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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text diff --git a/16773-8.txt b/16773-8.txt new file mode 100644 index 0000000..df89841 --- /dev/null +++ b/16773-8.txt @@ -0,0 +1,3596 @@ +The Project Gutenberg EBook of Scientific American Supplement, No. 443, +June 28, 1884, 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. 443, June 28, 1884 + +Author: Various + +Release Date: September 29, 2005 [EBook #16773] + +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. 443. + + + + +NEW YORK, JUNE 28, 1884. + +Scientific American Supplement. Vol. XVII., No. 443. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + * * * * * + + + + +TABLE OF CONTENTS. + + +I. CHEMISTRY AND METALLURGY.--Beeswax and its Adulterations. + --Chemical ingredients.--Detection of adulterations. 7064 + + Phenol in the Stem, Leaves, and Cones of Pinus Sylvestris. + --A discovery bearing on the flora of the Carboniferous + epoch and the formation of petroleum. 7065 + + The School of Physics and Chemistry of Paris.--With + engraving of laboratory. 7065 + + Some Relations of Heat to Voltaic and Thermo Electric + Action of Metals in Electrolysis.--By G. GORE. 7070 + +II. ENGINEERING, MECHANICS, ETC.--Air Refrigerating + Machine.--5 figures. 7071 + + A Gas Radiator and Heater. 7071 + + Concrete Water Pipes. 7071 + + The Sellers Standard System of Screw Threads. Nuts, and + Bolt Heads.--A table. 7072 + + An English Railway Ferry Boat.--3 figures. 7072 + + The Problem of Flight and the Flying Machine. 7072 + +III. TECHNICAL.--Concrete Buildings for Farms.--How to construct + them. 7063 + + What Causes Paint to Blister and Peel?--How to prevent it. 7063 + + Olive Oil.--Difficulties encountered in raising an olive + crop.--Process of making Oil. 7064 + +IV. ELECTRICITY. ETC.--Telephony and Telegraphy on the Same + Wires Simultaneously.--4 figures. 7067 + + The Electric Marigraph.--An apparatus for measuring the + height of the tide.--With engravings and diagrams showing + the Siemens and Halske marigraph and the operation of the + same. 7068 + + Delune & Co.'s System of Laying Underground Cables.--2 + figures. 7069 + + Electricity Applied to Horseshoeing.--Quieting an unruly + animal.--3 engravings. 7069 + + Esteve's Automatic Pile.--1 figure. 7070 + + Woodward's Diffusion Motor. 7070 + +V. ASTRONOMY.--Lunar Heat.--Its reflected and obscure + heat.--Trifling influence of the moon upon wind and + weather.--By Prof. C.A. YOUNG. 7073 + +VI. NATURAL HISTORY.--The Long-haired Pointer "Mylord." + --With engraving. 7073 + +VII. HORTICULTURE, ETC.--Apple Tree Borers.--Protection + against the same. 7074 + + Keffel's Germinating Apparatus.--With engraving. 7074 + + Millet.--Its Cultivation. 7074 + +VIII. MISCELLANEOUS.--Puerta del Sol, Madrid, Spain.--With + engraving. 7063 + + Dust-free Spaces.--A lecture delivered by Dr. OLIVER J. + LODGE before the Royal Dublin Society. 7067 + + * * * * * + + + + +PUERTA DEL SOL, MADRID. + + +Puerta del Sol, or Gate of the Sun, Madrid, is the most famous and +favorite public square in the Spanish city of Madrid. It was the +eastern portal of the old city. From this square radiate several of +the finest streets, such as Alcala, one of the handsomest +thoroughfares in the world, Mayor, Martera, Carretas, Geronimo. In our +engraving the post office is seen on the right. Large and splendid +buildings adorn the other sides, which embrace hotels, cafes, reading +rooms, elegant stores, etc. From this square the street railway lines +traverse the city in all directions. The population of the city is +about 400,000. It contains many magnificent buildings. Our engraving +is from _Illustrirte Zeitung_. + +[Illustration: THE PUERTA DEL SOL, MADRID, SPAIN (From a Photograph.)] + + * * * * * + + + + +CONCRETE BUILDINGS FOR FARMS. + + +Buildings made of concrete have never received the attention in this +country that they deserve. They have the merit of being durable and +fire-proof, and of not being liable to be blown down by violent winds. +It is very easy to erect them in places where sand and gravel are near +at hand and lime is comparatively cheap. Experiments made in England +show that coal screenings may be employed to good advantage in the +place of sand and gravel. Mr. Samuel Preston, of Mount Carroll, Ill., +has a dwelling and several other buildings made of concrete and +erected by himself. They were put up in 1851, and are in excellent +condition. In _The Farmers' Review_ he gives the following directions +for building concrete walls: + +First, secure a good stone foundation, the bottom below frost, the top +about one foot above ground. Near the top of the foundation bed in 2×4 +scantling edgewise transversely with the walls, at such distances +apart as the length of the planks that form the boxes to hold the +concrete may require, the ends of the scantling to run six inches +beyond the outside and inside of the wall. Now take 2×6 studding, one +foot longer than the height of the concrete walls are to be, bolt in +an upright position in pairs to each end of the 2×4 scantling, and, if +a foot wall is to be built, sixteen inches apart, as the box plank +will take up four inches. To hold the studding together at the top, +take pieces of 2×6 lumber, make two mortises in each piece large +enough to slip easily up and down on the studding, forming a tie. Make +one mortise long enough to insert a key, so that the studding can be +opened at the top when the box plank are to be raised. When the box +plank are in position, nail cleats with a hole in each of them on each +side of the studding, and corresponding holes in the studding, into +which insert a pin to hold the plank to the studding. Bore holes along +up in the studding, to hold the boxes when raised. + +To make the walls hollow, and I would do it in a building for any +purpose, use inch boards the same width of the box plank, one side +planed; put the two rough sides together with shingles between, +nailing them together with six-penny nails; place them in the middle +of the wall, the thin end of the shingle down. That gives them a bevel +and can be easily raised with the boxes. To tie the wall together, at +every third course place strips of boards a little shorter than the +thickness of the wall; cut notches in each so that the concrete will +fill in, holding all fast. The side walls being up, place two inch +planks on top of the wall upon which to rest the upper joists, put on +joist and rafters, remove the box plank, take inch boards for boxes, +cut to fit between joists and rafters, and fill with concrete to upper +side of rafters, which makes walls that will keep out cold and damp, +all kinds of vermin, and a roof which nothing but a cyclone can +remove. In making door and window frames, make the jambs two inches +narrower than the thickness of the walls, nailing on temporary two +inch strips. + +Make the mortar bed large enough to hold the material for one course; +put in unslaked quicklime in proportion to 1 to 20 or 30 of other +material; throw into it plenty of water, and don't have that +antediluvian idea that you can drown it; put in clean sand and gravel, +broken stone, making it thin enough, so that when it is put into boxes +the thinner portion will run in, filling all interstices, forming a +solid mass. A brick trowel is necessary to work it down alongside the +boxing plank. One of the best and easiest things to carry the concrete +to the boxes is a railroad wheelbarrow, scooping it in with a scoop +shovel. Two courses a week is about as fast as it will be safe to lay +up the walls. + + * * * * * + +The _Medical Summary_ recommends the external use of buttermilk to +ladies who are exposed to tan or freckles. + + * * * * * + + + + +WHAT CAUSES PAINT TO BLISTER AND PEEL? + +HOW TO PREVENT IT. + + +This subject has been treated by many, but out of the numerous ideas +that have been brought to bear upon it, the writers have failed to +elucidate the question fully, probably owing to the fact that in most +parts they were themselves dubious as to the real cause. Last year +W.S. gave a lengthy description in the _Building News_, in which he +classified blistering and peeling of paint into one of blistering +only. He stated in the beginning of his treatise the following: + +"The subject of blistering of paint has from time to time engrossed +the attention of practical men; but so far as we can follow it in the +literature pertaining to the building trade, its cause has never been +clearly laid down, and hence it is a detail enshrouded in mystery." + +W.S. dwells mostly, in his following explanations on blistering +paints, on steam raised in damp wood. Also an English painter, +according to the _Painters' Journal_, lately reiterates the same +theory, and gives sundry reasons how water will get into wood through +paint, but is oblivious that the channels which lead water into wood +are open to let it out again. He lays great stress on boiled oil +holding water in suspense to cause blistering, which is merely a +conjecture. Water boils at 212° F. and linseed oil at 600° F., +consequently no water can possibly remain after boiling, and a drop of +water put into boiling oil would cause an explosion too dangerous to +be encountered. + +It will be shown herewith that boiled oil, though in general use, is +unfit for durable painting, that it is the cause of most of the +troubles painters have to contend with, and that raw linseed oil +seasoned by age is the only source to bind pigments for durable +painting; but how to procure it is another trouble to overcome, as all +our American raw linseed oil has been heated by the manufacturers, to +qualify it for quick drying and an early market, thereby impairing its +quality. After linseed oil has been boiled, it becomes a poor varnish; +it remains soft and pliable when used in paint, giving way to air +pressure from the wood in hot weather, forming blisters. Turpentine +causes no blistering; it evaporates upon being exposed, and leaves the +paint in a porous condition for the gas in the wood to escape; but all +painters agree that blistering is caused by gas, and on investigation +we find two main sources from which gas is generated to blister +paint--one from the wood, the other from the ingredients of the paint. +The first named source of gas is started in hot weather by expansion +of air confined in painted wood, which presses against the paint and +raises blisters when the paint is too soft to resist. Tough, +well-cemented paint resists the pressure and keeps the air back. These +blisters mostly subside as soon as the air cools and returns to the +pores, but subsequently peel off. + +W.S. and others assert that damp in painted wood turns into steam when +exposed to sun heat, forming blisters, which cannot be possible when +we know that water does not take a gaseous form (steam) at less than +212° F. They have very likely been deluded by the known way of +distilling water with the aid of sunshine without concentrating the +rays of the sun, based upon the solubility of water in air, viz.: Air +holds more water in solution (or suspension) in a warmer than in a +cooler degree of temperature; by means of a simple apparatus +sun-heated air is guided over sun-heated water, when the air saturated +with water is conducted into a cooler, to give up its water again. But +water has an influence toward hastening to blister paint; it holds the +unhardened woodsap in solution, forming a slight solvent of the oil, +thereby loosening the paint from the wood, favoring blistering and +peeling. There is a certain kind of blister which appears in certain +spots or places only, and nowhere else, puzzling many painters. The +explanation of this is the same as before--soft paint at these spots, +caused by accident or sluggish workmen having saturated the wood with +coal oil, wax, tar, grease, or any other paint-softening material +before the wood was painted, which reacts on the paint to give way to +air pressure, forming blisters. + +The second cause of paint blistering from the ingredients of the paint +happens between any layer of paint or varnish on wood, iron, stone, or +any other substance. Its origin is the gaseous formation of volatile +oils during the heated season, of which the lighter coal oils play the +most conspicuous part; they being less valuable than all other +volatile oils, are used in low priced japan driers and varnishes. +These volatile oils take a gaseous form at different temperatures, lie +partly dormant until the thermometer hovers at 90° F. in the shade, +when they develop into gas, forming blisters in airtight paint, or +escape unnoticed in porous paint. This is the reason why coal-tar +paint is so liable to blister in hot weather; an elastic, soft +coal-tar covering holds part of its volatile oil confined until heated +to generate into gas; a few drops only of such oil is sufficient to +spoil the best painted work, and worse, when it has been applied in +priming, it settles into the pores of the wood, needing often from two +to three repetitions of scraping and repainting before the evil is +overcome. Now, inasmuch as soft drying paint is unfit to answer the +purpose, it is equally as bad when paint too hard or brittle has been +used, that does not expand and contract in harmony with the painted +article, causing the paint to crack and peel off, which is always the +case when either oil or varnish has been too sparingly and turpentine +too freely used. Intense cold favors the action, when all paints +become very brittle, a fact much to be seen on low-priced vehicles in +winter time. Damp in wood will also hasten it, as stated in +blistering, the woodsap undermining the paint. + +To avoid peeling and blistering, the paint should be mixed with raw +linseed oil in such proportions that it neither becomes too brittle +nor too soft when dry. Priming paint with nearly all oil and hardly +any pigment is the foundation of many evils in painting; it leaves too +much free oil in the paint, forming a soft undercoat. For durable +painting, paint should be mixed with as much of a base pigment as it +can possibly be spread with a brush, giving a thin coat and forming a +chemical combination called soap. To avoid an excess of oil, the +following coats need turpentine to insure the same proportion of oil +and pigment. As proof of this, prime a piece of wood and a piece of +iron with the same paint; when the wood takes up part of the oil from +the paint and leaves the rest in proportion to harden well, where at +the same time the paint on iron remains soft. To be more lucid, it +need be explained, linseed oil boiled has lost its oleic acid and +glycerine ether, which form with the bases of pigments the insoluble +soap, as well as its albumen, which in boiling is thrown out. It +coagulates at 160° F. heat; each is needed to better withstand the +action of wind and weather, preventing the dust from attaching itself +to a painted surface, a channel for ammonia in damp weather to +dissolve and wash off the paint. In later years linseed oil has been +extracted from linseed meal by the aid of naphtha and percolation, the +product of a very clear, quick drying oil, but lacking in its binding +quality, no doubt caused by the naphtha dissolving the fatty matter +only, leaving the glycerine and albumen in the meal. + +All pigments of paint group according to their affinity to raw linseed +oil into three classes. First, those that form chemical combinations, +called soap. This kind is the most durable, is used for priming +purposes, and consists of lead, zinc, and iron bases, of which red +lead takes up the most oil; next, white lead, the pure carbonate Dutch +process made, following with zinc white and iron carbonates, as iron +ore paint, Turkey umber, yellow ocher; also faintly the chromates of +lead--chrome-green and chrome-yellow, finishing with the poorest of +all, modern white lead, made by the wet or vinegar process. The second +class being neutrals have no chemical affinity to linseed oil; they +need a large quantity of drier to harden the paint, and include all +blacks, vermilion, Prussian, Paris, and Chinese blue, also terra di +Sienna, Vandyke brown, Paris green, verdigris, ultramarine, genuine +carmine, and madderlake. The last seven are, on account of their +transparency, better adapted for varnish mixtures--glazing. The third +class of pigments act destructively to linseed oil; they having an +acid base (mostly tin salt, hydrochloride of tin, and redwood dye), +form with the gelatinous matter of the oil a jelly that will neither +work well under the brush nor harden sufficiently, and can be used in +varnish for glazing only; they are not permanent in color, and among +the most troublesome are the lower grades of so-called carmines, +madderlakes, rose pinks, etc., which contain more or less acidous +dyes, forming a soft paint with linseed oil that once dry on a job can +be twisted or peeled off like the skin of a ripe peach. All these +combinations of paint have to be closely observed by the painter to +insure his success. + +Twenty-five years ago a house needed to be painted outside but once in +from five to seven years; it looked well all the time, as no dust +settled in the paint to make it unsightly. Painters then used the +Dutch-process-made white-lead, a base and raw linseed oil, a fat acid, +which formed the insoluble soap. They also put turpentine in the +following coats, to keep up the proportions of oil and pigment. All +held out well against wind and weather. Now they use the +wet-process-made white lead, neutralized by vinegar, with oil +neutralized by boiling, from the first to the last coat, and--fail in +making their work permanent. + +W.S., in the _Building News_, relates an unaccountable mysterious +blistering in a leaky house, where the rainwater came from above on a +painted wood wall, blistering the paint in streaks and filled at the +lower ends with water, which no doubt was caused by the water soaking +the wood at the upper ends where there was no paint, and following it +down through the fibers, pushed and peeled off the soft, inadhesive +paint. Green, sappy, and resinous wood is unfit for durable painting, +and to avoid blistering and peeling wood should be well seasoned and +primed with all raw linseed oil, some drier, to insure a moderately +slow drying, and as much of a base pigment as the painter can possibly +spread (much drier takes up too much oil acid, needed for the pigment +base to combine with), which insures a tough paint that never fails to +stand against blistering or peeling, as well as wind, weather, and +ammonia. + +The coach, car, and house painter can materially improve his painting +where his needs lie by first oiling the wood with raw oil, then +smoothing the surface down with lump pumicestone, washing it with a +mixture of japan drier or, better yet, gold sizing and turpentine, +wiping dry, and following it up with a coat of white lead, oil, and +turpentine. The explanation is: the raw oil penetrates the wood and +raises the wood fibers on the surface to be rubbed down with +pumicestone, insuring the best surface for the following painting: to +harden the oil in the wood it receives a coat of japan drier, which +follows into the pores and there forms a tough, resinous matter, +resisting any air pressure that might arise from within, and at the +same time reacts on the first coat of lead as a drier. This mode +insures the smoothest and toughest foundation for the following +painting, and may be exposed to the hottest July sun without fear of +either blistering or peeling. + +LOUIS MATERN. + +Bloomington, Ill. + + * * * * * + + + + +OLIVE OIL. + + +The following particulars with regard to the production of olive oil +in Tuscany have been furnished to Mr. Consul Inglis by one of the +principal exporters in Leghorn: + +The olive oil produced in Tuscany from the first pressing of the fruit +is intended for consumption as an article of food. Hence, great +attention is paid both to the culture of the olive tree and the +process of making oil. + +The olive crop is subject to many vicissitudes, and is an uncertain +one. It may be taken as a rule that a good crop does not occur more +frequently than once in three years. A prolonged drought in summer may +cause the greater part of the small fruit to fall off the trees. A +warm and wet autumn will subject the fruit to the ravages of a maggot +or worm, which eats its way into it. Fruit thus injured falls to the +ground prematurely, and the oil made from it is of very bad quality, +being nauseous in taste and somewhat thick and viscous. Frost +following immediately on a fall of snow or sleet, when the trees are +still wet, will irretrievably damage the fruit, causing it to shrivel +up and greatly diminishing the yield of oil, while the oil itself has +a dark color, and loses its delicate flavor. + +The olive tree in Tuscany generally blossoms in April. By November the +fruit has attained its full size, though not full maturity, and the +olive harvest generally commences then. The fruit, generally speaking, +is gathered as it falls to the ground, either from ripeness or in +windy weather. In some districts, however, and when the crop is short, +the practice is to strip the fruit from the trees early in the season. +When there is a full crop the harvest lasts many months, and may not +be finished till the end of May, as the fruit does not all ripen +simultaneously. + +Oil made early in the season has a deeper color, and is distinguished +by a fruity flavor, with a certain degree of pungency; while as the +season advances it becomes lighter in color, thinner in body, and +milder and sweeter in taste. Oil made toward the close of the harvest +in April or May from extremely ripe fruit is of a very pale straw +color, mild and sweet to the taste, though sometimes, if the fruit has +remained too long on the trees, it may be slightly rancid. Oil very +light in color is much prized in certain countries, notably France, +and hence, if it also possesses good quality, commands a higher price +in the Tuscan markets. + +The fruit of the olive tree varies just as much in quality as does the +grape, according to the species of the tree itself, the nature of the +soil, exposure, and climate of the locality where it grows. Some +varieties of the olive tree largely grown, because thought to be +better suited to the special conditions of some districts, yield a +fruit which imparts a bitter taste to the oil made from it; such oil, +even when otherwise perfect, ranks as a second rate quality. + +The highest quality of oil can only be obtained when the fruit is +perfectly and uniformly sound, well ripened, gathered as soon as it +has dropped from the trees, and crushed immediately with great +attention. Should the fruit remain any time on the ground, +particularly during wet weather, it deteriorates fast and gets an +earthy taste; while if allowed to remain an undue length of time in +the garners it heats, begins to decompose, and will yield only bad +oil. + +The process of making oil is as follows: The fruit is crushed in a +stone mill, generally moved by water power; the pulp is then put into +bags made of fiber, and a certain number of these bags, piled one upon +another, are placed in a press, most frequently worked by hand; when +pressure is applied, the oil flows down into a channel by which it is +conveyed to a receptacle or tank. + +When oil ceases to flow, tepid water is poured upon the bags to carry +off oil retained by the bags. The pulp is then removed from the bags, +ground again in the mill, then replaced in the bags, and pressed a +second time. The water used in the process of making oil must be quite +pure; the mill, press, bags, and vessels sweet and clean, as the least +taint would ruin the quality of the oil produced. + +The oil which has collected in the tank or receptacle just mentioned +is removed day by day, and the water also drained off, as oil would +suffer in quality if left in contact with water; the water also, which +necessarily contains some oil mingled with it, is sent to a deposit +outside, and at some distance from the crushing house, which is called +the "Inferno," where it is allowed to accumulate, and the oil which +comes to the surface is skimmed off from time to time. It is fit only +for manufacturing purposes. + +After the second pressing the olive-pulp is not yet done with; it is +beaten up with water by mechanical agitators moved by water-power, and +then the whole discharged into open-air tanks adjoining the crushing +house. There the crushed olive kernels sink to the bottom, are +gathered up and sold for fuel, fetching about 12 francs per 1,000 +kilos, while the _debris_ of the pulp is skimmed off the surface of +the tank and again pressed in bags, yielding a considerable quantity +of inferior oil, called "olio lavato," or washed oil, which, if +freshly made, is even used for food by the poorer classes. The pulp +then remaining has still further use. It is sold for treatment in +factories by the sulphide of carbon process, and by this method yields +from seven to nine per cent. of oil, of course suitable only for +manufacturing purposes. Only the first two pressings yield oil which +ranks as first quality, subject of course to the condition of the +fruit being unexceptionable. New oil is allowed to rest a while in +order to get rid of sediment; it is then clarified by passing through +clean cotton wool, when it is fit for use. + +The highest quality of olive oil for eating purposes should not only +be free from the least taint in taste or smell, but possessed of a +delicate, appetizing flavor. When so many favorable conditions are +needed as to growth, maturity, and soundness of the fruit, coupled +with great attention during the process of oil-making, it is not to be +wondered at that by no means all or even the greater part of the oil +produced in the most favored districts of Tuscany is of the highest +quality. On the contrary, the bulk is inferior and defective. + +These defective oils are largely dealt in both for home consumption +and export, when price and not quality is the object. + +In foreign countries there is always a market for inferior, defective +olive oil for cooking purposes, etc., provided the price be low. Price +and not quality is the object, so much so that when olive oil is dear, +cotton-seed, ground-nut, and other oils are substituted, which bear +the same relation to good olive oil that butterine and similar +preparations do to real butter. + +The very choicest qualities of pure olive oil are largely shipped from +Leghorn to England, along with the very lowest qualities, often also +adulterated. + +The oil put into Florence flasks is of the latter kind. Many years +back this was not the case, but now it is a recognized fact that +nothing but the lowest quality of oil is put into these flasks; oil +utterly unfit for food, and so bad that it is a mystery to what use it +is applied in England. Importers in England of oil in these flasks +care nothing, however, about quality; cheapness is the only +desideratum. + +The best quality of Tuscan olive oil is imported in London in casks, +bottled there, and bears the name of the importers alone on the label. +There is no difficulty in procuring in England the best Tuscan oil, +which nothing produced elsewhere can surpass; but consumers who wish +to get, and are willing to pay for, the best article must look to the +name and reputation of the importers and the general excellence of all +the articles they sell, which is the best guarantee they can have of +quality. + + * * * * * + + + + +BEESWAX AND ITS ADULTERATIONS. + + +Beeswax is a peculiar waxy substance secreted only by bees, and +consisting of 80.2 per cent. carbon, 13.4 per cent. hydrogen, and 6.4 +per cent. oxygen. It is a mixture of myricine, cerotic acid, and +cerolein, the first of which is insoluble in boiling alcohol, the +second is soluble in hot alcohol and crystallizes out on cooling, +while the third remains dissolved in cold alcohol. + +Although we are unable to produce real beeswax artificially, there are +many imitations which are made use of to adulterate the genuine +article, and their detection is a matter of considerable difficulty. +Huebl says (_Dingl. Jour._, p. 338) that the most reliable method of +estimating the adulteration of beeswax is that proposed by Becker, and +known as the saponification method. + +The quantity of potassic hydrate required to saponify one gramme or 15 +grains of pure beeswax varies from 97 to 107 milligrammes. Other kinds +of wax and its substitutes require in some cases more and in others +less of the alkali. This method would, however, lead to very erroneous +conclusions if applied to a mixture of which some of the constituents +have higher saponification numbers than beeswax and others higher, as +one error would balance the other. + +To avoid this, the quantity of alkali required to saponify the +myricine is first ascertained, and then that required to saturate the +free cerotic acid. In this way two numbers are obtained; and in an +investigation of twenty samples of Austrian yellow beeswax, the author +found these numbers stood to each other almost in the constant ratio +of 1 to 3.70. Although this ratio cannot be considered as definitely +established by so few experiments, it may serve as a guide in judging +of the purity of beeswax. + +The experiment is carried out as follows: 3 or 4 grammes of the wax +that has been melted in water are put in 20 c.c. of neutral 95 per +cent, alcohol, and warmed until the wax melts, when phenolphthaleine +is added, and enough of an alcoholic solution of potash run in from a +burette until on shaking it retains a faint but permanent red color. +The burette used by the author is divided in 0.05 c.c. After adding 20 +c.c. more of a half normal potash solution, it is heated on a water +bath for ¾ hour. Then the uncombined excess of alkali is titrated with +half normal hydrochloric acid. The alcohol must be tested as to its +reaction before using it, and carefully neutralized with the acid of +phenolphthalein. + +To saturate the free acid in 1 gramme of wax requires 19 to 21 +milligrammes of potassic hydrate, while 73 to 76 milligrammes more are +necessary to saponify the myricine ether. The lower numbers in the one +usually occur with low numbers for the other, so that the proportions +remain 1 to 3.6 or 1 to 3.8. + +For comparison he gives the following numbers obtained with one gramme +of the more common adulterants: + + + ----------------+----------+----------+---------+--------+ + | To | To | Total | | + |neutralize| convert |saponifi-| | + | the acid.