspiring as are the interiors of some of these caves, they are +frequently most beautiful. The natural pillars are often grand in +dimensions and sparkling with various hues, while stalactites and +stalagmites sometimes resemble familiar objects with astonishing +perfection. It is, however, not advisable to place implicit confidence +in accounts of the natives, for the reality, no matter how beautiful, +can hardly be equal to what the vivid imagination of the Indian has +pictured. Anything bearing the least resemblance to a woman is called +"a most beautiful Virgin Mary." Fantastic flutings become "an organ," +and a level rock "an altar." Only once we were not disappointed, when, +having been told to look for a pulpit, we found one that appeared as +if man must have fashioned it, supported on a slender pyramidal base, +the upper part very symmetrical, and ornamented with a perfect +imitation of bunches of grapes and other fruit. + +As I have already said, in these caves are sheets of water, some very +large, others only a few feet in circumference, fed by subterranean +currents. When the water is clear and sweet, it is peopled by a kind +of bagre, a blind fish called by the natives _tzau_, also a species of +_Silurus_. But there are likewise medicinal and thermal waters, by +bathing in which many people claim to have been cured of most painful +and obstinate diseases. + +Strange stories are told of some of these waters. Of one it is said +that those who approach it without holding their breath fall dead. +People who live near the place swear it is so, and say the water +appears to boil on such occasions. From the thermal waters, in some +cases 100 feet below the soil, and without means of access except by +buckets let down through an opening in the rock, warm vapors issue at +early morn, but when the sun is high the water is cool and pleasant to +drink. + +The name _senote_ is given to all these deposits of water, also to +some immense natural circular wells from 50 to 300 feet in diameter. +The walls are more or less perpendicular, generally covered with +tropical vegetation. The current in some is swift, but no inlets or +outlets are visible. The water is deliciously pure and sweet, much +better than that of wells opened by man in the same country. These +enormous deposits generally have a rugged path, sometimes very steep, +leading to the water's edge, but daring natives throw themselves from +the brink, afterward ascending by stout roots that hang like ropes +down the walls, the trees above sucking through these roots the +life-sustaining fluid more than a hundred feet below. + +In the west part of Yucatan is a village called _Bolonchen_ (nine +wells), because in the public square there are nine circular openings +cut through a stratum of rock. They are mouths of one immense cistern, +if natural or made by hand the natives do not know, but in times of +drought it is empty, which shows that it is not supplied by any +subterranean spring. Then the people depend entirely on water found in +a cave a mile and a half from the village; it is perhaps the most +remarkable cavern in the whole country. The entrance is magnificently +wild and picturesque. It is necessary to carry torches, for the way is +dark and dangerous. After advancing sixty or seventy feet we descend a +strong but rough ladder twenty feet long, placed against a very +precipitous rock. Not the faintest glimmer of daylight reaches that +spot; but after a while we stand on the brink of a perpendicular +precipice, the bottom of which is strongly illuminated through a hole +in the surface rock more than 200 feet above. Standing on the verge of +this awful pit in the dim light, the rocks and crags seem to take on +most weird shapes. We go down into the great hole by a ladder eighty +feet high and twelve wide, and, reaching the bottom, are as yet but at +the mouth of the cave, which, by the bye, is called _Xtacunbi Xunan_ +(the hidden lady), because, say the Indians, a lady was stolen from +her mother and hidden there by her lover. Now, to our right, we find a +narrow passage, and soon another ladder; the darkness is intense and +the descent continuous, though irregular, like a series of hills and +dales, ladders being placed against the steepest places. + +After an exhausting journey we reach a vast chamber, from which +crooked passages lead in various directions to wells, seven in all, +each named according to the peculiar kind of water. One, always warm, +is called _Chocohá_ (hot water); another, _O[c]ihá_* (milky water), and +_Akabhá_ (dark water). About 400 paces away from the chamber, passing +through a very narrow, close passage, there is a basin of red water +that ebbs and flows like the sea, receding with the south wind, +increasing with the northwest. + + *Transcriber's note: [c] denotes upside-down 'c' in original. + +To reach the most distant well, we go down yet one more ladder, the +seventh. On one side of it there is a perpendicular wall, on the other +a yawning gulf, so when one of the steps, merely round sticks tied +with withes, gave way beneath our feet, we tightly grasped the stick +above. Having reached the bottom of the ladder, we crawl on our hands +and feet through a broken, winding passage about 800 feet long, then +see before us a basin of crystalline water, and how thirsty we are! +This basin is 1,400 feet from the mouth of the cave, and about 450 +feet below the earth's surface. Several hundred people during five +months in every year depend entirely on that source for all the water +they use. With their frail pitchers and flaring torches they wend +their way, gasping for breath, through the intricate passages, and +reaching the water, are so profusely perspiring that they must wait +before quenching their thirst. The way back is even harder, and they +are tired and loaded; yet these people are such lovers of cleanliness +that on their arrival at their poor huts, before tasting food, they +will use some of the water that has cost them so much, to bathe their +smoke-begrimed skin. As several women once fainted in the cave, men +generally fetch the water now. + +Yucatan is, and has been for ages past, quite free from earthquakes, +while all surrounding countries are from time to time convulsed. This +immunity may be due to the vast caverns and numerous great wells +existing throughout the land. Pliny the Elder was of opinion that if +numerous deep wells were made in the earth to serve as outlets for the +gases that disturb its upper strata, the strength of the earthquakes +would be diminished, and if we may judge by Yucatan, Pliny was right +in his conjectures. After him, other scientists who have carefully +studied the subject have expressed the same opinion with regard to the +efficacy of large wells. + +ALICE D. LE PLONGEON. + +Brooklyn, July 15, 1885. + + * * * * * + + +Cholera failed to strike a single one of the 4,000 women employed in +the national tobacco factory at Valencia, Spain, though the disease +raged violently in that city, and the _Medical World_ recalls that +tobacco workers were also noticed to enjoy exemption from attack +during an epidemic at Amsterdam. + + * * * * * + + + + +THE CABBAGE BUTTERFLY. + + +A patch of eggs and the minute caterpillars or larvæ nearly emerged +from them are seen on the leaf. These tiny eggs are at first quite +white or pale yellow, and form an object for the microscope of +remarkable beauty, which is worthy of the examination of all who take +an interest in the garden and its insect life. An egg magnified is +drawn at the bottom left-hand corner of the woodcut. When the eggs are +near the hatching point they darken in color, and a magnifying glass +reveals through the delicate transparent shell a sight which fills the +observer with amazement; the embryo caterpillar is seen in gradual +course of formation, and if patience and warmth have permitted it, the +observer will witness slight movements within the life-case, and +presently the shell will break and a black head with moving jaws will +be thrust out; the little caterpillar unfolds and slowly crawls away +from the egg-shell, and inserts its jaws into the green leaf. It is +curious to witness how judiciously the little creatures avoid crowding +together, but strike out in different directions, and thus they make +sure of a plentiful supply of food, and distribute the effects of +their depredations. These caterpillars eat continually, and hence +rapidly increase in size, until they present the appearance shown in +our drawing at the bottom of the illustration, which is a full grown +caterpillar. + +[Illustration: THE CABBAGE AND PEACOCK BUTTERFLIES.] + +It will be observed that this insect is composed of thirteen segments +from head to tail, which is a distinctive characteristic of all +insects both in the larval and perfect states; but in the case of this +and most other caterpillars these segments are sharply defined and +readily recognized. It will also be noticed that the three segments or +"joints" nearest the head bear a pair of legs each; these are the real +feet, or claspers, as they are sometimes termed, which develop into +the feet of the future butterfly. There are four pairs of false feet +or suckers, which adhere to the ground by suction, and which disappear +in the butterfly. On the last or tail end is a fifth pair of suckers +also, which can attach themselves to a surface with considerable +force, as any one can attest who has noticed the wrigglings of one of +these caterpillars when feeling for new feeding ground. + +The caterpillar now ceases to eat, and quietly betakes itself to a +secluded corner, where in peace it spins a web around its body, and +wrapt therein remains quiescent, awaiting its change into the +butterfly. Although so dormant outwardly, activity reigns inside; +processes are going on within that chrysalis-case which are the +amazement and the puzzle of all naturalists. In course of time the +worm is changed into the beautiful winged butterfly, which breaks its +case and emerges soft and wet; but it quickly dries and spreads its +wings to commence its life in the air and sunshine. The chrysalis is +represented in the figure on the left. The butterfly, it will be +recognized, is one of the common insects so familiar to all, with +strongly veined white wings, bearing three black spots, two on the +upper and one on the lower wing, and dark coloring on the corner of +the upper wings. The antennæ, as with all butterflies, are clubbed at +the extremity--unlike moths', which are tapering--and the large black +staring eyes are the optical apparatus, containing, we are told, +thousands of lenses, each a perfect, simple eye. + +The wings derive their chief coloring from the covering of scales, +which lie on like slates on a roof, and are attached in a similar +manner. A small portion of the wing magnified is represented at the +bottom right hand corner, and detached scales more highly magnified +next to it, exhibiting somewhat the form of battledoors. + + +THE PEACOCK BUTTERFLY. + +Another well known insect is illustrated in the figure in the upper +portion--the peacock butterfly (Vanessa Io). The curious spiked and +spotted caterpillar feeds upon the common nettle. This beautiful +butterfly--common in most districts--is brilliantly colored and +figured on the upper side of the wings, but only of a mottled brown on +the under surface, somewhat resembling a dried and brown leaf, so that +it is no easy matter to detect the conspicuous, brightly-decked insect +when it alights from flight upon foliage, and brings its wings +together over its back after the manner of butterflies. At the +left-hand corner is seen the head of the insect, magnified, showing +the long spiral tongue. + +This is a curious structure, and one that will repay the trouble of +microscopic examination. In the figure the profile is seen, the large +compound eye at the side and the long curved tongue, so +elephantine-looking in form, though of minute size, is seen unrolled +as it is when about to be inserted into flowers to pump up the +honey-juice. This little piece of insect apparatus is a mass of +muscles and sensitive nerves comprising a machine of greater +complexity and of no less precision in its action than the modern +printing machine. When not in use, the tongue rolls into a spiral and +disappears under the head. A butterfly's tongue may readily be +unrolled by carefully inserting a pin within the first spiral and +gently drawing it out.--_The Gardeners' Chronicle._ + + * * * * * + + + + +THE BHOTAN CYPRESS. + +(CUPRESSUS TORULOSA.) + + +This cypress, apart from its elegant growth, is interesting as being +the only species of Cupressus indigenous to India. It is a native of +the Himalayas in the Bhotan district, and it also occurs on the +borders of Chinese Tartary. It forms, therefore, a connecting link, as +it were, between the true cypresses of the extreme east and those that +are natives of Europe. It is singular to note that this genus of +conifers extends throughout the entire breadth of the northern +hemisphere, Cupressus funebris representing the extreme east in China, +and C. macrocarpa the extreme west on the Californian seacoast. The +northerly and southerly limits, it is interesting to mark, are, on the +contrary, singularly restricted, the most southerly being found in +Mexico; the most northerly (C. nutkaensis) in Nootka Sound, and the +subject of these remarks (C. torulosa) in Bhotan. The whole of the +regions intervening between these extreme lateral points have their +cypresses. The European species are C. lusitanica (the cedar of Goa), +which inhabits Spain and Portugal; C. sempervirens (the Roman +cypress), which is centered chiefly in the southeasterly parts of +Europe, extending into Asia Minor. Farther eastward C. torulosa is met +with, and the chain is extended eastward by C. funebris, also known as +C. pendula. The headquarters of the cypresses are undoubtedly in the +extreme west, for here may be found some four or five distinct +species, including the well-known C. Lawsoniana, probably the most +popular of all coniferæ in gardens, C. Goveniana, C. Macnabiana, C. +macrocarpa, and C. nutkaensis (spelt C. nutkanus by the Californian +botanists). The eastern representative of the cypresses in the United +States of North America is C. thyoides, popularly known as the white +cedar. In Mexico three or four species occur, so that the genus in +round numbers only contains about a dozen species. The Californian +botanist Mr. Sereno Watson takes away Lawson's cypress from Cupressus +and puts it in the genus Chamæcyparis, the chief points of distinction +being the flattened two-ranked branchlets and the small globose cones +maturing the first year. + +[Illustration: CONES OF CUPRESSUS TORULOSA (NATURAL SIZE).] + +All the cypresses are undoubtedly valuable from a garden point of +view, but the various species vary in degree as regards their utility +as ornamental subjects. I should rank them in the following order in +point of merit: C. Lawsoniana, C. nutkaensis, C. macrocarpa, C. +sempervirens, C. thyoides, C. Macnabiana, and C. Goveniana; then would +follow C. torulosa, C. funebris, C. Knightiana, and other Mexican +species. These are placed last, not because they are less elegant than +the others, but on account of their tenderness, all being liable to +succumb to our damp and cold winters. The species which concerns us at +present, C. torulosa, is an old introduction, seeds of it having been +sent to this country by Wallich so long back as 1824, and previous to +this date it was found by Royle on the Himalayas, growing at +elevations of some 11,500 feet above sea level. Coming from such a +height, one would suppose it to be hardier than it really is, but its +tenderness may probably be accounted for by the wood not getting +thoroughly ripened during our summers. It is a very handsome tree, +said to reach from 20 feet to 125 feet in height in its native +habitat. It has a perfectly straight stem; the growth is pyramidal or +rather conical, and the old wood is of a warm purplish-brown. The +foliage is a glaucous gray-green, and the branches have a twisted and +tufted appearance. + +There are several varieties of it which are, or have been, in +cultivation. Of these one of the best is corneyana, which Gordon +ranked as a distinct species. It was supposed to be Chinese, and was +introduced to cultivation by Messrs. Knight & Perry, the predecessors +of Messrs. Veitch at the Chelsea Nurseries. It differs from C. +torulosa proper, its habit being of low stature, and has slender +pendulous branches; hence, it has been known in gardens by the names +of C. gracilis, C. cernua, and C. pendula. Other varieties of C. +torulosa are those named in gardens and nurseries--viridis, a kind +devoid of the glaucous foliage of the original; majestica, a robust +variety; and nana, a very dwarf and compact-growing sort. There is +also a so-called variegated form, but it is not worthy of mention. The +synonyms of C. torulosa itself are C. cashmeriana, C. nepalensis, and +C. pendula. Having regard to the tenderness of this Bhotan cypress, it +should only be planted in the warmest localities, and in dry sheltered +positions; upland districts, too, provided they are sheltered, are +undoubtedly suitable for it, inasmuch as growth is retarded in spring, +and, therefore, the young shoots escape injury from late spring +frosts.--_W.G., in The Garden._ + + * * * * * + + + + +THE PITCHER PLANT. + + +The variety of the pitcher plant (_Sarracenia variolaris_) found in +North America is carnivorous, being a feeder on various animal +substances. + +Mrs. Mary Treat, an American naturalist, made, a few years ago, +several experiments upon the plants of this species to be found in +Florida; and to the labors of this lady the writer has been indebted, +in some measure, in the preparation of this paper. + +The _Sarracenia_ derives its name of "pitcher plant" from the fact of +its possessing the following curious characteristics: The median nerve +is prolonged beyond the leaves in the manner of a tendril, and +terminates in a species of cup or urn. This cup is ordinarily three or +four inches in depth, and one to one and a half inches in width. The +orifice of the cup is covered with a lid, which opens and shuts at +certain periods. At sunrise the cup is found filled with sweet, limpid +water, at which time the lid is down. In the course of the day the lid +opens, when nearly half the water is evaporated; but during the night +this loss is made up, and the next morning the cup is again quite +full, and the lid is shut. + +About the middle of March the plants put forth their leaves, which are +from six to twelve inches long, hollow, and shaped something like a +trumpet, while the aperture of the apex is formed almost precisely in +the same manner as those of the plants previously described. A broad +wing extends along one side of the leaf, from the base to the opening +at the top; this wing is bound or edged with a purple cord, which +extends likewise around the cup. This cord secretes a sweet fluid, and +not only flying insects, but those also that crawl upon the ground, +are attracted by it to the plants. Ants, especially, are very fond of +this fluid, so that a line of aphides, extending from the base to the +summit of a leaf, may frequently be observed slowly advancing toward +the orifice of the cup, down which they disappear, never to return. +Flying insects of every kind are equally drawn to the plant; and +directly they taste the fluid, they act very curiously. After feeding +upon the secretions for two or three minutes they become quite stupid, +unsteady on their feet, and while trying to pass their legs over their +wings to clear them, they fall down. + +It is of no use to liberate any of the smaller insects; every fly, +removed from the leaf upon which it had been feeding, returned +immediately it was at liberty to do so, and walked down the fatal cup +as though drawn to it by a species of irresistible fascination. + +It is not alone that flies and other small insects are overpowered by +the fluid which exudes from the cord in question. Even large insects +succumb to it, although of course not so quickly. Mrs. Treat says: "A +large cockroach was feeding on the secretion of a fresh leaf, which +had caught but little or no prey. After feeding a short time the +insect went down the tube so tight that I could not dislodge it, even +when turning the leaf upside down and knocking it quite hard. It was +late in the evening when I observed it enter; the next morning I cut +the tube open; the cockroach was still alive, but it was covered with +a secretion produced from the inner surface of the tube, and its legs +fell off as I extricated it. From all appearance the terrible +_Sarracenia_ was eating its victim alive. And yet, perhaps, I should +not say 'terrible,' for the plant seems to supply its victims with a +Lethe-like draught before devouring them." + +If only a few insects alight upon a leaf, no unpleasant smell is +perceptible during or after the process of digestion; but if a large +number of them be caught, which is commonly the case, a most offensive +odor emanates from the cup, although the putrid matter does not appear +to injure in any manner the inner surface of the tube, food, even in +this condition, being readily absorbed, and going to nourish the +plant. In fact, it would seem that the _Sarracenia_, like some +animals, can feed upon carrion and thrive upon it. + +In instances in which experiments have been made with fresh, raw beef +or mutton, the meat has been covered in a few hours with the +secretions of the leaves, and the blood extracted from it. There is, +however, one difference between the digesting powers of the leaves +when exercised upon insects or upon meat. Even if the bodies of +insects have become putrid, the plant, as has already been stated, has +no difficulty in assimilating them; but as regards meat, it is only +when it is perfectly sweet that the secretions of the leaves will act +upon it. + +The pitcher plant undoubtedly derives its principal nourishment from +the insects it eats. It, too--unlike most other carnivorous plants, +which, when the quantity of food with which they have to deal is in +excess of their powers of digestion, succumb to the effort and +die--appears to find it easy to devour any number of insects, small or +large, the operation being with it simply a question of time. Flies, +beetles, or even cockroaches, at the expiration of three or four days +at most, disappear, nothing being left of them save their wings and +other hard, parts of their bodies. + +The _Sarracenia_ is, indeed, not only the most voracious of all known +species of carnivorous plants, but the least fastidious as to the +nature of the food upon which it feeds.