|the ether.| cation. | Ratio. | + ----------------+----------+----------+---------+--------+ + Japanese wax | 20 | 200 | 220 | 10 | + Carnauba wax | 4 | 75 | 79 | 19 | + Tallow | 4 | 176 | 180 | 44 | + Stearic acid | 195 | 0 | 195 | 0/195 | + Rosin | 110 | 1.6 | 112 | 0.015 | + Paraffine | 0 | 0 | 0 | 0 | + Ceresine | 0 | 0 | 0 | 0 | + Yellow beeswax | 20 | 75 | 95 | 3.75 | + ----------------+----------+----------+---------+--------+ + + +The author deduces the following conclusions as the results of these +investigations: + +1. If the numbers obtained lie between these limits, 19 to 21, 73 to +76, 92 to 97, and 3.6 to 3.8 respectively, it may be assumed that the +beeswax is pure, provided it also corresponds to beeswax in its +physical properties. + +2. If the saponification figures fall below 92 and yet the ratio is +correct, it is adulterated with some neutral substance like paraffine. + +3. If the ratio is above 3.8, it is very probable that Japanese or +carnauba wax or grease has been added. + +4. If the ratio falls below 3.6, stearic acid or resin has been used +as the adulterant. + + * * * * * + + + + +PHENOL IN THE STEM, LEAVES, AND CONES OF PINUS SYLVESTRIS. + +A DISCOVERY BEARING ON THE FLORA OF THE CARBONIFEROUS EPOCH AND THE +FORMATION OF PETROLEUM. + +By A.B. GRIFFITHS, Ph.D., F.C.S. Membre de la Societe Chimique de +Paris, Medallist in Chemistry and Botany, etc. + + +Having found, in small quantities, alcohols of the C_{n}H_{2n-7} +series, last summer, in the stem, acicular leaves, and cones of _Pinus +sylvestris_, I wish in this paper to say a few words on the subject. + +First of all, I took a number of cones, cut them up into small pieces, +and placed them in a large glass beaker, then nearly filled it with +distilled water, and heated to about 80° C., keeping the decoction at +this temperature for about half an hour, I occasionally stirred with a +glass rod, and then allowed it to cool, and filtered. This filtrate +was then evaporated nearly to dryness, when a small quantity of +six-sided prisms crystallized out, which subsequently were found to be +the hydrate of phenol (C_{6}H_{5}HO)_{2}H_{2}O. Its melting point was +found to be 17.2° C. Further, the crystals already referred to were +dissolved in ether, and then allowed to evaporate, when long colorless +needles were obtained, which, on being placed in a dry test tube and +the tube placed in a water bath kept at 42° C., were found to melt; +and on making a careful combustion analysis of these crystals, the +following composition was obtained: + + Carbon 76.6 + Hydrogen 6.4 + Oxygen 17.0 + ----- + 100.0 + +This gives C_{6}H_{6}O, which is the formula for phenol. + +On dissolving some of these crystals in water (excess) and adding +ferric chloride, a beautiful violet color was imparted to the +solution. To another aqueous solution of the crystals was added +bromine water, and a white precipitate was obtained, consisting of +tribromophenol. An aqueous solution of the crystals immediately +coagulated albumen. + +All these reactions show that the phenol occurs in the free state in +the cones of this plant. In the same manner I treated the acicular +leaves, and portions of the stem separately, both being previously cut +up into small pieces, and from both I obtained phenol. + +I have ascertained the relative amount of phenol in each part of the +plant operated upon; by heating the stem with water at 80° C., and +filtering, and repeating this operation until the aqueous filtrate +gave no violet color with ferric chloride and no white precipitate +with bromine water. + +I found various quantities according to the age of the stem. The older +portions yielding as much as 0.1021 per cent, while the young portions +only gave 0.0654 per cent. The leaves yielding according to their age, +0.0936 and 0.0315 per cent.; and the cones also gave varying amounts, +according to their maturity, the amounts varying between 0.0774 and +0.0293. + +Two methods were used in the quantitative estimation of the amount of +phenol. The first was the new volumetric method of M. Chandelon +(_Bulletin de la Societe Chemique de Paris_, July 20, 1882; and +_Deutsch-Americanishe Apotheker Zeitung_, vol. iii., No. 12, September +1, 1882), which I have found to be very satisfactory. The process +depends on the precipitation of phenol by a dilute aqueous solution of +bromine as tribromophenol. The second method was to extract, as +already staled, a known weight of each part of the plant with water, +until the last extract gives _no_ violet color with ferric chloride, +and no white precipitate with the bromine test (which is capable of +detecting in a solution the 1/60000 part of phenol). The aqueous +extract is at this point evaporated, then ether is added, and finally +the ethereal solution is allowed to evaporate. The residue (phenol) is +weighed directly, and from this the percentage can be ascertained. By +this method of extraction, the oil of turpentine, resins, etc., +contained in _Pinus sylvestris_ do not pass into solution, because +they are insoluble in water, even when boiling; what passes into +solution besides phenol is a little tannin, which is practically +insoluble in ether. + +From this investigation it will be seen that phenol exists in various +proportions in the free state in the leaves, stem, and cones of _Pinus +sylvestris_, and as this compound is a product in the distillation of +coal, and as geologists have to a certain extent direct evidence that +the flora of the Carboniferous epoch was essentially crytogamous, the +only phænogamous plants which constituted any feature in "the coal +forests" being the coniferæ, and as coal is the fossil remains of that +gigantic flora which contained phenol, I think my discovery of phenol +in the coniferæ of the present day further supports, from a chemical +point of view, the views of geologists that the coniferæ existed so +far back in the world's history as the Carboniferous age. + +I think this discovery also supports the theory that the origin of +petroleum in nature is produced by moderate heat on coal or similar +matter of a vegetable origin. For we know from the researches of +Freund and Pebal (_Ann. Chem. Pharm._, cxv. 19), that petroleum +contains phenol and its homologues, and as I have found this organic +compound in the coniferæ of to-day, it is probable that petroleum in +certain areas has been produced from the conifers and the flora +generally of some primæval forests. It is stated by numerous chemists +that "petroleum almost always contains solid paraffin" and similar +hydrocarbons. Professors Schorlemmer and Thorpe have found heptane in +Pinus, which heptane yielded primary heptyl-alcohol, and +methyl-pentyl-carbinol, exactly as the heptane obtained from petroleum +does (_Annalen de Chemie_, ccxvii., 139, and clxxxviii., 249; and +_Berichte der Deutschen Chemischen Gesellschaft_, viii., 1649); and, +further, petroleum contains a large number of hydrocarbons which are +found in coal. Again, Mendelejeff, Beilstein, and others (_Bulletin de +la Societe Chemique de Paris_, No. 1, July 5, 1883), have found +hydrocarbons of the-- + + C_{n}H_{2n2+}, C_{n}H_{2n-6}, + +also hydrocarbons of the C_{n}H_{2n} series in the petroleum of Baku, +American petroleum containing similar hydrocarbons. + +I think all these facts give very great weight to the theory that +petroleum is of organic origin. + +On the other hand, Berthelot, from his synthetic production of +hydrocarbons, believes that the interior of the globe contains +alkaline metals in the _free_ state, which yield acetylides in the +presence of carbonic anhydride, which are decomposed into acetylene by +aqueous vapor. But it has been already proved that acetylene may be +polymerized, so as to produce aromatic carbides, or the derivatives of +marsh gas, by the absorption of hydrogen. Berthelot's view, therefore, +is too imaginative; for the presence of _free_ alkaline metals in the +earth's interior is an unproved and very improbable hypothesis. +Byasson states that petroleum is formed by the action of water, +carbonic anhydride, and sulphureted hydrogen upon incandescent iron. +Mendelejeff thinks it is formed by the action of aqueous vapor upon +carbides of iron; and in his article, "Petroleum, the Light of the +Poor" (in this month's--February--number of _Good Words_), Sir Lyon +Playfair, K.C.B., F.R.S., etc., holds opinions similar to those of +Mendelejeff. + +Taking in consideration the facts that solid paraffin is found in +petroleum and is also found in coal, and from my own work that phenol +exists in _Pinus sylvestris_, and has been found by others in coal +which is produced from the decomposition of a flora containing +numerous gigantic coniferæ allied to Pinus, and that petroleum +contains phenol, and each (i.e., petroleum and coal) contains a number +of hydrocarbons common to both, I am inclined to think that the +balance of evidence is in favor of the hypothesis that petroleum has +been produced in nature from a vegetable source in the interior of the +globe. Of course, there can be no practical or direct evidence as to +the origin of petroleum; therefore "theories are the only lights with +which we can penetrate the obscurity of the unknown, and they are to +be valued just as far as they illuminate our path." + +In conclusion, I think that there is a connecting link between the old +pine and fir forest of bygone ages and the origin of petroleum in +nature.--_Chemical News._ + + * * * * * + + + + +THE SCHOOL OF PHYSICS AND CHEMISTRY OF PARIS. + + +Recently we paid a visit to the New Municipal School of Physics and +Chemistry that the city of Paris founded in 1882, and that is now in +operation in the large building of the old Rollin College. This +establishment is one of those that supply a long-felt want of our +time, and we are happy to make it known to our readers. The object for +which it was designed was, in the intention of its founders, to give +young people who have just graduated from the higher primary schools +special instruction which shall be at once scientific and practical, +and which shall fit them to become engineers or superintendents in +laboratories connected with chemical and physical industries. To reach +such a result it has been necessary to give the teaching an +essentially practical character, by permitting the pupils to proceed +of themselves in manipulations in well fitted laboratories. It is upon +this important point that we shall now more particularly dwell; but, +before making known the general mode of teaching, we wish to quote a +few passages from the school's official programme: + + "Many questions and problems, in physics as well as in chemistry, + find their solution only with the aid of mathematics and + mechanics. It therefore became necessary, through lectures + bearing upon the useful branches of mathematics, to supplement + the too limited ideas that pupils brought with them on entering + the school. Mathematics and mechanics are therefore taught here + at the same time with physics and chemistry, but they are merely + regarded in the light of auxiliaries to the latter. + + "The studies extend over three years. Each of the three divisions + (1st, 2d, and 3d years) includes thirty pupils. + + "During the three first semesters, pupils of the same grade + attend lectures and go through manipulations in chemistry, + physics, mathematics, and draughting in common. + + "At the end of the third semester they are divided into 10 + physical and 20 chemical students. + + "From this moment, although certain courses still remain wholly + or partially common to the two categories of pupils (physical and + chemical), the same is no longer the case with regard to the + practical exercises, for the physical students thereafter + manipulate only in the physical laboratories, and the chemical + only in the chemical laboratories; moreover, the manipulations + acquire a greater importance through the time that is devoted to + them. + + "At each promotion the three first semesters are taken up with + general and scientific studies. Technical applications are the + subject of the lectures and exercises of the three last + semesters. At the end of the third year certificates are given to + those pupils who have undergone examination in a satisfactory + manner, and diplomas to such as have particularly distinguished + themselves." + +When pupils have been received at the school, after passing the +necessary examination, their time of working is divided up between +lectures and questionings and different laboratory manipulations. + +The course of lectures on general and applied physics comprises +hydrostatics and heat (Prof. Dommer), electricity and magnetism (Prof. +Hospitalier), and optics and acoustics (Prof. Baille). Lectures on +general chemistry are delivered by Profs. Schultzenberger and +Henninger, on analytical chemistry by Prof. Silva, on chemistry +applied to the industries by Prof. Henninger (for inorganic) and Prof. +Schultzenberger (for organic). The lectures on pure and applied +mathematics and mechanics are delivered by Profs. Levy and Roze. + +[Illustration: GENERAL VIEW OF A LABORATORY AT THE PARIS SCHOOL OF +PHYSICS AND CHEMISTRY.] + +The pupils occupy themselves regularly every day, during half the time +spent at the school, with practical work in analytical and applied +chemistry and physics and general chemistry. This practical work is a +complement to the various lectures, and has reference to what has been +taught therein. Once or twice per week the pupils spend three hours in +a shop devoted to wood and metal working, and learn how to turn, +forge, file, adjust, etc. + +The school's cabinets are now provided with the best instruments for +study, and are daily becoming richer therein. The chemical +laboratories are none the less remarkably organized. In the +accompanying cut we give a view of one of these--the one that is under +the direction of Mr. Schultzenberger, professor of chemistry and +director of the new school. Each pupil has his own place in front of a +large table provided with a stand whereon he may arrange all the +products that he has to employ. Beneath the work-table he has at his +disposal a closet in which to place his apparatus after he is through +using them. Each pupil has in front of him a water-faucet, which is +fixed to a vertical column and placed over a sink. Alongside of this +faucet there is a double gas burner, which may be connected with +furnaces and heating apparatus by means of rubber tubing. A special +hall, with draught and ventilation, is set apart for precipitations by +sulphureted hydrogen and the preparation of chlorine and other +ill-smelling and deleterious gases. The great amount of light and +space provided secure the best of conditions of hygiene to this fine +and vast laboratory, where young people have all the necessary +requisites for becoming true chemists.--_La Nature._ + + * * * * * + + + + +DUST-FREE SPACES.[1] + + [Footnote 1: Lecture to the Royal Dublin Society by Dr. Oliver J. + Lodge, April 2, 1884.] + + +Within the last few years a singular interest has arisen in the +subject of dust, smoke, and fog, and several scientific researches +into the nature and properties of these phenomena have been recently +conducted. It so happened that at the time I received a request from +the secretary of this society to lecture here this afternoon I was in +the middle of a research connected with dust, which I had been +carrying on for some months in conjunction with Mr. J.W. Clark, +Demonstrator of Physics in University College, Liverpool, and which +had led us to some interesting results. It struck me that possibly +some sort of account of this investigation might not be unacceptable +to a learned body such as this, and accordingly I telegraphed off to +Mr. Moss the title of this afternoon's lecture. But now that the time +has come for me to approach the subject before you, I find myself +conscious of some misgivings, and the misgivings are founded upon this +ground: that the subject is not one that lends itself easily to +experimental demonstration before an audience. Many of the experiments +can only be made on a small scale, and require to be watched closely. +However, by help of diagrams and by not confining myself too closely +to our special investigation, but dealing somewhat with the wider +subject of dust in general, I may hope to render myself and my subject +intelligible if not very entertaining. + +First of all, I draw no distinction between "dust" and "smoke." It +would be possible to draw such a distinction, but it would hardly be +in accordance with usage. Dust might be defined as smoke which had +settled, and the term smoke applied to solid particles still suspended +in the air. But at present the term "smoke" is applied to solid +particles produced by combustion only, and "dust" to particles owing +their floating existence to some other cause. This is evidently an +unessential distinction, and for the present I shall use either term +without distinction, meaning by dust or smoke, solid particles +floating in the air. Then "fog"; this differs from smoke only in the +fact that the particles are liquid instead of solid. And the three +terms dust, smoke, and fog, come to much the same thing, only that the +latter term is applied when the suspended particles are liquid. I do +not think, however, that we usually apply the term "fog" when the +liquid particles are pure water; we call it then mostly either mist or +cloud. The name "fog," at any rate in towns, carries with it the idea +of a hideous, greasy compound, consisting of smoke and mist and +sulphur and filth, as unlike the mists on a Highland mountain as a +country meadow is unlike a city slum. Nevertheless, the finest cloud +or mist that ever existed consists simply of little globules of water +suspended in air, and thus for our present purpose differs in no +important respect from fog, dust, and smoke. A cloud or mist is, in +fact, fine water-dust. Rain is coarse water-dust formed by the +aggregation of smaller globules, and varying in fineness from the +Scotch mist to the tropical deluge. It has often been asked how it is +that clouds and mists are able to float about when water is so much +heavier (800 times heavier) than air. The answer to this is easy. It +depends on the resistance or viscosity of fluids, and on the smallness +of the particles concerned. Bodies falling far through fluids acquire +a "terminal velocity," at which they are in stable equilibrium--their +weight being exactly equal to the resistance--and this terminal +velocity is greater for large particles than for small; consequently +we have all sorts of rain velocity, depending on the size of the +drops; and large particles of dust settle more quickly than small. +Cloud-spherules are falling therefore, but falling very slowly. + +To recognize the presence of dust in air there are two principal +tests; the first is, the obvious one of looking at it with plenty of +light, the way one is accustomed to look for anything else; the other +is a method of Mr. John Aitken's, viz., to observe the condensation of +water vapor. + +Take these in order. When a sunbeam enters a darkened room through a +chink, it is commonly said to be rendered visible by the motes or dust +particles dancing in it; but of course really it is not the motes +which make the sunbeam visible, but the sunbeam the motes. A dust +particle is illuminated like any other solid screen, and is able to +send a sufficient fraction of light to our eyes to render itself +visible. If there are no such particles in the beam--nothing but +clear, invisible air--then of course nothing is seen, and the beam +plunges on its way quite invisible to us unless we place our eyes in +its course. In other words, to be visible, light must enter the eye. +(A concentrated beam was passed through an empty tube, and then +ordinary air let in.) + +The other test, that of Mr. Aitken, depends on the condensation of +steam. When a jet of steam finds itself in dusty air, it condenses +around each dust particle as a nucleus, and forms the white visible +cloud popularly called steam. In the absence of nuclei Mr. Aitken has +shown that the steam cannot condense until it is highly +supersaturated, and that when it does it condenses straight into +rain--that is, into large drops which fall. The condensation of steam +is a more delicate test for dust than is a beam of light. A curious +illustration of the action of nuclei in condensing moisture has just +occurred to me, in the experiment--well known to children--of writing +on a reasonably clean window-pane with, say, a blunt wooden point, and +then breathing on the glass; the condensation of the breath renders +the writing legible. No doubt the nuclei are partially wiped away by +the writing, and the moisture will condense into larger drops with +less light-scattering power along the written lines than over the +general surface of the pane where the nuclei are plentiful, and the +drops therefore numerous and minute. Mr. Aitken points out that if the +air were ever quite dustless, vapor could not condense, but the air +would gradually get into a horribly supersaturated condition, soaking +all our walls and clothes, dripping from every leaf, and penetrating +everywhere, instead of falling in an honest shower, against which +umbrellas and slate roofs are some protection. But let us understand +what sort of dust it is which is necessary for this condensing +process. It is not the dust and smoke of towns, it is not the dust of +a country road; all such particles as these are gross and large +compared with those which are able to act as condensers of moisture. +The fine dust of Mr. Aitken exists everywhere, even in the upper +regions of the atmosphere; many of its particles are of +ultra-microscopic fineness, one of them must exist in every raindrop, +nay, even in every spherule of a mist or cloud, but it is only +occasionally that one can find them with the microscope. It is to such +particles as these that we owe the blue of the sky, and yet they are +sufficiently gross and tangible to be capable of being filtered out of +the air by a packed mass of cotton-wool. Such dust as this, then, we +need never be afraid of being without. Without it there could be no +rain, and existence would be insupportable, perhaps impossible; but it +is not manufactured in towns; the sea makes it; trees and wind make +it; but the kind of dust made in towns rises only a few hundred yards +or so into the atmosphere, floating as a canopy or pall over those +unfortunate regions, and sinks and settles most of it as soon as the +air is quiet, but scarcely any of it ever rises into the upper regions +of the atmosphere at all. + +Dust, then, being so universally prevalent, what do I mean by +dust-free spaces? How are such things possible? And where are they to +be found? In 1870 Dr. Tyndall was examining dusty air by means of a +beam of light in which a spirit-lamp happened to be burning, when he +noticed that from the flame there poured up torrents of apparently +thick black smoke. He could not think the flame was really smoky, but +to make sure he tried, first a Bunsen gas flame and then a hydrogen +flame. They all showed the same effect, and smoke was out of the +question. He then used a red-hot poker, a platinum wire ignited by an +electric current, and ultimately a flask of hot water, and he found +that from all warm bodies examined in dusty air by a beam of light the +upstreaming convection currents were dark. Now, of course smoke would +behave very differently. Dusty air itself is only a kind of smoke, and +it looks bright, and the thicker the smoke the brighter it looks; the +blackness is simply the utter absence of smoke; there is nothing at +all for the light to illuminate, accordingly we have the blankness of +sheer invisibility. Here is a flame burning under the beam, and, to +show what real smoke looks like, I will burn also this spirit lamp +filled with turpentine instead of alcohol. _Why_ the convention +currents were free from dust was unknown; Tyndall thought the dust was +burnt and consumed; Dr. Frankland thought it was simply evaporated. + +In 1881 Lord Rayleigh took the matter up, not feeling satisfied with +these explanations, and repeated the experiment very carefully. He +noted several new points, and hit on the capital idea of seeing what a +cold body did. From the cold body the descending current was just as +dark and dust-free as from a warm body. Combustion and evaporation +explanations suffered their death-blow. But he was unable to suggest +any other explanation in their room, and so the phenomenon remained +curious and unexplained. + +In this state Mr. Clark and I took the matter up last summer, and +critically examined all sorts of hypotheses that suggested themselves, +Mr. Clark following up the phenomena experimentally with great +ingenuity and perseverance. One hypothesis after another suggested +itself, seemed hopeful for a time, but ultimately had to be discarded. +Some died quickly, others lingered long. In the examination of one +electrical hypothesis which suggested itself we came across various +curious phenomena which we hope still to follow up.