--_W.C.M., Nature._ + + * * * * * + + + + +WHAT IS A PLANT? + + +Mr. Worsley-Benison has been discussing this question in a very +interesting way, and he says in conclusion that "_physiologically_ the +most distinctive feature of plant-life is the power to manufacture +protein from less complex bodies; that of animal-life, the absence of +such power." He finds that in form, in the presence of starch, of +chlorophyl, in power of locomotion, in the presence of circulatory +organs, of the body called nitrogen, in the functions of respiration +and sensation, there are no diagnostic characters. He finds, however, +"fairly constant and well-marked distinctions" in the presence of a +cellulose coat in the plant-cell, in digestion followed by absorption, +and in the power to manufacture protein. + +The _morphological_ feature of plants is this cellulose coat; of +animals, its absence; the _physiological_ peculiarity of plants, this +_manufacturing power_; of animals, the want of it. But after all the +discussion he says: "To the question, _Is this an animal or a plant?_ +we must often reply, _We do not know_."--_The Microscope._ + + * * * * * + + + + +CAMELLIAS. + + +Next to the rose, no flower* is more beautiful or more useful than the +camellia. It may readily be so managed that its natural season of +blooming shall be from October to March, thus coming in at a time when +roses can hardly be had without forcing. In every quality, with the +single exception of scent, the camellia may be pronounced the equal of +the rose. It can be used in all combinations or for all purposes for +which roses can be employed. In form and color it is probably more +perfect, and fully as brilliant. It is equally or more durable, either +on the plant or as a cut flower. It is a little dearer to buy, and +perhaps slightly more difficult to cultivate; but like most plants the +camellia has crucial periods in its life, when it needs special +treatment. That given, it may be grown with the utmost ease; that +withheld, its culture becomes precarious, or a failure. The camellia +is so hardy that it will live in the open air in many parts of Great +Britain, and herein lies a danger to many cultivators. Because it is +quite or almost hardy, they keep it almost cool. This is all very well +if the cool treatment be not carried to extremes, and persisted in all +the year round. Camellias in a dormant state will live and thrive in +any temperature above the freezing point, and will take little or no +hurt if subjected to from 3°-4° below it, or a temperature of 27° +Fahr. + + * Transcriber's Note: Original "flour". + +They will also bloom freely in a temperature of 40°, though 45° suits +them better. Hence, during the late summer and early autumn it is +hardly possible to keep camellias too cool either out of doors or in. +They are also particularly sensitive to heat just before the +flower-buds begin to swell in late autumn or winter; a sudden or +sensible rise of temperature at that stage sends the flower-buds off +in showers. This is what too often happens, in fact, to the camellias +of amateurs. No sooner do the buds begin to show then a natural +impatience seizes the possessor's of well-budded camellias to have the +flowers opened. More warmth, a closer atmosphere, is brought to bear +upon them, and down fall the buds in showers on stage or floor--the +chief cause of this slip between the buds and the open flowers being a +rise of temperature. A close or arid atmosphere often leads to the +same results. Camellias can hardly have too free a circulation of air +or too low a temperature. Another frequent cause of buds dropping +arises from either too little or too much water at the roots. Either a +paucity or excess of water at the roots should lead to identical +results. Most amateurs overwater their camellias during their +flowering stages. Seeing so many buds expanding, they naturally rush +to the conclusion that a good deal of water must be used to fill them +to bursting point. But the opening of camellia buds is less a +manufacture than a mere development, and the strain on the plant and +drain on the roots is far less during this stage than many suppose. Of +course the opposite extreme of over-dry roots must be provided +against, else this would also cause the plants to cast off their buds. + +But our object now is less to point out how buds are to be developed +into fully expanded flowers than to show how they were to be formed in +plenty, and the plants preserved in robust health year after year. One +of the simplest and surest modes of reaching this desirable end is to +adopt a system of semi-tropical treatment for two months or so after +flowering. The moment or even before the late blooms fade, the plants +should be pruned if necessary. Few plants bear the knife better than +camellias, though it is folly to cut them unless they are too tall or +too large for their quarters or have grown out of form. As a rule +healthy camellias produce sufficient or even a redundancy of shoots +without cutting back; but should they need pruning, after flowering is +the best time to perform the operation. + +During the breaking of the tender leaves and the growth of the young +shoots in their first stages, the plant should be shaded from direct +sunshine, unless, indeed, they are a long way from the glass, when the +diffusion and dispersion of the rays of light tone down or break their +scorching force; few young leaves and shoots are more tender and +easily burned than camellia, and scorching not only disfigures the +plants, but also hinders the formation of fine growths and the +development of flower-buds. + +The atmosphere during the early season of growth may almost touch +saturation. It must not fail to be genial, and this geniality of the +air must be kept up by the surface-sprinkling of paths, floors, +stages, walls, and the plants themselves at least twice a day. + +With the pots or border well drained it is hardly possible to +overwater the roots of camellias during their period of wood-making. +The temperature may range from 50° to 65° during most of the period. +As the flower-buds form, and become more conspicuous, the tropical +treatment may become less and less tropical, until the camellias are +subjected to the common treatment of greenhouse or conservatory plants +in summer. Even at this early stage it is wise to attend to the +thinning of the buds. Many varieties of camellias--notably that most +useful of all varieties, the double white--will often set and swell +five or ten times more buds than it ought to be allowed to carry. +Nothing is gained, but a good deal is lost, by allowing so many embryo +flower-buds to be formed or partially developed. It is in fact far +wiser to take off the majority of the excess at the earliest possible +point, so as to concentrate the strength of the plant into those that +remain. + +As it is, however, often a point of great moment to have a succession +of camellia flowers for as long a period as possible on the same +plants, buds of all sizes should be selected to remain. Fortunately, +it is found in practice that the plants, unless overweighted with +blooms, do not cast off the smaller or later buds in their efforts to +open their earlier and larger ones. With the setting, thinning, and +partial swelling of the flower-buds the semi-tropical treatment of +camellias must close; continued longer, the result would be their +blooming out of season, or more probably their not blooming at all. + +The best place for camellias from the time of setting their +flower-buds to their blooming season is a vexed question, which can +hardly be said to have been settled as yet. They may either be left in +a cool greenhouse, or placed in a shaded, sheltered position in the +open air. Some of the finest camellias ever seen have been placed in +the open air from June to October. These in some cases have been stood +behind south, and in others behind west walls. Those facing the east +in their summer quarters were, on the whole, the finest, many of them +being truly magnificent plants, not a few of them having been imported +direct from Florence at a time when camellias were far less grown in +England than now. + +In all cases where camellias are placed in the open air in summer, +care will be taken to place the pots on worm proof bases, and to +shield the tops from direct sunshine from 10 to 4 o'clock. If these +two points are attended to, and also shelter from high winds, it +matters little where they stand. In all cases it is well to place +camellias under glass shelter early in October, less for fear of cold +than of saturating rains causing a sodden state of the soil in the +pots. + +While adverting, however, to the safety and usefulness of placing +camellias in the open air in summer, it must not be inferred that this +is essential to the successful culture; it is, in fact, far otherwise, +as the majority of the finest camellias in the country are planted out +in conservatories with immovable roofs. Many such houses are, however, +treated to special semi-tropical treatment as has been described, and +are kept as cool and open as possible after the flower-buds are fairly +set, so that the cultural and climatic conditions approximate as +closely as possible to those here indicated. + +Soil and seasons of potting may be described as vexed questions in +camellia culture. As to the first, some affect pure loam, others peat +only, yet more a half and half of both, with a liberal proportion of +gritty sand, or a little smashed charcoal or bruised bones as porous +or feeding agents, or both. Most growers prefer the mixture, and as +good camellias are grown in each of its constituents, it follows +without saying that they may also be well grown in various proportions +of both. + +Under rather than over potting suits the plants best, and the best +time is doubtless just before they are about to start into fresh +growth, though many good cultivators elect to shift their plants in +the late summer or autumn, that is, soon after the growth is +finishing, and the flower-buds fairly and fully set for the next +season. From all which it is obvious that the camellia is not only +among the most useful and showy, but likewise among the most +accommodating of plants. + +Under good cultivation it is also one of the cleanest, though when +scab gets on it, it is difficult to get rid of it. Mealy-bugs also +occasionally make a hurried visit to camellias when making their +growth, as well as aphides. But the leaves once formed and advanced to +semi-maturity are too hard and leathery for such insects, while they +will bear scale being rubbed off them with impunity. But really +well-grown camellias, as a rule, are wholly free from insect pests, +and their clean, dark, glossy leaves are only of secondary beauty to +their brilliant, exquisitely formed, and many sized flowers.--_D.T., +The Gardeners' Chronicle._ + + * * * * * + + + + +ARISÆMA FIMBRIATUM. + +_Mast.; sp. nov._ + + +[Illustration: ARISÆMA FIMBRIATUM: LEAF, SPATHE, AND FLORAL DETAILS.] + +Some few years since we had occasion to figure some very remarkable +Himalayan species of this genus, in which the end of the spadix was +prolonged into a very long, thread-like appendage thrown over the +leaves of the plant or of its neighbors, and ultimately reaching the +ground, and thus, it is presumed, affording ants and other insects +means of access to the flowers, and consequent fertilization. These +species were grown by Mr. Elwes, and exhibited by him before the +Scientific Committee. The present species is of somewhat similar +character, but is, we believe, new alike to gardens and to science. We +met with it in the course of the autumn in the nursery of Messrs. +Sander, at St. Alban's; but learn that it has since passed into the +hands of Mr. W. Bull, of Chelsea. It was imported accidentally with +orchids, probably from the Philippine Islands. It belongs to Engler's +section, trisecta, having two stalked leaves, each deeply divided into +three ovate acute glabrous segments. The petioles are long, pale +purplish, rose-colored, sprinkled with small purplish spots. The +spathes are oblong acute or acuminate, convolute at the base, +brownish-purple, striped longitudinally with narrow whitish bands. The +spadix is cylindrical, slender, terminating in along, whip-like +extremity, much longer than the spathe. The flowers have the +arrangement and structure common to the genus, the females being +crowded at the base of the spadix, the males immediately above them, +and these passing gradually into fleshy incurved processes, which in +their turn pass gradually into long, slender, purplish threads, +covering the whole of the free end of the spadix.--_M.T.M., in The +Gardeness' Chronicle._ + + * * * * * + + + + +STRIKING A LIGHT. + + +In the new edition of Mason's "Burma" we read that among other uses to +which the bamboo is applied, not the least useful is that of producing +fire by friction. For this purpose a joint of thoroughly dry bamboo is +selected, about 1½ inches in diameter, and this joint is then split in +halves. A ball is now prepared by scraping off shavings from a +perfectly dry bamboo, and this ball being placed on some firm support, +as a fallen log or piece of rock, one of the above halves is held by +its ends firmly down on it, so that the ball of soft fiber is pressed +with some force against its inner or concave surface. Another man now +takes a piece of bamboo a foot long or less, and shaped with a blunt +edge, something like a paper knife, and commences a sawing motion +backward and forward across the horizontal piece of bamboo, and just +over the spot where the ball of soft fiber is held. The motion is slow +at first, and by degrees a groove is formed, which soon deepens as the +motion increases in quickness. Soon smoke arises, and the motion is +now made as rapid as possible, and by the time the bamboo is cut +through not only smoke but sparks are seen, which soon ignite the +materials of which the ball beneath is composed. The first tender +spark is now carefully blown, and when well alight the ball is +withdrawn, and leaves and other inflammable materials heaped over it, +and a fire secured. This is the only method that I am aware of for +procuring fire by friction in Burma, but on the hills and out of the +way parts, that philosophical toy, the "pyrophorus," is still in use. +This consists[1] of a short joint of a thick woody bamboo, neatly cut, +which forms a cylinder. At the bottom of this a bit of tinder is +placed, and a tightly-fitting piston inserted composed of some hard +wood. The tube being now held in one hand, or firmly supported, the +piston is driven violently down on the tinder by a smart blow from the +hand, with the result of igniting the tinder beneath. + + [Footnote 1: It is also made of a solid cylinder of buffalo's + horn, with a central hollow of three-sixteenths of an inch in + diameter and three inches deep burnt into it. The piston, which + fits very tightly in it, is made of iron-wood or some wood + equally hard.] + +Another method of obtaining fire by friction from bamboos is thus +described by Captain T.H. Lewin ("Hill Tracts of Chittagong, and the +Dwellers Therein", Calcutta, 1869, p. 83), as practiced in the +Chittagong Hills. The Tipporahs make use of an ingenious device to +obtain fire; they take a piece of dry bamboo, about a foot long, split +it in half, and on its outer round surface cut a nick, or notch, about +an eighth of an inch broad, circling round the semi-circumference of +the bamboo, shallow toward the edges, but deepening in the center +until a minute slit of about a line in breadth pierces the inner +surface of the bamboo fire-stick. Then a flexible strip of bamboo is +taken, about 1½ feet long and an eighth of an inch in breadth, to fit +the circling notch, or groove, in the fire-stick. This slip or band is +rubbed with fine dry sand, and then passed round the fire-stick, on +which the operator stands, a foot on either end. Then the slip, +grasped firmly, an end in each hand, is pulled steadily back and +forth, increasing gradually in pressure and velocity as the smoke +comes. By the time the fire-band snaps with the friction there ought +to appear through the slit in the fire-stick some incandescent dust, +and this placed, smouldering as it is, in a nest of dry bamboo +shavings, can be gently blown into a flame.--_The Gardeners' +Chronicle._ + + * * * * * + + + + +EXPERIMENTS IN MEMORY. + + +When we read how one mediæval saint stood erect in his cell for a week +without sleep or food, merely chewing a plantain-leaf out of humility, +so as not to be too perfect; how another remained all night up to his +neck in a pond that was freezing over; and how others still performed +for the glory of God feats no less tasking to their energies, we are +inclined to think, that, with the gods of yore, the men, too, have +departed, and that the earth is handed over to a race whose will has +become as feeble as its faith. But we ought not to yield to these +instigations, by which the evil one tempts us to disparage our own +generation. The gods have somewhat changed their shape, 'tis true, and +the men their minds; but both are still alive and vigorous as ever for +an eye that can look under superficial disguises. The human energy no +longer freezes itself in fish-ponds, and starves itself in cells; but +near the north pole, in central Africa, on Alpine "couloirs," and +especially in what are nowadays called "psycho-physical laboratories," +it maybe found as invincible as ever, and ready for every fresh +demand. To most people a north pole expedition would be an easy task +compared with those ineffably tedious measurements of simple mental +processes of which Ernst Heinrich Weber set the fashion some forty +years ago, and the necessity of extending which in every possible +direction becomes more and more apparent to students of the mind. +Think of making forty thousand estimates of which is the heavier of +two weights, or seventy thousand answers as to whether your skin is +touched at two points or at one, and then tabulating and +mathematically discussing your results! Insight is to be gained at no +less price than this. The new sort of study of the mind bears the same +relation to the older psychology that the microscopic anatomy of the +body does to the anatomy of its visible form, and the one will +undoubtedly be as fruitful and as indispensable as the other. + +Dr. Ebbinghaus[1] makes an original addition to heroic psychological +literature in the little work whose title we have given. For more than +two years he has apparently spent a considerable time each day in +committing to memory sets of meaningless syllables, and trying to +trace numerically the laws according to which they were retained or +forgotten. Most of his results, we are sorry to say, add nothing to +our gross experience of the matter. Here, as in the case of the +saints, heroism seems to be its own reward. But the incidental results +are usually the most pregnant in this department; and two of those +which Dr. Ebbinghaus has reached seems to us to amply justify his +pains. The first is, that, in _forgetting_ such things as these lists +of syllables, the loss goes on very much more rapidly at first than +later on. He measured the loss by the number of seconds required to +_relearn_ the list after it had been once learned. Roughly speaking, +if it took a thousand seconds to learn the list, and five hundred to +relearn it, the loss between the two learnings would have been +one-half. Measured in this way, full half of the forgetting seems to +occur within the first half-hour, while only four-fifths is forgotten +at the end of a month. The nature of this result might have been +anticipated, but hardly its numerical proportions. + + [Footnote 1: "Ueber das Gedächtniss. Untersuchungen zur + experimentellen Psychologie." Von Herm. + Ebbinghaus. Leipzig: Duncker u. Humblot, 1885. 10+169 pp. 8vo.] + +The other important result relates to the question whether ideas are +recalled only by those that previously came immediately before them, +or whether an idea can possibly recall another idea, with which it was +never in _immediate_ contact, without passing through the intermediate +mental links. The question is of theoretic importance with regard to +the way in which the process of "association of ideas" must be +conceived; and Dr. Ebbinghaus' attempt is as successful as it is +original, in bringing two views, which seem at first sight +inaccessible to proof, to a direct practical test, and giving the +victory to one of them. His experiments conclusively show that an idea +is not only "associated" directly with the one that follows it, and +with the rest _through that_, but that it is _directly_ associated +with _all_ that are near it, though in unequal degrees. He first +measured the time needed to impress on the memory certain lists of +syllables, and then the time needed to impress lists of the same +syllables with gaps between them. Thus, representing the syllables by +numbers, if the first list was 1, 2, 3, 4 ... 13, 14, 15, 16, the +second would be 1, 3, 5 ... 15, 2, 4, 6 ... 16, and so forth, with +many variations. + +Now, if 1 and 3 in the first list were learned in that order merely by +1 calling up 2, and by 2 calling up 3, leaving out the 2 ought to +leave 1 and 3 with no tie in the mind; and the second list ought to +take as much time in the learning as if the first list had never been +heard of. If, on the other hand, 1 has a _direct_ influence on 3 as +well as on 2, that influence should be exerted even when 2 is dropped +out; and a person familiar with the first list ought to learn the +second one more rapidly than otherwise he could. This latter case is +what actually occurs; and Dr. Ebbinghaus has found that syllables +originally separated by as many as seven intermediaries still reveal, +by the increased rapidity with which they are learned in order, the +strength of the tie that the original learning established between +them, over the heads, so to speak, of all the rest. It may be that +this particular series of experiments is the entering wedge of a new +method of incalculable reach in such questions. The future alone can +show. Meanwhile, when we add to Dr. Ebbinghaus' "heroism" in the +pursuit of true averages, his high critical acumen, his modest tone, +and his polished style, it will be seen that we have a new-comer in +psychology from whom the best may be expected.--_W.J., Science._ + + * * * * * + + + + +SINKING OF THE QUIEVRECHAIN WORKING SHAFT. + + +The sinking of mine shafts in certain Belgian and French basins, where +the coal deposit is covered with thick strata of watery earth, has +from all times been considered as the most troublesome and delicate, +and often the most difficult operation, of the miner's art. Of the few +modern processes that have been employed for this purpose, that of +Messrs. Kind and Chaudron has been found most satisfactory, although +it leaves much to be desired where it is a question of traversing +moving sand. An interesting modification of this well-known process +has recently been described by Mr. E. Chavatte, in the Bulletin de la +Societe Industrielle du Nord de la France. Two years ago the author +had to sink a working shaft at Quievrechain, 111 feet of which was to +traverse a mass of moving and flowing sand, inconsistent earth, +gravel, and marls, and proceeded as follows: + +He first put down two beams, A B (Pl. 1, Figs. 2, 3, and 9), each 82 +feet in length and of 20×20 inch section in the center, and upon these +placed two others, E F, of 16×16 inch section. Beneath the two first +were inserted six joists, _c c c c c c_, about 82 feet in length and +of 14 or 16 inch section in the center. Finally these were +strengthened at their extremities with two others, _d d_, about 82 +feet in length. All these timbers, having been connected by tie bands +and bolts, constituted a rigid structure that covered a surface of +nearly seven hundred square yards. + +From the beams, A B and E F, there was suspended a red fir frame by +means of thirty-four iron rods. + +Upon this frame, which was entirely immersed in the moving sand, there +was established brick masonry (Figs. 1, 2, and 3). As the ends of the +timbers entered the latter, and were connected by 1½ inch bolts, they +concurred in making the entire affair perfectly solid. The frame, K K, +was provided with an oaken ring, which was affixed to it with bolts. + +After this, a cast iron tubbing, having a cutting edge, and being +composed of rings 3.28 feet wide and made of six segments, was +lowered. This tubbing was perfectly tight, all the surfaces of the +joints having been made even and provided with strips of lead +one-tenth of an inch thick. It weighed 4,000 pounds to the running +foot. + +[Illustration: FIG. 1.--Section through A B. FIG. 2.--Plan. FIG. +3.--Section through C D. FIG. 5.--Section through E F of Fig. 4. FIGS. +6 AND 7.--Work Prepared and finished. FIG. 10.--Section through A B +and C D of Fig. 12. FIGS. 11 6 AND 12.--Arrangement of jack-screw. +FIG. 13.--Section through A B and C D of Fig. 11. + + PLATE I.--SINKING A MINE SHAFT.] + +It was first raised to a height of fifteen feet, so as to cause it to +enter the sand by virtue of its own gravity. It thus penetrated to a +depth of about twenty inches. After this the workmen were ordered to +man the windlasses and hoist out some of the sand. This caused the +tubbing to descend about eight inches more, when it came to a +standstill. It was now loaded with 17,000 pounds of pig iron, but in +vain, for it refused to budge. Mr. Chavatte therefore had recourse to +a dredge with vertical axis, constructed as follows: + +Upon a square axis, A B (Pl. 2, Figs. 1, 2, and 3), provided with +double cross braces, C D, and strengthened by diagonals, were riveted, +by their upper extremities, two cheeks, G H, whose lower extremities +held the steel plates, I J I' J', which, in turn, were fastened to the +axis, A B, by their other extremities. These plates were so inclined +as to scrape the surface of the ground over which they were moved. +They each carried two bags made of coarse canvas and strengthened by +five strong leather straps (Figs. 2 and 4). To the steel plates were +riveted two plates of iron containing numerous apertures, through +which passed leather straps designed for fastening thereto the lower +part of the mouth of the bags. That portion of the mouth of the latter +that was to remain open was fastened in the same way to two other +plates, X Y, X¹ Y¹ (Fig. 1), held between the lower cross-braces. + +When the apparatus was revolved, the plates scraped the earth to be +removed, and descended in measure as the latter entered the bags. +These bags, when full, were hooked, by means of the five rings which +they carried, to the device shown in Fig. 8 (Pl. 2), and raised to the +surface and emptied into cars. + +The dredge was set in motion by four oak levers (Figs. 5 and 6). Two +of these were manned by workmen stationed upon the surface flooring, +and the other two by workmen upon the flooring in the tubbing. The +axis was elongated, in measure as the apparatus descended, by rods of +the same dimensions fastened together by cast iron sleeves and bolts +(Fig. 7). + +The steel plates were not capable of acting alone, even in cases where +they operated in pure moving sand containing no pebbles, for the sand +was too compact to be easily scraped up by the steel, and so it had to +be previously divided. For this purpose Mr. Chavatte used rakes which +were in form exactly like those of the extirpators, U and V, of Figs. +1, 2, and 3, of Pl. 2, except that the dividers carried teeth that +were not so strong as those of the extirpators, and that were set +closer together. These rakes were let down and drawn up at will. They +were maneuvered as follows: + +The dredge descended with the extirpators pointing upward. When their +heads reached the level of the upper floor, the tools were removed. +Then the dredge was raised again. In this way the extirpators lay upon +the floor, and, if the lifting was continued, they placed themselves +in their working position, in which they were fixed by the bolts A" B" +C" (Fig. 1). After this, the apparatus was let down and revolved. The +rakes divided the earth, the scrapers collected it, and the bags +pocketed it. + +The great difficulty was to cause the tubbing to descend vertically, +and also to overcome the enormous lateral pressure exerted upon it by +the earth that was being traversed. Water put into the shaft helped +somewhat, but the great stress to be exerted had to be effected by +means of powerful jack screws. These were placed directly upon the +tubbing, and bore against strong beams whose extremities were inserted +into the masonry. + +As a usual thing it is not easy to use more than four or six such +jacks, since the number of beams that can be employed is limited, +owing to the danger of obstructing the mouth of the shaft. Yet twelve +were used by Mr. Chavatte, and this number might have been doubled had +it been necessary. As we have seen, the frame, K K (Pl. 1, Fig. 3), +was provided with an oak circle traversed by 32 bolts. The length of +these latter was two inches and a quarter longer than they needed to +have been, or they were provided with wooden collars of that +thickness. Later on, these collars were replaced with iron bars that +held the wood against which the jacks bore in order to press the +tubbing downward (Pl. 1, Figs. 10, 11, 12, and 13). + +Mr. Chavatte's great anxiety was to know whether he should succeed in +causing the first section of tubbing to traverse the four feet of +gravel; for in case it did not pass, he would be obliged to employ a +second section of smaller diameter, thus increasing the expense. He +was persuaded that the coarse gravel remaining in the side of the +shaft would greatly retard the descent of the tubbing. So he had +decided to remove such obstructions at the proper moment through +divers or a diving bell. Then an idea occurred to him that dispensed +with all that trouble, and allowed him to continue with the first +section. This was to place upon the dredge two claw-bars, T (Pl. 2, +Fig. 3), which effected the operation of widening with wonderful ease. +To do this it was only necessary to turn up the bags, and revolve the +apparatus during its descent. The claw at the extremity of the bar +pulled out everything within its reach, and thus made an absolutely +free passage for the tubbing. + +The sands and gravels were passed by means of a single section of +tubbing 31 feet in length, which was not stopped until it had +penetrated a stratum of white chalk to a depth of two yards. This +chalk had no consistency, although it contained thin plates of quite +large dimensions. These were cut, as if with a punch, by means of the +teeth of the extirpator. + +It now remains to say a few words concerning the sinking of the shaft, +which, after the operation of the dredge, was continued by the process +called "natural level" The work was not easy until a depth of 111 feet +had been reached. Up to this point it had been necessary to proceed +with great prudence, and retain the shifting earth by means of four +iron plate tubes weighing 54 tons. Before finding a means of widening +the work already done by the dredge, Mr. Chavatte was certain that he +would have to use two sections of tubbing, and so had given the first +section a diameter of 16½ feet. He could then greatly reduce the +diameter, and bring it to 15¾ feet as soon as the ground auger was +used. + +After two yards of soil had been removed from beneath the edge of the +tubbing, the earth began to give way. Seeing this, Mr. Chavatte let +down a tube 13 feet in length and 15.4 in diameter. The exterior of +this was provided with 12 oak guides, which sliding over the surface +of the tubbing had the effect of causing the tube to descend +vertically. And this was necessary, because this tube had to be driven +down every time an excavation of half a yard had been made. + +Afterward, a diameter of 15.35 feet was proceeded with, and the small +central shaft of 4¼ feet diameter was begun. This latter had not as +yet been sunk, for fear of causing a fall of the earth. + +Next, the earth was excavated to a depth of 8.2 feet, and a tube 16.4 +feet in length was inserted; then a further excavation of 8.2 feet was +made, and the tube driven home. + +After this an excavation of 26¼ feet was made, and a tube of the same +length and 14½ feet in diameter was driven down. Finally, the shifting +soil was finished with a fourth tube 19½ feet in length and 14 feet in +diameter. + +A depth of 111 feet had now been reached, and the material encountered +was solid white chalk. From this point the work proceeded with a +diameter of 13.9 feet to a depth of 450 feet. The small shaft had been +sunk directly to a depth of 475 feet. At 450 feet the diameter was +diminished by three inches. Then an advance of a foot was made, and +the diameter reduced by one and a half inch. + +The reason for this reduction in the diameter and change in the mode +of deepening was as follows: + +The Chaudron moss-box, when it chances to reach its seat intact, and +can consequently operate well, undoubtedly makes a good wedging. But +how many times does it not happen that it gets injured before reaching +its destination? Besides, as it often rests upon earth that has caved +in upon its seat during the descent of the tubbing, it gets askew, and +later on has to be raised on one side by means of jacks or other +apparatus. Under such circumstances, Mr. Chavatte considered this +moss-box as more detrimental than useful, and not at all +indispensable, and so substituted beton for it, as had previously been +done by Mr. Bourg, director of the Bois-du-Luc coal mines. + +[Illustration: FIGS. 1, 2, 3, 6 AND 4.--Details of dredge. FIGS. 5 6 +AND 6.--Details of maneuvering lever. FIG. 7.--Mode of lengthening the +axis of the dredge. FIG. 8.--Hooks for lifting the dredge bags. FIG. +9.--Arrangement of valves in the beton box. FIG. 10.--Device for +centering the tubbing. + + PLATE II.] + +This engineer likewise suppressed the balancing column, which is often +a source of trouble in the descent of the tubbing, and forced his +tubbing to center itself with the shaft through a guide with four +branches riveted under the false bottom that entered the small shaft +(Pl. 2, Fig. 10). Mr. Bourg so managed that there remained an empty +space of ten inches to fill in with beton. Mr. Chavatte had at first +intended to proceed in the same way, but the two last tubbings, upon +which he had not counted, forced him to reduce the space to 5¾ inches. +Under such circumstances it was not prudent to employ the same means +for guiding the base of the tubbing, because, if the central shaft had +not exactly the same center as the large one, there would have been +danger of throwing the tubbing sideways and causing it to leak. Seeing +which, Mr. Chavatte strengthened the lower part of the base ring and +placed it upon another ring tapering downward, and 27½ inches in +height (Pl. 1, Fig. 5). The object of this lower ring was to force the +tubbing to remain concentric with the shaft, to form a tight joint +with its upper conical portion, and to form a joint upon the seat with +its lower flange, so as to prevent the beton from flowing into the +small shaft. + +After the shaft was pumped out, digging by hand was begun with a +diameter of 12 feet. After descending 20 inches an 8×10 inch curb was +laid, in order to consolidate the earth and prevent any movement of +the tubbing. Then the excavating was continued to a depth of 31½ +inches, and with a diameter of 9¾ feet. At this point another curb was +put in for consolidating the earth. Finally, the bottom was widened +out as shown in Fig. 7, so that three basal wedged curbs could be put +in. This done, the false tubbing was put in place; and finally, when +proceeding upward, the last ring composed of twelve pieces was +reached, the earth was excavated and at once replaced with a collar +composed of twelve pieces of oak tightened up by oak wedges. Each of +these pieces was cemented separately and in measure as they were +assembled. + +Through motive of economy no masonry was placed under the base of the +three wedged curbs. In fact, by replacing this with a wedged curb of +wood traversed by six bolts designed to fix the cast iron curb +immediately above, Mr. Chavatte obtained a third curb that he would +have had to have made of cast iron. + + * * * * * + + + + +ON THE ELEMENTARY PRINCIPLES OF THE GAS-ENGINE.[1] + + [Footnote 1: A paper read before the Gas Institute, Manchester, + June, 1885.] + +By DENNY LANE, of Cork. + + +Among the most useful inventions of the latter half of the nineteenth +century the gas-engine holds a prominent place. While its development +has not been so brilliant or so startling as that which we can note in +the employment of electricity, it holds, among the applications of +heat, the most important place of any invention made within that +period. Even amid the contrivances by which, in recent times, the +other forces of nature have been subdued to the uses of man, there are +only a few which rival the gas-engine in practical importance. With +regard to the steam-engine itself, it is remarkable how little that is +new has really been invented since the time of Watt and Woulfe. In the +specifications of the former can be shown completely delineated, or +fully foreshadowed, nearly every essential condition of the economy +and efficiency attained in our own days; and it is only by a gradual +"survival of the fittest" of the many contrivances which were made to +carry out his broad ideas that the steam-engine of the present has +attained its great economy. + +It is but within the last fifty years that the laws of the relation +between the different physical forces were first enunciated by Justice +Grove, and confirmed by the classical researches of Dr. Joule--the one +a lawyer, working hard at his profession, the other a man of business +engaged in manufacture. Both are still living among us; the latter +having withdrawn from business, while the former is a Judge of the +High Court of Justice. I always regret that the claims of his +profession have weaned Justice Grove from science; for, while it may +be possible to find in the ranks of the Bar many who might worthily +occupy his place on the Bench, it would be hard to find among men of +science any with as wide-reaching and practical philosophy as that +which he owns. The chemist demonstrated long since that it was +impossible for man to create or destroy a single particle of +ponderable matter; but it remained for our own time to prove that it +was equally impossible to create or destroy any of the energy which +existed in nature as heat, mechanical power, electricity, or chemical +affinity. All that it is in the power of man to do is to convert one +of these forms into another. This, perhaps the greatest of all +scientific discoveries since the time of Newton, was first, I believe, +enunciated in 1842 by Grove, in a lecture given at the London +Institution; and it was experimentally proved by the researches of +Joule, described in a paper which he read at the meeting of the +British Association which was held at Cork--my native city--in 1843. +My friend Dr. Sullivan, now President of Queen's College, Cork, and I +myself had the privilege of being two of a select audience of half a +dozen people, who alone took sufficient interest in the subject to +hear for the first time developed the experimental proof of the theory +which welds into one coherent system the whole physical forces of the +universe, and enables one of these to be measured by another. One +branch of the "correlation of physical forces," as it was termed by +Grove, was the relation between mechanical power and heat, and the +convertibility of each into the other, which, under the name of +"Thermodynamics," has become one of the most important branches of +practical science. + +Joule's first experiments clearly proved that each of these forms of +energy was convertible into the other; but some discrepancies arose in +determining the exact equivalent of each. His subsequent researches, +however, clearly demonstrated the true relation between both. Taking +as the unit of heat the amount which would be necessary to raise 1 lb. +of water 1° of Fahrenheit's scale (now called "the English thermal +unit"), he proved that this unit was equivalent to the mechanical +power which would be required to raise 772 lb. 1 foot, or to raise 1 +lb. 772 ft. perpendicularly against the force of gravity. The +heat-unit--the pound-degree--which I will distinguish by the Greek +letter [theta], is a compound unit of mass and temperature; the +second--the foot-pound = f.p.--a compound unit of mass and space. This +equation, called "Joule's equivalent," or 1 thermal unit = 772 +foot-pounds, is the foundation and the corner-stone of thermodynamics. + +It is essential to understand the meaning of this equation. It +expresses the maximum effect of the given cause, viz., that if _all_ +the heat were converted into power, or _all_ the power were converted +into heat, 1 thermal unit would produce 772 foot-pounds, or 772 +foot-pounds would raise 1 lb. of water 1° Fahr. But there is never a +complete conversion of any form of energy. Common solid coal may be +partly converted into gases in a retort; but some of the carbon +remains unchanged, and more is dissipated but not lost. In the same +way, if I take five sovereigns to Paris and convert them into francs, +and return to London and convert the francs into shillings, I shall +not have 100 shillings, but only perhaps 95 shillings. But the five +shillings have not been lost; three of them remain in the French +_change de monnaies_, and two of them in the English exchange office. +I may have forfeited something, but the world has forfeited nothing. +There remains in it exactly the same number of sovereigns, francs, and +shillings as there was before I set out on my travels. Nothing has +been lost, but some of my money has been "dissipated;" and the +analogous case, "the dissipation of energy," has formed the subject of +more than one learned essay. + +Before the invention of the steam-engine, the only powers employed in +mechanics were those of wind and water mills, and animal power. In the +first two, no conversion of one force into another took place; they +were mere kinematic devices for employing the mechanical force already +existing in the gale of wind and the head of water. With regard to the +power developed by man and other animals, we had in them examples of +most efficient heat-engines, converting into power a large percentage +of the fuel burnt in the lungs. But animal power is small in amount, +and it is expensive for two reasons--first, because the agents require +long intervals of rest, during which they still burn fuel; and next, +because the fuel they require is very expensive. A pound of bread or +beef, or oats or beans, costs a great deal more than a pound of coal; +while it does not, by its combustion, generate nearly so much heat. +The steam-engine, therefore, took the place of animal power, and for a +long time stood alone; and nearly all the motive power derived from +heat is still produced by the mechanism which Watt brought to such +great efficiency in so short a time. + +Now the practical question for all designers and employers of +heat-engines is to determine how the greatest quantity of motive force +can be developed from the heat evolved from a given kind of fuel; and +coal being the cheapest of all, we will see what are the results +obtainable from it by the steam-engine. In this we have three +efficiencies to consider--those of the furnace, the boiler, and the +cylinder. + +First, with respect to the furnace. The object is to combine the +carbon and the hydrogen of the coal with a sufficient quantity of the +oxygen of the air to effect complete combustion into carbonic acid and +water. In order to do this, we have to use a quantity of air much +larger than is theoretically necessary, and also to heat an amount of +inert nitrogen five times greater than the necessary oxygen; and we +are therefore obliged to create a draught which carries away to the +chimney a considerable portion of the heat developed. The combustion, +moreover, is never perfect; and some heat is lost by conduction and +radiation. The principal loss is by hot gases escaping from the flues +to the chimney. Even with well-set boilers, the temperature in the +chimney varies from 400° to 600° Fahr. Taking the mean of 500°, this +would represent a large proportion of the total heat, even if the +combustion were perfect; for, as a general rule, the supply of air to +a furnace is double that which is theoretically necessary. For our +present purpose, it will be sufficient to see how much the whole loss +is, without dividing it under the several heads of "imperfect +combustion," "radiation," and "convection," by the heated gases +passing to the chimney. + +With a very good boiler and furnace each pound of coal evaporates 10 +pounds of water from 62° Fahr., changing it into steam of 65 lb. +pressure at a temperature of 312°, or 250° above that of the water +from which it is generated. Besides these 250°, each pound of steam +contains 894 units of latent heat, or 1,144 units in all. A very good +condensing engine will work with 2.2 lb. of coal and 22 lb. of steam +per horse power per hour. Now. 1 lb. of good coal will, by its +combustion, produce 14,000 heat-units; and the 2.2 lb. of coal +multiplied by 14,000 represent 30,800[theta]. Of these we find in the +boiler 22 × 1,144, or 25,168 units, or about 81½ per cent., of the +whole heat of combustion; so that the difference (5,632 units, or 18½ +per cent.) has been lost by imperfect combustion, radiation, or +convection. The water required for condensing this quantity of steam +is 550 lb.; and, taking the temperature in the hot well as 102°, 550 +lb. have been raised 40° from 62°. Thus we account for 550 × 40 = +22,000, or (say) 71½ per cent. still remaining as heat. If we add this +71½ per cent. to 18½ per cent. we have 90 per cent., and there remain +only 10 per cent. of the heat that can possibly have been converted +into power. But some of this has been lost by radiation from +steam-pipes, cylinder, etc. Allowing but 1 per cent. for this, we have +only 9 per cent. as the efficiency of a really good condensing engine. +This estimate agrees very closely with the actual result; for the 2.2 +lb. of coal would develop 30,800[theta]; and this, multiplied by +Joule's equivalent, amounts to nearly 24 millions of foot-pounds. As 1 +horse power is a little less than 2 million foot-pounds per hour, only +one-twelfth, or a little more than 8 per cent. of the total heat