[2] It was some +months before what we now believe to be the true explanation began to +dawn upon us. Meanwhile we had acquired various new facts, and first +and foremost we found that the dark plane rising from a warm body was +only the upstreaming portion of a dust-free _coat_ perpetually being +renewed on the surface of the body. Let me describe the appearance and +mode of seeing it by help of a diagram. (For full description see +_Philosophical Magazine_ for March, 1884.) + + [Footnote 2: For instance, the electric properties of crystals + can be readily examined in illuminated dusty air; the dust grows + on them in little bushes and marks out their poles and neutral + regions, without any need for an electrometer. Magnesia smoke + answers capitally.] + +Surrounding all bodies warmer than the air is a thin region free from +dust, which shows itself as a dark space when examined by looking +along a cylinder illuminated transversely, and with a dark background. +At high temperatures the coat is thick; at very low temperatures it is +absent, and dust then rapidly collects on the rod. On a warm surface +only the heavy particles are able to settle--there is evidently some +action tending to drive small bodies away. An excess of temperature of +a degree or two is sufficient to establish this dust-free coat, and it +is easy to see the dust-free plane rising from it. The appearances may +also be examined by looking along a cylinder _toward_ the source of +light, when the dust-free spaces will appear brighter than the rest. A +rod of electric light carbon warmed and fixed horizontally across a +bell-jar full of dense smoke is very suitable for this experiment, and +by means of a lens the dust-free regions may be thus projected on to a +screen. Diminished pressure makes the coat thicker. Increased pressure +makes it thinner. In hydrogen it is thicker, and in carbonic acid +thinner, than in air. We have also succeeded in observing it in +liquids--for instance, in water holding fine rouge in suspension, the +solid body being a metal steam tube. Quantitative determinations are +now in progress. + +[Illustration: Fig. 1 and Fig. 2] + +Fig. 1 shows the appearance when looking along a copper or carbon rod +laterally illuminated; the paths of the dust particles are roughly +indicated. Fig. 2 shows the coat on a semi-cylinder of sheet copper +with the concave side turned toward the light. + +It is difficult to give the full explanation of the dust free spaces +in a few words, but we may say roughly that there is a molecular +bombardment from all warm surfaces by means of which small suspended +bodies get driven outward and kept away from the surface. It is a sort +of differential bombardment of the gas molecules on the two faces of a +dust particle somewhat analogous to the action on Mr. Crookes' +radiometer vanes. Near cold surfaces the bombardment is very feeble, +and if they are cold enough it appears to act toward the body, driving +the dust inward--at any rate, there is no outward bombardment +sufficient to keep the dust away, and bodies colder than the +atmosphere surrounding them soon get dusty. Thus if I hold this piece +of glass in a magnesium flame, or in a turpentine or camphor flame, it +quickly gets covered with smoke--white in the one case, black in the +other. I take two conical flasks with their surfaces blackened with +camphor black, and filling one with ice, the other with boiling water, +I cork them and put a bell jar over them, under which I burn some +magnesium wire; in a quarter of an hour or so we find that the cold +one is white and hoary, the hot one has only a few larger specks of +dust on it, these being of such size that the bombardment was unable +to sustain their weight, and they have settled by gravitation. We thus +see that when the air in a room is warmer than the solids in it--as +will be the case when stoves, gas-burners, etc., are used--things will +get very dusty; whereas when walls and objects are warmer than the +air--as will be the case in sunshine, or when open fireplaces are +used, things will tend to keep themselves more free from dust. Mr. +Aitken points out that soot in a chimney is an illustration of this +kind of deposition of dust; and as another illustration it strikes me +as just possible that the dirtiness of snow during a thaw may be +partly due to the bombardment on to the cold surface of dust out of +the warmer air above. Mr. Aitken has indeed suggested a sort of +practical dust or smoke filter on this principle, passing air between +two surfaces--one hot and one cold--so as to vigorously bombard the +particles on to the cold surface and leave the air free. + +But we have found another and apparently much more effectual mode of +clearing air than this. We do it by discharging electricity into it. +It is easily possible to electrify air by means of a point or flame, +and an electrified body has this curious property, that the dust near +it at once aggregates together into larger particles. It is not +difficult to understand why this happens; each of the particles +becomes polarized by induction, and they then cling together end to +end, just like iron filings near a magnet. A feeble charge is often +sufficient to start this coagulating action. And when the particles +have grown into big ones, they easily and quickly fall. A stronger +charge forcibly drives them on to all electrified surfaces, where they +cling. A fine water fog in a bell jar, electrified, turns first into a +coarse fog or Scotch mist, and then into rain. Smoke also has its +particles coagulated, and a space can thus be cleared of it. I will +illustrate this action by making some artificial fogs in a bell-jar +furnished with a metal point. First burn some magnesium wire, +electrify it by a few turns of this small Voss machine, and the smoke +has become snow; the particles are elongated, and by pointing to the +charged rod indicate the lines of electrostatic force very +beautifully; electrify further, and the air is perfectly clear. Next +burn turpentine, and electrify gently; the dense black smoke +coagulates into black masses over an inch long; electrify further, and +the glass is covered with soot, but the air is clear. Turpentine smoke +acts very well, and can be tried on a larger scale; a room filled with +turpentine smoke, so dense that a gas-light is invisible inside it, +begins to clear in a minute or two after the machine begins to turn, +and in a quarter of an hour one can go in and find the walls thickly +covered with stringy blacks, notably on the gas-pipes and everything +most easily charged by induction. Next fill a bell-jar full of steam, +and electrify, paying attention to insulation of the supply point in +this case. In a few seconds the air looks clear, and turning on a beam +of light we see the globules of water dancing about, no longer fine +and impalpable, but separately visible and rapidly falling. Finally, +make a London fog by burning turpentine and sulphur, adding a little +sulphuric acid, either directly as vapor or indirectly by a trace of +nitric oxide, and then blowing in steam. Electrify, and it soon +becomes clear, although it lakes a little longer than before; and on +removing the bell-jar we find that even the smell of SO2 has +disappeared, and only a little vapor of turpentine remains. Similarly +we can make a Widnes fog by sulphureted hydrogen, chlorine, sulphuric +acid, and a little steam. Probably the steam assists the clearing when +gases have to be dealt with. It may be possible to clear the air of +tunnels by simply discharging electricity into the air--the +electricity being supplied by Holtz machines, driven say by small +turbines--a very handy form of power, difficult to get out of order. +Or possibly some hydro-electric arrangement might be devised for the +locomotive steam to do the work. I even hope to make some impression +on a London fog, discharging from lightning conductors or captive +balloons carrying flames, but it is premature to say anything about +this matter yet. I have, however, cleared a room of smoke very quickly +with a small hand machine. + +It will naturally strike you how closely allied these phenomena must +be to the fact of popular science that "thunder clears the air." Ozone +is undoubtedly generated by the flashes, and may have a beneficial +effect, but the dust-coagulating and dust-expelling power of the +electricity has a much more rapid effect, though it may not act till +the cloud is discharged. Consider a cloud electrified slightly; the +mists and clouds in its vicinity begin to coagulate, and go on till +large drops are formed, which may be held up by electrical action, the +drops dancing from one cloud to another and thus forming the very +dense thunder cloud. The coagulation of charged drops increases the +potential, as Prof. Tait points out, until at length--flash--the cloud +is discharged, and the large drops fall in a violent shower. Moreover, +the rapid excursion to and fro of the drops may easily have caused +them to evaporate so fast as to freeze, and hence we may get hail. + +While the cloud was electrified, it acted inductively on the earth +underneath, drawing up an opposite charge from all points, and thus +electrifying the atmosphere. When the discharge occurs this +atmospheric electrification engages with the earth, clearing the air +between, and driving the dust and germs on to all exposed surfaces. In +some such way also it may be that "thunder turns milk sour," and +exerts other putrefactive influences on the bodies which receive the +germs and dust from the air. + +But we are now no longer on safe and thoroughly explored territory. I +have allowed myself to found upon a basis of experimental fact, a +superstructure of practical application to the explanation of the +phenomena of nature and to the uses of man. The basis seems to me +strong enough to bear most of the superstructure, but before being +sure it will be necessary actually to put the methods into operation +and to experiment on a very large scale. I hope to do this when I can +get to a suitable place of operation. Liverpool fogs are poor affairs, +and not worth clearing off. Manchester fogs are much better and more +frequent, but there is nothing to beat the real article as found in +London, and in London if possible I intend to rig up some large +machines and to see what happens. The underground railway also offers +its suffocating murkiness as a most tempting field for experiment, and +I wish I were able already to tell you the actual result instead of +being only in a position to indicate possibilities. Whether anything +comes of it practically or not, it is an instructive example of how +the smallest and most unpromising beginnings may, if only followed up +long enough, lead to suggestions for large practical application. When +we began the investigation into the dust-free spaces found above warm +bodies, we were not only without expectation, but without hope or idea +of any sort, that anything was likely to come of it; the phenomenon +itself possessed its own interest and charm. + +And so it must ever be. The devotee of pure science never has +practical developments as his primary aim; often he not only does not +know, but does not in the least care whether his researches will ever +lead to any beneficial result. In some minds this passive ignoring of +the practical goes so far as to become active repulsion; so that some +singularly biased minds will not engage in anything which seems likely +to lead to practical use. I regard this as an error, and as the sign +of a warped judgment, for after all man is to us the most important +part of nature; but the system works well nevertheless, and the +division of labor accomplishes its object. One man investigates nature +impelled simply by his own genius, and because he feels he cannot help +it; it never occurs to him to give a reason for or to justify his +pursuits. Another subsequently utilizes his results, and applies them +to the benefit of the race. Meanwhile, however, it may happen that the +yet unapplied and unfruitful results evoke a sneer, and the question: +"Cui bono?" the only answer to which question seems to be: "No one is +wise enough to tell beforehand what gigantic developments may not +spring from the most insignificant fact." + + * * * * * + + + + +TELEPHONY AND TELEGRAPHY ON THE SAME WIRES SIMULTANEOUSLY. + + +For the last eighteen months a system has been in active operation in +Belgium whereby the ordinary telegraph wires are used to convey +telephonic communications at the same time that they are being +employed in their ordinary work of transmitting telegraphic messages. +This system, the invention of M. Van Rysselberghe, whose previous +devices for diminishing the evil effects of induction in the telephone +service will be remembered, has lately been described in the _Journal +Telegraphique_ of Berne, by M.J. Banneux of the Belgian Telegraph +Department. Our information is derived from this article and from +others by M. Hospitalier. + +The method previously adopted by Van Rysselberghe, to prevent +induction from taking place between the telegraph wires and those +running parallel to them used for telephone work, was briefly as +follows: The system of sending the dots and dashes of the +code--usually done by depressing and raising a key which suddenly +turns on the current and then suddenly turns it off--was modified so +that the current should rise gradually and fall gradually in its +strength by the introduction of suitable resistances. These were +introduced into the circuit at the moment of closing or opening by a +simple automatic arrangement worked exactly as before by a key. The +result, of the gradual opening and gradual closing of the circuit was +that the current attained its full strength gradually instead of +suddenly, and died away also gradually. And as induction from one wire +to another depends not on the strength of the current, but on the rate +at which the strength changes, this very simple modification had the +effect of suppressing induction. Later Van Rysselberghe changed these +arrangements for the still simpler device of introducing permanently +into the circuit either condensers or else electro-magnets having a +high coefficient of self-induction. These, as is well known to all +telegraphic engineers, retard the rise or fall of an electric current; +they fulfill the conditions required for the working of Van +Rysselberghe's method better than any other device. + +Having got thus far in his devices for destroying induction from one +line to another, Van Rysselberghe saw that, as an immediate +consequence, it might be concluded that, if the telegraph currents +were thus modified and graduated so that they produced no induction in +a neighboring telephone line, they would produce no sound in the +telephone if that instrument were itself joined up in the telegraph +line. And such was found to be case. Why this is so will be more +readily comprehended if it be remembered that a telephone is sensitive +to the changes in the strength of the current if those changes occur +with a frequency of some hundreds or in some cases thousands of times +_per second_. On the other hand, currents vibrating with such rapidity +as this are utterly incompetent to affect the moving parts of +telegraphic instruments, which cannot at the most be worked so as to +give more than 200 to 800 separate signals _per minute_. + +[Illustration: Fig. 1] + +[Illustration: Fig. 2] + +The simplest arrangement for carrying out this method is shown in Fig. +1, which illustrates the arrangements at one end of a line. M is the +Morse key for sending messages, and is shown as in its position of +rest for receiving. The currents arriving from the line pass first +through a "graduating" electromagnet, E2, of about 500 ohms +resistance, then through the key, thence through the electromagnet, R, +of the receiving Morse instrument, and so to the earth. A condenser, +C, of 2 microfarads capacity is also introduced between the key and +earth. There is a second "graduating" electromagnet, E1, of 500 ohms +resistance introduced between the sending battery, B, and the key. +When the key, M, is depressed in order to send a signal, the current +from the battery must charge the condenser, C, and must magnetize the +cores of the two electromagnets, E1 and E2, and is thereby retarded in +rising to its full strength. Consequently no sound is heard in a +telephone, T, inserted in the line-circuit. Neither the currents which +start from one end nor those which start from the other will affect +the telephones inserted in the line. And, if these currents do not +affect telephones in the actual line, it is clear that they will not +affect telephones in neighboring lines. Also the telephones so +inserted in the main line might be used for speaking to one another, +though the arrangement of the telephones in the same actual line would +be inconvenient. Accordingly M. Van Rysselberghe has devised a further +modification in which a separate branch taken from the telegraph line +is made available for the telephone service. To understand this +matter, one other fact must be explained. Telephonic conversation can +be carried on, even though the actual metallic communication be +severed by the insertion of a condenser. Indeed, in quite the early +days of the Bell telephone, an operator in the States used a condenser +in the telegraph line to enable him to talk through the wire. If a +telephonic set at T1 (Fig. 2) communicate through the line to a +distant station, T2, through a condenser, C, of a capacity of half a +microfarad, conversation is still perfectly audible, provided the +telephonic system is one that acts by induction currents. And since in +this case the interposition of the condenser prevents any continuous +flow of current through the line, no perceptible weakening will be +felt if a shunt S, of as high a resistance as 500 ohms and of great +electromagnetic rigidity, that is to say, having a high coefficient of +self-induction, be placed across the circuit from line to earth. In +this, as well as in the other figures, the telephones indicated are of +the Bell pattern, and if set up as shown in Fig. 2, without any +battery, would be used both as transmitter and receiver on Bell's +original plan. But as a matter of fact any ordinary telephone might be +used. In practice the Bell telephone is not advantageous as a +transmitter, and has been abandoned except for receiving; the Blake, +Ader, or some other modification of the microphone being used in +conjunction with a separate battery. To avoid complication in the +drawings, however, the simplest case is taken. And it must be +understood that instead of the single instrument shown at T1 or T2, a +complete set of telephonic instruments, including transmitter, +battery, induction-coil, and receiver or receivers, may be +substituted. And if a shunt, S, of 500 ohms placed across the circuit +makes no difference to the talking in the telephones because of the +interposition of the separating condenser, C, it will readily be +understood that a telegraphic system properly "graduated," and having +also a resistance of 500 ohms, will not affect the telephones if +interposed in the place of S. This arrangement is shown in Fig. 3, +where the "graduated" telegraph-set from Fig. 1 is intercalated into +the telephonic system of Fig. 2, so that both work simultaneously, but +independently, through a single line. The combined system at each end +of the line will then consist of the telephone-set, T1, the telegraph +instruments (comprising battery, B1, key, M1 and Morse receiver, R1), +the "graduating" electromagnets, E1, and E2, the "graduating" +condenser, C1, and the "separating" condenser, C2. It was found by +actual experiments that the same arrangement was good for lines +varying from 28 to 200 miles in length. A single wire between +Brussels, Ghent, and Ostend is now regularly employed for transmission +by telegraph of the ordinary messages and of the telemeteorographic +signals between the two observatories at those places, and by +telephone of verbal simultaneous correspondence, for one of the Ghent +newspapers. A still more interesting arrangement is possible, and is +indicated in Fig. 4. Here a separating condenser is introduced at the +intermediate station at Ghent between earth and the line, which is +thereby cut into two independent sections for telephonic purposes, +while remaining for telegraphic purposes a single undivided line +between Brussels and Ostend. Brussels can telegraph to Ostend, or +Ostend to Brussels, and at the same time the wire can be used to +telephone between Ghent and Ostend, or between Ghent and Brussels, or +both sections may be simultaneously used. + +[Illustration: Fig. 3] + +[Illustration: Fig. 4] + +It would appear, then, that M. Van Rysselberghe has made an advance of +very extraordinary merit in devising these combinations. We have seen +in recent years how duplex telegraphy superseded single working, only +to be in turn superseded by the quadruplex system. Multiplex +telegraphy of various kinds has been actively pursued, but chiefly on +the other side of the Atlantic rather than in this country, where our +fast-speed automatic system has proved quite adequate hitherto. +Whether we shall see the adoption in the United Kingdom of Van +Rysselberghe's system is, however, by no means certain. The essence of +it consists in retarding the telegraphic signals to a degree quite +incompatible with the fast-speed automatic transmission of telegraphic +messages in which our Post Office system excels. We are not likely to +spoil our telegraphic system for the sake of simultaneous telephony, +unless there is something to be gained of much greater advantage than +as yet appears.--_Nature._ + + * * * * * + + + + +THE ELECTRIC MARIGRAPH. + + +For registering the height of the tide at every instant, hydrographic +services generally adopt quite a simple marigraph. The apparatus +consists in principle of a counterpoised float whose rising and +falling motion, reduced to a tenth, by means of a system of toothed +wheels, is transmitted to a pencil which moves in front of a vertical +cylinder. This cylinder itself moves around its axis by means of a +clockwork mechanism, and accomplishes one entire revolution every +twenty-four hours. By this means is obtained a curve of the tide in +which the times are taken for abscisses and the heights of the sea for +ordinates. However little such marigraphs have had to be used, great +defects have been recognized in them. When we come to change the sheet +on the cylinder (and such change should be made at least once every +fifteen days), there is an interruption in the curve. It is necessary, +besides, to perform office work of the most detailed kind in order to +refer to the same origin all these curves, which are intercrossed and +often superposed in certain parts upon the original sheet. In order to +render such a disentanglement possible, it is indispensable to mark by +hand, at least once every twenty-four hours, upon each curve, the date +of the day corresponding to it. It is equally useful to verify the +exactness of the indications given by the apparatus by making readings +several times a day on a scale of tides placed alongside of the float. +Nine times out of ten the rise of the waves renders such readings very +difficult and the control absolutely illusory. + +All these conditions united, as well as others that we neglect in this +brief discussion, necessitate a surveillance at every instant. The +result is that these marigraphs must be installed in a special +structure, very near the bank, so as to be reachable at all times, and +that the indications that they give are always vitiated by error, +since the operation is performed upon a level at which are exerted +disturbing influences that are not found at a kilometer at sea. It +were to be desired that the float could be isolated by placing it a +certain distance from the shore, and transmit its indications, by +meant of a play of currents, to a registering apparatus situated upon +_terra firma_. + +In the course of one of his lectures published in the December number +(1883) of the _Elektrotechnische Zeitschrift_, Mr. Von Hefner-Alteneck +tells us that such a desideratum has been supplied by the firm of +Siemens & Halske. This marigraph, constructed on an order of the +German Admiralty, gives the level of the sea every ten minutes with an +approximation of 0.12 per cent., and that too for a difference of 8 +meters between the highest and lowest sea. The apparatus consists, as +we said above, of a float and registering device, connected with each +other by means of a cable. This latter is formed of three ordinary +conductors covered with gutta percha and surrounded with a leaden +sheath, which latter is itself protected against accident by means of +a strong covering of iron wire and hemp. The return is effected +through the earth. We shall enter into details concerning each of +these two apparatus in-succession, by beginning with the float, of +which Fig. 1 gives a general view, and Fig. 2 a diagrammatic sketch. +The float moves in a cast iron cylinder, having at its lower part a +large number of apertures of small diameter, so that the motion of the +waves does not perceptibly influence the level of the water in the +interior of the cylinder. It is attached to a copper ribbon, B, whose +other extremity is fixed to the drum, T. The ribbon winds around the +latter in the rising motion of the float, owing to a spiral spring +arranged so as to act upon the drum. The tension of this spring goes +on increasing in measure as the float descends. + +[Illustration: FIG. 1.