is +converted; so that whether we look at the total quantity of heat which +we show unconverted, or the total heat converted, we find that each +supplements and corroborates the other. If we take the efficiency of +the engine alone, without considering the loss caused by the boiler, +we find that the 25,168[theta] which entered the boiler should have +given 19,429,696 foot-pounds; so that the 2 millions given by the +engine represent about 10 per cent. of the heat which has left the +boiler. The foregoing figures refer to large stationary or marine +engines, with first-rate boilers. When, however, we come to +high-pressure engines of the best type, the consumption of coal is +twice as much; and for those of any ordinary type it is usual to +calculate 1 cubic foot, or 62½ lb., of water evaporated per horse +power. This would reduce the efficiency to about 6 per cent. for the +best, and 3 per cent. for the ordinary non-condensing engines; and if +to this we add the inefficiency of some boilers, it is certain that +many small engines do not convert into power more than 2 per cent. of +the potential energy contained in the coal. + +At one time the steam-engine was threatened with serious rivalry by +the hot-air engine. About the year 1816 the Rev. Mr. Stirling, a +Scotch clergyman, invented one which a member of this Institute (Mr. +George Anderson) remembers to have seen still at work at Dundee. The +principle of it was that a quantity of air under pressure was moved by +a mass, called a "displacer," from the cold to the hot end of a large +vessel which was heated by a fire beneath and cooled by a current of +water above. The same air was alternately heated and cooled, expanded +and contracted; and by the difference of pressure moved the piston in +a working cylinder. In this arrangement the furnace was inefficient. +As only a small portion of heat reached the compressed air, the loss +by radiation was very great, and the wear and tear exceedingly heavy. +This system, with some modifications, was revived by Rankine, +Ericsson, Laubereau, Ryder, Buckett, and Bailey. Siemens employed a +similar system, only substituting steam for air. Another system, +originally proposed by Sir George Cayley, consisted in compressing by +a pump cold air which was subsequently passed partly through a +furnace, and, expanding, moved a larger piston at the same pressure; +and the difference of the areas of the pistons multiplied by the +pressure common to both represented the indicated power. This +principle was subsequently developed by a very able mechanic, Mr. +Wenham; but his engine never came much into favor. The only hot-air +engines at present in use are Ryder's, Buckett's, and Bailey's, +employed to a limited extent for small powers. I have not said +anything of the thermal principles involved in the construction of +these engines, as they are precisely the same as those affecting the +subject of the present paper. + +Before explaining the principle upon which the gas-engine and every +other hot-air engine depends, I shall remind you of a few data with +which most of you are already familiar. The volume of every gas +increases with the temperature; and this increase was the basis of the +air thermometer--the first ever used. It is to be regretted that it +was not the foundation of all others; for it is based on a physical +principle universally applicable. Although the volume increases with +the temperature, it does not increase in proportion to the degrees of +any ordinary scale, but much more slowly. Now, if to each of the terms +of an arithmetical series we add the same number, the new series so +formed increases or decreases more slowly than the original; and it +was discovered that, by adding 461 to the degrees of Fahrenheit's +scale, the new scale so formed represented exactly the increment of +volume caused by increase of temperature. This scale, proposed by Sir +W. Thomson in 1848, is called the "scale of absolute temperature." Its +zero, called the "absolute zero," is 461° below the zero of +Fahrenheit, or 493° below the freezing point of water; and the degree +of heat measured by it is termed the "absolute temperature." It is +often convenient to refer to 39° Fahr. (which happens to be the point +at which water attains its maximum density), as this is the same as +500° absolute; for, counting from this datum level, a volume of air +expands exactly 1 per cent. for 5°, and would be doubled at 1,000° +absolute, or 539° Fahr. + +Whenever any body is compressed, its specific heat is diminished; and +the surplus portion is, as it were, pushed out of the body--appearing +as sensible heat. And whenever any body is expanded, its specific heat +is increased; and the additional quantity of heat requisite is, as it +were, sucked in from surrounding bodies--so producing cold. This +action may be compared to that of a wet sponge from which, when +compressed, a portion of the water is forced out, and when the sponge +is allowed to expand, the water is drawn back. This effect is +manifested by the increase of temperature in air-compressing machines, +and the cold produced by allowing or forcing air to expand in +air-cooling machines. At 39° Fahr., 1 lb. of air measures 12½ cubic +feet. Let us suppose that 1 lb. of air at 39° Fahr. = 500° absolute, +is contained in a non-conducting cylinder of 1 foot area and 12½ feet +deep under a counterpoised piston. The pressure of the atmosphere on +the piston = 144 square inches × 14.7 lb., or 2,116 lb. If the air be +now heated up to 539° Fahr. = 1,000° absolute, and at the same time +the piston is not allowed to move, the pressure is doubled; and when +the piston is released, it would rise 12½ feet, provided that the +temperature remained constant, and the indicator would describe a +hyperbolic curve (called an "isothermal") because the temperature +would have remained equal throughout. But, in fact, the temperature is +lowered, because expansion has taken place, and the indicator curve +which would then be described is called an "adiabatic curve," which is +more inclined to the horizontal line when the volumes are represented +by horizontal and the pressures by vertical co-ordinates. In this case +it is supposed that there is no conduction or transmission (diabasis) +of heat through the sides of the containing vessel. If, however, an +_additional_ quantity of heat be communicated to the air, so as to +maintain the temperature at 1,000° absolute, the piston will rise +until it is 12½ feet above its original position, and the indicator +will describe an isothermal curve. Now mark the difference. When the +piston was fixed, only a heating effect resulted; but when the piston +moved up 12½ feet, not only a heating but a mechanical, in fact, a +thermodynamic, effect was produced, for the weight of the atmosphere +(2,116 lb.) was lifted 12½ feet = 26,450 foot-pounds. + +The specific heat of air at constant pressure has been proved by the +experiments of Regnault to be 0.2378, or something less than +one-fourth of that of water--a result arrived at by Rankine from +totally different data. In the case we have taken, there have been +expended 500 × 0.2378, or (say) 118.9[theta] to produce 26,450 f.p. +Each unit has therefore produced (26,450 / 118.0) = 222.5 f.p., +instead of 772 f.p., which would have been rendered if every unit had +been converted into power. We therefore conclude that (222.5 / 772) = 29 +per cent. of the total heat has been converted. The residue, or 71 per +cent., remains unchanged as heat, and may be partly saved by a +regenerator, or applied to other purposes for which a moderate heat is +required. + +The quantity of heat necessary to raise the heat of air at a constant +volume is only 71 per cent. of that required to raise to the same +temperature the same weight of air under constant pressure. This is +exactly the result which Laplace arrived at from observations on the +velocity of sound, and may be stated thus-- + + Specific Foot- Per + heat. pounds. cent. + +Kp = 1 lb. of air at constant pressure 0.2378 × 772 = 183.5 = 100 +Kv = 1 lb. of air at constant volume 0.1688 × 772 = 130.3 = 71 + ------ --- ----- --- +Difference, being heat converted into power 0.0690 × 772 = 53.2 = 29 + + +Or, in a hot-air engine without regeneration, the maximum effect of 1 +lb. of air heated 1° Fahr. would be 53.2 f.p. The quantity of heat +Ky necessary to heat air under constant volume is to Kv, or that +necessary to heat it under constant pressure, as 71:100, or as +1:1.408, or very nearly as 1:SQRT(2)--a result which was arrived +at by Masson from theoretical considerations. The 71 per cent. +escaping as heat may be utilized in place of other fuel; and with the +first hot-air engine I ever saw, it was employed for drying blocks of +wood. In the same way, the unconverted heat of the exhaust steam from +a high-pressure engine, or the heated gases and water passing away +from a gas-engine, may be employed. + +[Illustration] + +We are now in a position to judge what is the practical efficiency of +the gas-engine. Some years since, in a letter which I addressed to +_Engineering_, and which also appeared in the _Journal of Gas +Lighting_,[2] I showed (I believe for the first time) that, in the +Otto-Crossley engine, 18 per cent. of the total heat was converted +into power, as against the 8 per cent. given by a very good +steam-engine. About the end of 1883 a very elaborate essay, by M. +Witz, appeared in the _Annales de Chimie et de Physique_, reporting +experiments on a similar engine, which gave an efficiency somewhat +lower. Early in 1884 there appeared in _Van Nostrand's Engineering +Magazine_ a most valuable paper, by Messrs. Brooks and Steward, with a +preface by Professor Thurston,[3] in which the efficiency was estimated + at 17 to 18 per cent. of the total heat of combustion. Both these +papers show what I had no opportunity of ascertaining, that is, what +becomes of the 82 per cent. of heat which is not utilized--information +of the greatest importance, as it indicates in what direction +improvement may be sought for, and how loss may be avoided. But, short +as is the time that has elapsed since the appearance of these papers, +you will find that progress has been made, and that a still higher +efficiency is now claimed. + + [Footnote 2: See _Journal_, vol. xxxv, pp. 91, 133.] + + [Footnote 3: Ibid., vol. xliii., pp. 703, 744.] + +When I first wrote on this subject, I relied upon some data which led +me to suppose that the heating power of ordinary coal gas was higher +than it really is. At our last meeting, Mr. Hartley proved, by +experiments with his calorimeter, that gas of 16 or 17 candles gave +only about 630 units of heat per cubic foot. Now, if all this heat +could be converted into power, it would yield 630 × 772, or 486,360 +f.p.; and it would require only 1,980,000 / 486,360 = 4.07 cubic feet to +produce 1 indicated horse power. Some recent tests have shown that, +with gas of similar heating power, 18 cubic feet have given 1 +indicated horse power, and therefore 4.07 / 18 = 22.6 of the whole heat +has been converted--a truly wonderful proportion when compared with +steam-engines of a similar power, showing only an efficiency of 2 to 4 +per cent. + +The first gas-engine which came into practical use was Lenoir's, +invented about 1866, in which the mixture of gas and air drawn in for +part of the stroke at atmospheric pressure was inflamed by the spark +from an induction coil. This required a couple of cells of a strong +Bunsen battery, was apt to miss fire, and used about 90 cubic feet of +gas per horse power. This was succeeded by Hugon's engine, in which +the ignition was caused by a small gas flame, and the consumption was +reduced to 80 cubic feet. In 1864 Otto's atmospheric engine was +invented, in which a heavily-loaded piston was forced upward by an +explosion of gas and air drawn in at atmospheric pressure. In its +upward stroke the piston was free to move; but in its downward stroke +it was connected with a ratchet, and the partial vacuum formed after +the explosion beneath the piston, together with its own weight in +falling, operated through a rack, and caused rotation of the flywheel. +This engine (which, in an improved form, uses only about 20 cubic feet +of gas) is still largely employed, some 1,600 having been constructed. +The great objection to it was the noise it produced, and the wear and +tear of the ratchet and rack arrangements. In 1876 the Otto-Crossley +silent engine was introduced. As you are aware, it is a single-acting +engine, in which the gas and air are drawn in by the first outward, +and compressed by the first inward stroke. The compressed mixture is +then ignited; and, being expanded by heat, drives the piston outward +by the second outward stroke. Near the end of this stroke the +exhaust-valve is opened, the products of combustion partly escape, and +are partly driven out by the second inward stroke. I say partly, for a +considerable clearance space, equal to 38 per cent. of the whole +cylinder volume, remains unexhausted at the inner end of the cylinder. +When working to full power, only one stroke out of every four is +effective; but this engine works with only 18 to 22 cubic feet of gas +per horse power. Up to the present time I am informed that about +18,000 of these engines have been manufactured. Several other +compression engines have been introduced, of which the best known is +Mr. Dugald Clerk's, using about 20 feet of Glasgow cannel gas. It +gives one effective stroke for every revolution; the mixture being +compressed in a separate air-pump. But this arrangement leads to +additional friction; and the power measured by the brake is a smaller +percentage of the indicated horse power than in the Otto-Crossley +engine. A number of gas engines--such as Bisschop's (much used for +very small powers), Robson's (at present undergoing transformation in +the able hands of Messrs. Tangye), Korting's, and others--are in use; +but, so far as I can learn, all require a larger quantity of gas than +those previously referred to. + +[Illustration: OTTO ATMOSPHERIC GAS ENGINE.] + +[Illustration: CLERCK'S GAS ENGINE, 6 HORSE POWER.] + +[Illustration: OTTO-CROSSLEY GAS ENGINE, 16 H.P. + + Consumption 17.6 cubic feet of 16-candle gas per + theoretical horse power per hour. + + Average pressure, 90.4 × constant, .568 theoretical + horse power per pound = 50.8 theoretical horse power.] + +[Illustration: ATKINSON'S DIFFERENTIAL GAS ENGINE, 8 H.P.] + +I have all along spoken of efficiency as a percentage of the total +quantity of heat evolved by the fuel; and this is, in the eyes of a +manufacturer, the essential question. Other things being equal, that +engine is the most economical which requires the smallest quantity of +coal or of gas. But men of science often employ the term efficiency in +another sense, which I will explain. If I wind a clock, I have spent a +certain amount of energy lifting the weight. This is called "energy of +position;" and it is returned by the fall of the weight to its +original level. In the same way if I heat air or water, I communicate +to it energy of heat, which remains potential as long as the +temperature does not fall, but which can be spent again by a decrease +of temperature. In every heat-engine, therefore, there must be a fall +from a higher to a lower temperature; otherwise no work would be done. +If the water in the condenser of a steam-engine were as hot as that in +the boiler, there would be equal pressure on both sides of the piston, +and consequently the engine would remain at rest. Now, the greater the +fall, the greater the power developed; for a smaller proportion of the +heat remains as heat. If we call the higher temperature T and the +lower T' on the absolute scale, T - T' is the difference; and the +ratio of this to the higher temperature is called the "efficiency." +This is the foundation of the formula we meet so often: E = (T - T')/T. +A perfect heat-engine would, therefore, be one in which the +temperature of the absolute zero would be attained, for (T - O)/T = 1. +This low temperature, however, has never been reached, and in all +practical cases we are confined within much narrower limits. Taking +the case of the condensing engine, the limits were 312° to 102°, or +773° and 563° absolute, respectively. The equation then becomes +(773 - 563)/773 = 210/773 or (say) 27 per cent. With non-condensing +engines, the temperatures may be taken as 312° and 212°, or 773° and +673° absolute respectively. The equation then becomes (773 - 673)/773 += 100/773, or nearly 13 per cent. The practical efficiencies are not +nearly this, but they are in about the same ratio--27/13. If, then, we +multiply the theoretical efficiencies by 0.37, we get the practical +efficiencies, say 10 per cent. and 5 per cent.; and it is in the +former sense that M. Witz calculated the efficiency of the +steam-engine at 35 per cent.--a statement which, I own, puzzled me a +little when I first met it. These efficiencies do not take any account +of loss of heat before the boiler. In the case of the gas-engine, the +question is much more complicated on account of the large clearance +space and the early opening of the exhaust. The highest temperature +has been calculated by the American observers at 3,443° absolute, and +the observed temperature of the exhaust gases was 1,229°. The fraction +then becomes (3443 - 1229)/3443 = 64 per cent. If we multiply this by +0.37, as we did in the case of the steam-engine, we get 23.7 per +cent., or approximately the same as that arrived at by direct +experience. Indeed, if the consumption is, as sometimes stated, less +than 18 feet, the two percentages would be exactly the same. I do not +put this forward as scientifically true; but the coincidence is at +least striking. + +I have spoken of the illuminating power of the gas as of importance; +for the richer gases have also more calorific power, and an engine +would, of course, require a smaller quantity of them. The heat-giving +power does not, however, vary as the illuminating power, but at a much +slower rate; and, adopting the same contrivance as that on which the +absolute scale of temperature is formed, I would suggest a formula of +the following type: H = C (I + K), in which H represents the number of +heat-units given out by the combustion of 1 cubic foot of gas, I is +the illuminating power in candles, and C and K two constants to be +determined by experiment. If we take the value for motive power of the +different qualities of gas as given in Mr. Charles Hunt's interesting +paper in our Transactions for 1882, C might without any great error be +taken as 22 and K as 7.5. With Pintsch's oil gas, however, as compared +with coal gas, this formula does not hold; and C should be taken much +lower, and K much higher than the figures given above. That is to say, +the heating power increases in a slower progression. The data +available, however, are few; but I trust that Mr. Hartley will on +this, as he has done on so many other scientific subjects, come to our +aid. + +I will now refer to the valuable experiments of Messrs. Brooks and +Steward, which were most carefully made. Everything was measured--the +gas by a 60 light, and the air by a 300 light meter; the indicated +horse power, by a steam-engine indicator; the useful work, by a Prony +brake; the temperature of the water, by a standard thermometer; and +that of the escaping gases, by a pyrometer. The gas itself was +analyzed; and its heating power calculated, from its composition, as +617.5[theta]. Its specific gravity was .464; and the volume of air was +about seven times that of the gas used (or one-eighth of the mixture), +and was only 11½ per cent. by weight more than was needed for perfect +combustion. The results arrived at were as follows: + + Per cent. + Converted into indicated horse power, + including friction, etc. 17.0 + Escaped with the exhaust gas. 15.5 + Escaped in radiation. 15.5 + Communicated to water in the jacket. 52.0 + + +It will thus be seen that more than half of the heat is communicated +to the water in the jacket. Now, this is the opposite of the +steam-engine, where the jacket is used to transmit heat _to_ the +cylinder, and not _from_ it. This cooling is rendered necessary, +because without it the oil would be carbonized, and lubrication of the +cylinder rendered impossible. Indeed, a similar difficulty has +occurred with all hot-air engines, and is, I think, the reason they +have not been more generally adopted. I felt this so strongly that, +for some time after the introduction of the gas-engine, I was very +cautious in recommending those who consulted me to adopt it. I was +afraid that the wear and tear would be excessive. I have, however, for +some time past been thoroughly satisfied that this fear was needless; +as I am satisfied that a well-made gas-engine is as durable as a +steam-engine, and the parts subject to wear can be replaced at +moderate cost. We have no boiler, no feed pump, no stuffing-boxes to +attend to--no water-gauges, pressure-gauges, safety-valve, or +throttle-valve to be looked after; the governor is of a very simple +construction; and the slide-valves may be removed and replaced in a +few minutes. An occasional cleaning out of the cylinder at +considerable intervals is all the supervision that the engine +requires. + +The very large percentage of heat absorbed by the water-jacket should +point out to the ingenuity of inventors the first problem to be +attacked, viz., how to save this heat without wasting the lubricant or +making it inoperative; and in the solution of this problem, I look for +the most important improvement to be expected in the engine. The most +obvious contrivance would be some sort of intercepting shield, which +would save the walls of the cylinder and the rings of the piston from +the heat of the ignited gases. I have just learned that something of +the kind is under trial. Another solution may possibly be found in the +employment of a fluid piston; but here we are placed in a dilemma +between the liquids that are decomposed and the metals that are +oxidized at high temperatures. Next, the loss by radiation--15 per +cent.--seems large; but this is to be attributed to the fact that the +inside surface of the cylinder is at each inward stroke exposed to the +atmosphere--an influence which contributes to the cooling necessary +for lubrication. The remaining 15 per cent., which is carried away by +the exhaust, is small compared with the proportion passing away with +the exhaust steam of a high-pressure or the water of a condensing +engine. As the water in the jacket can be safely raised to 212° Fahr., +the whole of the jacket heat can be utilized where hot water is +required for other purposes; and this, with the exhaust gases, has +been used for drying and heating purposes. + +With such advantages, it may be asked: Why does not the gas-engine +everywhere supersede the steam-engine? My answer is a simple one: The +gas we manufacture is a dear fuel compared with coal. Ordinary coal +gas measures 30 cubic feet to the pound; and 1,000 cubic feet, +therefore, weigh 33 lb. Taking the price at 2s. 9d. per 1,000 cubic +feet, it costs 1d. per lb. The 30 cubic feet at 630[theta] give +19,000[theta] all available heat. Although good coal may yield 14,000 +units by its combustion, only about 11,000 of these reach the boiler; +so that the ratio of the useful heat is 11/19. The thermal efficiency +of the best non-condensing engine to that of the gas-engine is in the +ratio 4/22. Multiplying together these two ratios, we get + + 11 4 44 + -- x ------- = ---- + 19 22_{1/2} 4.28 + +That is, speaking roughly, 1 lb. of gas gives about ten times as much +power as 1 lb. of coal does in a good non-condensing engine. But at +18s. 8d. a ton we get 10 lb. of coal for 1d.; so that with these +figures the cheapness of the coal would just compensate for the +efficiency of the gas. As to the waste heat passing away from the +engine being utilized, here the gas-engine has no advantage; and, so +far as this is concerned, the gas is about eight times dearer than +coal. The prices of gas and coal vary so much in different places that +it is hard to determine in what cases gas or coal will be the dearer +fuel, considering this point alone. + +But there are other kinds of non-illuminating gases--such as Wilson's, +Strong's, and Dowson's--which are now coming into use; and at Messrs. +Crossley's works you will have an opportunity of seeing a large +engineering factory employing several hundred mechanics, and without a +chimney, in which every shaft and tool is driven by gas-engines +supplied by Dowson's gas, and in which the consumption of coal is only +1.2 lb. per indicated horse power. The greatest economy ever claimed +for the steam-engine was a consumption of 1.6 lb.; and this with steam +of very high pressure, expanded in three cylinders successively. Thus +in a quarter of a century the gas-engine has beaten in the race the +steam-engine; although from Watt's first idea of improvement, nearly a +century and a quarter have elapsed. + +As regards the steam-engine, it is the opinion of competent +authorities that the limits of temperature between which it works are +so restricted, and so much of the heat is expended in producing a +change of state from liquid to vapor, that little further improvement +can be made. With respect to gas-engines, the limits of temperature +are much further apart. A change of state is not required, and so very +great improvement may still be looked for. It is not impossible even +that some of the younger members of our body may live to see that +period foretold by one of the greatest of our civil engineers--that +happy time when boiler explosions will only be matters of history; +that period, not a millennium removed by a thousand years, but an era +deferred perhaps by only half a dozen decades, when the use of the +gas-engine will be universal, and "a steam-engine can be found only in +a cabinet of antiquities." + + +_Discussion._ + +The President said this was a very delightful paper; and nothing could +be finer than Mr. Lane's description of the conversion of heat into +power, and the gradual growth of theory into practical work. + +Mr. W. Foulis (Glasgow) agreed that it was admirable; but it required +to be read to be thoroughly appreciated. When members were able to +read it, they would find Mr. Lane had given a very clear description +of the elementary principles of thermo-dynamics in their relation to +the gas-engine and the steam-engine. There was very little in the +paper to raise discussion; but Mr. Lane had made exceedingly clear how +the present loss in a gas-engine was occasioned, and had also shown +how, in the future development of the engine, the loss might be saved, +and the engine rendered more efficient. + +Mr. H.P. Holt (of Messrs. Crossley Bros., Limited) said he could +indorse everything Mr. Lane had said. He had found the paper most +interesting and instructive even to himself, though he had some little +practical experience of gas-engines, and was supposed to know a little +about them. He did not pretend to be able to teach other people; but +if he could say anything as to indicator cards, or answer any +questions, he should be happy to do so. (He then described the +indicator diagram of the atmospheric gas-engine.) In this engine the +proportion of the charging stroke to the whole sweep of the piston was +about 10 per cent.; and as the charge drawn in consisted of about 10 +per cent. of gas, about 1-100 of the total sweep of the piston was +composed of the gas. + +Mr. Foulis asked what proportion the power indicated on the diagram +bore to the power indicated on the brake in the atmospheric engine. + +Mr. Holt said unfortunately he had not any figures with him which +would give this information; and it was so long since he had anything +practically to do with this form of engine, that he should not like to +speak from memory. He might add that the largest size of gas-engine +made (of about 100 horse power indicated) was at work at Messrs. Edwin +Butterworth and Co.'s, of Manchester. It was now driven by ordinary +coal gas; but Dowson plant was to be put up very shortly in order to +reduce the cost of working, which, though not excessive, would be +still more economical with the Dowson gas--probably only about 30s. +per week. The present cost was about £4 per week, though it was not +working always at full power. + +Mr. T. Holgate (Batley) said he thought it was generally understood, +by those who had studied the subject, that the adoption of compression +of the gaseous mixture before ignition had, so far, more than anything +else, contributed to the improved working of gas-engines. This fact +had not been sufficiently brought out in the paper, although Mr. Lane +had clearly indicated some of the directions in which further +improvements were likely to obtain. Gas engineers were largely +indebted to Mr. Dugald Clerk for the statement he had made of the +theory of the gas-engine.[4] Mr. Lane had given some figures, arrived +at by Messrs. Brooks and Steward, from experiments made in America; +but, prior to these Mr. Clerk had given others which were in the main +in accordance with them. Professor Kennedy had also made experiments, +the results of which agreed with them.[5] The extent of the loss by +the cooling water was thus well ascertained; and it was no doubt by a +reduction of this loss that further improvement in the working of +gas-engines would eventually be obtained. + + [Footnote 4: See Journal, vol. xxxix., p. 648.] + + [Footnote 5: Ibid., vol. xl., p. 955.] + +Mr. J. Paterson (Warrington) expressed his appreciation of the paper, +as one of exceptional interest and value. He said he did not rise with +a view to make any observations thereon. The analysis of first +principles required more matured consideration and thought than could +be given to it here. The opinion, however, he had formed of the paper +placed it beyond the reach of criticism. It was now many years since +his attention had been drawn to the name of Denny Lane; and everything +that had come from his facile pen conveyed sound scientific +conclusions. The paper to which they had just listened was no +exception. It was invested with great interest, and would be regarded +as a valuable contribution to the Transactions of the Institute. + +Mr. Lane, in reply, thanked the members for the kind expressions used +with respect to his paper. His object in writing it was that any one +who had not paid any attention to the subject before should be able to +understand thoroughly the principles on which gas and hot-air engines +operated; and he believed any one who read it with moderate care would +perfectly understand all the essential conditions of the gas-engine. +He might mention that not long after the thermo-dynamic theory was so +far developed as to determine the amount of heat converted into power, +a very eminent French Engineer--M. Hirn--conducted some experiments on +steam-engines at a large factory, and thought he could account for the +whole heat of combustion in the condensed water and the heat which +passed away; so much so that he actually doubted altogether the theory +of thermo-dynamics. However, being open to conviction, he made further +experiments, and discovered that he had been in error, and ultimately +became one of the most energetic supporters of the theory. This showed +how necessary it was to be careful before arriving at a conclusion on +such a subject. He had endeavored, as far as the nature of the case +allowed, to avoid any scientific abstractions, because he knew that +when practical men came to theory--_x's_ and _y's_, differentials, +integrals, and other mathematical formulæ--they were apt to be +terrified. + +The President said it was like coming down to every day life to say +that it was important that gas managers should be familiar with the +appliances used in the consumption of gas, and should be able, when +called upon, to give an intelligent description of their method of +working. A study of Mr. Lane's paper would reveal many matters of +interest with regard to this wonderful motor, which was coming daily +more and more into use, not only to the advantage of gas +manufacturers, but of those who employed them. + + * * * * * + + + + +M. MEIZEL'S RECIPROCATING EXHAUSTER. + + +At the recent Congress of the Societe Technique de l'Industrie du Gaz +en France, M. Meizel, Chief Engineer of the St. Etienne Gas Works, +described a new exhauster devised by him on the reciprocating +principle, and for which he claims certain advantages over the +appliances now in general use. Exhausters constructed on the +above-named principle have hitherto, M. Meizel says, been costly to +fit up, owing to the necessity for providing machinery and special +mechanism for the transmission of motion. This has prevented the +employment of cylinders of large dimensions; and, consequently, when +the quantity of gas to be dealt with has been considerable, the number +of exhausters has had to be increased. The result of this has been +inconvenience, which has led to a preference being shown for other +kinds of exhausters, notwithstanding the manifest advantages which, in +M. Meizel's opinion, those of the reciprocating type possess. The +improvement which he has effected in these appliances consists in the +application to them of cylinders working automatically; and the +general features of the arrangement are shown in the accompanying +illustrations. + +[Illustration: IMPROVED RECIPROCATING GAS EXHAUSTER.] + +The principal advantages to be gained by the use of this exhauster are +stated by M. Meizel to be the following: Considerably less motive +force is necessary than is the case with other exhausters, which +require steam engines and all the auxiliary mechanism for the +transmission of power. By its quiet and regular action, it prevents +oscillation and unsteadiness in the flow of gas in the hydraulic main, +as well as in the pipes leading therefrom--a defect which has been +found to exist with other exhausters. The bells, being of large area, +serve the purpose of a condenser; and as, owing to its density, the +tar falls to the bottom of the lower vessels, which are filled with +water, contact between the gas and tar is avoided. Although the +appliance is of substantial construction, its action is so sensitive +that it readily adapts itself to the requirements of production. It +may be placed in the open air; and therefore its establishment is +attended with less outlay than is the case with other exhausters, +which have to be placed under cover, and provided with driving +machinery and, of course, a supply of steam. + +The total superficial area of the exhauster above described, including +the governor, is 150 square feet; and its capacity per 24 hours is +230,000 cubic feet. It works silently, with an almost entire absence +of friction; and consequently there are few parts which require +lubrication. Exhausters of this type (which, M. Meizel says, could be +made available for ventilation purposes, in case of necessity) may be +constructed of all sizes, from 500 cubic feet per hour upward. + + * * * * * + + + + +AUTOMATIC SIPHON FOR IRRIGATION. + + +When, at an elevated point in a meadow, there exists a spring or vein +of water that cannot be utilized at a distance, either because the +supply is not sufficient, or because of the permeability of the soil, +it becomes very advantageous to accumulate the water in a reservoir, +which may be emptied from time to time through an aperture large +enough to allow the water to flow in abundance over all parts of the +field. + +[Illustration: GIRAL'S AUTOMATIC SIPHON.] + +The storing up of the water permits of irrigating a much greater area +of land, and has the advantage of allowing the watering to be effected +intermittingly, this being better than if it were done continuously. +But this mode of irrigating requires assiduous attention. It is +necessary, in fact, when the reservoir is full, to go and raise the +plug, wait till the water has flowed out, and then put in the plug +again as accurately as possible--a thing that it is not always easy to +do. The work is a continuous piece of drudgery, and takes just as much +the longer to do in proportion as the reservoir is more distant from +one's dwelling. In order to do away with this inconvenience, Mr. +Giral, of Langogne (Lozere), has invented a sort of movable siphon +that primes itself automatically, however small be the spring that +feeds the reservoir in which it is placed. The apparatus (see figure) +consists of an elbowed pipe, C A B D E, of galvanized iron, whose +extremity, C, communicates with the outlet, R, where it is fixed by +means of a piece of rubber of peculiar form that allows the other +extremity, B D E, to revolve around the axis, K, while at the same +time keeping the outlet pipe hermetically closed. This rubber, whose +lower extremity is bent back like the bell of a trumpet, forms a +washer against which there is applied a galvanized iron ring that is +fixed to the mouth of the outlet pipe by means of six small screws. +This ring is provided with two studs which engage with two flexible +thimbles, K and L, that are affixed to the siphon by four rivets. +These studs and thimbles, as well as the screws, are likewise +galvanized. Between the branches, A B D E, of the pipe there is +soldered a sheet of galvanized iron, which forms isolatedly a +receptacle or air-chamber, F, that contains at its upper part a small +aperture, _b_, that remains always open, and, at its lower part, a +copper screw-plug, _d_, and a galvanized hook, H. + +In the interior of this chamber there is arranged a small leaden +siphon, _a b c_, whose longer leg, _a_, passes through the bottom, +where it is soldered, and whose shorter one, _c_, ends in close +proximity to the bottom. Finally, a galvanized iron chain, G H, fixed +at G to the bottom of the reservoir, and provided with a weight, P, of +galvanized iron, is hooked at H to the siphon and allows it to rise +more or less, according as it is given a greater or less length. + +From what precedes, it will be seen that the outlet is entirely +closed, so that, in order that the water may escape, it must pass into +the pipe in the direction, E D B A C. + +This granted, let us see how the apparatus works: In measure as the +water rises in the reservoir, the siphon gradually loses weight, and +its extremity, B D H, is finally lifted by the thrust, so that the +entire affair revolves upon the studs, K, until the chain becomes +taut. The apparatus then ceases to rise; but the water, ever +continuing to rise, finally reaches the apex, _b_, of the smaller +siphon, and, through it, enters the air chamber and fills it. The +equilibrium being thus broken, the siphon descends to the bottom, +becomes primed, and empties the reservoir. When the level of the +water, in descending, is at the height of the small siphon, _a b c_, +this latter, which is also primed, empties the chamber, F, in turn, so +that, at the moment the large siphon loses its priming, the entire +apparatus is in the same state that it was at first. + +In short, when the water enters the reservoir, the siphon, movable +upon its base, rises to the height at which it is desired that the +flow shall take place. Being arrested at this point by the chain, it +becomes primed, and sinks, and the water escapes. When the water is +exhausted, the siphon rises anew in order to again sink; and this goes +on as long as the period of irrigation lasts. + +This apparatus, which is simple in its operation, and not very costly, +is being employed with success for irrigating several meadows in the +upper basin of the Allier.--_Le Genie Civil._ + + * * * * * + + + + +ASSAY OF EARTHENWARE GLAZE. + + +Lead oxide melted or incompletely vitrified is still in common use in +the manufacture of inferior earthenware, and sometimes leads to +serious results. To detect lead in a glaze, M. Herbelin moistens a +slip of white linen or cotton, free from starch, with nitric acid at +10 per cent. and rubs it for ten to fifteen seconds on the side of the +utensil under examination, and then deposits a drop of a solution of +potassium iodide, at 5 per cent. on the part which has been in +contact. A lead glaze simply fused gives a very highly colored yellow +spot of potassium iodide; a lead glaze incompletely vitrified gives +spots the more decided, the less perfect the vitrification; and a +glaze of good quality gives no sensible color at all.--_M. Herbelin._ + + * * * * * + + + + +ON THE ELECTRICAL FURNACE AND THE REDUCTION OF THE OXIDES OF BORON, +SILICON, ALUMINUM, AND OTHER METALS BY CARBON.[1] + + [Footnote 1: Read at the recent meeting of the American + Association, Ann Arbor, Mich.] + +By EUGENE H. COWLES, ALFRED H. COWLES, AND CHARLES F. MABERY. + + +The application of electricity to metallurgical processes has hitherto +been confined to the reduction of metals from solutions, and few +attempts have been made to effect dry reductions by means of an +electric current. Sir W. Siemens attempted to utilize the intense heat +of an electric arc for this purpose, but accomplished little beyond +fusing several pounds of steel. A short time since, Eugene H. Cowles +and Alfred H. Cowles of Cleveland conceived the idea of obtaining a +continuous high temperature on an extended scale by introducing into +the path of an electric current some material that would afford the +requisite resistance, thereby producing a corresponding increase in +the temperature. After numerous experiments that need not be described +in detail, coarsely pulverized carbon was selected as the best means +for maintaining a variable resistance and at the same time as the most +available substance for the reduction of oxides. When this material, +mixed with the oxide to be reduced, was made a part of the electric +circuit in a fire clay retort, and submitted to the action of a +current from a powerful dynamo machine, not only was the oxide +reduced, but the temperature increased to such an extent that the +whole interior of the retort fused completely. In other experiments +lumps of lime, sand, and corundum were fused, with indications of a +reduction of the corresponding metal; on cooling, the lime formed +large, well-defined crystals, the corundum beautiful red, green, and +blue hexagonal crystals. + +Following up these results with the assistance of Charles F. Mabery, +professor of chemistry in the Case School of Applied Science, who +became interested at this stage of the experiments, it was soon found +that the intense heat thus produced could be utilized for the +reduction of oxides in large quantities, and experiments were next +tried on a large scale with a current from two dynamos driven by an +equivalent of fifty horse power. For the protection of the walls of +the furnace, which were made of fire brick, a mixture of the ore and +coarsely pulverized gas carbon was made a central core, and it was +surrounded on the sides and bottom by fine charcoal, the current +following the lesser resistance of the central core from carbon +electrodes which were inserted at the ends of the furnace in contact +with the core. In order to protect the machines from the variable +resistance within the furnace, a resistance box consisting of a coil +of German silver wire placed in a large tank of water was introduced +into the main circuit, and a Brush ammeter was also attached by means +of a shunt circuit, to indicate the quantity of current that was being +absorbed in the furnace. The latter was charged by first filling it +with charcoal, making a trough in the center, and filling this central +space with the ore mixture, which was covered with a layer of coarse +charcoal. The furnace was closed at the top with fire brick slabs +containing two or three holes for the escape of the gaseous products +of the reduction, and the entire furnace made air-tight by luting with +fire clay. Within a few minutes after starting the dynamo, a stream of +carbonic oxide issued through the openings, burning usually with a +flame eighteen inches in height. The time required for complete +reduction was ordinarily about an hour. + +The furnace at present in use is charged in substantially the same +manner, and the current is supplied by a Brush machine of variable +electromotive force driven by an equivalent of forty horse power. A +Brush machine capable of utilizing 125 horse power, or two and +one-half times as large as any hitherto constructed by the Brush +Electric Company, is being made for the Cowles Electric Smelting and +Aluminum Company, and this machine will soon be in operation. +Experiments already made so that aluminum, silicon, boron, manganese, +magnesium, sodium and potassium can be reduced from their oxides with +ease. In fact, there is no oxide that can withstand temperatures +attainable in this electrical furnace. Charcoal is changed to +graphite. Does this indicate fusion or solution of carbon? As to what +can be accomplished by converting enormous electrical energy into heat +within a limited space, it can only be said that it opens the way into +an extensive field for both pure and applied chemistry. It is not +difficult to conceive of temperatures limited only by the capability +of carbon to resist fusion. The results to be obtained with the large +Brush machine above mentioned will be of some importance in this +direction. + +Since the cost of the motive power is the chief expense in +accomplishing reductions by this method, its commercial success is +closely connected with the cheapest form of power to be obtained. +Realizing the importance of this point, the Cowles Electric Smelting +and Aluminum Company has purchased an extensive and reliable water +power, and works are soon to be erected for the utilization of 1,200 +horse power. An important feature in the use of these furnaces, from a +commercial standpoint, is the slight technical skill required in their +manipulation. The four furnaces in operation in the experimental +laboratory at Cleveland are in charge of two young men twenty years of +age, who, six months ago, knew absolutely nothing of electricity. The +products at present manufactured are the various grades of aluminum +bronze made from a rich furnace product that is obtained by adding +copper to the charge of ore, silicon bronze prepared in the same +manner, and aluminum silver, an alloy of aluminum with several other +metals. A boron bronze may be prepared by the reduction of boracic +acid in contact with copper. + +As commercial results may be mentioned the production in the +experimental laboratory, which averages fifty pounds of 10 per cent. +aluminum bronze daily, and it can be supplied to the trade in large +quantities at prices based on $5 per pound for the aluminum contained, +the lowest market quotation of this metal being at present $15 per +pound. Silicon bronze can be furnished at prices far below those of +the French manufacturers. + +The alloys which the metals obtained by the methods above described +form with copper have been made the subject of careful study. An alloy +containing 10 per cent. of aluminum and 90 per cent. of copper forms +the so-called aluminum bronze with a fine golden color, which it +retains for a long time. The tensile strength of this alloy is usually +given as 100,000 pounds to the square inch; but castings of our ten +per cent. bronze have stood a strain of 109,000 pounds. It is a very +hard, tough alloy, with a capacity to withstand wear far in excess of +any other alloy in use. All grades of aluminum bronze make fine +castings, taking very exact impressions, and there is no loss in +remelting, as in the case of alloys containing zinc. The 5 per cent. +aluminum alloy is a close approximation in color to 18 carat gold, and +does not tarnish readily. Its tensile strength in the form of castings +is equivalent to a strain of 68,000 pounds to the square inch. An +alloy containing 2 or 3 per cent. aluminum is stronger than brass, +possesses greater permanency of color, and would make an excellent +substitute for that metal. When the percentage of aluminum reaches 13, +an exceedingly hard, brittle alloy of a reddish color is obtained, and +higher percentages increase the brittleness, and the color becomes +grayish-black. Above 25 per cent. the strength again increases. + +The effect of silicon in small proportions upon copper is to greatly +increase its tensile strength. When more than 5 per cent. is present, +the product is exceedingly brittle and grayish-black in color. It is +probable that silicon acts to a certain extent as a fluxing material +upon the oxides present in the copper, thereby making the metal more +homogeneous. On account of its superior strength and high conductivity +for electrical currents, silicon bronze is the best material known for +telegraph and telephone wire. + +The element boron seems to have almost as marked an effect upon copper +as carbon does upon iron. A small percentage in copper increases its +strength to 50,000 or 60,000 pounds per square inch without +diminishing to any large extent its conductivity. + +Aluminum increases very considerably the strength of all metals with +which it is alloyed. An alloy of copper and nickel containing a small +percentage of aluminum, called Hercules metal, withstood a strain of +105,000 pounds, and broke without elongation. Another grade of this +metal broke under a strain of 111,000 pounds, with an elongation +equivalent to 33 per cent. It must be remembered that these tests were +all made upon castings of the alloys. The strength of common brass is +doubled by the addition of 2 or 3 per cent. of aluminum. Alloys of +aluminum and iron are obtained without difficulty; one product was +analyzed, containing 40 per cent. of aluminum. In the furnace iron +does not seem to be absorbed readily by the reduced aluminum when +copper is present; but in one experiment a mixture composed of old +files, 60 per cent.; nickel, 5 per cent.; and of 10 per cent. aluminum +bronze 35 per cent., was melted together, and it gave a malleable +product that stood a strain of 69,000 pounds. + +When the reduction of aluminic oxide by carbon is conducted without +the addition of copper, a brittle product is obtained that behaves in +many respects like pig iron as it comes from the blast furnace. The +same product is formed in considerable quantities, even when copper is +present, and frequently the copper alloy is found embedded in it. +Graphite is always found associated with it, even when charcoal is the +reducing material, and analysis invariably shows a very high +percentage of metallic aluminum. This extremely interesting substance +is at present under examination. + + * * * * * + + + + +THE COWLES ELECTRIC SMELTING PROCESS. + + +The use of electricity in the reduction of metals from their ores is +extending so rapidly, and the methods of its generation and +application have been so greatly improved within a few years, that the +possibility of its becoming the chief agent in the metallurgy of the +future may now be admitted, even in cases where the present cost of +treatment is too high to be commercially advantageous. + +The refining of copper and the separation of copper, gold, and silver +by electrolysis have thus far attracted the greatest amount of +attention, but a commercial success has also been achieved in the dry +reduction by electricity of some of the more valuable metals by the +Cowles Electric Smelting and Aluminum Company, of Cleveland, Ohio. +Both this method of manufacture and the qualities of the products are +so interesting and important that it is with pleasure we call +attention to them as steps toward that large and cheap production of +aluminum that the abundance of its ores and the importance of its +physical properties have for several years made the unattained goal of +many skillful metallurgists. + +The Messrs. Cowles have succeeded in greatly reducing the market value +of aluminum and its alloys, and thereby vastly extending its uses, and +they are now by far the largest producers in the world of these +important products. As described in their patents, the Cowles process +consists essentially in the use for metallurgical purposes of a body +of granular material of high resistance or low conductivity interposed +within the circuit in such a manner as to form a continuous and +unbroken part of the same, which granular body, by reason of its +resistance, is made incandescent, and generates all the heat required. +The ore or light material to be reduced--as, for example, the hydrated +oxide of aluminum, alum, chloride of sodium, oxide of calcium, or +sulphate of strontium--is usually mixed with the body of granular +resistance material, and is thus brought directly in contact with the +heat at the points of generation, at the same time the heat is +distributed through the mass of granular material, being generated by +the resistance of all the granules, and is not localized at one point +or along a single line. The material best adapted for this purpose is +electric light carbon, as it possesses the necessary amount of +electrical resistance, and is capable of enduring any known degree of +heat when protected from oxygen without disintegrating or fusing; but +crystalline silicon or other equivalent of carbon can be employed for +the same purpose. This is pulverized or granulated, the degree of +granulation depending upon the size of the furnace. Coarse granulated +carbon works better than finely pulverized carbon, and gives more even +results. The electrical energy is more evenly distributed, and the +current can not so readily form a path of highest temperature, and +consequently of least resistance through the mass along which the +entire current or the bulk of the current can pass. The operation must +necessarily be conducted within an air-tight chamber or in a +non-oxidizing atmosphere, as otherwise the carbon will be consumed and +act as fuel. The carbon acts as a deoxidizing agent for the ore or +metalliferous material treated, and to this extent it is consumed, but +otherwise than from this cause, it remains unimpaired. + +Fig. I. of the accompanying drawings is a vertical longitudinal +section through a retort designed for the reduction of zinc ore, +according to this process, and Fig. II. is a front elevation of the +same. Fig. III. is a perspective view of a furnace adapted to +withstand a very high temperature, and Figs. IV. and V. are +respectively longitudinal and transverse sections of the same. + +[Illustration: THE COWLES ELECTRIC SMELTING PROCESS.] + +This retort consists of a cylinder, A, made of silica or other +non-conducting material, suitably embedded in a body, B, of powdered +charcoal, mineral wool, or of some other material which is not a good +conductor of heat. The rear end of the retort-cylinder is closed by +means of a carbon plate, C, which plate forms the positive electrode, +and with this plate the positive wire of the electric circuit is +connected. The outer end of the retort is closed by means of an +inverted graphite crucible, D, to which the negative wire of the +electric circuit is attached. The graphite crucible serves as a plug +for closing the end of the retort. It also forms a condensing chamber +for the zinc fumes, and it also constitutes the negative electrode. +The term "electrode" is used in this case as designating the terminals +of the circuit proper, or that portion of it which acts simply as an +electrical conductor, and not with the intention of indicating the +ends of a line between which there is no circuit connection. The +circuit between the "electrodes," so called, is continuous, being +established by means of and through the body of broken carbon +contained in the retort, A. There is no deposit made on either plate +of the decomposed constituents of the material reduced. The mouth of +the crucible is closed with a luting of clay, or otherwise, and the +opening, _d_, made in the upper side of the crucible, near its +extremity, comes entirely within the retort, and forms a passage for +the zinc fumes from the retort chamber into the condensing chamber. +The pipe, E, serves as a vent for the condensing chamber. The zinc ore +is mixed with pulverized or granular carbon, and the retort charged +nearly full through the front end with the mixture, the plug, D, being +removed for this purpose. + +A small space is left at the top, as shown. After the plug has been +inserted and the joint properly luted, the electric circuit is closed +and the current allowed to pass through the retort, traversing its +entire length through the body of mixed ore and carbon. The carbon +constituents of the mass become incandescent, generating a very high +degree of heat, and being in direct contact with the ore, the latter +is rapidly and effectually reduced and distilled. The heat evolved +reduces the ore and distills the zinc, and the zinc fumes are +condensed in the condensing chamber, precisely as in the present +method of zinc making, with this important exception that, aside from +the reaction produced by heating carbon in the presence of zinc oxide, +the electric current, in passing through the zinc oxide, has a +decomposing and disintegrating action upon it, not unlike the effect +produced by an electric current in a solution. This action accelerates +the reduction, and promotes economy in the process. + +Another form of furnace is illustrated by Fig. III., which is a +perspective view of a furnace adapted for the reduction of ores and +salts of non-volatile metals and similar chemical compounds. Figs. IV. +and V. are longitudinal and transverse sections, respectively, through +the same, illustrating the manner of packing and charging the furnace. + +The walls and floors L L', of the furnace are made of fire bricks, and +do not necessarily have to be very thick or strong, the heat to which +they are subjected not being excessive. The carbon plates are smaller +than the cross section of the box, as shown, and the spaces between +them and the end walls are packed with fine charcoal. + +The furnace is covered with a removable slab of fireclay, N, which is +provided with one or more vents, _n_, for the escaping gases. + +The space between the carbon plates constitutes the working part of +the furnace. This is lined on the bottom and sides with a packing of +fine charcoal, O, or such other material as is both a poor conductor +of heat and electricity--as, for example, in some cases, silica or +pulverized corundum or well-burned lime--and the charge, P, of ore and +broken, granular, or pulverized carbon occupies the center of the box, +extending between the carbon plates. A layer of granular charcoal, O', +also covers the charge on top. The protection afforded by the charcoal +jacket, as regards the heat, is so complete, that with the +covering-slab removed, the hand can be held within a few inches of the +exposed charcoal jacket; but with the top covering of charcoal also +removed and the core exposed, the hand cannot be held within several +feet. The charcoal packing behind the carbon plates is required to +confine the heat and to protect them from combustion. + +With this furnace, aluminum can be reduced directly from its ores; and +chemical compounds from corundum, cryolite, clay, etc., and silicon, +boron, calcium, manganese, magnesium, and other metals are in like +manner obtained from their ores and compounds. The reduction of ores +according to this process can be practiced, if circumstances require +it, without any built furnace. + +At present, the Cowles company is engaged mostly in the producing of +aluminum bronze and aluminum silver and silicon bronze. The plant, +were it run to its full capacity, is capable of turning out eighty +pounds of aluminum bronze, containing 10 per cent. of aluminum daily; +or, were it to run upon silicon bronze, could turn out one hundred and +twenty pounds of that per day, or, we believe, more aluminum bronze +daily than can be produced by all other plants in the world combined. +This production, however, is but that of the experimental laboratory, +and arrangements are making to turn out a ton of bronze daily, and the +works have an ultimate capacity of from eight to ten thousand horse +power. The energy consumed by the reduction of the ore is almost +entirely electrical, only enough carbon being used to unite with the +oxygen of the ore to carry it out of the furnace in the form of the +carbon monoxide, the aluminum remaining behind. Consequently, the +plant necessary to produce aluminum on a large scale involves a large +number of the most powerful dynamos. These are to be driven by +water-power or natural gas and marine engines of great capacity. + +The retail price of standard 10 per cent. aluminum bronze is $1 per +pound avoirdupois, which means less than $9 per pound for aluminum, +the lowest price at which it has ever been sold, yet the Cowles +company has laid a proposition before the Government to furnish this +same bronze in large quantities at very much lower prices than this. +The Hercules alloy, castings of which will stand over 100,000 pounds +to the square inch tensile strain, sells at 75 c. a pound, and is also +offered the Government or other large consumers at a heavy discount. +The alloys are guaranteed to contain exactly what is advertised; they +are standardized into 10 per cent., 7.5 per cent., 5 per cent. and 2.5 +per cent. aluminum bronze before shipment. + +The current available at the Cowles company's works was, until +recently, 330 amperes, driven by an electromotive force of 110 volts +and supplied by two Edison dynamos; but the company has now added a +large Brush machine that has a current of 560 amperes and 52 volts +electromotive force. We shall, on another occasion, give some +particulars of experiments in the reduction of refractory ores by the +process.--_Eng. and Mining Jour._ + + * * * * * + + + + +OPTICAL TELEGRAPHY.[1] + + [Footnote 1: Continued from page 8094.] + + +CRYPTOGRAPHY.--PRESERVATION OF TELEGRAMS. + +Optical telegraphy, by reason of its very principle, presents both the +advantage and inconvenience of leaving no automatic trace of the +correspondence that it transmits. The advantage is very evident in +cases in which an optical station falls into the hands of the enemy; +on the other hand, the inconvenience is shown in cases where a badly +transmitted or badly collated telegram allows an ambiguity to stand +subject to dispute. Moreover, in case of warfare between civilized +nations that have all the resources of science at their disposal, +there may be reason to fear lest one of the enemy's optical stations +substitute itself for the corresponding station, and take advantage of +the situation to throw confusion into the orders transmitted. The +remedy for this appears to reside in the use of cryptography and in +the exchange, at various intervals, of certain words that have been +agreed upon beforehand, and that the enemy is ignorant of. + +As for the automatic preservation of telegrams, the problem has not +been satisfactorily solved. It has been proposed to connect the key of +the manipulator of the optical apparatus with the manipulator of an +ordinary Morse apparatus, thus permitting the telegram to be preserved +upon a band of paper. It is unnecessary to say that the space occupied +by a dispatch thus transmitted would be considerable; but this is not +what has stopped innovators. The principal objection resides in the +increase in muscular work imposed by this arrangement upon the +telegrapher. Obliged to keep his eye fixed intently at the receiving +telescope, while at the same time maneuvering the manipulator and +spelling aloud the words that he is receiving, the operator should +have a very sensitive manipulator at his disposal, and not be +submitted to mental or physical overtaxation. So the apparatus that +have been devised have not met with much success. + +Two French officers, working independently, have hit upon the same +idea of receiving the indications transmitted by the vibration of the +luminous fascicle directly upon their travel. The method consists in +the use of that peculiar property of selenium of becoming a good +conductor under the action of a luminous ray, while in darkness it +totally prevents the passage of the electric current. Such +modification of the physical properties of selenium, moreover, occurs +without the perceptible development of any mechanical work. If, then, +in the line of travel of the luminous fascicle emitted by the optical +apparatus, or in a portion of such fascicle, we interpose a fragment +of selenium connected with the two poles of a local pile, it is easy +to see that the current from the latter will be opened or closed +according as the luminous ray from the apparatus will or will not +strike the selenium, and that the length of time during which the +current passes will depend upon the length of the luminous attacks. A +Morse apparatus interposed in this annexed circuit will therefore give +an automatic inscription of the correspondence exchanged. Such is the +principle. But, practically, very great difficulties present +themselves, these being connected with the rapid weakening of the +electric properties of the selenium, and with the necessity of having +recourse to infinitely small mechanical actions only. The problem is +nevertheless before us, and it is to be hoped that the perseverance of +the scientists who are at work upon it will some day succeed in +solving it. + +Finally, we may call attention to the attempts made to receive the +luminous impression upon a band prepared with gelatino-bromide of +silver. In practice this band would unwind uniformly at the focus of +the receiving telescope, which would be placed in a box, forming a +camera obscura. The velocity of this band prepared for photographing +the signals would be regulated by clockwork. The experiments that have +been made have not given results that are absolutely satisfactory, by +reason of the length of the signals received and the mechanical +complication of the device. + + +OPTICAL TELEGRAPHY BY MEANS OF PROJECTORS. + +[Illustration: FIG. 23.] + +The projectors employed for lighting to a distance the surroundings of +a stronghold or of a ship have likewise been applied in optical +telegraphy. For this purpose Messrs. Sautter, Lemonnier & Co. have +added to their usual projecting apparatus some peculiar arrangements +that permit of occultations of the luminous focus at proper intervals. +Figs. 21 and 22 show the arrangement of the apparatus, the principle +of which is as follows: When the axis of the projector points toward +the clouds, and in the direction occupied by a corresponding station, +the occultations of the luminous source placed in the focus of the +apparatus produce upon the clouds, which act as a screen, an alternate +series of flashes and extinctions. It is therefore possible with this +arrangement, and by the use of the Morse alphabet, to establish an +optical communication at a distance. The use of this projector (the +principal inconvenience of which is that it requires a clouded sky) +even permits two observers who are hidden from each other by the +nature of the ground to easily communicate at a distance of 36 or 48 +miles. + + +USE OF THE PROJECTOR IN OPTICAL TELEGRAPHY. + +[Illustration: FIGS. 21 AND 22.