--FLOAT OF SIEMENS AND HALSKE'S MARIGRAPH.] + +[Illustration: FIG. 2.] + +This difference in tension is utilized for balancing at every instant +the weight of the ribbon unwound, and thus causing the float to +immerse itself in the water to a constant degree. The ribbon, B, is +provided throughout its length with equidistant apertures that exactly +correspond to tappets that project from the circumference of the +wheel, R. When the float moves its position, the wheel, R, begins to +turn and carries along in doing so the pinion, w, which revolves +over the toothed wheels, s1, s2, and s3. The thickness of w +is equal to that of the three wheels, s1, s2, and s3, and a +special spring secures at every instant an intimate contact between +the pinion and the said wheels. These latter are insulated from each +other and from the axle upon which they are keyed, and communicate, +each of them, with conductors, I., II., and III. They are so formed +and mounted that, in each of them, the tooth in one corresponds to the +interspace in the two others. As a result of this, in the motion of +the pinion, w, the latter is never in contact with but one of the +three wheels, s1, s2, and s3. + +If we add that the lines, I., II., and III. are united at the shore +station with one of the poles of a pile whose other pole is connected +with the earth, and that w communicates with the earth through the +intermedium of R, and the body of the apparatus, it is easy to see +that in a vertical motion of the float in one direction we shall have +currents succeeding each other in the order I., II., III., I., II., +etc., while the order will become III., II., I., III., II., etc., if +the direction of the float's motion happen to change. + +[Illustration: FIG. 3.] + +[Illustration: FIG. 4.] + +In order to understand how a variation in currents of this kind can be +applied in general for producing a rotary motion in the two +directions, it will only be necessary to refer to Figs. 3 and 4. The +conductors, L1, L2, and L3 communicate with the bobbins of +three electromagnets, E1, E2, and E3, whose poles are bent at +right angles to the circumference of the wheel, R. There is never but +one pole opposite a tooth. The distance between two consecutive poles +must be equal to a multiple of the pitch increased (Fig. 3) or +diminished (Fig. 4) by one-third thereof. It will be seen upon a +simple inspection of the figures that R will revolve in the direction +of the hands of a watch when the currents follow the order L1, +L2, L3, etc., in the case shown in Fig. 3, while in the case +shown in Fig. 4 the rotary motion will be in the contrary direction +for this same order of currents. But, in both cases, and this is the +important point, the direction of rotation changes when the order in +the succession of currents; is inverted. Fig. 6 gives a perspective +view of the registering apparatus, and Fig. 5 represents it in +diagram. It will be at once seen that, the toothed wheel, r, is +reduced to its simplest expression, since it consists of two teeth +only. The electro-magnets are arranged at an angle of 120°, and for a +change of current the wheel, r, describes an angle of 60°, that is +to say, a sixth of a circumference. The motion of r is transmitted, by +means of the pinion, d, and the wheel, e, to the wheel, T. For a +one-meter variation in level the wheel, T, makes one complete +revolution. It is divided into 100 equal parts, and each arc therefore +corresponds to a difference of one centimeter in the level, and +carries, engraved in projection, the corresponding number. As a +consequence, there is upon the entire circumference a series of +numbers from to 99. The axle upon which the wheel, T, is keyed is +prolonged, on the side opposite e, by a threaded part, a, which +actuates a stylet, g. This latter is held above by a rod, I, which +is connected with a fork movable around a vertical axis, shown in Fig. +6. The rectilinear motion of g is 5 mm. for a variation of one meter +in level. Its total travel is consequently 40 mm. The sheet of paper +upon which the indications are taken, and which is shown of actual +size in Fig. 7, winds around the drum, P, and receives its motion from +the cylinder, W. This sheet is covered throughout its length with fine +prepared paper that permits of taking the imprints by impression. + +[Illustration: FIG. 5] + +[Illustration: FIG. 6--RECEIVER OF SIEMENS AND HALSKE'S MARIGRAPH.] + +[Illustration: FIG. 7] + +This stated, the play of the apparatus may be easily understood. Every +ten minutes a regulating clock closes the circuit of the local pile, +B2, and establishes a contact at C. The electro-magnet, E4, +attracts its armature, and thus acts upon the lever, h, which +presses the sheet of paper against the stylet in front that serves to +mark the level of the lowest waters, and against the stylet, g, and +the wheels, T and Z. In falling back, the lever, h, causes the +advance, by one notch, of the ratchet wheel that is mounted at the +extremity of the cylinder W, and thus displaces the sheet of paper a +distance of 5 mm. The wheel, Z, carries engraved in projection upon +its circumference the hours in Roman figures, and moves forward one +division every 60 minutes. The motion of this wheel is likewise +controlled by the cylinder, W. + +It will be seen upon referring to Fig. 7, that there is obtained a +very sharp curve marked by points. We have a general view on +considering the curve itself, and the height in meters is read +directly. The fractions of a meter, as well as the times, are in the +margin. Thus, at the point, a, the apparatus gives at 3 o'clock and +20 minutes a height of tide of 4.28 m. above the level of the lowest +water. + +This apparatus might possibly operate well, and yet not be in accord +with the real indications of the float, so it has been judged +necessary to add to it the following control. + +Every time the float reaches 3 meters above the level of the lowest +tide, the circuit of one of the lines that is open at this moment +(that of line I, for example) closes at C (Fig. 2), into this new +circuit there is interposed a considerable resistance, W, so that the +energy of the current is weakened to such a point that it in nowise +influences the normal travel of the wheel, r. At the shore station, +there is placed in deviation a galvanoscope, K, whose needle is +deflected. It suffices, then, to take datum points upon the +registering apparatus, upon the wheel, T, and the screw, a, in such +a way as to ascertain the moment at which the stylet, g, is going to +mark 3 meters. At this moment the circuit of the galvanoscope, K, is +closed, and we ascertain whether there is a deviation of the needle. + +As the sea generally rises to the height of 3 meters twice a day, it +is possible to control the apparatus twice a day, and this is fully +sufficient. + +It always belongs to practice to judge of an invention. Mr. Von +Hefner-Alteneck tells us that two of these apparatus have been set +up--one of them a year ago in the port of Kiel, and the other more +recently at the Isle of Wangeroog in the North Sea--and that both have +behaved excellently since the very first day of their installation. We +shall add nothing to this, since it is evidently the best eulogium +that can be accorded them.--_La Lumiere Electrique._ + + * * * * * + + + + +DELUNE & CO.'S SYSTEM OF LAYING UNDERGROUND CABLES. + + +In recent times considerable attention has been paid to the subject of +laying telegraph cables underground, and various methods have been +devised. In some cases the cables have been covered with an armor of +iron, and in others they have been inclosed in cast-iron pipes. For +telephonic service they are generally inclosed in leaden tubes. What +this external envelope shall be that is to protect the wires from +injury is a question of the highest importance, since not only the +subject of protection is concerned, but also that of cost. It is +therefore interesting to note the efforts that are being made in this +line of electric industry. + +[Illustration: FIG. 1. Section of the Pipe Open.] + +[Illustration: FIG. 2. Section of the Pipe Closed.] + +Messrs. Delune & Co. have recently taken out a patent for an +arrangement consisting of pipes made of beton. The annexed cuts, +borrowed from _L'Electricite_, represent this new system. The pipes, +which are provided with a longitudinal opening, are placed end to end +and coupled with a cement sleeve. The cables are put in place by +simply unwinding them as the work proceeds, and thus all that traction +is done away with that they are submitted to when cast iron pipes are +used. When once the cables are in place the longitudinal opening is +stopped up with cement mortar, and in this way a very tight conduit is +obtained whose hardness increases with time. The value of the system +therefore depends, as in all cement work, on the care with which the +manufacturing is done. + +Experiments have been made with the system at Toulouse, by the +Minister of Post Offices and Telegraphs, and at Lyons, by the General +Society of Telephones. Here, as with all similar questions, no opinion +can be pronounced until after a prolonged experience. But we cannot +help setting forth the advantages that the system offers. These are, +in the first place, a saving of about 50 per cent. over iron pipe, and +in the second, a better insulation, and consequently a better +protection of the currents against all kinds of disturbance, since a +non-conducting mass of cement is here substituted for metal. + + * * * * * + + + + +ELECTRICITY APPLIED TO HORSE-SHOEING. + + +"There is nothing new but what has been forgotten," said Marie +Antoinette to her milliner, Mdlle. Bertin, and what is true of fashion +is also somewhat so of science. Shoeing restive horses by the aid of +electricity is not new, experiments thereon having been performed as +long ago as 1879 by Mr. Defoy, who operated with a small magneto +machine. + +But the two photographs reproduced in Figs. 1 and 2 have appeared to +us curious enough to be submitted to our readers, as illustrating Mr. +Defoy's method of operating with an unruly animal. + +[Illustration: FIG. 1.--THE HORSE RECEIVING THE CURRENT.] + +The battery used was a small Grenet bichromate of potash pile, which +was easy to graduate on account of the depth to which the zinc could +be immersed. This pile was connected with the inductor of a small +Ruhmkorff coil, whose armature was connected with a snaffle-bit placed +in the horse's mouth. + +[Illustration: FIG. 2.--THE HORSE CONQUERED.] + +This bit was arranged as follows (Fig. 3): The two conductors, which +were uncovered for a length of about three centimeters at their +extremity, were placed opposite each other on the two joints of the +snaffle, and about five or six centimeters apart. The mouth-pieces of +the bit had previously been inclosed in a piece of rubber tubing, in +order to insulate the extremities of the conductors and permit the +recomposition of the current to take place through the animal's tongue +or palate. + +Each of the bare ends of the conductors was provided, under a circular +brass ligature, with a small damp sponge, which, surrounding the +mouth-piece, secured a perfect contact of each end of the circuit with +the horse's mouth. + +[Illustration: FIG. 3.--ARRANGEMENT OF THE BIT] + +The horse having been led in, defended himself vigorously as long as +an endeavor was made to remove his shoes by the ordinary method, but +the current had acted scarcely fifteen seconds when it became possible +to lift his feet and strike his shoes with the hammer. + +The experimenter having taken care during this experiment to place the +bobbin quite near the horse's ear, so that he could hear the humming +of the interrupter, undertook a second experiment in the following +way: Having detached the conductors from the armature, he placed +himself in front of the horse (as shown in Fig. 2), and began to +imitate the humming sound of the interrupter with his mouth. The +animal at once assumed the stupefied position that the action of the +current gave him in the first experiment, and allowed his feet to be +lifted and shod without his even being held by the snaffle. + +The horse was for ever after subdued, and yet his viciousness and his +repugnance to shoeing were such that he could only be shod previously +by confining his legs with a kicking-strap. + +It should be noted that the action of the induction coil, mounted as +this was, was very feeble and not very painful; and yet it was very +disagreeable in the mouth, and gave in this case a shock with a +sensation of light before the eyes, as we have found by experimenting +upon ourselves. + +From our own most recent experiments, we have ascertained the +following facts, which may guide every horse-owner in the application +of electricity to an animal that is opposed to being shod: (1) To a +horse that defends himself because he is irritable by temperament, and +nervous and impressionable (as happens with animals of pure or nearly +pure blood), the shock must be administered feebly and gradually +before an endeavor is made to take hold of his leg. The horse will +then make a jump, and try to roll over. The jump must be followed, +while an assistant holds the bridle, and the action of the current +must be at once arrested. After this the horse will not endeavor to +defend himself, and his leg may be easily handled. + +(2) Certain large, heavy, naturally ugly horses kick through sheer +viciousness. In this case, while the current is being given it should +be gradually increased in intensity, and the horse's foot must be +seized during its action. In most cases the passage of a current +through such horses (whose mucous membrane is less sensitive) produces +only a slightly stupefied and contracted position of the head, +accompanied with a slight tremor. The current must be shut off as soon +as the horse's foot is well in one's hand, and be at once renewed if +he endeavors to defend himself again, as is rarely the case. It is a +mare of this nature that is represented in the annexed figures. + +We know that this same system has been applied for bringing to an +abrupt standstill runaway horses, harnessed to vehicles; but knowing +the effect of a sudden stoppage under such circumstances, we believe +that the remedy would prove worse than the disease, since the coachman +and vehicle, in obedience to the laws of inertia, would continue their +motion and pass over the animals, much to their detriment.--_Science +et Nature._ + + * * * * * + + + + +ESTEVE'S AUTOMATIC PILE. + + +Mr. Esteve has recently devised a generator of electricity which he +claims to be energetic, constant, and always ready to operate. The +apparatus is designed for the production of light and for actuating +electric motors, large induction bobbins, etc. + +We give a description of it herewith from data communicated by its +inventor. + +The accompanying cut represents a battery of 6 elements, with a +reservoir, R, for the liquid, provided at its lower part with a cock +for allowing the liquid to enter the pile. The vessels of the +different elements are of rectangular form. At the upper part, and in +the wider surfaces of each, there are two tubes. The first tube of the +first vessel receives the extremity of a safety-tube, A, whose other +extremity enters the upper part of the reservoir, R. This tube is +designed for regulating the flow of the liquid into the pile. When the +cock, r, is too widely open, the liquid might have a tendency to +flow over the edges of the vessel; but this would close the orifice of +the tube, A, and, as the air would then no longer enter the reservoir, +R, the flow would be stopped automatically. The second tube of the +first vessel is connected with a lead tube, 1, one of the extremities +of which enters the second vessel. The other tubes are arranged in the +same way in the other vessels. The renewal of the liquids is effected +by displacement, in flowing upward from one element over into another; +and the liquids make their exit from the pile at D, after having +served six times. The electrodes of the two first elements are +represented as renewed in the cut, in order to show the arrangement of +the tubes. + +[Illustration: ESTEVE'S AUTOMATIC PILE.] + +_Dimensions._--The zinc, 2, has a superficies of 15×20 centimeters, +and is cut out of the ordinary commercial sheet metal. It may be +turned upside down when one end has become worn away, thus permitting +of its being entirely utilized. The negative electrode is formed of +four carbons, which have, each of them, a superficies of 8×21 +centimeters. These four carbons are less fragile and are more easily +handled than two having the same surface. Their arrangement is shown +at the left of the figure. They are fixed to a strip of copper, a, +to which is soldered another strip, L, bent at right angles. There are +thus two pairs of carbon per element, and these are simply suspended +from a piece of wood, as shown in the figure. Upon this wooden holder +will be seen the two strips, LL, that are designed to be put in +contact with the zinc of the succeeding element by means of pinchers +that connect the electrodes with one another. This arrangement permits +the pile to be taken apart very quickly. + +_Charging, Work, and Duration of the Pile._--The inventor has made a +large number of experiments with solutions of bichromate of potash of +various degrees of saturation, and has found the following to give the +best results: + + + Bichromate of potash. 1 kilogramme. + Sulphuric acid 2 liters. + Water 8 " + + +When a larger quantity of the salt is used, crystallization occurs in +the pile. + + Constants and work Constants and work + of an element of a round Bunsen + having a zinc of element, 20×30 cm. + 16×20 cm. + + Volts. 1.9 1.8 + Resistance. 0.05 0.24 + Work disposable in the + external circuit. 1.839 k. 0.344 k. + + +The work disposable in the external circuit is deduced from the +formula: + + T = E²/(4R × 9.81) + +It will be seen that an element thus charged gives as much energy as +5.3 large Bunsen elements. + +The battery is charged with 10 liters of solution, and is capable of +furnishing for 5 hours a current of 7 amperes with a difference of +potential of 9 volts at the pile terminals. The work, according to the +formula (EI)/g, equals 6.422 kilogram-meters; with a feebler +resistance in the external circuit it is capable of producing a +current of 19 amperes for an hour and an half. In this case the +resistance of the external circuit equals the interior resistance of +the pile. Upon immersing the electrodes in new liquid, and with no +resistance in the external circuit, the current may reach 100 amperes. +On renewing the liquids during the operation of the pile, a current of +7 amperes is kept up if about a liter of saturation per hour be +allowed to pass into the battery. For five hours, then, only 5 liters +are used instead of the 10 that are necessary when the liquid is not +renewed while the pile is in action.--_La Nature._ + + * * * * * + + + + +WOODWARD'S DIFFUSION MOTOR. + + +The energy produced by the phenomena of diffusion is exhibited in +lecture courses by placing a bell glass filled with hydrogen over a +porous vessel at whose base is fixed a glass tube that dips into +water. The hydrogen, in diffusing, enters the porous vessel, increases +the internal pressure, and a number of bubbles escapes from the tube. +On withdrawing the bell glass of hydrogen, the latter becomes diffused +externally, a lower pressure occurs in the porous vessel, and the +level of the water rises. + +The arrangement devised by Mr. C.J. Woodward, and recently presented +to the Physical Society of London, is an adaptation of this experiment +to the production of an oscillating motion by alternations in the +internal and external diffusion of the hydrogen. + +The apparatus, represented herewith, consists of a scale beam about +three feet in length that supports at one end a scale pan and weights, +and, at the other, a corked porous vessel that carries a glass tube, +c, which dips into a vessel containing either water or methylic +alcohol. Three or four gas jets, one of which is shown at E, are +arranged around the porous vessel, as close as possible, but in such a +way as not to touch it during the oscillation of the beam. These gas +jets communicate with a gasometer tilled with hydrogen, the bell of +which is so charged as to furnish a jet of sufficient strength. +Experience will indicate the best place to give the gas jets, but, in +general, it is well to locate them at near the center of the porous +vessel when the beam is horizontal. + +[Illustration] + +It is now easy to see how the device operates. When the hydrogen comes +in presence of the porous vessel it becomes diffused therein, and the +pressure exerted in the interior then produces an ascent. When the +bottom of the porous vessel gets above the jets, the internal +diffusion ceases and the hydrogen becomes diffused externally, the +internal pressure diminishes, and the vessel descends. The vessel then +comes opposite the jets of hydrogen and the same motion occurs again, +and soon indefinitely. The work produced by this motor, which has +purely a scientific interest, is very feeble, and much below that +assigned to it by theory. In order to obtain a maximum, it would be +necessary to completely surround the porous vessel each time with +hydrogen, and afterward remove the jets to facilitate the access of +air. All the mechanical arrangements employed for obtaining such a +result have failed, because the friction introduced by the maneuvering +parts also introduces a resistance greater than the motor can +overcome. There is therefore a waste of energy due to the continuous +flow of hydrogen; but the apparatus, for all that, constitutes none +the less an original and interesting device.--_La Nature._ + + * * * * * + + + + +SOME RELATIONS OF HEAT TO VOLTAIC AND THERMO-ELECTRIC ACTION OF METALS +IN ELECTROLYTES.[1] + + [Footnote 1: Read before the Royal Society, Nov., 1883.] + +By G. GORE, F.R.S., LL.D. + + +The experiments described in this paper throw considerable light upon +the real cause of the voltaic current. The results of them are +contained in twenty tables; and by comparing them with each other, and +also by means of additional experiments, the following general +conclusions and chief facts were obtained. + +When metals in liquids are heated, they are more frequently rendered +positive than negative in the proportion of about 2.8 to 1.0; and +while the proportion in weak solutions was about 2.29 to 1.0, in +strong ones it was about 3.27 to 1.0, and this accords with their +thermo-electric behavior as metals alone. The thermo-electric order of +metals in liquids was, with nearly every solution, whether strong or +weak, widely different from the thermo-electric order of the same +metals alone. A conclusion previously arrived at was also confirmed, +viz., that the liquids in which the hot metal was thermo-electro-positive +in the largest proportion of cases were those containing highly +electro-positive bases, such as the alkali metals. The thermo-electric +effect of _gradually_ heating a metal in a liquid was sometimes +different from that of _suddenly_ heating it, and was occasionally +attended by a reversal of the current. + +Degree of strength of liquid greatly affected the thermo-electric +order of metals. Increase of strength usually and considerably +increased the potential of metals thermo-electro-negative in liquids, +and somewhat increased that of those positive in liquids. + +The electric potential of metals, thermo-electro-positive in weak +liquids, was usually about 3.87 times, and in strong ones 1.87 times, +as great as of those which were negative. The potential of the +strongest thermo-electric couple, viz., that of aluminum in weak +solution of sodic phosphate, was 0.66 volt for 100° F. difference of +temperature, or about 100 times that of a bismuth and antimony couple. + +Heating one of the metals, either the positive or negative, of a +voltaic couple, usually increased their electric difference, making +most metals more positive, and some more negative; while heating the +second one also usually neutralized to a large extent the effect of +heating the first one. The electrical effect of heating a voltaic +couple is nearly wholly composed of the united effects of heating each +of the two metals separately, but is not however exactly the same, +because while in the former case the metals are dissimilar, and are +heated to the same temperature, in the latter they are similar, but +heated to different temperatures. Also, when heating a voltaic pair, +the heat is applied to two metals, both of which are previously +electro-polar by contact with each other as well as by contact with +the liquid; but when heating one junction of a metal and liquid +couple, the metal has not been previously rendered electro-polar by +contact with a different one, and is therefore in a somewhat different +state. When a voltaic combination, in which the positive metal is +thermo-negative, and the negative one is thermo-positive, is heated, +the electric potential of the couple diminishes, notwithstanding that +the internal resistance is decreased. + +Magnesium in particular, also zinc and cadmium, were greatly depressed +in electromotive force in electrolytes by elevation of temperature. +Reversals of position of two metals of a voltaic couple in the tension +series by rise of temperature were chiefly due to one of the two +metals increasing in electromotive force faster than the other, and in +many cases to one metal increasing and the other decreasing in +electromotive force, but only in a few cases was it a result of +simultaneous but unequal diminution of potential of the two metals. +With eighteen different voltaic couples, by rise of temperature from +60° to 160° F., the electromotive force in twelve cases was increased, +and in six decreased, and the average proportions of increase for the +eighteen instances was 0.10 volt for the 100° F. of elevation. + +A great difference in chemical composition of the liquid was attended +by a considerable change in the order of the volta-tension series, and +the differences of such order in two similar liquids, such as +solutions of hydric chloride and potassic chloride, were much greater +than those produced in either of those liquids by a difference of 100° +F. of temperature. Difference of strength of solution, like difference +of composition or of temperature, altered the order of such series +with nearly every liquid; and the amount of such alteration by an +increase of four or five times in the strength of the liquid was +rather less than that caused by a difference of 100° F. of +temperature. While also a variation of strength of liquid caused only +a moderate amount of change of order in the volta-tension series, it +produced more than three times that amount of change in the +thermo-electric tension series. The usual effect of increasing the +strength of the liquid upon the volta-electromotive force was to +considerably increase it, but its effect upon the thermo-electro-motive +force was to largely decrease it. The degree of potential of a metal +and liquid thermo-couple was not always exactly the same at the same +temperature during a rise as during a fall of temperature; this is +analogous to the variations of melting and solidifying points of +bodies under such conditions, and also to that of supersaturation of a +liquid by a salt, and is probably due to some hinderance to change of +molecular movement. + +The rate of ordinary chemical corrosion of each metal varied in every +different liquid; in each solution also it differed with every +different metal. The most chemically positive metals were usually the +most quickly corroded, and the corrosion of each metal was usually the +fastest with the most acid solutions. The rate of corrosion at any +given temperature was dependent both upon the nature of the metal and +upon that of the liquid, and was limited by the most feebly active of +the two, usually the electrolyte. The order of rate of corrosion of +metals also differed in every different liquid. The more dissimilar +the chemical characters of two liquids, the more diverse usually was +the order of rapidity of corrosion of a series of metals in them. The +order of rate of simple corrosion in any of the liquids examined +differed from that of chemico-electric and still more from that of +thermo-electric tension. Corrosion is not the cause of thermo-electric +action of metals in liquids. + +Out of fifty-eight cases of rise of temperature the rate of ordinary +corrosion was increased in every instance except one, and that was +only a feeble exception--the increase of corrosion from 60° to 160° F. +with different metals was extremely variable, and was from 1.5 to 321.6 +times. Whether a metal increased or decreased in thermo-electromotive +force by being heated, it increased in rapidity of corrosion. The +proportions in which the most corroded metal was also the most +thermo-electro-positive one was 65.57 per cent. in liquids at 60° F., +and 69.12 in the same liquids at 160° F.; and the proportion in which +it was the most chemico-electro-positive at 60 F. was 84.44 per cent, +and at 160° F. 80.77 per cent. The proportion of cases therefore in +which the most chemico-electro-negative metal was the most corroded +one increased from 15.56 to 19.23 per cent, by a rise of temperature +of 100° F. Comparison of these proportions shows that corrosion +usually influenced in a greater degree chemico-electric rather than +thermo-electric actions of metals in liquids. Not only was the +relative number of cases in which the volta-negative metal was the +most corroded increased by rise of temperature, but also the average +relative loss by corrosion of the negative to that of the positive one +was increased from 3.11 to 6.32. + +The explanation most consistent with all the various results and +conclusions is a kinetic one: That metals and electrolytes are +throughout their masses in a state of molecular vibration. That the +molecules of those substances, being frictionless bodies in a +frictionless medium, and their motion not being dissipated by +conduction or radiation, continue incessantly in motion until some +cause arises to prevent them. That each metal (or electrolyte), when +unequally heated, has to a certain extent an unlike class of motions +in its differently heated parts, and behaves in those parts somewhat +like two metals (or electrolytes), and those unlike motions are +enabled, through the intermediate conducting portion of the substance, +to render those parts electro-polar. That every different metal and +electrolyte has a different class of motions, and in consequence of +this, they also, by contact alone with each other at the same +temperature, become electro-polar. The molecular motion of each +different substance also increases at a different rate by rise of +temperature. + +This theory is equally in agreement with the chemico-electric results. +In accordance with it, when in the case of a metal and an electrolyte, +the two classes of motions are sufficiently unlike, chemical corrosion +of the metal by the liquid takes place, and the voltaic current +originated by inherent molecular motion, under the condition of +contact, is maintained by the portions of motion lost by the metal and +liquid during the act of uniting together. Corrosion therefore is an +effect of molecular motion, and is one of the modes by which that +motion is converted into and produces electric current. + +In accordance with this theory, if we take a thermo-electric pair +consisting of a non-corrodible metal and an electrolyte (the two being +already electro-polar by mutual contact), and heat one of their points +of contact, the molecular motions of the heated end of each substance +at the junction are altered; and as thermo-electric energy in such +combinations usually increases by rise of temperature, the metal and +liquid, each singly, usually becomes more electro polar. In such a +case the unequally heated metal behaves to some extent like two +metals, and the unequally heated liquid like two liquids, and so the +thermo-electric pair is like a feeble chemico-electric one of two +metals in two liquids, but without corrosion of either metal. If the +metal and liquid are each, when alone, thermo-electro-positive, and if, +when in contact, the metal increases in positive condition faster than +the liquid by being heated, the latter appears thermo-electro-negative, +but if less rapidly than the liquid, the metal appears +thermo-electro-negative. + +As also the proportion of cases is small in which metals that are +positive in the ordinary thermo-electric series of metals only become +negative in the metal and liquid ones (viz., only 73 out of 286 in +weak solutions, and 48 out of the same number in strong ones), we may +conclude that the metals, more frequently than the liquids, have the +greatest thermo-electric influence, and also that the relative +largeness of the number of instances of thermo-electro-positive metals +in the series of metals and liquids, as in the series of metals only, +is partly a consequence of the circumstance that rise of temperature +usually makes substances--metals in particular--electro-positive. +These statements are also consistent with the view that the elementary +substances lose a portion of their molecular activity when they unite +to form acids or salts, and that electrolytes therefore have usually a +less degree of molecular motion than the metals of which they are +partly composed. + +The current from a thermo-couple of metal and liquid, therefore, may +be viewed as the united result of difference of molecular motion, +first, of the two junctions, and second, of the two heated (or cooled) +substances; and in all cases, both of thermo- and chemico-electric +action, the immediate true cause of the current is the original +molecular vibrations of the substances, while contact is only a static +permitting condition. Also that while in the case of thermo-electric +action the sustaining cause is molecular motion, supplied by an +external source of heat, in the case of chemico-electric action it is +the motion lost by the metal and liquid when chemically uniting +together. The direction of the current in thermo-electric cases +appears to depend upon which of the two substances composing a +junction increases in molecular activity the fastest by rise of +temperature, or decreases the most rapidly by cooling. + + * * * * * + + + + +AIR REFRIGERATING MACHINE. + + +[Illustration: IMPROVED AIR REFRIGERATING MACHINE.] + +Messrs. J. & E. Hall, Dartford, exhibit at the International Health +Exhibition, London, in connection with a cold storage room, two sizes +of Ellis' patent air refrigerator, the larger one capable of +delivering 5,000 cubic feet of cold air per hour, when running at a +speed of 150 revolutions per minute; and the smaller one 2,000 cubic +feet of cold air per hour, at 225 revolutions per minute. The special +features in these machines are the arrangement of parts, by which +great compactness is secured, and the adoption of flat slides for the +compressor, instead of the ordinary beat valves, which permits of a +high rate of revolution without the objectionable noise which is +caused by clacks beating on their seats. The engraving shows the +general arrangement of the apparatus. Figs. 1 to 4 show details of the +compression and expansion valves, which are ordinary flat slides, +partly balanced, and held up to their faces by strong springs from +behind. The steam, compression, and expansion cylinders are severally +bolted to the end of a strong frame, which though attached to the +cooler box does not form part of it, the object being to meet the +strains between the cylinders and shaft in as direct a manner as +possible without allowing them to act on the cooler casting. Each +cylinder is double acting, the pistons being coupled to the shaft by +three connecting rods, the two outer ones working upon crank pins +fixed to overhung disks, and the center one on a crank formed in the +shaft. The slide valves for all the cylinders are driven from two +weigh shafts, the main valve shaft being actuated by a follow crank, +and the expansion and cut off valves from the crosshead pin of the +compressor. The machines may be used either in the vertical position +as exhibited, or may be fixed horizontally; and it is stated that the +construction is such as to admit of speeds of 200 and 300 revolutions +per minute respectively for the larger and smaller machines, under +which conditions the delivery of cold air may be taken at about 7,000 +and 2,600 cubic feet per hour. Messrs. Hall also make this class of +refrigerator without the steam cylinder, and arranged to be driven by +a belt from a gas engine or any existing motive power. + + * * * * * + + + + +A GAS RADIATOR AND HEATER. + + +[Illustration: Fig. 1 & Fig. 2 A GAS RADIATOR AND HEATER.] + +There is now being introduced into Germany a gas radiator and heater, +the invention of Herr Wobbe. It consists, as will be seen in engraving +above, of a series of vertical U-shaped pipes, of wrought iron, 50 +millimeters (2 inches) in diameter. The two legs of the U are of +unequal length; the longer being about 5 feet, and the shorter 3 feet +(exclusive of the bend at the top). Beneath the open end of the +shorter leg of each pipe is placed a burner, attached to a horizontal +gas-pipe, which turns upon an axis. The object of having this pipe +rotate is to bring the burners into an inclined position--shown by the +dotted lines in Fig. 2--for lighting them. On turning them back to the +vertical position, the heated products of combustion pass up the +shorter tube and down the longer, where they enter a common +receptacle, from which they pass into the chimney or out of doors. +Surrounding the pipes are plates of sheet iron, inclined at the angle +shown in Fig. 2. The object of the plates is to prevent the heated air +of the room from passing up to the ceiling, and send it out into the +room. To prevent any of the pipes acting as chimneys, and bringing the +products of combustion back into the room, as well as to avoid any +back-pressure, a damper is attached to the outlet receptacle. The +heated gas becomes cooled so much (to about 100° Fahr.) that water is +condensed and precipitated, and collects in the vessel below the +outlet. Each burner has a separate cock, by which it may be kept +closed, half-open, or open. To obviate danger of explosion, there is a +strip of sheet iron in front of the burners, which prevents their +being lighted when in a vertical position; so that, in case any +unburned gas gets into the pipes, it cannot be ignited, for the +burners can only be lighted when inclined to the front. In starting +the stove the burners are lighted, in the inclined position; the chain +from the damper pulled up; the burners set vertical; and, as soon as +they are all drawing well into the tubes, the damper is closed. If +less heat is desired, the cocks are turned half off. It is not +permissible to entirely extinguish some of the burners, unless the +unused pipes are closed to prevent the products of combustion coming +back into the room. The consumption of gas per burner, full open, with +a pressure of 8/10, is said to be only 4-3/8 cubic feet per hour. + + * * * * * + + + + +CONCRETE WATER PIPES. + + +Concrete water pipes of small diameter, according to a foreign +contemporary, are used in parts of France, notably for water mains for +the towns of Coulommiers and Aix-en-Provence. The pipes were formed of +concrete in the trench itself. The mould into which the concrete was +stamped was sheet iron about two yards in length. The several pipes +were not specially joined to each other, the joints being set with +mortar. The concrete consisted of three parts of slow setting cement +and three parts of river sand, mixed with five parts of limestone +debris. The inner diameter of the pipes was nine inches; their +thickness, three inches. The average fall is given at one in five +hundred; the lowest speed of the current at one foot nine inches per +second. To facilitate the cleaning of the pipes, man-holes are +constructed every one hundred yards or so, the sides of which are also +made of concrete. The trenches are about five feet deep. The work was +done by four men, who laid down nearly two hundred feet of pipe in a +working day; the cost was about ninety-three cents per running yard. +It is claimed as an advantage for the new method that the pipes adhere +closely to the inequalities of the trench, and thus lie firmly on the +ground. When submitted to great pressure, however, they have not +proved effective, and the method, consequently, is only suitable for +pipes in which there is no pressure, or only a very trifling one. + + * * * * * + + + + +THE SELLERS STANDARD SYSTEM OF SCREW THREADS, NUTS, AND BOLT HEADS. + + + _____________________________________________________ + | | + | SCREW THREADS. | + |_____________________________________________________| + | | | | | | + | Diam. |Threads | Diameter | Area of | Width | + | of | per | at root of | Bolt at | of | + | Screw. | inch. | Thread. | root of | Flat. | + | | | | Thread. | | + |________|________|_________________|_________|_______| + | | | | | | | + | 1/4 | 20 | .185 | 13/64 | .026 | .0062 | + | 5/16 | 18 | .240 | 15/64 | .045 | .0074 | + | 3/8 | 16 | .294 | 19/64 | .067 | .0078 | + | 7/16 | 14 | .344 | 11/32 | .092 | .0089 | + | 1/2 | 13 | .400 | 13/32 | .125 | .0096 | + | 9/16 | 12 | .454 | 29/64 | .161 | .0104 | + | 5/8 | 11 | .507 | 33/64 | .201 | .0113 | + | 3/4 | 10 | .620 | 5/8 | .301 | .0125 | + | 7/8 | 9 | .731 | 47/64 | .419 | .0138 | + | | | | | | | + | 1 | 8 | .837 | 27/32 | .550 | .0156 | + | 1-1/8 | 7 | .940 | 15/16 | .693 | .0178 | + | 1-1/4 | 7 | 1.065 | 1- 1/16 | .890 | .0178 | + | 1-3/8 | 6 | 1.160 | 1- 5/32 | 1.056 | .0208 | + | 1-1/2 | 6 | 1.284 | 1- 9/32 | 1.294 | .0208 | + | 1-5/8 | 5-1/2 | 1.389 | 1-25/64 | 1.515 | .0227 | + | 1-3/4 | 5 | 1.491 | 1-31/64 | 1.746 | .0250 | + | 1-7/8 | 5 | 1.616 | 1-39/64 | 2.051 | .0250 | + | | | | | | | + | 2 | 4-1/2 | 1.742 | 1-23/32 | 2.301 | .0277 | + | 2-1/4 | 4-1/2 | 1.962 | 1-31/32 | 3.023 | .0277 | + | 2-1/2 | 4 | 2.176 | 2-11/64 | 3.718 | .0312 | + | 2-3/4 | 4 | 2.426 | 2-27/64 | 4.622 | .0312 | + | | | | | | | + | 3 | 3-1/2 | 2.629 | 2- 5/8 | 5.428 | .0357 | + | 3-1/4 | 3-1/2 | 2.879 | 2- 7/8 | 6.509 | .0357 | + | 3-1/2 | 3-1/4 | 3.100 | 3- 3/32 | 7.547 | .0384 | + | 3-3/4 | 3 | 3.317 | 3- 5/16 | 8.614 | .0413 | + | | | | | | | + | 4 | 3 | 3.567 | 3- 9/16 | 9.993 | .0413 | + | 4-1/4 | 2-7/8 | 3.798 | 3-51/64 | 11.329 | .0435 | + | 4-1/2 | 2-3/4 | 4.028 | 4- 1/32 | 12.742 | .0454 | + | 4-3/4 | 2-5/8 | 4.256 | 4- 1/4 | 14.226 | .0476 | + | | | | | | | + | 5 | 2-1/2 | 4.480 | 4-31/64 | 15.763 | .0500 | + | 5-1/4 | 2-1/2 | 4.730 | 4-47/64 | 17.570 | .0500 | + | 5-1/2 | 2-3/8 | 4.953 | 4-61/64 | 19.267 | .0526 | + | 5-3/4 | 2-3/8 | 5.203 | 5-13/64 | 21.261 | .0526 | + | 6 | 2-1/4 | 5.423 | 5-27/64 | 23.097 | .0555 | + |________|________|_________________|_________|_______| + _____________________________________________________________ + | | + | NUTS. | + |___________________ __________________________________________| + | | | | | | | + | Short | Short | Long | Long | Thick- | Thick- | + | Diam. | Diam. | Diam. | Diam. | ness | ness | + | Rough. | Finish. | Rough. | Rough. | Rough. | Finish. | + | | | | | | | + | (Hex.) | (Hex.) | (Hex.) | (Square) | | | + |_________|_________ |__________|__________|_________|_________| + | | | | | | | + | 1/2 | 7/16 | 37/64 | 7/10 | 1/4 | 3/16 | + | 19/32 | 17/32 | 11/16 | 10/12 | 5/16 | 1/4 | + | 11/16 | 5/8 | 51/64 | 63/64 | 3/8 | 5/16 | + | 25/32 | 23/33 | 9/10 | 1- 7/64 | 7/16 | 3/8 | + | 7/8 | 13/16 | 1 | 1-15/64 | 1/2 | 7/16 | + | 31/32 | 29/32 | 1- 1/8 | 1-23/64 | 9/16 | 1/2 | + | 1-1/16 | 1 | 1- 7/32 | 1- 1/2 | 5/8 | 9/16 | + | 1-1/4 | 1-3/16 | 1- 7/16 | 1-49/64 | 3/4 | 11/16 | + | 1-7/16 | 1-3/8 | 1-21/32 | 2- 1/32 | 7/8 | 13/16 | + | | | | | | | + | 1- 5/8 | 1-9/16 | 1- 7/8 | 2-19/64 | 1 | 15/16 | + | 1-13/16| 1- 3/4 | 2- 5/32 | 2- 9/16 | 1-1/8 | 1- 1/16 | + | 2 | 1-15/16 | 2- 5/16 | 2-53/64 | 1-1/4 | 1- 3/16 | + | 2- 3/16| 2- 1/8 | 2-17/32 | 3- 3/32 | 1-3/8 | 1- 5/16 | + | 2- 3/8 | 2- 5/16 | 2- 3/4 | 3-23/64 | 1-1/2 | 1- 7/16 | + | 2- 9/16| 2- 1/2 | 2-31/32 | 3- 5/8 | 1-5/8 | 1- 9/16 | + | 2- 3/4 | 2-11/16 | 3- 3/16 | 3-57/64 | 1-3/4 | 1-11/16 | + | 2-15/16| 2- 7/8 | 3-13/32 | 4- 5/32 | 1-7/8 | 1-13/16 | + | | | | | | | + | 3-1/8 | 3- 1/16 | 3- 5/8 | 4-27/64 | 2 | 1-15/16 | + | 3-1/2 | 3- 7/16 | 4- 1/16 | 4-61/64 | 2-1/4 | 2- 3/16 | + | 3-7/8 | 3-13/16 | 4- 1/2 | 5-31/64 | 2-1/2 | 2- 7/16 | + | 4-1/4 | 4- 3/16 | 4-29/32 | 6 | 2-3/4 | 2-11/16 | + | | | | | | | + | 4-5/8 | 4- 9/16 | 5- 3/8 | 6-17/32 | 3 | 2-15/16 | + | 5 | 4-15/16 | 5-13/16 | 7- 1/16 | 3-1/4 | 3- 3/16 | + | 5-3/8 | 5- 5/16 | 6- 7/32 | 7-39/64 | 3-1/2 | 3- 7/16 | + | 5-3/4 | 5-11/16 | 6-21/32 | 8- 1/8 | 3-3/4 | 3-11/16 | + | | | | | | | + | 6-1/8 | 6- 1/16 | 7- 3/32 | 8-41/64 | 4 | 3-15/16 | + | 6-1/2 | 6- 7/16 | 7- 9/16 | 9- 3/16 | 4-1/4 | 4- 3/16 | + | 6-7/8 | 6-13/16 | 7-31/32 | 9- 3/4 | 4-1/2 | 4- 7/16 | + | 7-1/4 | 7- 3/16 | 8-13/32 | 10- 1/4 | 4-3/4 | 4-11/16 | + | | | | | | | + | 7-5/8 | 7- 9/16 | 8-27/32 | 10-49/64 | 5 | 4-15/16 | + | 8 | 7-15/16 | 9- 9/32 | 11-23/64 | 5-1/4 | 5- 3/16 | + | 8-3/8 | 8- 5/16 | 9-23/32 | 11- 7/8 | 5-1/2 | 5- 7/16 | + | 8-3/4 | 8-11/16 | 10- 5/32 | 12- 3/8 | 5-3/4 | 5-11/16 | + | 9-1/8 | 9- 1/16 | 10-19/32 | 12-15/16 | 6 | 5-15/16 | + |_________|__________|__________|__________|_________|_________| + _____________________________________________________________ + | | + | BOLT HEADS. | + |_____________________________________________________________| + | | | | | | | + | Short | Short | Long | Long | Thick- | Thick- | + | Diam. | Diam. | Diam. | Diam. | ness | ness | + | Rough. | Finish. | Rough. | Rough. | Rough. | Finish. | + | | | | | | | + | (Hex.) | (Hex.) | (Hex.) | (Square) | | | + |_________|_________|__________|__________|_________|_________| + | | | | | | | + | 1/2 | 7/16 | 37/64 | 7/10 | 1/4 | 3/16 | + | 19/32 | 17/32 | 11/16 | 10/12 | 19/64 | 1/4 | + | 11/16 | 5/8 | 51/64 | 63/64 | 11/32 | 5/16 | + | 25/32 | 23/32 | 9/16 | 1-7/64 | 25/64 | 3/8 | + | 7/8 | 13/16 | 1 | 1-15/64 | 7/16 | 7/16 | + | 31/32 | 29/32 | 1- 1/8 | 1-23/64 | 31/64 | 1/2 | + | 1- 1/16 | 1 | 1- 7/32 | 1- 1/2 | 17/32 | 9/16 | + | 1- 1/4 | 1- 3/16 | 1- 7/16 | 1-49/64 | 5/8 | 11/16 | + | 1- 7/16 | 1- 3/8 | 1-21/32 | 2- 1/32 | 23/32 | 13/16 | + | | | | | | | + | 1- 5/8 | 1- 9/16 | 1- 7/8 | 2-19/64 | 13/16 | 15/16 | + | 1-13/16 | 1- 3/4 | 2- 5/32 | 2- 7/16 | 29/32 | 1- 1/16 | + | 2 | 1-15/16 | 2- 5/16 | 2-53/64 | 1 | 1- 3/16 | + | 2- 3/16 | 2- 1/8 | 2-17/32 | 3- 3/32 | 1- 3/32 | 1- 5/16 | + | 2- 3/8 | 2- 5/16 | 2- 3/4 | 3-23/64 | 1- 3/16 | 1- 7/16 | + | 2- 9/16 | 2- 1/2 | 2-31/32 | 3- 5/8 | 1- 9/32 | 1- 9/16 | + | 2- 3/4 | 2-11/16 | 3- 3/16 | 3-57/64 | 1- 3/8 | 1-11/16 | + | 2-15/16 | 2- 7/8 | 3-13/32 | 4- 5/32 | 1-15/32 | 1-13/16 | + | | | | | | | + | 3- 1/8 | 3- 1/16 | 3- 5/8 | 4-27/64 | 1- 9/16 | 1-15/16 | + | 3- 1/2 | 3- 7/16 | 4- 1/16 | 4-61/64 | 1- 3/4 | 2- 3/16 | + | 3- 7/8 | 3-13/16 | 4- 1/2 | 5-31/64 | 1-15/16 | 2- 7/16 | + | 4- 1/4 | 4- 3/16 | 4-29/32 | 6 | 2- 1/8 | 2-11/16 | + | | | | | | | + | 4- 5/8 | 4- 9/16 | 5- 3/8 | 6-17/32 | 2- 5/16 | 2-15/16 | + | 5 | 4-15/16 | 5-13/16 | 7- 1/16 | 2- 1/2 | 3- 3/16 | + | 5- 3/8 | 5- 5/16 | 6- 7/32 | 7-39/64 | 2-11/16 | 3- 7/16 | + | 5- 3/4 | 5-11/16 | 6-21/32 | 8- 1/8 | 2- 7/8 | 3-11/16 | + | | | | | | | + | 6- 1/8 | 6- 1/16 | 7- 3/32 | 8-41/64 | 3- 1/16 | 3-15/16 | + | 6- 1/2 | 6- 7/16 | 7- 9/16 | 9- 3/16 | 3- 1/4 | 4- 3/16 | + | 6- 7/8 | 6-13/16 | 7-31/32 | 9- 3/4 | 3- 7/16 | 4- 7/16 | + | 7- 1/4 | 7- 3/16 | 8-13/32 | 10- 1/4 | 3- 5/8 | 4-11/16 | + | | | | | | | + | 7- 5/8 | 7- 9/16 | 8-27/32 | 10-49/64 | 3-13/16 | 4-15/16 | + | 8 | 7-15/16 | 9- 9/32 | 11-23/64 | 4 | 5- 3/16 | + | 8- 3/8 | 8- 5/16 | 9-23/32 | 11- 7/8 | 4- 3/16 | 5- 7/16 | + | 8- 3/4 | 8-11/16 | 10- 5/32 | 12- 3/8 | 4- 3/8 | 5-11/16 | + | 9- 1/8 | 9- 1/16 | 10-19/32 | 12-15/16 4- 9/16 | 5-15/16 | + |_________|_________|__________|__________|_________|_________| + + +The dimensions given for diameter at root of threads are also those +for diameter of hole in nuts and diameter of lap drills. All bolts and +studs 3/4 in. diameter and above, screwed into boilers, have 12 +threads per inch, sharp thread, a taper of 1/16 in. per 1 inch; tap +drill should be 9/64 in. less than normal diameter of bolts. + +The table is based upon the following general formulæ for certain +dimensions: + + Short diam. rough nut or head = 11/2 diam. of bolt + 1/8. + " finished nut or head = 11/2 diam. of bolt + 1/16. + Thickness rough nut = diameter of bolt. + Thickness finished nut = diameter of bolt - 1/16. + Thickness rough head = 1/2 short diameter. + Thickness finished head = diameter of bolt - 1/16. + + * * * * * + + + + +AN ENGLISH RAILWAY FERRY BOAT. + + +[Illustration: AN ENGLISH RAILWAY FERRY BOAT.] + +The illustrations above represent a double screw steam ferry boat for +transporting railway carriages, vehicles, and passengers, etc., +designed and constructed by Messrs. Edwards and Symes, of Cubitt Town, +London. The hull is constructed of iron, and is of the following +dimensions: Length 60 ft.; beam 16 ft.; over sponsons 25 ft. The +vessel was fitted with a propeller, rudder, and steering gear at each +end, to enable it to run in either direction without having to turn +around. The boat was designed for the purpose of working the train +service across the bay of San Juan, in the island of Puerto Rico, and +for this purpose a single line of steel rails, of meter gauge, is laid +along the center of the deck, and also along the hinged platforms at +each end. In the engraving these platforms are shown, one hoisted up, +and the other lowered to the level of the deck. When the boat is at +one of the landing stages, the platform is lowered to the level of the +rails on the pier, and the carriages and trucks are run on to the deck +by means of the small hauling engine, which works an endless chain +running the whole length of the deck. The trucks, etc., being on +board, the platform is raised by means of two compact hand winches +worked by worm and worm-wheels in the positions shown; thus these two +platforms form the end bulwarks to the boat when crossing the bay. On +arriving at the opposite shore the operation is repeated, the other +platform is lowered, and the hauling engine runs the trucks, etc., on +to the shore. With a load of 25 tons the draught is 4 ft. + +The seats shown on the deck are for the convenience of foot +passengers, and the whole of the deck is protected from the sun of +that tropical climate by a canvas awning. The steering of the vessel +is effected from the bridge at the center, which extends from side to +side of the vessel, and there are two steering wheels with independent +steering gear for each end, with locking gear for the forward rudder +when in motion. The man at the wheel communicates with the engineer by +means of a speaking tube at the wheel. There is a small deck house for +the use of deck stores, on one side of which is the entrance to the +engine room. The cross battens, shown between the rails, are for the +purpose of horse traffic, when horses are used for hauling the trucks, +or for ordinary carts or wagons. The plan below deck shows the +arrangement of the bulkheads, with a small windlass at each end for +lifting the anchors, and a small hatch at each side for entrance to +these compartments. The central compartment contains the machinery, +which consists of a pair of compound surface condensing engines, with +cylinders 11 in. and 20 in. in diameter; the shafting running the +whole length of the vessel, with a propeller at each end. Steam is +generated in a steel boiler of locomotive form, so arranged that the +funnel passes through the deck at the side of the vessel; and it is +designed for a working pressure of 100 lb. per square inch. This +boiler also supplies steam for the small hauling engine fixed on the +bulkhead. Light to this compartment is obtained by means of large side +scuttles along each side of the boat and glass deck lights, and the +iron grating at the entrance near the deck house. This boat was +constructed in six pieces for shipment, and the whole put together in +the builders' yard. The machinery was fixed, and the engine driven by +steam from its own boiler, then the whole was marked and taken +asunder, and shipped to the West Indies, where it was put together and +found to answer the purpose intended.--_Engineering._ + + * * * * * + +[For THE SCIENTIFIC AMERICAN.] + + + + +THE PROBLEM OF FLIGHT, AND THE FLYING MACHINE. + + +As a result of reading the various communications to the SCIENTIFIC +AMERICAN and SUPPLEMENT, and _Van Nostrand's Engineering Magazine_, +including descriptions of proposed and tested machines, and the +reports of the British Aeronautical Society, the writer of the +following concludes: + +That, as precedents for the construction of a successful flying +machine, the investigation of some species of birds as a base of the +principles of all is correct only in connection with the species and +habits of the bird; that the _general mechanical principles_ of flight +applicable to the _operation_ of the _same unit_ of wing in _all_ +species are alone applicable to the flying machine. + +That these principles of _operation_ do not demand the principles of +_construction_ of the bird. + +That as the wing is in its stroke an arc of a screw propeller's +operation, and in its angle a screw propeller blade, its animal +operation compels its reciprocation instead of rotation. + +That the swifter the wing beat, the more efficient its effect per unit +of surface, the greater the load carried, and the swifter the flight. + +That the screw action being, in full flight, that of a screw propeller +whose axis of rotation forms a slight angle with the vertical, the +distance of flight per virtual "revolution" of "screw" wing far +exceeds the pitch distance of said "screw." + +That consequently a bird's flight answers to an iceboat close hauled; +the wing _force_ answering to the _wind_, the wing _angle_ to the +_sail_, the bird's _weight_ to the leeway fulcrum of the _ice_, and +the passage across direction of the _wing_ flop to the fresh _moving_ +"inertia" of the wind, both yielding a maximum of force to bird or +iceboat. + +That the speed of _reciprocation_ of a fly's _wing_ being equivalent +to a _screw rotation_ of 9,000 per minute, proves that a _screw_ may +be run at this speed without losing efficiency by centrifugal vacuum. + +That as the _object_ of wing or screw is to mount upon the inertia of +the particles of a mobile fluid, and as the rotation of steamship +propellers in water--a fluid of many times the inertia of air--is +_already_ in _excess_ of the highest speed heretofore tried in the +propellers of moderately successful flying machines, it is plain that +the speed employed in _water_ must be many times exceeded in _air_. + +That with a _sufficient_ speed of rotation, the supporting power of +the inertia of air must _equal_ that of _water_. + +That as mere speed of rotation of propeller _shaft_, minus blades, +must absorb but a small proportion of power of engine, the addition of +blades will not cause more resistance than that actually encountered +from inertia of air. + +That this must be the measure of load lifted. + +That without _slip_ of screw, the actual _power_ expended, will be +little in _excess_ of that required to support the machine in _water_, +with a slower rotation of screw. + +That in case the same _power_ is expended in water or air, the only +difference will lie in the sizes and speed of engines or screws. + +That the _greater_ the speed, the _less_ weight of engine, boiler, and +screw must be, and the stronger their construction. + +That, in consequence, solid metal worked down, instead of bolts and +truss work, must be used. + +That as the bird wing is a screw in action, and acts _directly_ +between the inertias of the load and the air, the position and +operation of the screw, to the load, must imitate it. + +That, in consequence, machines having wing planes, driven _against_ +one inertia of air by screws acting in the line, of flight against +another inertia of air, lose fifty per cent. of useful effect, besides +exposing to a head wind the cross section of the stationary screw wing +planes and the rotating screw discs; and supporting the dead weight of +the wing planes, and having all the screw slip in the line of flight, +and carrying slow and heavy engines. + +That as a result of these conclusions, the supporting and propelling +power should be expressed in the rotation of screws combining both +functions, the position of whose planes of rotation to a fixed +horizontal line of direction determines the progress and speed of +machine upon other lines. + +That the whole weight carried by the screws should be at all times +exactly below the center of gravity of the plane of support, whether +it be horizontal or inclined. + +That while the _permanently_ positioned weight, such as the engines, +frame, holding screws, etc., may be rigidly connected to or around the +screw plane of support, the variable positioned weight, such as the +passenger and the car, should be connected by a _flexible joint_ to +the said plane of support. + +Consequently, the car may oscillate without altering its weight +position under center of supporting plane, thus avoiding an +involuntary alteration of speed or direction of flight. + +That to steer a machine so constructed, it is merely necessary to move +the point of attachment of car to _machine_ proper, out of the center +of plane of support in the desired direction, and thus cause the plane +of support or rotation of propellers to incline in that direction. + +That the reservoir of power, the boiler, etc., should be placed in the +_car_, and steam carried to engines through joint connecting car with +machine. + +That at present material exists, and power also, of sufficient +lightness and strength to admit of a machine construction capable of a +limited successful flight in any fair wind and direction. + +That such _machine_ once built, the finding of a _power_ for long +flights will be easy, if not already close at hand in _electricity_. + +That the _easiest_ design for such _actual machine_ should be adopted, +leaving the adaptation of the principles involved to the making of +more perfect machines, to a time after the success of the _first_. + +That such design may be a propeller, and its engine at each end of a +steel frame tube, supporting tube horizontally, a car to be supported +by a universal joint from center of said tube, and the joint apparatus +movable along the tube or a short distance transverse to it, to alter +position of center of gravity. + +That the machine so built might traverse the water as well as air. + + * * * * * + + + + +THE LONGHAIRED POINTER MYLORD. + + +Pointers are trained to search for game, and to indicate that they +have found the same by standing motionless in front of it, and, when +it has been shot, to carry the game to the huntsman. Several kinds of +pointers are known, such as smooth, longhaired, and bushyhaired +pointers. The smoothhaired pointers are better for hunting on high +land, whereas the longhaired or bushyhaired dogs are better for low, +marshy countries, crossed by numerous streams, etc. Mylord, the dog +represented in the annexed cut taken from the _Illustrirte Zeitung_, +is an excellent specimen of the longhaired pointer, and is owned by +Mr. G. Borcher, of Braunschweig, Germany. + +[Illustration: THE LONGHAIRED POINTER, "MYLORD."] + +The