--FRONT VIEW AND LONGITUDINAL SECTION +OF THE MANGIN PROJECTOR. + +(Scale 1/15). A. Elliptical mirror. B. Arm of the same. C. Nut for +fixing the mirror. D. Support of the mirror. E. Occultator. F. Support +for same. G. Lever for maneuvering the occultator. I. Support of the +occultator rod. J. Screw for fixing the mirror support. K. Screw for +fixing the support of the occultator rod. L. Screw for fixing the +occultator support.] + +The apparatus shown in Figs. 21 and 22 permits of signaling in three +ways: + +1. _Upon the Clouds._--In this case the mirror, A, is removed, and the +projector inclined above the horizon in such a way as to illuminate +the clouds to as great a distance as possible. A maneuver of the +occultator, E, between the lamp and the mirror arrests the luminous +rays of the source, or allows them to pass, and thus produces upon the +clouds the dots and dashes of the conventional alphabet. + +2. _Isolated Communication by Luminous Fascicles._--When it is desired +to correspond to a short distance of 2 or 3 miles, and establish a +communication between two isolated posts, the mirror, A, is put in +place upon its support, B. The luminous fascicle emanating from the +source reflected by the mirror is thrown vertically. By revolving the +mirror 90° around its horizontal axis the fascicle becomes horizontal, +and may thus be thrown in a given direction at unequal intervals and +during irregular times, and furnish conventional signs. + +3. _Night Communication upon the Entire Horizon._--When we wish to +correspond at a short distance, say two miles, and make signals +visible from the entire horizon, the mirror, A, is put in place, so +that it shall reflect the luminous fascicle vertically. The fascicle, +at a distance of about fifty feet, meets a white balloon which it +renders visible from every point in the horizon. The maneuver of the +occultator brings the balloon out of darkness or plunges it thereinto +again, and thus produces the signs necessary for aerial communication. + +[Illustration: FIG. 24.] + +These ingenious arrangements, which depend upon the state of the +atmosphere, do not appear to have been imitated outside of the navy. + + +CAPT. GAUMET'S OPTICAL TELEGRAPH. + +The system of optical communication proposed by Capt. Gaumet, and +which he names the _Telelogue_, is based upon the visibility of +colored or luminous objects, and upon the possibility of piercing the +opaque curtain formed by the atmosphere between the observer's eye and +a signal, by utilizing the difference in brightness that exists +between such objects and the atmosphere. It is a question, then, of +giving such difference in intensity its maximum of brightness. To do +this, Capt. Gaumet proposes to employ silvered signals upon a black +background. He uses the simple letters of the alphabet, but changes +their value. His apparatus has the form of a large album glued at the +back to a sloping desk. Each silvered letter, glued to a piece of +black cloth, is seen in relief upon the open register. A sort of index +along the side, as in commercial blank-books, permits of quickly +finding any letter at will. Such is the manipulator of the apparatus. + +The receiver consists of a spy-glass affixed to the board that carries +the register. For a range of two and a half miles, the complete +apparatus, with a 12×16 inch manipulator and telescope, weighs but +four and a half pounds. For double this range, with a 20×28 inch +manipulator and telescope, the total weight is thirteen pounds. The +larger apparatus, according to the inventor, have a range of seven +miles. + +For night work the manipulator is lighted either by one lamp, or by +two lamps with reflector, placed laterally against it. + +This apparatus, although well known, and having been publicly +experimented with, has not, to our knowledge, been applied +practically. From a military standpoint, its short range will +evidently not permit it to compete with optical telegraphic apparatus, +properly so called. Perhaps it might rather be of service for private +communications between localities not very far apart, since it costs +but little and is easily operated. + + +OPTICAL SIGNALING BETWEEN BODIES OF TROOPS. + +Optical communications by signals, during day and night, with +experienced men, may, in the absence of telephones, telegraphs, and +messengers, render important service when the distance involved is +greater than two thousand feet. + +This mode of correspondence is based upon the use of the Morse +alphabet. The signals are divided into night and day ones. The day +signals are made with small flags. When these are wanting, sheets of +white cardboard may be used. The night signals are made with a lantern +provided with a support, which may be fixed to a wall or upon a +bayonet. + +In day signaling, the dashes of the Morse alphabet are formed by means +of two flags (Fig. 23) held simultaneously at arm's length by the +signaler. The dots are formed with a single flag held in the right +hand (Fig. 24). In this way it is possible, by extremely simple +combinations, to establish a correspondence, and produce any +conventional signal. By means of relay stations, the signals may be +transmitted from one to another to a great distance. + +In signaling with the lantern, long and short interruptions of the +luminous source are produced by means of a screen. + + +OPTICAL TELEGRAPHY BY LUMINOUS BALLOONS. + +Various interesting experiments have been made with a view to +utilizing luminous captive balloons for optical communications. As we +have already seen, this maybe effected by using opaque balloons, and +throwing upon them at unequal intervals a luminous fascicle by means +of a projector. As for using a luminous source placed in the car of a +balloon, that cannot be thought of in the present state of aeronautic +science; the continual rotation of the balloon around its axis would +render the projection and reception of the signals in a given +direction impossible. + + +OPTICAL TELEGRAPHY IN THE MARINE. + +For communicating optically from ship to ship during the day, the +marine uses flags of different forms and colors, and flames. Between +ships and the land there are used what are called semaphore signals, +which are made by means of a mast provided with three arms and a disk +placed at the upper part. The combinations of signs thus obtained, +which are analogous in principle to those of the Chappe telegraph, +permit of satisfactorily communicating to a distance. + +On board ship, hand signals are used like those employed by the army +for communicating between bodies of troops. For night communications +the marine employs lights corresponding to the day flags, as well as +rockets, and luminous rays projected by means of reflectors and +intercepted by screens. + +In conclusion, it may be said that optical telegraphy, which has only +within a few years emerged from the domain of theory to enter that of +practice, has taken a remarkable stride in the military art and in +science. It is due to its processes that Col. Perrier has in recent +years been enabled to carry out certain geodesic work that would have +formerly been regarded as impracticable, notably the prolongation of +the arc of the meridian between France and Spain. Very recently, an +optical communication established between Mauritius and Reunion +islands, to a distance of 129 miles, with 24 inch apparatus, proved +that, in certain cases, the costly laying of a submarine cable may be +replaced by the direct emission of a luminous ray. + + * * * * * + + + + +A NEW STYLE OF SUBMARINE TELEGRAPH. + + +Mr. F. Von Faund-Szyll has devised an original system of submarine +telegraph, which is based upon the well known property that selenium +exhibits of modifying its resistance under the influence of luminous +rays, and which he styles the _Selen-Differenzialrecorder_. + +Contrary to what is found in the other systems hitherto employed, the +Faund-Szyll system utilizes the cable current merely for starting the +receiving apparatus, which are operated by means of strong local +batteries. The result is that the mechanical work that devolves upon +the line current, which is, as well known, very weak, is exceedingly +reduced. + +The system consists of two essential parts: (1) The receiver, properly +so called. (2) The relay as well as the registering apparatus or +_differenzialrecorder_. The receiver consists of a closed box, K, in +the interior of which there is a very intense source of light whose +rays escape by passing through apertures, _a a'_, in the front part +(Fig. 1). + +As a source of light, there may be conveniently employed an +incandescent lamp, _g_, capable of giving an intense light, and +arranged (as shown in Fig. 2) behind the side that contains the slits, +_a a'_. + +The starting apparatus consists of a small galvanometric helix, _r_, +analogous to Thomson's siphon recorder, which is suspended from a +cocoon fiber and capable of moving in an extremely powerful magnetic +field, N S. This helix carries, as may be seen in Figs. 1, 3 and 4, a +prolongation, _v_, at its lower end whose form is that of a prism, and +which is arranged in front of the partition of the box, K, in such a +way that it exactly covers the two slits, a and _a_ when the bobbin is +at rest, and in this case prevents the luminous rays of the lamp, _g_, +from escaping from the box. But, as soon as the current sent through +the cable reaches the spirals of the bobbin, through the conductors, +_y y'_, the sum of the elementary electrodynamic actions that arise +causes the helix to revolve to the right or left, according to the +polarity of the current, while at the same time the helix slightly +approaches one or the other of the poles of the magnet. The +prolongation, _v_, of the helix, being firmly united with the latter, +follows it in its motion, and has the effect of permitting the +luminous rays to escape through one or the other of the slits, _a a'_, +so that the freeing of the luminous fascicle, if such an expression is +allowable, is effected. + +[Illustration: FIG. 1.] + +In order to prevent oscillations, which could not fail to occur after +each emission of a current (so that the helix, instead of returning to +a position of equilibrium and stopping there, would go beyond it and +alternately uncover the slits, _a a'_), the apparatus is provided with +a liquid deadener. To this end, the prolongation, _v_, carries a +piece, _o_, which dips into a cup containing a mixture of glycerine +and water. + +We shall now describe the _differenzialrecorder_. Opposite the two +slits, _a_ and _a'_, there are two powerful converging lenses, _l_ and +_l'_, whose foci coincide with two sorts of selenium plate rheostat, +_z_ and _z'_. The result of this arrangement is that as soon as one of +the slits, as a consequence of the displacement of the helix, _r_, +allows a luminous fascicle to escape, this latter falls upon the +corresponding lens, which concentrates it and sends it to the selenium +plates just mentioned. Under the influence of the luminous rays, the +resistance that the selenium offers to the passage of an electric +current instantly changes. At M and M' are placed two horseshoe +magnets whose poles are provided with pieces of soft iron that serve +as cores to exceedingly fine wire bobbins, _d_. These polarized pieces +are arranged in the shape of a St. Andrew's cross, and in such a way +that the poles of the same name occupy the two extremities of the same +arm of the cross, an arrangement very clearly shown in Fig. 2. + +[Illustration: FIG. 2.] + +Between the poles of the magnets, M and M', there is a permanent +magnet, A, movable around a vertical axis, _i_. Four spiral springs, +_f_, whose tension may be regulated, permit of centering this latter +piece in such a way that when the current is traversing the spirals of +the polar bobbins it is equally distant from the four poles, _n_, _s_, +_s'_, and _n'_. Under such circumstances it is evident that a +difference in the power of attraction of these four poles, however +feeble it be, will result in moving the magnet, A, in one direction or +the other around its axis. The energy and extent of such motion may, +moreover, be magnified by properly acting upon the four regulating +springs. + +The bobbins of the magnet, M, are mounted in series with the selenium +plates, _z_, the local battery, B, and a resistance box, W. Those of +the magnet, M', are in series with _z'_, B', and W'. The local +batteries, B and B', are composed of quite a large number of elements. +The current from the battery, B, traverses the selenium plates and the +bobbins of the magnet, M, and returns to B through the rheostat, W; +and the same occurs with the current from B'. The two currents, then, +are absolutely independent of one another. + +From this description it is very easy to see how the system works. Let +us suppose, in fact, that the current which is traversing the spirals +of the helix, _r_, has a direction such that the helix in its movement +approaches the pole, S; then the prolongation, _v_, will uncover the +slit, _a_, which, along with _a'_, had up to this moment been closed, +and a luminous fascicle escaping through _a_ will strike the lens, +_l'_, and from thence converge upon the selenium plates, _z'_. This is +all the duty that the line current has to perform. + +The luminous rays, in falling upon the selenium plates, _z'_, modify +the resistance that these offered to the passage of the current +produced by the battery, B'. As this resistance diminishes, the +intensity of the current in the circuit supplied by the battery, B', +increases, the attractive action of the polar pieces of the magnet, +M', diminishes, the equilibrium is destroyed, and the piece, A, +revolves around the axis, _i_. If the polarity of the line current +were different, the same succession of phenomena would occur, save +that the direction of A's rotation would be contrary. As for the +rheostats, W W', their object is to correct variations in the +selenium's resistance and to balance the resistances of the two +corresponding circuits. The magnet, A, will be combined with a +registering apparatus so as to directly or indirectly actuate the +printing lever. The entire first part of this apparatus, which is very +sensitive, may be easily protected from all external influence by +placing it in a box, and, if need be, in a room distant from the one +in which the employes work. + +[Illustration: FIGS. 3 AND 4.] + +The _differenzialrecorder_ alone has to be in the work room. + +As may be seen, the system is not wanting in originality. Experience +alone will permit of pronouncing upon the question as to whether it is +as practical as ingenious.--_La Lumiere Electrique._ + + * * * * * + + + + +A NEW CIRCUIT CUTTER. + + +Messrs. Thomson & Bottomley have recently invented a peculiar circuit +cutter based upon the use of a metal whose melting point is +exceedingly low. Recourse is had to this process for breaking the +current within as short a time as possible. In this new device the +ends of the conductors are soldered together with the metal in +question at one or several points of the circuit. The metal employed +is silver or copper of very great conductivity, seeing that the +increase of temperature in a conductor, due to a sudden increase of +the current, is inversely proportional to the product of the electric +resistance by the specific heat of the conductor; that these metals +are best adapted for giving constant and definite results; and that +the contacts are better than with lead or the other metals of low +melting point which are frequently employed in circuit cutters. + +[Illustration: FIG. 1.] + +Fig. 1 represents one form of the new device. Here, a is the copper or +silver wire, and _b_ is a soldering made with a very fusible metal and +securing a continuity of the circuit. Each extremity of the wire, _a_, +is connected with a heavy ring, _c_, of copper or other good +conducting metal. The hook, _d_, with which the upper ring, _c_, is in +contact, communicates metallically with one of the extremities of the +conductor at the place where the latter is interrupted for the +insertion of the circuit cutter. The hook, _e_, with which the lower +ring, _c_, is in contact, tends constantly to descend under the action +of a spiral spring, _f_, which is connected metallically with the +other extremity of the principal conductor. The hooks, _d_ and _e_, +are arranged approximately in the same vertical plane, and have a +slightly rounded upper and lower surface, designed to prevent the +rings, _c_, of the fusible wire, _a_, from escaping from the hooks. In +Fig. 1 the position of the arm, _e_, when there is no fusible wire in +circuit, is shown by dotted lines. When this arm occupies the position +shown by entire lines, it exerts a certain traction upon the +soldering, _b_, and separates the two halves of the wire, _a_, as soon +as the intensity of circulation exceeds its normal value. The mode of +putting the wire with fusible soldering into circuit is clearly shown +in the engraving. + +[Illustration: FIG. 2.] + +Fig. 2 shows a different mode of mounting the wire. The wire, _q_, is +soldered in the center, and is bent into the shape of a U, and kept in +place by the pieces, _r_ and _s_. In this way the two ends of it tend +constantly to separate from each other. Messrs. Thomson & Bottomley +likewise employ weights, simply, for submitting the wire to a constant +stress. The apparatus is inclosed in a box provided with a glass +cover.--_La Lumiere Electrique._ + + * * * * * + + + + +NEW MICRO-TELEPHONIC APPARATUS. + + +Despite the simplicity of their parts, and the slight value of the +materials employed, the existing micro-telephonic apparatus keep at +relatively high prices, and the use of them is often rejected, to the +benefit of speaking tubes, when the distance between stations is not +too great. We propose to describe a new style of apparatus that are in +no wise inferior to those in general use, and the price of which is +relatively low. + +The microphone transmitter may have several forms. The most elementary +of these consists of two pieces of carbon, from one to one and a +quarter inches in length by one-half inch in width, between which are +fixed two _nails_, about two inches in length, whose extremities, +filed to a point, enter small conical apertures in the carbons. Fig. 1 +gives an idea of the arrangement. + +[Illustration: FIG. 1.] + +Fig. 2 represents a model which is a little more complicated, but +which gives remarkable results. The largest nail is here two inches in +length, and the shortest three-quarter inch. + +[Illustration: FIG. 2.] + +The receivers may be Bell telephones of the simplest form found in the +market (Fig. 3); but for these there may be substituted a bar of soft +iron, cast iron, or steel, one of the extremities of which is provided +with a bobbin upon, which is wound insulated copper wire 0.02 inch in +diameter. The apparatus is mounted like an ordinary Bell telephone. A +horseshoe electro may also be used, and the poles be made to act (Fig. +4). The current sent by the transmitter suffices to produce a magnetic +field in which the variations in intensity produced by the microphone +succeed perfectly in reproducing speech and music. With four Leclanche +elements, the sounds are perceived very clearly. The elements used may +be bichromate of potash ones, those of Lelande and Chaperon, etc. + +[Illustration: FIG. 3.--RECEIVER.] + +[Illustration: FIG. 4.] + +To this apparatus there may be added a second bobbin of coarser wire +into which is passed a current from a local pile. This produces a much +intenser magnetic field, and, consequently, louder sounds. This +modification, however, is really useful only for long distances. + +Any arrangement imaginable may be given the transmitter and receiver; +but, aside from the fact that the ones just indicated are the +simplest, they give results that are at least equal, if not superior, +to all others. + +We shall insist here only upon the arrangement of the microphone, +which is new (at least in practice), and upon the uselessness of +having well magnetized steel bars and wires of extreme fineness in the +receiver. + +[Illustration: FIG. 5.] + +We have stated that the nail microphones are the simplest. The nails +may be replaced by copper or any other metal, or they may be well +nickelized; but common nails answer very well, and do not oxidize +much. An apparatus of this kind (Fig. 5) that has been for more than a +year in a laboratory filled with acid vapors is yet working very well. +These apparatus possess the further advantage of being very strong, +and of undergoing violent shocks without breaking or even getting out +of order. They may be used either with or without induction coils. We +have not yet measured their range, but can cite the following fact: + +One of these apparatus, quite crudely mounted, was put into a circuit +with a resistance of 300 ohms. With a single already exhausted +bichromate element, giving scarcely 2 volts, musical sounds and speech +reached the receiver without being notably weakened. Such resistance +represents a length of eighteen miles of ordinary telegraph wire. +After this, 700 ohms were overcome with 3.4 volts. This result was +obtained by direct transmission, and without an induction coil, and it +is probable that it might be much exceeded without sensibly increasing +the electromotive force of the current.--_Le Genie Civil._ + + * * * * * + + + + +MESSRS. KAPP AND CROMPTON'S MEASURING INSTRUMENTS. + + +We give herewith, from the _Elektrotechnische Zeitschrift_, a few +interesting details in regard to the measuring apparatus of Messrs. +Kapp and Crompton. + +It is evident that when we use permanent magnets or springs as +directing forces in measuring instruments, we cannot count upon an +absolute constancy in the indications, as the magnetism of the +magnetized pieces, or the tension of the springs, modifies in time. +The apparatus require to be regulated from time to time, and hence the +idea of substituting electro-magnets for permanent ones. + +[Illustration: FIG. 1.] + +If we suppose (Fig. 1) a magnetized needle, _n s_, placed between the +extremities of a soft iron core, N S, and if we group the circuit in +such a way that the current, after traversing the coil, _e e_, of the +electro, traverses a circle, _d d_, situated in a plane at right +angles with the plane of the needle's oscillation, it is evident that +we shall have obtained an apparatus that satisfies the aforesaid +conditions. It seems at first sight that in such an instrument the +directing force should be constant from the moment the electro was +saturated, and it would be possible, were sufficiently thin cores +used, to obtain a constancy in the directing magnetic field for +relatively feeble intensities. In reality, the actions are more +complex. The needle, _n s_, is, in fact, induced to return to its +position of equilibrium by two forces, the first of which (the +attraction of the poles, N S) rapidly increases with the intensity so +as to become quickly and perceptibly constant, while the second (the +sum of the elementary electrodynamic actions that are exerted between +the spirals, _e e_, and the needle, _n s_) increases proportionally to +the intensity of the current. If we represent these two sections +graphically by referring the magnetic moments as ordinates and the +current intensities as abscissas to two co-ordinate axes (Fig. 2), we +shall obtain for the first force the curve, O A B, which, starting +from A, becomes sensibly parallel with the axis of X, and for the +second the right line, O D. The resultant action is represented by the +curve, O E E'_F. It will be seen that this action, far from being +constant, increases quite rapidly with the intensity of the current, +so that the deflections would become feebler and feebler for strong +intensities, of current; and this, as well known, would render the +apparatus very defective from a practical point of view. + +[Illustration: FIG. 2.] + +But the action of the spirals can be annulled without sensibly +diminishing the magnetism of the core by arranging a second system of +spirals identical with the first, but placed in a plane at right +angles therewith, or, more simply still, by having a single system of +spirals comprising the coil of the electro-magnet, but distributed in +a plane that is oblique with respect to the needle's position of rest. +It then becomes possible, by properly modifying such angle of +inclination, to obtain a total directing action that shall continue to +increase with the intensity, and which, graphically represented, shall +give the curve, O G G'_H, for example (Fig. 2). + +[Illustration: FIG. 3.] + +[Illustration: FIG. 4.] + +[Illustration: FIG. 5.] + +This arrangement, which is adopted in Mr. Kapp's instruments, gives +very good results, as may be easily seen by reference to Figs. 3 and +4, in which the current intensities or differences of potential are +referred as ordinates and the degrees of deflection of the needle as +abscissas. The unbroken lines represent the curves obtained with the +apparatus just described, while the dotted ones give the curve of +deflection of an ordinary tangent galvanometer. These curves show that +for strong intensities of current Mr. Kapp's instrument is more +advantageous than the tangent galvanometer. Mr. Crompton has +constructed an amperemeter upon the same principle, which is shown in +Fig. 5.