longhaired pointer is generally above the medium size, powerful, +somewhat longer than the normal dog, the body is narrower and not +quite as round as that of the smoothhaired dog, and the muscles of the +shoulders and hind legs are not as well developed and not as +prominent. The head and neck are erect, the head being specially long, +and the tail is almost horizontal to the middle, and then curves +upward slightly. The long hair hangs in wavy lines on both sides of +his body. The expression of his face is intelligent, bright, and +good-natured, and his step is light and almost noiseless. + +The pointer is specially valuable, as it can be employed for many +different purposes; he is an excellent dog for the woods, for the +woodsman and hunter who uses only one dog for different kinds of game. +The intelligence of the German pointer is very great, but he does not +develop as rapidly as the English dog, which has been raised for +generations for one purpose only. The German pointer hunts very +slowly, but surely. It is not difficult to train this dog, but he +cannot be trained until he has reached a certain age. + + * * * * * + + + + +LUNAR HEAT. + +By Professor C.A. YOUNG. + + +One of the most interesting inquiries relating to the moon is that +which deals with the heat she sends us, and the probable temperature +of her surface. The problem seems to have been first attacked by +Tschirnhausen and La Hire, about 1700; and they both found, that even +when the moon's rays were concentrated by the most powerful +burning-lenses and mirrors they could obtain, its heat was too small +to produce the slightest perceptible effect on the most delicate +thermometers then known. For more than a hundred years, this was all +that could be made out, though the experiment was often repeated. + +It was not until 1831 that Melloni, with his newly-invented +"thermopile," [1] succeeded in making the lunar heat sensible; and in +1835, taking his apparatus to the top of Vesuvius, he obtained not +only perceptible, but measurable, results, getting a deviation of four +or five divisions of his galvanometer. + + [Footnote 1: Probably most of our readers know that the + thermopile consists of a number of little bars of two different + metals, connected in pairs, and having the ends joined in a + conducting circuit with a galvanometer. If, now, one set of the + junctures is heated more than the other set, a current of + electricity will be generated, which will affect the + galvanometer. The bars are usually made of bismuth and antimony + though iron and German silver answer pretty well. They are + commonly about half or three-quarters of an inch long, and about + half as large as an ordinary match. The "pile" is made of from + fifty to a hundred such bars packed closely, but insulated by + thin strips of mica, except just at the soldered junctions. With + an instrument of this kind and a very delicate galvanometer, + Professor Henry found that the heat from a person's face could be + perceived at a distance of several hundred feet. There is + however, some doubt whether he was not mistaken in respect to + this extreme sensitiveness.] + +Others repeated the experiment several times between this time and +1856, with more or less success; but, so far as I know, the first +quantitative result was that obtained in 1856 by Piazzi Smyth during +his Teneriffe expedition. On the top of the mountain, at an elevation +of ten thousand feet, he found that the moon's rays affected his +thermopile to the same extent as a standard candle ten feet away. +Marie Davy has since shown that this corresponds to a heating effect +of about 1/1300 of a Centigrade degree. + +The subject was resumed in 1868 by Lord Rosse in Ireland; and a long +series of observations, running through several years, was made by the +aid of his three-foot reflector (not the great _six_-foot instrument, +which is too unwieldy for such work). The results of his work have, +until very recently, been accepted as authoritative. It should be +mentioned that, at about the same time, observations were also made at +Paris by Marie Davy and Martin; but they are generally looked upon +merely as corroborative of Rosse's work, which was more elaborate and +extensive. Rosse considered that his results show that the heat from +the moon is mainly _obscure, radiated_ heat; the _reflected_ heat, +according to him, being much less in amount. + +A moment's thought will show that the moon's heat must consist of two +portions. First, there will be _reflected solar heat_. The amount and +character of this will depend in no way upon the temperature of the +moon's surface, but solely upon its reflecting power. And it is to be +noted that moon-_light_ is only a part of this reflected radiant +energy, differing from the invisible portion of the same merely in +having such a wave-length and vibration period as to bring it within +the range of perception of the human eye. + +The second portion of the heat sent us by the moon is that which she +emits on her own account as a warm body--warmed, of course, mainly, if +not entirely, by the action of the sun. The amount of _this_ heat will +depend upon the temperature of the moon's surface and its radiating +power; and the temperature will depend upon a number of things +(chiefly heat-absorbing power of the surface, and the nature and +density of the lunar atmosphere, as well as the supply of heat +received from the sun), being determined by a balance between give and +take. So long as more heat is received in a second than is thrown off +in the same time, the temperature will rise, and _vice versa_. + +It is to be noted, further, that this second component of the moon's +thermal radiance must be mainly what is called "obscure" or dark heat, +like that from a stove or teakettle, and characterized by the same +want of penetrative power. No one knows why at present; but it is a fact +that the heat-radiations from bodies at a low temperature--radiations +of which the vibrations are relatively slow, and the wave-length +great--have no such power of penetrating transparent media as the +higher-pitched vibrations which come from incandescent bodies. A great +part, therefore, of this contingent of the lunar heat is probably +stopped in the upper air, and never reaches the surface of the earth +at all. + +Now, the thermopile cannot, of course, discriminate directly between +the two portions of the lunar heat; but to some extent it does enable +us to do so indirectly, since they vary in quite a different way with +the moon's age. The simple _reflected_ heat must follow the same law +as moonlight, and come to its maximum at full moon. The _radiated_ +heat, on the other hand, will reach its maximum when the average +temperature of that part of the moon's surface turned toward the earth +is highest; and this must be some time after full moon, for the same +sort of reasons that make the hottest part of a summer's day come two +or three hours after noon. + +The conclusion early reached by Lord Rosse was that nearly all the +lunar heat belonged to the second category--dark heat _radiated_ from +the moon's warmed surface, the _reflected_ portion being comparatively +small--and he estimated that the temperature of the hottest parts of +the moon's surface must run as high as 500° F.; well up toward the +boiling-point of mercury. Since the lunar day is a whole month long, +and there are never any clouds in the lunar sky, it is easy to imagine +that along toward two or three o'clock in the lunar afternoon (if I +may use the expression), the weather gets pretty hot; for when the sun +stands in the lunar sky as it does at Boston at two P.M., it has been +shining continuously for more than two hundred hours. On the other +hand, the coldest parts of the moon's surface, when the sun has only +just risen after a night of three hundred and forty hours, must have a +temperature more than a hundred degrees below zero. + +Lord Rosse's later observations modified his conclusions, to some +extent, showing that he had at first underestimated the percentage of +simple reflected heat, but without causing him to make any radical +change in his ideas as to the maximum heat of the moon's surface. + +For some time, however, there has been a growing skepticism among +astronomers, relating not so much to the correctness of his measures +as to the computations by which he inferred the high percentage of +obscure radiated beat compared with the reflected heat, and so deduced +the high temperature of lunar noon. + +Professor Langley, who is now engaged in investigating the subject, +finds himself compelled to believe that the lunar surface never gets +even comfortably warm--because it has no blanket. It receives heat, it +is true, from the sun, and probably some twenty-five or thirty per +cent. more than the earth, since there are no clouds and no air to +absorb a large proportion of the incident rays; but, at the same time, +there is nothing to retain the heat, and prevent the radiation into +space as soon as the surface begins to warm. We have not yet the data +to determine exactly how much the temperature of the lunar rocks would +have to be raised above the absolute zero (-273° C. or -459° F.) in +order that they might throw off into space as much heat in a second as +they would get from the sun in a second. But Professor Langley's +observations, made on Mount Whitney at an elevation of fifteen +thousand feet, when the barometer stood at seventeen inches +(indicating that about fifty-seven per cent. of the air was still +above him), showed that rocks exposed to the perpendicular rays of the +sun were not heated to any such extent as those at the base of the +mountain similarly exposed; and the difference was so great as to make +it almost certain that a mass of rock not covered by a reasonably +dense atmosphere could never attain a temperature of even 200° or 300° +F. under solar radiation, however long continued. + +It must, in fact, be considered at present extremely doubtful whether +any portion of the moon's surface ever reaches a temperature as high +as -100°. + +The subject, undoubtedly, needs further investigation, and it is now +receiving it. Professor Langley is at work upon it with new and +specially constructed apparatus, including a "bolometer" so sensitive +that, whereas previous experimenters have thought themselves fortunate +if they could get deflections of ten or twelve galvanometric divisions +to work with, he easily obtains three or four hundred. We have no time +or space here to describe Professor Langley's "bolometer;" it must +suffice to say that it seems to stand to the thermopile much as that +does to the thermometer. There is good reason to believe that its +inventor will be able to advance our knowledge of the subject by a +long and important step; and it is no breach of confidence to add that +so far, although the research is not near completion yet, everything +seems to confirm the belief that the radiated heat of the moon, +instead of forming the principal part of the heat we get from her, is +relatively almost insignificant, and that the lunar surface now never +experiences a _thaw_ under any circumstances. + +Since the superstition as to the moon's influence upon the wind and +weather is so widespread and deep seated, a word on that subject may +be in order. In the first place, since the total heat received from +the moon, even according to the highest determination (that of Smyth), +is not so much as 0.00001 of that received from the sun, and since the +only hold the moon has on the earth's weather is through the heat she +sends us (I ignore here the utterly insignificant atmospheric _tide_), +it follows necessarily that her influence _must_ be very trifling. In +the next place, all carefully collated observations show that it _is_ +so, and not only trifling, but generally absolutely insensible. + +For example, different investigators have examined the question of +nocturnal cloudiness at the time of full moon, there being a prevalent +belief that the full moon "eats up" light clouds. On comparing thirty +or forty years' observations at each of several stations (Greenwich. +Paris, etc.), it is found that there is no ground for the belief. And +so in almost every case of imagined lunar meteorological influence. As +to the coincidence of weather changes with changes of the moon, it is +enough to say that the idea is absolutely inconsistent with that +progressive movement of the "weather" across the country from west to +east, with which the Signal Service has now made us all so familiar. + +Princeton, April 12, 1884. + + * * * * * + + + + +APPLE TREE BORERS. + + +The apple tree borers have destroyed thousands of trees in New +England, and are likely to destroy thousands more. There are three +kinds of borers which assail the apple tree. The round headed or two +striped apple tree borer, _Saperda candida_, is a native of this +country, infesting the native crabs, thorn bushes, and June berry. It +was first described by Thomas Say, in 1824, but was probably widely +distributed before that. In his "Insects Injurious to Fruit," Prof. +Saunders thus describes the borer: + +"In its perfect state it is a very handsome beetle, about +three-quarters of an inch long, cylindrical in form, of a pale brown +color, with two broad, creamy white stripes running the whole length +of its body; the face and under surface are hoary white, the antennæ +and legs gray. The females are larger than the males, and have shorter +antennæ. The beetle makes its appearance during the months of June and +July, usually remaining in concealment during the day, and becoming +active at dusk. The eggs are deposited late in June and during July, +one in a place, on the bark of the tree, near its base. Within two +weeks the young worms are hatched, and at once commence with their +sharp mandibles to gnaw their way through the outer bark to the +interior. It is generally conceded that the larvæ are three years in +reaching maturity. The young ones lie for the first year in the +sapwood and the inner bark, excavating flat, shallow cavities, about +the size of a silver dollar, which are filled with their sawdust-like +castings. The holes by which they enter being small are soon filled +up, though not until a few grains of castings have fallen from them. +Their presence may, however, often be detected in young trees from the +bark becoming dark colored, and sometimes dry and dead enough to +crack." + +On the approach of winter, it descends to the lower part of its +burrow, where it remains inactive until spring. The second season it +continues its work in the sapwood, and in case two or three are at +work in the same tree may completely girdle it, thus destroying it. +The third year it penetrates to the heart of the tree, makes an +excavation, and awaits its transformation. The fourth spring it comes +forth a perfect beetle, and lays its eggs for another generation. + + +THE FLAT-HEADED BORER. + +The flat-headed apple tree borer, _Chrysobothris femorata_, is also a +native of this country. It is a very active insect, delights to bask +in the hot sunshine; runs up and down the tree with great rapidity, +but flies away when molested. It is about half an inch in length. "It +is of a flattish, oblong form, and of a shining, greenish black color, +each of its wing cases having three raised lines, the outer two +interrupted by two impressed transverse spots of brassy color dividing +each wing cover into three nearly equal portions. The under side of +the body and legs shine like burnished copper; the feet are shining +green." This beetle appears in June and July, and does not confine its +work to the base of the tree, but attacks the trunk in any part, and +sometimes the larger branches. The eggs are deposited in cracks or +crevices of the bark, and soon hatch. The young larva eats its way +through the bark and sapwood, where it bores broad and flat channels, +sometimes girdling and killing the tree. As it approaches maturity, it +bores deeper into the tree, working upward, then eats out to the bark, +but not quite through the bark, where it changes into a beetle, and +then cuts through the bark and emerges to propagate its kind. This +insect is sought out when just beneath the bark, and devoured by +woodpeckers and insect enemies. + +Another borer, the long-horned borer, _Leptostylus aculifer_, is +widely distributed, but is not a common insect, and does not cause +much annoyance to the fruit grower. It appears in August, and deposits +its eggs upon the trunks of apple trees. The larvæ soon hatch, eat +through the bark, and burrow in the outer surface of the wood just +under the bark. + + +PROTECTION AGAINST BORERS. + +The practical point is, What remedies can be used to prevent the +ravages of the borers? The usual means of fighting the borers is, to +seek after them in the burrows, and try to kill them by digging them +out, or by reaching them with a wire. This seems to be the most +effectual method of dealing with them after they have once entered the +tree, but the orchardist should endeavor to prevent the insects from +entering the tree. For this purpose, various washes have been +recommended for applying to the tree, either for destroying the young +larvæ before they enter the bark, or for preventing the beetles +depositing their eggs. It has been found that trees which have been +coated with alkaline washes are avoided by beetles when laying their +eggs. Prof. Saunders recommends that soft soap be reduced to the +consistency of a thick paint, by the addition of a strong solution of +washing soda in water, and be applied to the bark of the tree, +especially about the base or collar, and also extended upward to the +crotches where the main branches have their origin. It should be +applied in the evening of a warm day, so that it may dry and form a +coating not easily dissolved by the rain. This affords a protection +against all three kinds of borers. It should be applied early in June, +before the beetles begin to lay their eggs, and again in July, so as +to keep the tree well protected. + +Hon. T.S. Gold, of Connecticut, at a meeting of the Massachusetts +State Board of Agriculture, in regard to preventing the ravages of the +borer, said: + +"A wash made of soap, tobacco water, and fresh cow manure mingled to +the consistency of cream, and put on early with an old broom, and +allowed to trickle down about the roots of the tree, has proved with +me a very excellent preventive of the ravages of the borer, and a +healthful wash for the trunk of the tree, much to be preferred to the +application of lime or whitewash, which I have often seen applied, but +which I am inclined to think is not as desirable an application as the +potash, or the soda, as this mixture of soft soap and manure." + +J.B. Moore, of Concord, Mass., at the same meeting said, in regard to +the destruction of the borer: + +"I have found, I think, that whale oil soap can be used successfully +for the destruction of that insect. It is a very simple thing; it will +not hurt the tree if you put it on its full strength. You can take +whale oil soap and dilute until it is about as thick as paint, and put +a coating of it on the tree where the holes are, and I will bet you +will never see a borer on that tree until the new crop comes. I feel +certain of it, because I have done it." + +For borers, tarred paper 1 or 2 feet wide has been recommended to be +wrapped about the base of the trunk of the tree, the lower edge being +1 or 2 inches below the surface of the soil. This prevents the +two-striped borer from laying its eggs in the tree, but would not be +entirely effectual against the flat-headed borer, which attacks any +part of the trunk and the branches. By the general use of these means +for the prevention of the ravages of the borers, the damages done by +these insects could be brought within very narrow limits, and hundreds +of valuable apple trees saved. + +H. REYNOLDS, M.D. + +Livermore Falls, Me. + + * * * * * + + + + +KEFFEL'S GERMINATING APPARATUS. + + +The apparatus represented in the annexed cut is designed to show the +quality of various commercial seeds, and make known any fraudulent +adulterations that they may have undergone. It is based upon a direct +observation, of the germination of the seeds to be studied. + +[Illustration: KEFFEL'S GERMINATING APPARATUS.] + +The apparatus consists of a cylindrical vessel containing water to the +height of 0.07 m. Above the water is a germinating disk containing 100 +apertures for the insertion of the seeds to be studied, the +germinating end of the latter being directed toward the water. After +the seeds are in place the disk is filled with damp sand up to the top +of its rim, and the apparatus is closed with a cover which carries in +its center a thermometer whose bulb nearly reaches the surface of the +water. + +The apparatus is then set in a place where the temperature is about +18°, and where there are no currents of air. An accurate result is +reached at the end of about twenty or twenty-four hours. As the +germinating disk contains 100 apertures for as many seeds, it is only +necessary to count the number of seeds that have germinated in order +to get the percentage of fresh and stale ones. + +The aqueous vapor that continuously moistens all the seeds, under +absolutely identical conditions for each, brings about their +germination under good conditions for accuracy and comparison. If it +be desired to observe the starting of the leaves, it is only necessary +to remove the cover after the seeds have germinated. + +This ingenious device is certainly capable of rendering services to +brewers, distillers, seedsmen, millers, farmers, and gardeners, and it +may prove useful to those who have horses to feed, and to amateur +gardeners, since it permits of ascertaining the value and quality of +seeds of every nature.--_La Nature._ + + * * * * * + + + + +MILLET. + + +The season is now at hand when farmers who have light lands, and who +may possibly find themselves short of fodder for next winter feeding, +should prepare for a crop of millet. This is a plant that rivals corn +for enduring a drought, and for rapid growth. There are three popular +varieties now before the public, besides others not yet sufficiently +tested for full indorsement--the coarse, light colored millet, with a +rough head, Hungarian millet, with a smooth, dark brown head, yielding +seeds nearly black, and a newer, light colored, round seeded, and +later variety, known as the golden millet. + +Hungarian millet has been the popular variety with us for many years, +although the light seeded, common millet is but slightly different in +appearance or value for cultivation. They grow in a short time, eight +weeks being amply sufficient for producing a forage crop, though a +couple of weeks more would be required for maturing the seed. Millet +should not be sown in early spring, when the weather and ground are +both cold. It requires the hot weather of June and July to do well; +then it will keep ahead of most weeds, while if sown in April the +weeds on foul land would smother it. + +Millet needs about two months to grow in, but if sowed late in July it +will seem to "hurry up," and make a very respectable showing in less +time. We have sown it in August, and obtained a paying crop, but do +not recommend it for such late seeding, as there are other plants that +will give better satisfaction. Golden millet has been cultivated but a +few years in this country, and as yet is but little known, but from a +few trials we have been quite favorably impressed with it. It is +coarser than the other varieties, but cattle appear to be very fond of +it nevertheless. It resembles corn in its growth nearly as much as +grass, and, compared with the former, it is fine and soft, and it +cures readily, like grass, and may be packed away in hay mows with +perfect safety. It is about two weeks later than the other millets, +and consequently cannot be grown in quite so short a time, although it +may produce as much weight to the acre, in a given period, as either +of the other more common varieties. A bushel of seed per acre is not +too much for either variety of millet.--_N.E. Farmer._ + + * * * * * + + +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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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. 443, June 28, 1884 + +Author: Various + +Release Date: September 29, 2005 [EBook #16773] + +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 + + + + + + +</pre> + +<div class="center"><div class="wide"> +<a href="./images/title.png"><img src="./images/title_th.png" alt="Issue Title" /></a> +</div> +</div> +<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 443.</h1> +<h2>NEW YORK, JUNE 28, 1884.</h2> +<h4>Scientific American Supplement. Vol. XVII., No. 443.</h4> +<h4>Scientific American established 1845</h4> +<h4>Scientific American Supplement, $5 a year.</h4> +<h4>Scientific American and Supplement, $7 a year.</h4> +<hr /> + +<div class="center"> +<table summary="Contents" border="0" cellspacing="5"> +<tr> +<th colspan="2">TABLE OF CONTENTS.</th> +</tr> +<tr> +<td align="left" valign="top">I.</td> +<td align="left"><a href="#art01">CHEMISTRY AND METALLURGY.—Beeswax and its Adulterations. + —Chemical ingredients.—Detection of adulterations.</a></td> +<td align="left">7064</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art02">Phenol in the Stem, Leaves, and Cones of Pinus Sylvestris. + —A discovery bearing on the flora of the Carboniferous + epoch and the formation of petroleum.</a></td> +<td>7065</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art03">The School of Physics and Chemistry of Paris.—With + engraving of laboratory.</a></td> +<td>7065</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art04">Some Relations of Heat to Voltaic and Thermo Electric + Action of Metals in Electrolysis.—By G. GORE.</a></td> +<td>7070</td> +</tr> + +<tr> +<td align="left" valign="top">II.</td> +<td align="left"><a href="#art05">ENGINEERING, MECHANICS, ETC.—Air Refrigerating + Machine.—5 figures.</a></td> +<td>7071</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art06">A Gas Radiator and Heater.</a></td> +<td>7071</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art07">Concrete Water Pipes.</a></td> +<td>7071</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art08">The Sellers Standard System of Screw Threads. Nuts, and + Bolt Heads.—A table.</a></td> +<td>7072</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art09">An English Railway Ferry Boat.—3 figures.</a></td> +<td>7072</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art10">The Problem of Flight and the Flying Machine.</a></td> +<td>7072</td> +</tr> + +<tr> +<td align="left" valign="top">III.</td> +<td align="left"><a href="#art11">TECHNICAL.—Concrete Buildings for Farms.—How to construct + them.</a></td> +<td>7063</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art12">What Causes Paint to Blister and Peel?—How to prevent it.</a></td> +<td>7063</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art13">Olive Oil.—Difficulties encountered in raising an olive + crop.—Process of making Oil.</a></td> +<td>7064</td> +</tr> + +<tr> +<td align="left" valign="top">IV.</td> +<td align="left"><a href="#art14">ELECTRICITY. ETC.—Telephony and Telegraphy on the Same + Wires Simultaneously.—4 figures.</a></td> +<td>7067</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art15">The Electric Marigraph.—An apparatus for measuring the + height of the tide.—With engravings and diagrams showing + the Siemens and Halske marigraph and the operation of the + same.</a></td> +<td>7068</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art16">Delune & Co.'s System of Laying Underground Cables.—2 + figures.</a></td> +<td>7069</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art17">Electricity Applied to Horseshoeing.—Quieting an unruly + animal.—3 engravings.</a></td> +<td>7069</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art18">Esteve's Automatic Pile.—1 figure.</a></td> +<td>7070</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art19">Woodward's Diffusion Motor.</a></td> +<td>7070</td> +</tr> + +<tr> +<td align="left" valign="top">V.</td> +<td align="left"><a href="#art20">ASTRONOMY.—Lunar Heat.—Its reflected and obscure + heat.—Trifling influence of the moon upon wind and + weather.—By Prof. C.A. YOUNG.</a></td> +<td>7073</td> +</tr> + +<tr> +<td align="left" valign="top">VI.</td> +<td align="left"><a href="#art21">NATURAL HISTORY.—The Long-haired Pointer "Mylord." + —With engraving.</a></td> +<td>7073</td> +</tr> + +<tr> +<td align="left" valign="top">VII.</td> +<td align="left"><a href="#art22">HORTICULTURE, ETC.—Apple Tree Borers.—Protection + against the same.</a></td> +<td>7074</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art23">Keffel's Germinating Apparatus.—With engraving.</a></td> +<td>7074</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art24">Millet.—Its Cultivation.</a></td> +<td>7074</td> +</tr> + +<tr> +<td align="left" valign="top">VIII.</td> +<td align="left"><a href="#art25">MISCELLANEOUS.—Puerta del Sol, Madrid, Spain.—With + engraving.</a></td> +<td>7063</td> +</tr> +<tr><td></td> +<td align="left"><a href="#art26">Dust-free Spaces.—A lecture delivered by Dr. OLIVER J. + LODGE before the Royal Dublin Society.</a></td> +<td>7067</td> +</tr> +</table> +</div> + +<hr /> + + +<h2><a name="art25" id="art25"></a><a name="Page_7063" id="Page_7063"></a>PUERTA DEL SOL, MADRID.</h2> + +<p>Puerta del Sol, or Gate of the Sun, Madrid, is the most famous and +favorite public square in the Spanish city of Madrid. It was the +eastern portal of the old city. From this square radiate several of +the finest streets, such as Alcala, one of the handsomest +thoroughfares in the world, Mayor, Martera, Carretas, Geronimo. In our +engraving the post office is seen on the right. Large and splendid +buildings adorn the other sides, which embrace hotels, cafes, reading +rooms, elegant stores, etc. From this square the street railway lines +traverse the city in all directions. The population of the city is +about 400,000. It contains many magnificent buildings. Our engraving +is from <i>Illustrirte Zeitung</i>.</p> + +<div class="figcenter"><a href="./images/1a.png"><img src="./images/1a_th.png" alt="THE PUERTA DEL SOL, MADRID, SPAIN (From a Photograph.)" /></a><br /> THE PUERTA DEL SOL, MADRID, SPAIN (From a Photograph.)</div> + +<hr /> + +<h2><a name="art11" id="art11"></a>CONCRETE BUILDINGS FOR FARMS.</h2> + +<p>Buildings made of concrete have never received the attention in this +country that they deserve. They have the merit of being durable and +fire-proof, and of not being liable to be blown down by violent winds. +It is very easy to erect them in places where sand and gravel are near +at hand and lime is comparatively cheap. Experiments made in England +show that coal screenings may be employed to good advantage in the +place of sand and gravel. Mr. Samuel Preston, of Mount Carroll, Ill., +has a dwelling and several other buildings made of concrete and +erected by himself. They were put up in 1851, and are in excellent +condition. In <i>The Farmers' Review</i> he gives the following directions +for building concrete walls:</p> + +<p>First, secure a good stone foundation, the bottom below frost, the top +about one foot above ground. Near the top of the foundation bed in 2×4 +scantling edgewise transversely with the walls, at such distances +apart as the length of the planks that form the boxes to hold the +concrete may require, the ends of the scantling to run six inches +beyond the outside and inside of the wall. Now take 2×6 studding, one +foot longer than the height of the concrete walls are to be, bolt in +an upright position in pairs to each end of the 2×4 scantling, and, if +a foot wall is to be built, sixteen inches apart, as the box plank +will take up four inches. To hold the studding together at the top, +take pieces of 2×6 lumber, make two mortises in each piece large +enough to slip easily up and down on the studding, forming a tie. +Make one mortise long enough to insert a key, so that the studding can +be opened at the top when the box plank are to be raised. When the box +plank are in position, nail cleats with a hole in each of them on each +side of the studding, and corresponding holes in the studding, into +which insert a pin to hold the plank to the studding. Bore holes along +up in the studding, to hold the boxes when raised.</p> + +<p>To make the walls hollow, and I would do it in a building for any +purpose, use inch boards the same width of the box plank, one side +planed; put the two rough sides together with shingles between, +nailing them together with six-penny nails; place them in the middle +of the wall, the thin end of the shingle down. That gives them a bevel +and can be easily raised with the boxes. To tie the wall together, at +every third course place strips of boards a little shorter than the +thickness of the wall; cut notches in each so that the concrete will +fill in, holding all fast. The side walls being up, place two inch +planks on top of the wall upon which to rest the upper joists, put on +joist and rafters, remove the box plank, take inch boards for boxes, +cut to fit between joists and rafters, and fill with concrete to upper +side of rafters, which makes walls that will keep out cold and damp, +all kinds of vermin, and a roof which nothing but a cyclone can +remove. In making door and window frames, make the jambs two inches +narrower than the thickness of the walls, nailing on temporary two +inch strips.</p> + +<p>Make the mortar bed large enough to hold the material for one course; +put in unslaked quicklime in proportion to 1 to 20 or 30 of other +material; throw into it plenty of water, and don't have that +antediluvian idea that you can drown it; put in clean sand and gravel, +broken stone, making it thin enough, so that when it is put into boxes +the thinner portion will run in, filling all interstices, forming a +solid mass. A brick trowel is necessary to work it down alongside the +boxing plank. One of the best and easiest things to carry the concrete +to the boxes is a railroad wheelbarrow, scooping it in with a scoop +shovel. Two courses a week is about as fast as it will be safe to lay +up the walls.</p> + +<hr /> + +<p>The <i>Medical Summary</i> recommends the external use of buttermilk to +ladies who are exposed to tan or freckles.</p> + +<hr /> + +<h2><a name="art12" id="art12"></a>WHAT CAUSES PAINT TO BLISTER AND PEEL?</h2> + +<h3>HOW TO PREVENT IT.</h3> + +<p>This subject has been treated by many, but out of the numerous ideas +that have been brought to bear upon it, the writers have failed to +elucidate the question fully, probably owing to the fact that in most +parts they were themselves dubious as to the real cause. Last year +W.S. gave a lengthy description in the <i>Building News</i>, in which he +classified blistering and peeling of paint into one of blistering +only. He stated in the beginning of his treatise the following:</p> + +<p>"The subject of blistering of paint has from time to time engrossed +the attention of practical men; but so far as we can follow it in the +literature pertaining to the building trade, its cause has never been +clearly laid down, and hence it is a detail enshrouded in mystery."</p> + +<p>W.S. dwells mostly, in his following explanations on blistering +paints, on steam raised in damp wood. Also an English painter, +according to the <i>Painters' Journal</i>, lately reiterates the same +theory, and gives sundry reasons how water will get into wood through +paint, but is oblivious that the channels which lead water into wood +are open to let it out again. He lays great stress on boiled oil +holding water in suspense to cause blistering, which is merely a +conjecture. Water boils at 212° F. and linseed oil at 600° F., +consequently no water can possibly remain after boiling, and a drop of +water put into boiling oil would cause an explosion too dangerous to +be encountered.</p> + +<p>It will be shown herewith that boiled oil, though in general use, is +unfit for durable painting, that it is the cause of most of the +troubles painters have to contend with, and that raw linseed oil +seasoned by age is the only source to bind pigments for durable +painting; but how to procure it is another trouble to overcome, as all +our American raw linseed oil has been heated by the manufacturers, to +qualify it for quick drying and an early market, thereby impairing its +quality. After linseed oil has been boiled, it becomes a poor varnish; +it remains soft and pliable when used in paint, giving way to air +pressure from the wood in hot weather, forming blisters. Turpentine +causes no blistering; it evaporates upon being exposed, and leaves the +paint in a porous condition for the gas in the wood to escape; but all +<a name="Page_7064" id="Page_7064"></a>painters agree that blistering is caused by gas, and on investigation +we find two main sources from which gas is generated to blister +paint—one from the wood, the other from the ingredients of the paint. +The first named source of gas is started in hot weather by expansion +of air confined in painted wood, which presses against the paint and +raises blisters when the paint is too soft to resist. Tough, +well-cemented paint resists the pressure and keeps the air back. These +blisters mostly subside as soon as the air cools and returns to the +pores, but subsequently peel off.</p> + +<p>W.S. and others assert that damp in painted wood turns into steam when +exposed to sun heat, forming blisters, which cannot be possible when +we know that water does not take a gaseous form (steam) at less than +212° F. They have very likely been deluded by the known way of +distilling water with the aid of sunshine without concentrating the +rays of the sun, based upon the solubility of water in air, viz.: Air +holds more water in solution (or suspension) in a warmer than in a +cooler degree of temperature; by means of a simple apparatus +sun-heated air is guided over sun-heated water, when the air saturated +with water is conducted into a cooler, to give up its water again. But +water has an influence toward hastening to blister paint; it holds the +unhardened woodsap in solution, forming a slight solvent of the oil, +thereby loosening the paint from the wood, favoring blistering and +peeling. There is a certain kind of blister which appears in certain +spots or places only, and nowhere else, puzzling many painters. The +explanation of this is the same as before—soft paint at these spots, +caused by accident or sluggish workmen having saturated the wood with +coal oil, wax, tar, grease, or any other paint-softening material +before the wood was painted, which reacts on the paint to give way to +air pressure, forming blisters.</p> + +<p>The second cause of paint blistering from the ingredients of the paint +happens between any layer of paint or varnish on wood, iron, stone, or +any other substance. Its origin is the gaseous formation of volatile +oils during the heated season, of which the lighter coal oils play the +most conspicuous part; they being less valuable than all other +volatile oils, are used in low priced japan driers and varnishes. +These volatile oils take a gaseous form at different temperatures, lie +partly dormant until the thermometer hovers at 90° F. in the shade, +when they develop into gas, forming blisters in airtight paint, or +escape unnoticed in porous paint. This is the reason why coal-tar +paint is so liable to blister in hot weather; an elastic, soft +coal-tar covering holds part of its volatile oil confined until heated +to generate into gas; a few drops only of such oil is sufficient to +spoil the best painted work, and worse, when it has been applied in +priming, it settles into the pores of the wood, needing often from two +to three repetitions of scraping and repainting before the evil is +overcome. Now, inasmuch as soft drying paint is unfit to answer the +purpose, it is equally as bad when paint too hard or brittle has been +used, that does not expand and contract in harmony with the painted +article, causing the paint to crack and peel off, which is always the +case when either oil or varnish has been too sparingly and turpentine +too freely used. Intense cold favors the action, when all paints +become very brittle, a fact much to be seen on low-priced vehicles in +winter time. Damp in wood will also hasten it, as stated in +blistering, the woodsap undermining the paint.</p> + +<p>To avoid peeling and blistering, the paint should be mixed with raw +linseed oil in such proportions that it neither becomes too brittle +nor too soft when dry. Priming paint with nearly all oil and hardly +any pigment is the foundation of many evils in painting; it leaves too +much free oil in the paint, forming a soft undercoat. For durable +painting, paint should be mixed with as much of a base pigment as it +can possibly be spread with a brush, giving a thin coat and forming a +chemical combination called soap. To avoid an excess of oil, the +following coats need turpentine to insure the same proportion of oil +and pigment. As proof of this, prime a piece of wood and a piece of +iron with the same paint; when the wood takes up part of the oil from +the paint and leaves the rest in proportion to harden well, where at +the same time the paint on iron remains soft. To be more lucid, it +need be explained, linseed oil boiled has lost its oleic acid and +glycerine ether, which form with the bases of pigments the insoluble +soap, as well as its albumen, which in boiling is thrown out. It +coagulates at 160° F. heat; each is needed to better withstand the +action of wind and weather, preventing the dust from attaching itself +to a painted surface, a channel for ammonia in damp weather to +dissolve and wash off the paint. In later years linseed oil has been +extracted from linseed meal by the aid of naphtha and percolation, the +product of a very clear, quick drying oil, but lacking in its binding +quality, no doubt caused by the naphtha dissolving the fatty matter +only, leaving the glycerine and albumen in the meal.</p> + +<p>All pigments of paint group according to their affinity to raw linseed +oil into three classes. First, those that form chemical combinations, +called soap. This kind is the most durable, is used for priming +purposes, and consists of lead, zinc, and iron bases, of which red +lead takes up the most oil; next, white lead, the pure carbonate Dutch +process made, following with zinc white and iron carbonates, as iron +ore paint, Turkey umber, yellow ocher; also faintly the chromates of +lead—chrome-green and chrome-yellow, finishing with the poorest of +all, modern white lead, made by the wet or vinegar process. The second +class being neutrals have no chemical affinity to linseed oil; they +need a large quantity of drier to harden the paint, and include all +blacks, vermilion, Prussian, Paris, and Chinese blue, also terra di +Sienna, Vandyke brown, Paris green, verdigris, ultramarine, genuine +carmine, and madderlake. The last seven are, on account of their +transparency, better adapted for varnish mixtures—glazing. The third +class of pigments act destructively to linseed oil; they having an +acid base (mostly tin salt, hydrochloride of tin, and redwood dye), +form with the gelatinous matter of the oil a jelly that will neither +work well under the brush nor harden sufficiently, and can be used in +varnish for glazing only; they are not permanent in color, and among +the most troublesome are the lower grades of so-called carmines, +madderlakes, rose pinks, etc., which contain more or less acidous +dyes, forming a soft paint with linseed oil that once dry on a job can +be twisted or peeled off like the skin of a ripe peach. All these +combinations of paint have to be closely observed by the painter to +insure his success.</p> + +<p>Twenty-five years ago a house needed to be painted outside but once in +from five to seven years; it looked well all the time, as no dust +settled in the paint to make it unsightly. Painters then used the +Dutch-process-made white-lead, a base and raw linseed oil, a fat acid, +which formed the insoluble soap. They also put turpentine in the +following coats, to keep up the proportions of oil and pigment. All +held out well against wind and weather. Now they use the +wet-process-made white lead, neutralized by vinegar, with oil +neutralized by boiling, from the first to the last coat, and—fail in +making their work permanent.</p> + +<p>W.S., in the <i>Building News</i>, relates an unaccountable mysterious +blistering in a leaky house, where the rainwater came from above on a +painted wood wall, blistering the paint in streaks and filled at the +lower ends with water, which no doubt was caused by the water soaking +the wood at the upper ends where there was no paint, and following it +down through the fibers, pushed and peeled off the soft, inadhesive +paint. Green, sappy, and resinous wood is unfit for durable painting, +and to avoid blistering and peeling wood should be well seasoned and +primed with all raw linseed oil, some drier, to insure a moderately +slow drying, and as much of a base pigment as the painter can possibly +spread (much drier takes up too much oil acid, needed for the pigment +base to combine with), which insures a tough paint that never fails to +stand against blistering or peeling, as well as wind, weather, and +ammonia.</p> + +<p>The coach, car, and house painter can materially improve his painting +where his needs lie by first oiling the wood with raw oil, then +smoothing the surface down with lump pumicestone, washing it with a +mixture of japan drier or, better yet, gold sizing and turpentine, +wiping dry, and following it up with a coat of white lead, oil, and +turpentine. The explanation is: the raw oil penetrates the wood and +raises the wood fibers on the surface to be rubbed down with +pumicestone, insuring the best surface for the following painting: to +harden the oil in the wood it receives a coat of japan drier, which +follows into the pores and there forms a tough, resinous matter, +resisting any air pressure that might arise from within, and at the +same time reacts on the first coat of lead as a drier. This mode +insures the smoothest and toughest foundation for the following +painting, and may be exposed to the hottest July sun without fear of +either blistering or peeling.</p> + +<p class="signature">LOUIS MATERN.</p> + +<p>Bloomington, Ill.</p> + +<hr /> + +<h2><a name="art13" id="art13"></a>OLIVE OIL.</h2> + +<p>The following particulars with regard to the production of olive oil +in Tuscany have been furnished to Mr. Consul Inglis by one of the +principal exporters in Leghorn:</p> + +<p>The olive oil produced in Tuscany from the first pressing of the fruit +is intended for consumption as an article of food. Hence, great +attention is paid both to the culture of the olive tree and the +process of making oil.</p> + +<p>The olive crop is subject to many vicissitudes, and is an uncertain +one. It may be taken as a rule that a good crop does not occur more +frequently than once in three years. A prolonged drought in summer may +cause the greater part of the small fruit to fall off the trees. A +warm and wet autumn will subject the fruit to the ravages of a maggot +or worm, which eats its way into it. Fruit thus injured falls to the +ground prematurely, and the oil made from it is of very bad quality, +being nauseous in taste and somewhat thick and viscous. Frost +following immediately on a fall of snow or sleet, when the trees are +still wet, will irretrievably damage the fruit, causing it to shrivel +up and greatly diminishing the yield of oil, while the oil itself has +a dark color, and loses its delicate flavor.</p> + +<p>The olive tree in Tuscany generally blossoms in April. By November the +fruit has attained its full size, though not full maturity, and the +olive harvest generally commences then. The fruit, generally speaking, +is gathered as it falls to the ground, either from ripeness or in +windy weather. In some districts, however, and when the crop is short, +the practice is to strip the fruit from the trees early in the season. +When there is a full crop the harvest lasts many months, and may not +be finished till the end of May, as the fruit does not all ripen +simultaneously.</p> + +<p>Oil made early in the season has a deeper color, and is distinguished +by a fruity flavor, with a certain degree of pungency; while as the +season advances it becomes lighter in color, thinner in body, and +milder and sweeter in taste. Oil made toward the close of the harvest +in April or May from extremely ripe fruit is of a very pale straw +color, mild and sweet to the taste, though sometimes, if the fruit has +remained too long on the trees, it may be slightly rancid. Oil very +light in color is much prized in certain countries, notably France, +and hence, if it also possesses good quality, commands a higher price +in the Tuscan markets.</p> + +<p>The fruit of the olive tree varies just as much in quality as does the +grape, according to the species of the tree itself, the nature of the +soil, exposure, and climate of the locality where it grows. Some +varieties of the olive tree largely grown, because thought to be +better suited to the special conditions of some districts, yield a +fruit which imparts a bitter taste to the oil made from it; such oil, +even when otherwise perfect, ranks as a second rate quality.</p> + +<p>The highest quality of oil can only be obtained when the fruit is +perfectly and uniformly sound, well ripened, gathered as soon as it +has dropped from the trees, and crushed immediately with great +attention. Should the fruit remain any time on the ground, +particularly during wet weather, it deteriorates fast and gets an +earthy taste; while if allowed to remain an undue length of time in +the garners it heats, begins to decompose, and will yield only bad +oil.</p> + +<p>The process of making oil is as follows: The fruit is crushed in a +stone mill, generally moved by water power; the pulp is then put into +bags made of fiber, and a certain number of these bags, piled one upon +another, are placed in a press, most frequently worked by hand; when +pressure is applied, the oil flows down into a channel by which it is +conveyed to a receptacle or tank.</p> + +<p>When oil ceases to flow, tepid water is poured upon the bags to carry +off oil retained by the bags. The pulp is then removed from the bags, +ground again in the mill, then replaced in the bags, and pressed a +second time. The water used in the process of making oil must be quite +pure; the mill, press, bags, and vessels sweet and clean, as the least +taint would ruin the quality of the oil produced.</p> + +<p>The oil which has collected in the tank or receptacle just mentioned +is removed day by day, and the water also drained off, as oil would +suffer in quality if left in contact with water; the water also, which +necessarily contains some oil mingled with it, is sent to a deposit +outside, and at some distance from the crushing house, which is called +the "Inferno," where it is allowed to accumulate, and the oil which +comes to the surface is skimmed off from time to time. It is fit only +for manufacturing purposes.</p> + +<p>After the second pressing the olive-pulp is not yet done with; it is +beaten up with water by mechanical agitators moved by water-power, and +then the whole discharged into open-air tanks adjoining the crushing +house. There the crushed olive kernels sink to the bottom, are +gathered up and sold for fuel, fetching about 12 francs per 1,000 +kilos, while the <i>debris</i> of the pulp is skimmed off the surface of +the tank and again pressed in bags, yielding a considerable quantity +of inferior oil, called "olio lavato," or washed oil, which, if +freshly made, is even used for food by the poorer classes. The pulp +then remaining has still further use. It is sold for treatment in +factories by the sulphide of carbon process, and by this method yields +from seven to nine per cent. of oil, of course suitable only for +manufacturing purposes. Only the first two pressings yield oil which +ranks as first quality, subject of course to the condition of the +fruit being unexceptionable. New oil is allowed to rest a while in +order to get rid of sediment; it is then clarified by passing through +clean cotton wool, when it is fit for use.</p> + +<p>The highest quality of olive oil for eating purposes should not only +be free from the least taint in taste or smell, but possessed of a +delicate, appetizing flavor. When so many favorable conditions are +needed as to growth, maturity, and soundness of the fruit, coupled +with great attention during the process of oil-making, it is not to be +wondered at that by no means all or even the greater part of the oil +produced in the most favored districts of Tuscany is of the highest +quality. On the contrary, the bulk is inferior and defective.</p> + +<p>These defective oils are largely dealt in both for home consumption +and export, when price and not quality is the object.</p> + +<p>In foreign countries there is always a market for inferior, defective +olive oil for cooking purposes, etc., provided the price be low. Price +and not quality is the object, so much so that when olive oil is dear, +cotton-seed, ground-nut, and other oils are substituted, which bear +the same relation to good olive oil that butterine and similar +preparations do to real butter.</p> + +<p>The very choicest qualities of pure olive oil are largely shipped from +Leghorn to England, along with the very lowest qualities, often also +adulterated.</p> + +<p>The oil put into Florence flasks is of the latter kind. Many years +back this was not the case, but now it is a recognized fact that +nothing but the lowest quality of oil is put into these flasks; oil +utterly unfit for food, and so bad that it is a mystery to what use it +is applied in England. Importers in England of oil in these flasks +care nothing, however, about quality; cheapness is the only +desideratum.</p> + +<p>The best quality of Tuscan olive oil is imported in London in casks, +bottled there, and bears the name of the importers alone on the label. +There is no difficulty in procuring in England the best Tuscan oil, +which nothing produced elsewhere can surpass; but consumers who wish +to get, and are willing to pay for, the best article must look to the +name and reputation of the importers and the general excellence of all +the articles they sell, which is the best guarantee they can have of +quality.</p> + +<hr /> + +<h2><a name="art01" id="art01"></a>BEESWAX AND ITS ADULTERATIONS.</h2> + +<p>Beeswax is a peculiar waxy substance secreted only by bees, and +consisting of 80.2 per cent. carbon, 13.4 per cent. hydrogen, and 6.4 +per cent. oxygen. It is a mixture of myricine, cerotic acid, and +cerolein, the first of which is insoluble in boiling alcohol, the +second is soluble in hot alcohol and crystallizes out on cooling, +while the third remains dissolved in cold alcohol.</p> + +<p>Although we are unable to produce real beeswax artificially, there are +many imitations which are made use of to adulterate the genuine +article, and their detection is a matter of considerable difficulty. +Huebl says (<i>Dingl. Jour.</i>, p. 338) that the most reliable method of +estimating the adulteration of beeswax is that proposed by Becker, and +known as the saponification method.</p> + +<p>The quantity of potassic hydrate required to saponify one gramme or 15 +grains of pure beeswax varies from 97 to 107 milligrammes. Other kinds +of wax and its substitutes require in some cases more and in others +less of the alkali. This method would, however, lead to very erroneous +conclusions if applied to a mixture of which some of the constituents +have higher saponification numbers than beeswax and others higher, as +one error would balance the other.</p> + +<p>To avoid this, the quantity of alkali required to saponify the +myricine is first ascertained, and then that required to saturate the +free cerotic acid. In this way two numbers are obtained; and in an +investigation of twenty samples of Austrian yellow beeswax, the author +found these numbers stood to each other almost in the constant ratio +of 1 to 3.70. Although this ratio cannot be considered as definitely +established by so few experiments, it may serve as a guide in judging +of the purity of beeswax.