--_La Lumiere Electrique._ + + * * * * * + + + + +THE CHEMICAL ACTION OF LIGHT. + + +Professor A. Vogel, in a communication to the "Sitzungsberichte der +Munchener Akademie," brings into prominence the fact that the hemlock +plant, which yields coniine in Bavaria, contains none in Scotland. +Hence he concludes that solar light plays a part in the generation of +the alkaloids in plants. This view is corroborated by the circumstance +that the tropical cinchonas, if cultivated in our feebly lighted +hothouses, yield scarcely any alkaloids. Prof. Vogel has proved this +experimentally. He has examined the barks of cinchona plants obtained +from different conservatories, but has not found in any of them the +characteristic reaction of quinine. Of course it is still possible +that quinine might be discovered in other conservatory-grown +cinchonas, especially as the specimens operated upon were not fully +developed. But as the reaction employed indicates very small +quantities of quinine, it may be safely assumed that the barks +examined contained not a trace of this alkaloid, and it can scarcely +be doubted that the deficiency of sunlight in our hothouses is one of +the causes of the deficiency of quinine. + +It will at once strike the reader as desirable that specimens of +cinchonas should be cultivated in hothouses under the influence of the +electric light, in addition to that of the sun. + +If sunlight can be regarded as a factor in the formation of alkaloids +in the living plant, it has, on the other hand, a decidedly injurious +action upon the quinine in the bark stripped from the tree. On drying +such bark in full sunlight the quinine is decomposed, and there are +formed dark-colored, amorphous, resin-like masses. In the manufacture +of quinine the bark is consequently dried in darkness. + +This peculiar behavior of quinine on exposure to sunlight finds its +parallel in the behavior of chlorophyl with the direct rays of the +sun. It is well known that the origin of chlorophyl in the plant is +entirely connected with light, so that etiolated leaves growing in the +dark form no chlorophyl. But as soon as chlorophyl is removed from the +sphere of vegetable life, a brief exposure to the direct rays of the +sun destroys its green color completely. + +Prof. A. Vogel conjectures that the formation of tannin in the living +plant is to some extent influenced by light. This supposition is +supported by the fact that the proportion of tannin in beech or larch +bark increases from below upward--that is, from the less illuminated +to the more illuminated parts, and this in the proportions of 4:6 and +5:10. + +Sunny mountain slopes of a medium height yield, according to wide +experience, on an average the pine-barks richest in tannin. In woods +in level districts the proportion of tannin is greatest in localities +exposed to the light, while darkness seems to have an unfavorable +effect. Here, also, we must refer to the observation that leaves +exceptionally exposed to the light are relatively rich in tannin. + +We may here add that in the very frequent cases where a leaf is +shadowed by another in very close proximity, or where a portion of a +leaf has been folded over by some insect, the portion thus shaded +retains a pale green color, while adjacent leaves, or other portions +of the same leaf, assume their yellow, red, or brown autumnal tints. +If, as seems highly probable, these tints are due to transformation +products of tannin, we may not unnaturally conclude that they will be +absent where tannin has not been generated.--_Jour. of Science._ + + * * * * * + + + + +EUTEXIA.[1] + + [Footnote 1: Read before the Birmingham Philosophical Society, + January 22, 1885.] + +By THOMAS TURNER, Assoc. R.S.M., F.C.S., Demonstrator of Chemistry, +Mason College. + + +There are a number of interesting facts, some of which are known to +most persons, and many of them have been long recognized, of which, +however, it must be owned that the explanation is somewhat obscure, +and the connections existing between them have been but recently +pointed out. As an example of this, it is well known that salt water +freezes at a lower temperature than fresh water, and hence sea-water +may be quite liquid while rivers and ponds are covered with ice. +Again, it is noticed that mixtures of salts often have a fusing-point +lower than that of either of the constituent salts, and of this fact +we often take advantage in fluxing operations. Further, it is well +known that certain alloys can be prepared, the melting-points of which +are lower than the melting-point of either of the constituent metals +alone. Thus, while potassium melts at 62.5° C., and sodium at about +98°, an alloy of these metals is fluid at ordinary temperatures, and +fusible metal melts below the temperature of boiling water, or more +than 110° lower than the melting-point of tin, the most fusible of the +three metals which enter into the composition of this alloy. But +though these and many similar facts have been long known, it is but +recently, owing largely to the labors of Dr. Guthrie, that fresh +truths have been brought to light, and a connection shown to exist +throughout the whole which was previously unseen, though we have still +to acknowledge that at present there is much at the root of the matter +which is but imperfectly understood. Still Dr. Guthrie proves a +relationship to exist between the several facts we have previously +mentioned, and also between a number of other phenomena which at first +sight appear to be equally isolated and unexpected, and we are asked +to regard them all as examples of what he has called "eutexia." + +We may define a eutectic substance as a body composed of two or more +constituents, which constituents are in such proportion to one another +as to give to the resultant compound body a minimum temperature of +liquefaction--that is, a lower temperature of liquefaction than that +given by any other proportion.[2] It will be seen at once by this +definition that the temperature of liquefaction of a eutectic +substance is lower than the temperature of liquefaction of either or +any of the constituents of the mixture. And, further, it is plain that +those substances only can be eutectic which we can obtain both as +liquid and solid, and hence the property of eutexia is closely +connected with solution. + + [Footnote 2: Guthrie, _Phil. Mag._ [5], xvii., p. 462.] + +Following in the natural divisions adopted by Dr. Guthrie, we may +consider eutexia in three aspects: + + +I. CRYOHYDRATES. + +If a _dilute_ aqueous saline solution be taken at ordinary +temperatures, and then slowly cooled to some point below zero on the +Centigrade scale, the following series of changes will in general be +observed: On reaching a point below zero, the position of which is +dependent upon the nature of the salt and the amount of dilution, it +will be found that ice is formed; this will float upon the surface of +the solution, and may be readily removed. If the ice so removed be +afterward pressed, or carefully drained, it will be found to consist +of nearly pure water, the liquid draining away being a strong saline +solution which had become mechanically entangled among the crystals of +ice during solidification. If we further cool the brine which remains, +we notice a tolerably uniform fall of temperature with accompanying +formation of ice. But at length a point is reached at which the +temperature ceases to fall until the whole of the remaining +mother-liquor has solidified, with the production of a compound called +a cryohydrate,[3] which possesses physical properties different from +those of either the ice or the salt from which it is formed. + + [Footnote 3: Guthrie, _Phil. Mag._, 4th Series, xlix., pp. 1, + 206, 266; 5th Series, i., pp. 49, 354, 446, vi., p. 35.] + +If, on the other hand, we commence with a _saturated_ saline solution, +in general it is noticed on cooling the liquid a separation of salt +ensues, which salt sinks to the bottom of the mass, and may be +removed. The salt so separating may be either anhydrous or a "hydrate" +of greater concentration than the mother-liquor. So long as this +separation proceeds the temperature falls, but at length a point is +reached at which the thermometer remains stationary until the whole is +solidified, with the production of a cryohydrate. This temperature of +solidification is the same whether we start with a dilute or a +saturated solution, and the composition of the cryohydrate is found to +be constant. The temperature of production of the cryohydrate is +identical with the lowest temperature which can be produced on +employing a mixture of ice and the salt as a freezing mixture or +cryogen. + +It will be readily seen that in the formation of a cryohydrate we have +an example of eutexia, since the constituents are present in such +proportion as to give to the resultant compound body a minimum +temperature of liquefaction. + + +II. EUTECTIC SALT ALLOYS.[4] + + [Footnote 4: F. Guthrie, _Phil. Mag._ [5], xvii., p. 469; F.B. + Guthrie, _Journ. Chem. Soc_,. 1885, p. 94.] + +Although it has been long known that on mixing certain salts the +resulting substance possessed a lower melting-point than either of the +constituent salts alone, still but few determinations of the +melting-points of mixtures of salts have been made, and even these are +often of small value, on account of the very considerable range of +temperature observed during solidification. This is due largely to the +fact that eutectic mixtures were not known, as equivalent proportions +of various salts have been employed, while eutectic mixtures are +seldom found to possess any simple arithmetical molecular relationship +between their constituents. + +Eutectic salt alloys closely resemble cryohydrates in behavior. If for +simplicity we confine our attention to a fused mixture of two salts in +any proportion other than eutectic, it is found that, on cooling, the +thermometer falls steadily, until at length that salt which is in +excess of the proportion required for a eutectic mixture begins to +separate out. If this is removed, the thermometer falls until a fixed +point is reached at which the temperature remains stationary until the +whole of the mixture solidifies. On remelting, the temperature of +solidification is found to be quite fixed, and the mixture is +evidently eutectic. + +It is of interest to notice that from our knowledge of the +cryohydrates it becomes possible to predict the existence, +composition, and temperature of solidification of a eutectic alloy, if +we are previously furnished with the melting-points of mixtures of the +substances in question. Or, in other cases, we may predict from the +curve of melting-points that no eutectic alloy is possible. + +As an example, we may take the determinations of the melting-points of +mixtures of potassium and sodium nitrate by M. Maumené.[5] These are +graphically represented in Fig. 1, the curve being derived from the +mean of the temperatures given in the memoir. From this diagram we +should be led to expect a eutectic mixture, since the curve dips below +a horizontal line passing through the melting-point of the more +fusible of its constituents. From our curve we should expect a +eutectic mixture with about 35 per cent. KNO_{3}, and with a +temperature of solidification below 233°. Dr. Guthrie gives 32.9 per +cent. at 215°. This agreement is as good as might be expected when one +remembers that the melting-points, not being of eutectic mixtures, are +difficult to determine, and a considerable range is given; that +analyses of mixtures of potassium and sodium salts are apt to vary; +and that the two observers differ by ±7° in the temperatures given for +the melting-points of the original salts. + + [Footnote 5: _Comptes Rendus_, 1883, 2, p. 45.] + +[Illustration: FIG. 1.] + +Dr. Tilden has drawn my attention to an interesting example of the +lowering of melting-point by the mixture of salts. The melting-point +of monohydrochloride of turpentine oil is 125°, while that of the +dihydrochloride is 50°; but on simply stirring together these +compounds in a mortar at common temperatures, they immediately +liquefy. Two molecules of the monohydrochloride and one molecule of +the dihydrochloride form a mixture which melts at about 20°. + + +III. EUTECTIC METALLIC ALLOYS. + +Although many fusible alloys have been long known, I believe no true +eutectic metallic alloy had been studied until Dr. Guthrie[6] worked +at the subject, employing the same methods as with his cryohydrates. +It is found if two metals are fused together and the mixture allowed +to cool, that the temperature falls until a point is reached at which +that metal which is present in a proportion greater than is required +to form the eutectic alloy begins to separate. If this solid be +removed as it forms, the temperature gradually falls until a fixed +point is reached, at which the eutectic alloy solidifies. Here the +thermometer remains stationary until the whole has become solid, and, +on remelting, this temperature is found to be quite fixed. In addition +to the di-eutectic alloys, we have also tri- and tetra-eutectic +alloys, and as an example of the latter we may take the +bismuth-tin-lead-cadmium eutectic alloy, melting at 71°. + + [Footnote 6: _Phil. Mag._, 5th Series, xvii., p. 462.] + +We have already seen with salt eutectics that, given the curve of +melting-points of a mixture in various proportions, we may predict the +existence, composition, and melting-point of the eutectic alloy. As a +matter of course, the same thing holds good for metallic eutectics. An +interesting example of this is furnished by the tin-lead alloys, the +melting-points of which have been determined by Pillichody.[7] From +these determinations we obtain the curve given in Fig. 2, and from +this curve, since it dips below a horizontal line passing through the +melting-point of the more fusible constituent, we are at once able to +predict a eutectic alloy. We should further expect this to have a +constitution between PbSn_{3} and PbSn_{4} and a melting-point +somewhat below 181°. On melting together tin and lead, and allowing +the alloy to cool, we find our expectation justified; for by pouring +off the fluid portion which remains after solidification has +commenced, and repeating this several times with the portion so +removed, we at length obtain an alloy which solidifies at the constant +temperature of 180°, when the melting-point of tin is taken as 228°. +On analysis 1.064 grm. of this alloy gave 0.885 grm. SnO_{2}, which +corresponds to Sn 65.43 per cent., or PbSn_{3.3}. This, therefore, is +the composition of the eutectic alloy, and it finds its place +naturally on the curve given in Fig. 2. + + [Footnote 7: _Dingler's Polyt. Journ._, 162, p. 217; + _Jahresberichte_, 1861, p. 279.] + +[Illustration: FIG. 2.] + +It will be seen that the subject of eutexia embraces many points of +practical importance and of theoretical interest. Thus it has been +shown by Dr. Guthrie that the desilverizing of lead in Pattinson's +process is but a case of eutexia, the separation of lead on cooling a +bath of argentiferous lead poor in silver being analogous to the +separation of ice from a salt solution. Dr. Guthrie has also shown +that eutexia may reasonably be supposed to have played an important +part in the production and separation of many rock-forming minerals. + +It is with considerable diffidence that I suggest the following as an +explanation of the multitude of facts to which previous reference has +been made. + +In a mixture of two substances, A and B, we have the following forces +active, tending to produce solidification: + + 1. The cohesion between the particles of A. + + 2. The cohesion between the particles of B. + + 3. The cohesion between the particles of A and the particles of B. + +With regard to this last factor, it will be seen that there are three +cases possible: + + 1. The cohesion of the mixture A B may be greater than the + cohesion of A + the cohesion of B. + + 2. The cohesion of A B may be equal to the cohesion of A + the + cohesion of B. + + 3. The cohesion of A B may be less than the cohesion of A + the + cohesion of B. + +Now, since cohesion tends to produce solidification, we should in the +first case expect to find the melting-point of the mixture _higher_ +than the mean of the melting-points of its constituents, or the curve +of melting-points would be of the form given in _a_, Fig. 3. Here no +eutectic mixture is possible. + +[Illustration: FIG. 3.] + +In the second case, where cohesion A B = cohesion A + B, we should +obtain melting-points for the mixture which would agree with the mean +of the melting-points of the constituents, the curve of melting-points +would be a straight line, and again no eutectic mixture would be +possible. + +In the third case, however, where cohesion A B is less than cohesion A ++ B, we should find the melting-points of the mixture lower than the +mean of the melting-points of its constituents, and the curve of +melting-points would be of the form given in _e_, Fig. 3. Here, in +those cases where the difference of cohesion on mixture is +considerable, the curve of melting-points may dip below the line _e +f_. This is the _only case_ in which a eutectic mixture is possible, +and it is, of course, found at the lowest point of the curve. + +If it be true, as above suggested, that the force of cohesion is at +its minimum in the eutectic alloy, we should expect to find, in +preparing a eutectic substance, either that actual expansion took +place, or that the molecular volume would gradually increase in +passing along our curve of melting-points, from either end, for each +molecule added, and that it would obtain its greatest value at the +point corresponding to the eutectic alloy. + +Of this I have no direct evidence as yet, but it is a point of +considerable interest, and I may possibly return to it at some future +time.--_Chemical News._ + + * * * * * + + + + +CHINOLINE. + + +Dr. Conrad Berens, of the University of Pennsylvania, reaches the +following: + + 1. Chinoline tartrate is a powerful agent, producing death by +asphyxia. + + 2. The drug increases the force and frequency of the respirations by +stimulating the vagus roots in the lung. + + 3. It paralyzes respiration finally by a secondary depressant action +upon the respiratory center. + + 4. It does not cause convulsions. + + 5. It lessens and finally abolishes reflex action by a direct action +upon the cord, and by a slight action upon the muscles and nerves. + + 6. It diminishes or abolishes muscular contractility respectively +when applied through the circulation or directly. + + 7. It coagulates myosin and albumen. + + 8. It causes insalivation by paralysis of the secretory fibers of the +chorda tympani; increases the flow of bile; has no action upon the +spleen. + + 9. It lowers blood-pressure by paralyzing the vaso-motor centers and +by a direct depressant action upon the heart muscle. + + 10. It diminishes the pulse rate by direct action upon the heart. + + 11. It lowers the temperature by increasing the loss of heat. + + 12. It is a powerful antiseptic; and, finally, + + 13. Its paths of elimination are not known. + + * * * * * + + + + +METHOD FOR RAPID ESTIMATION OF UREA. + + +Being called upon to make a good many brief and rapid analyses of +urine on "clinic days" of our medical department, I devised the +following modification of Knop's method of estimating urea; and after +using it for a year with perfectly satisfactory results, venture to +describe and recommend it as especially adapted for physicians' use, +by reason of simplicity, cheapness, and accuracy. In perfecting and +testing it I was assisted greatly by J. Torrey, Jr., then working with +me. + +[Illustration] + +The apparatus consists of the glass tube, A, which is about 8 cm. long +and 2½ cm. in diameter, joined to the tube, B, which is about 25 or 30 +cm. in length in its longer arm and 8 or 10 in its shorter, and has a +diameter of about 5 mm. Near the bend is an outlet tube, _c_, provided +with "ball valve" or pinch cock. _d_, _e_, _f_, _g_, are marks upon the +tubes. C is a rubber cork with two holes through which the bent tube, +D, passes. D is of such size and length as to hold about 1 c.c., and +one of its ends may be a trifle longer than the other. + +The apparatus is used as follows: Remove the cork and pour in mercury +until it stands at _e_ and _g_, then fill up to the mark, _f_, with +sodium or potassium hypobromite (made by shaking up bromine with a +strong solution of sodium or potassium hydroxide). Next carefully fill +the tube in the cork with the urine, being careful especially not to +run it over or leave air bubbles in it. This can easily be done by +using a small pipette, but if accidentally a little runs over, it +should be wiped off the end of the cork with blotting paper. The cork +is then to be inserted closely into the tube; the urine tube being so +small, the urine will not run out in so doing. The mercury is then +drawn out through _c_ till it stands in B at _d_. Its level in A will +of course not be changed greatly. Now, incline the apparatus till the +surface of the hypobromite touches the urine in the longer part of the +urine tube, and then bring it upright again. The urine will thus be +discharged into the hypobromite, which will of course decompose the +urea, liberating nitrogen, which will cause the mercury to rise in B. +Shake until no further change of level is seen, and mark the level of +mercury in B with a rubber band, then remove the cork, draw out the +liquid with a pipette, dry out the tube above the mercury with scrap +of blotting paper, pour back the mercury drawn out, and repeat the +process to be sure that no error was made. + +If now two or three marks have been made upon the tube, B, indicating +the height of the mercury when solutions containing known per cents. +of urea are used, an accurate opinion can be at once formed as to the +condition of the urine as regards urea. + +As is well known, normal urine contains about 2.5-3 per cent. of urea, +so that graduations representing 2, 2.5, 3, and 4 per cent. are +usually all that are needed, though of course many more can be easily +made. + +The results obtained with this apparatus have been repeatedly compared +with those of more elaborate ones, and no practical difference +observed. Evidently the same apparatus, differently graduated, might +be employed to determine the carbonate present in such a substance as +crude soda ash or other similar mixture. In such a case the weighed +material would be put upon the mercury with water and the small tube +filled with acid. + +Bowdoin College Chemical Laboratory.--_F.C. Robinson, in Amer. Chem. +Jour._ + + * * * * * + +A CATALOGUE containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at +this office. + + * * * * * + + +THE +SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +Terms of Subscription, $5 a year. + +Sent by mail, postage prepaid, to subscribers in any part of the +United States or Canada. Six dollars a year, sent, prepaid, to any +foreign country. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. Price, 10 cents each. + +All the back volumes of THE SUPPLEMENT can likewise be supplied. 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