</p> + +<p>The experiment is carried out as follows: 3 or 4 grammes of the wax +that has been melted in water are put in 20 c.c. of neutral 95 per +cent, alcohol, and warmed until the wax melts, when phenolphthaleine +is added, and enough of an alcoholic solution of potash run in from a +burette until on shaking it retains a faint but permanent red color. +The burette used by the author is divided in 0.05 c.c. After adding 20 +c.c. more of a half normal potash solution, it is heated on a water +bath for ¾ hour. Then the uncombined excess of alkali is titrated with +half normal hydrochloric acid. The alcohol must be tested as to its +reaction before using it, and carefully neutralized with the acid of +phenolphthalein.</p> + +<p>To saturate the free acid in 1 gramme of wax requires 19 to 21 +milligrammes of potassic hydrate, while 73 to 76 milligrammes more are +necessary to saponify the myricine ether. The lower numbers in the one +usually occur with low numbers for the other, so that the proportions +remain 1 to 3.6 or 1 to 3.8.</p> + +<p>For comparison he gives the following numbers obtained with one gramme +of the more common adulterants:</p> + + +<div class='center'> +<table border="1" cellspacing="0" summary=""> +<tr><td align="center"> </td><td align="center">To neutralize<br /> the acid.</td><td align="center">To convert<br />the ether.</td><td align="center">Total <br />saponification.</td><td align="center">Ratio.</td></tr> +<tr><td align="left">Japanese wax</td><td align="right">20</td><td align="right">200</td><td align="right">220</td><td align="right">10</td></tr> +<tr><td align="left">Carnauba wax</td><td align="right">4</td><td align="right">75</td><td align="right">79</td><td align="right">19</td></tr> +<tr><td align="left">Tallow</td><td align="right">4</td><td align="right">176</td><td align="right">180</td><td align="right">44</td></tr> +<tr><td align="left">Stearic acid</td><td align="right">195</td><td align="right">0</td><td align="right">195</td><td align="right">0/195</td></tr> +<tr><td align="left">Rosin</td><td align="right">110</td><td align="right">1.6</td><td align="right">112</td><td align="right">0.015</td></tr> +<tr><td align="left">Paraffine</td><td align="right">0</td><td align="right">0</td><td align="right">0</td><td align="right">0</td></tr> +<tr><td align="left">Ceresine</td><td align="right">0</td><td align="right">0</td><td align="right">0</td><td align="right">0</td></tr> +<tr><td align="left">Yellow beeswax</td><td align="right">20</td><td align="right">75</td><td align="right">95</td><td align="right">3.75</td></tr> +</table></div> + +<p>The author deduces the following conclusions as the results of these +investigations:</p> + +<p>1. If the numbers obtained lie between these limits, 19 to 21, 73 to +76, 92 to 97, and 3.6 to 3.8 respectively, it may be assumed <a name="Page_7065" id="Page_7065"></a>that the +beeswax is pure, provided it also corresponds to beeswax in its +physical properties.</p> + +<p>2. If the saponification figures fall below 92 and yet the ratio is +correct, it is adulterated with some neutral substance like paraffine.</p> + +<p>3. If the ratio is above 3.8, it is very probable that Japanese or +carnauba wax or grease has been added.</p> + +<p>4. If the ratio falls below 3.6, stearic acid or resin has been used +as the adulterant.</p> + +<hr /> + +<h2><a name="art02" id="art02"></a>PHENOL IN THE STEM, LEAVES, AND CONES OF PINUS SYLVESTRIS.</h2> + +<h3>A DISCOVERY BEARING ON THE FLORA OF THE CARBONIFEROUS EPOCH AND +THE FORMATION OF PETROLEUM.</h3> + +<h3>By A.B. GRIFFITHS, Ph.D., F.C.S. Membre de la Societe Chimique de +Paris, Medallist in Chemistry and Botany, etc.</h3> + +<p>Having found, in small quantities, alcohols of the C<ins class="trans" title="Transcriber's Note: Subscript added. Missing in two different original versions."><sub><i>n</i></sub></ins>H<sub>2<i>n</i>-7</sub> +series, last summer, in the stem, acicular leaves, and cones of <i>Pinus +sylvestris</i>, I wish in this paper to say a few words on the subject.</p> + +<p>First of all, I took a number of cones, cut them up into small pieces, +and placed them in a large glass beaker, then nearly filled it with +distilled water, and heated to about 80° C., keeping the decoction at +this temperature for about half an hour, I occasionally stirred with a +glass rod, and then allowed it to cool, and filtered. This filtrate +was then evaporated nearly to dryness, when a small quantity of +six-sided prisms crystallized out, which subsequently were found to be +the hydrate of phenol (C<sub>6</sub>H<sub>5</sub>HO)<sub>2</sub>H<sub>2</sub>O. Its melting point was +found to be 17.2° C. Further, the crystals already referred to were +dissolved in ether, and then allowed to evaporate, when long colorless +needles were obtained, which, on being placed in a dry test tube and +the tube placed in a water bath kept at 42° C., were found to melt; +and on making a careful combustion analysis of these crystals, the +following composition was obtained:</p> + + +<div class='center'> +<table border="0" width="33%" cellspacing="0" summary=""> +<tr><td align='left'>Carbon</td><td align='right'>76.6</td></tr> +<tr><td align='left'>Hydrogen</td><td align='right'>6.4</td></tr> +<tr><td align='left'>Oxygen</td><td align='right'>17.0</td></tr> +<tr><td align='left'></td><td align='right'><span class="over">100.0</span></td></tr> +</table></div> + + +<p>This gives C<sub>6</sub>H<sub>6</sub>O, which is the formula for phenol.</p> + +<p>On dissolving some of these crystals in water (excess) and adding +ferric chloride, a beautiful violet color was imparted to the +solution. To another aqueous solution of the crystals was added +bromine water, and a white precipitate was obtained, consisting of +tribromophenol. An aqueous solution of the crystals immediately +coagulated albumen.</p> + +<p>All these reactions show that the phenol occurs in the free state in +the cones of this plant. In the same manner I treated the acicular +leaves, and portions of the stem separately, both being previously cut +up into small pieces, and from both I obtained phenol.</p> + +<p>I have ascertained the relative amount of phenol in each part of the +plant operated upon; by heating the stem with water at 80° C., and +filtering, and repeating this operation until the aqueous filtrate +gave no violet color with ferric chloride and no white precipitate +with bromine water.</p> + +<p>I found various quantities according to the age of the stem. The older +portions yielding as much as 0.1021 per cent, while the young portions +only gave 0.0654 per cent. The leaves yielding according to their age, +0.0936 and 0.0315 per cent.; and the cones also gave varying amounts, +according to their maturity, the amounts varying between 0.0774 and +0.0293.</p> + +<p>Two methods were used in the quantitative estimation of the amount of +phenol. The first was the new volumetric method of M. Chandelon +(<i>Bulletin de la Societe Chemique de Paris</i>, July 20, 1882; and +<i>Deutsch-Americanishe Apotheker Zeitung</i>, vol. iii., No. 12, September +1, 1882), which I have found to be very satisfactory. The process +depends on the precipitation of phenol by a dilute aqueous solution of +bromine as tribromophenol. The second method was to extract, as +already staled, a known weight of each part of the plant with water, +until the last extract gives <i>no</i> violet color with ferric chloride, +and no white precipitate with the bromine test (which is capable of +detecting in a solution the 1/60000 part of phenol). The aqueous +extract is at this point evaporated, then ether is added, and finally +the ethereal solution is allowed to evaporate. The residue (phenol) is +weighed directly, and from this the percentage can be ascertained. By +this method of extraction, the oil of turpentine, resins, etc., +contained in <i>Pinus sylvestris</i> do not pass into solution, because +they are insoluble in water, even when boiling; what passes into +solution besides phenol is a little tannin, which is practically +insoluble in ether.</p> + +<p>From this investigation it will be seen that phenol exists in various +proportions in the free state in the leaves, stem, and cones of <i>Pinus +sylvestris</i>, and as this compound is a product in the distillation of +coal, and as geologists have to a certain extent direct evidence that +the flora of the Carboniferous epoch was essentially crytogamous, the +only phænogamous plants which constituted any feature in "the coal +forests" being the coniferæ, and as coal is the fossil remains of that +gigantic flora which contained phenol, I think my discovery of phenol +in the coniferæ of the present day further supports, from a chemical +point of view, the views of geologists that the coniferæ existed so +far back in the world's history as the Carboniferous age.</p> + +<p>I think this discovery also supports the theory that the origin of +petroleum in nature is produced by moderate heat on coal or similar +matter of a vegetable origin. For we know from the researches of +Freund and Pebal (<i>Ann. Chem. Pharm</i>., cxv. 19), that petroleum +contains phenol and its homologues, and as I have found this organic +compound in the coniferæ of to-day, it is probable that petroleum in +certain areas has been produced from the conifers and the flora +generally of some primæval forests. It is stated by numerous chemists +that "petroleum almost always contains solid paraffin" and similar +hydrocarbons. Professors Schorlemmer and Thorpe have found heptane in +Pinus, which heptane yielded primary heptyl-alcohol, and +methyl-pentyl-carbinol, exactly as the heptane obtained from petroleum +does (<i>Annalen de Chemie</i>, ccxvii., 139, and clxxxviii., 249; and +<i>Berichte der Deutschen Chemischen Gesellschaft</i>, viii., 1649); and, +further, petroleum contains a large number of hydrocarbons which are +found in coal. Again, Mendelejeff, Beilstein, and others (<i>Bulletin de +la Societe Chemique de Paris</i>, No. 1, July 5, 1883), have found +hydrocarbons of the—</p> + + +<p class="center">C<sub><i>n</i></sub>H<sub>2<i>n</i>2+</sub>, C<sub><i>n</i></sub>H<sub>2<i>n</i>-6</sub>,</p> + + +<p>also hydrocarbons of the C<sub><i>n</i></sub>H<sub>2<i>n</i></sub> series in the petroleum of +Baku, American petroleum containing similar hydrocarbons.</p> + +<p>I think all these facts give very great weight to the theory that +petroleum is of organic origin.</p> + +<p>On the other hand, Berthelot, from his synthetic production of +hydrocarbons, believes that the interior of the globe contains +alkaline metals in the <i>free</i> state, which yield acetylides in the +presence of carbonic anhydride, which are decomposed into acetylene by +aqueous vapor. But it has been already proved that acetylene may be +polymerized, so as to produce aromatic carbides, or the derivatives of +marsh gas, by the absorption of hydrogen. Berthelot's view, therefore, +is too imaginative; for the presence of <i>free</i> alkaline metals in the +earth's interior is an unproved and very improbable hypothesis. +Byasson states that petroleum is formed by the action of water, +carbonic anhydride, and sulphureted hydrogen upon incandescent iron. +Mendelejeff thinks it is formed by the action of aqueous vapor upon +carbides of iron; and in his article, "Petroleum, the Light of the +Poor" (in this month's—February—number of <i>Good Words</i>), Sir Lyon +Playfair, K.C.B., F.R.S., etc., holds opinions similar to those of +Mendelejeff.</p> + +<p>Taking in consideration the facts that solid paraffin is found in +petroleum and is also found in coal, and from my own work that phenol +exists in <i>Pinus sylvestris</i>, and has been found by others in coal +which is produced from the decomposition of a flora containing +numerous gigantic coniferæ allied to Pinus, and that petroleum +contains phenol, and each (<i>i.e.</i>, petroleum and coal) contains a +number of hydrocarbons common to both, I am inclined to think that the +balance of evidence is in favor of the hypothesis that petroleum has +been produced in nature from a vegetable source in the interior of the +globe. Of course, there can be no practical or direct evidence as to +the origin of petroleum; therefore "theories are the only lights with +which we can penetrate the obscurity of the unknown, and they are to +be valued just as far as they illuminate our path."</p> + +<p>In conclusion, I think that there is a connecting link between the old +pine and fir forest of bygone ages and the origin of petroleum in +nature.—<i>Chemical News</i>.</p> + +<hr /> + +<h2><a name="art03" id="art03"></a>THE SCHOOL OF PHYSICS AND CHEMISTRY OF PARIS.</h2> + +<p>Recently we paid a visit to the New Municipal School of Physics and +Chemistry that the city of Paris founded in 1882, and that is now in +operation in the large building of the old Rollin College. This +establishment is one of those that supply a long-felt want of our +time, and we are happy to make it known to our readers. The object for +which it was designed was, in the intention of its founders, to give +young people who have just graduated from the higher primary schools +special instruction which shall be at once scientific and practical, +and which shall fit them to become engineers or superintendents in +laboratories connected with chemical and physical industries. To reach +such a result it has been necessary to give the teaching an +essentially practical character, by permitting the pupils to proceed +of themselves in manipulations in well fitted laboratories. It is upon +this important point that we shall now more particularly dwell; but, +before making known the general mode of teaching, we wish to quote a +few passages from the school's official programme:</p> + +<p>"Many questions and problems, in physics as well as in chemistry, find +their solution only with the aid of mathematics and mechanics. It +therefore became necessary, through lectures bearing upon the useful +branches of mathematics, to supplement the too limited ideas that +pupils brought with them on entering the school. Mathematics and +mechanics are therefore taught here at the same time with physics and +chemistry, but they are merely regarded in the light of auxiliaries to +the latter.</p> + +<p>"The studies extend over three years. Each of the three divisions +(1st, 2d, and 3d years) includes thirty pupils.</p> + +<p>"During the three first semesters, pupils of the same grade attend +lectures and go through manipulations in chemistry, physics, +mathematics, and draughting in common.</p> + +<p>"At the end of the third semester they are divided into 10 physical +and 20 chemical students.</p> + +<p>"From this moment, although certain courses still remain wholly or +partially common to the two categories of pupils (physical and +chemical), the same is no longer the case with regard to the practical +exercises, for the physical students thereafter manipulate only in the +physical laboratories, and <a name="Page_7066" id="Page_7066"></a>the chemical only in the chemical +laboratories; moreover, the manipulations acquire a greater importance +through the time that is devoted to them.</p> + +<p>"At each promotion the three first semesters are taken up with general +and scientific studies. Technical applications are the subject of the +lectures and exercises of the three last semesters. At the end of the +third year certificates are given to those pupils who have undergone +examination in a satisfactory manner, and diplomas to such as have +particularly distinguished themselves."</p> + +<p>When pupils have been received at the school, after passing the +necessary examination, their time of working is divided up between +lectures and questionings and different laboratory manipulations.</p> + +<p>The course of lectures on general and applied physics comprises +hydrostatics and heat (Prof. Dommer), electricity and magnetism (Prof. +Hospitalier), and optics and acoustics (Prof. Baille). Lectures on +general chemistry are delivered by Profs. Schultzenberger and +Henninger, on analytical chemistry by Prof. Silva, on chemistry +applied to the industries by Prof. Henninger (for inorganic) and Prof. +Schultzenberger (for organic). The lectures on pure and applied +mathematics and mechanics are delivered by Profs. Levy and Roze.</p> + +<div class="figcenter"><a href="./images/3a.png"><img src="./images/3a_th.png" alt="GENERAL VIEW OF A LABORATORY AT THE PARIS SCHOOL OF PHYSICS AND CHEMISTRY." /></a><br /> GENERAL VIEW OF A LABORATORY AT THE PARIS SCHOOL OF PHYSICS AND CHEMISTRY.</div> + +<p>The pupils occupy themselves regularly every day, during half the time +spent at the school, with practical work in analytical and applied +chemistry and physics and general chemistry. This practical work is a +complement to the various lectures, and has reference to what has been +taught therein. Once or twice per week the pupils spend three hours in +a shop devoted to wood and metal working, and learn how to turn, +forge, file, adjust, etc.</p> + +<p>The school's cabinets are now provided with the best instruments for +study, and are daily becoming richer therein. The chemical +laboratories are none the less remarkably organized. In the +accompanying cut we give a view of one of these—the one that is under +the direction of Mr. Schultzenberger, professor of chemistry and +director of the new school. Each pupil has his own place in front of a +large table provided with a stand whereon he may arrange all the +products that he has to employ. Beneath the work-table he has at his +disposal a closet in which to place his apparatus after he is through +using them. Each pupil has in front of him a water-faucet, which is +fixed to a vertical column and placed over a sink. Alongside of this +faucet there is a double gas burner, which may be connected with +furnaces and heating apparatus by means of rubber tubing. A special +hall, with draught and ventilation, is set apart for precipitations by +sulphureted hydrogen and the preparation of chlorine and other +ill-smelling and deleterious gases. The great amount of light and +space provided secure the best of conditions of hygiene to this fine +and vast laboratory, where young people have all the necessary +requisites for becoming true chemists.—<i>La Nature</i>.</p> + +<hr /> + +<h2><a name="art26" id="art26"></a>DUST-FREE SPACES.<a name="FNanchor_1" id="FNanchor_1"></a><a href="#Footnote_1"><sup>1</sup></a></h2> + + +<p>Within the last few years a singular interest has arisen in the +subject of dust, smoke, and fog, and several scientific researches +into the nature and properties of these phenomena have been recently +conducted. It so happened that at the time I received a request from +the secretary of this society to lecture here this afternoon I was in +the middle of a research connected with dust, which I had been +carrying on for some months in conjunction with Mr. J.W. Clark, +Demonstrator of Physics in University College, Liverpool, and which +had led us to some interesting results. It struck me that possibly +some sort of account of this investigation might not be unacceptable +to a learned body such as this, and accordingly I telegraphed off to +Mr. Moss the title of this afternoon's lecture. But now that the time +has come for me to approach the subject before you, I find myself +conscious of some misgivings, and the misgivings are founded upon this +ground: that the subject is not one that lends itself easily to +experimental demonstration before an audience. Many of the experiments +can only be made on a small scale, and require to be watched closely. +However, by help of diagrams and by not confining myself too closely +to our special investigation, but dealing somewhat with the wider +subject of dust in general, I may hope to render myself and my subject +intelligible if not very entertaining.</p> + +<p>First of all, I draw no distinction between "dust" and "smoke." It +would be possible to draw such a distinction, but it would hardly be +in accordance with usage. Dust might be defined as smoke which had +settled, and the term smoke applied to solid particles still suspended +in the air. But at present the term "smoke" is applied to solid +particles produced by combustion only, and "dust" to particles owing +their floating existence to some other cause. This is evidently an +unessential distinction, and for the present I shall use either term +without distinction, meaning by dust or smoke, solid particles +floating in the air. Then "fog"; this differs from smoke only in the +fact that the particles are liquid instead of solid. And the three +terms dust, smoke, and fog, come to much the same thing, only that the +latter term is applied when the suspended particles are liquid. I do +not think, however, that we usually apply the term "fog" when the +liquid particles are pure water; we call it then mostly either mist or +cloud. The name "fog," at any rate in towns, carries with it the idea +of a hideous, greasy compound, consisting of smoke and mist and +sulphur and filth, as unlike the mists on a Highland mountain as a +country meadow is unlike a city slum. Nevertheless, the finest cloud +or mist that ever existed consists simply of little globules of water +suspended in air, and thus for our present purpose differs in no +important respect from fog, dust, and smoke. A cloud or mist is, in +fact, fine water-dust. Rain is coarse water-dust formed by the +aggregation of smaller globules, and varying in fineness from the +Scotch mist to the tropical deluge. It has often been asked how it is +that clouds and mists are able to float about when water is so much +heavier (800 times heavier) than air. The answer to this is easy. It +depends on the resistance or viscosity of fluids, and on the smallness +of the particles concerned. Bodies falling far through fluids acquire +a "terminal velocity," at which they are in stable equilibrium—their +weight being exactly equal to the resistance—and this terminal +velocity is greater for large particles than for small; consequently +we have all sorts of rain velocity, depending on the size of the +drops; and large particles of dust settle more quickly than small. +Cloud-spherules are falling therefore, but falling very slowly.</p> + +<p>To recognize the presence of dust in air there are two principal +tests; the first is, the obvious one of looking at it with plenty of +light, the way one is accustomed to look for anything else; the other +is a method of Mr. John Aitken's, viz., to observe the condensation of +water vapor.</p> + +<p>Take these in order. When a sunbeam enters a darkened room through a +chink, it is commonly said to be rendered visible by the motes or dust +particles dancing in it; but of course really it is not the motes +which make the sunbeam visible, but the sunbeam the motes. A dust +particle is illuminated like any other solid screen, and is able to +send a sufficient fraction of light to our eyes to render itself +visible. If there are no such particles in the beam—nothing but +clear, invisible air—then of course nothing is seen, and the beam +plunges on its way quite invisible to us unless we place our eyes in +its course. In other words, to be visible, light must enter the eye. +(A concentrated beam was passed through an empty tube, and then +ordinary air let in.)</p> + +<p>The other test, that of Mr. Aitken, depends on the condensation of +steam. When a jet of steam finds itself in dusty air, it condenses +around each dust particle as a nucleus, and forms the white visible +cloud popularly called steam. In the absence of nuclei Mr. Aitken has +shown that the steam cannot condense until it is highly +supersaturated, and that when it does it condenses straight into +rain—that is, into large drops which fall. The condensation of steam +is a more delicate test for dust than is a beam of light. A curious +illustration of the action of nuclei in condensing moisture has just +occurred to me, in the experiment—well known to children—of writing +on a reasonably clean window-pane with, say, a blunt wooden point, and +then breathing on the glass; the condensation of the breath renders +the writing legible. No doubt the nuclei are partially wiped away by +the writing, and the moisture will condense into larger drops with +less light-scattering power along the written lines than over the +general surface of the pane where the nuclei are plentiful, and the +drops therefore numerous and minute. Mr. Aitken points out that if the +air were ever quite dustless, vapor could not condense, but the air +would gradually get into a horribly supersaturated condition, soaking +all our walls and clothes, dripping from every leaf, and penetrating +everywhere, instead of falling in an honest shower, against which +umbrellas and slate roofs are some protection. But let us understand +what sort of dust it is which is necessary for this condensing +process. It is not the dust and smoke of towns, it is not the dust of +a country road; all such particles as these are gross and large +compared with those which are able to act as condensers of moisture. +The fine dust of Mr. Aitken exists everywhere, even in the upper +regions of the atmosphere; many of its particles are of +ultra-microscopic fineness, one of them must exist in every raindrop, +nay, even in every spherule of a mist or cloud, but it is only +occasionally that one can find them with the microscope. It is to such +particles as these that we owe the blue of the sky, and yet they are +sufficiently gross and tangible to be capable of being filtered out of +the air by a packed mass of cotton-wool. Such dust as this, then, we +need never be afraid of being without. Without it there could be no +rain, and existence would be insupportable, perhaps impossible; but it +is not manufactured in towns; the sea makes it; trees and wind make +it; but the kind of dust made in towns rises only a few hundred yards +or so into the atmosphere, floating as a canopy or pall over those +unfortunate regions, and sinks and settles most of it as soon as the +air is quiet, but scarcely any of it ever rises into the upper regions +of the atmosphere at all.</p> + +<p>Dust, then, being so universally prevalent, what do I mean by +dust-free spaces? How are such things possible? And where are they to +be found? In 1870 Dr. Tyndall was examining dusty air by means of a +beam of light in which a spirit-lamp happened to be burning, when he +noticed that from the flame there poured up torrents of apparently +thick black smoke. He could not think the flame was really smoky, but +to make sure he tried, first a Bunsen gas flame and then a hydrogen +flame. They all showed the same effect, and smoke was out of the +question. He then used a red-hot poker, a platinum wire ignited by an +electric current, and ultimately a flask of hot water, and he found +that from all warm bodies examined in dusty air by a beam of light the +upstreaming convection currents were dark. Now, of course smoke would +behave very differently. Dusty air itself is only a kind of smoke, and +it looks bright, and the thicker the smoke the brighter it looks; the +blackness is simply the utter absence of smoke; there is nothing at +all for the light to illuminate, accordingly we have the blankness of +sheer invisibility. Here is a flame burning under the beam, and, to +show what real smoke looks like, I will burn also this spirit lamp +filled with turpentine instead of alcohol. <i>Why</i> the convention +currents were free from dust was unknown; Tyndall thought the dust was +burnt and consumed; Dr. Frankland thought it was simply evaporated.</p> + +<p>In 1881 Lord Rayleigh took the matter up, not feeling satisfied with +these explanations, and repeated the experiment very carefully. He +noted several new points, and hit on the capital idea of seeing what a +cold body did. From the cold body the descending current was just as +dark and dust-free as from a warm body. Combustion and evaporation +explanations suffered their death-blow. But he was unable to suggest +any other explanation in their room, and so the phenomenon remained +curious and unexplained.</p> + +<p>In this state Mr. Clark and I took the matter up last summer, and +critically examined all sorts of hypotheses that suggested themselves, +Mr. Clark following up the phenomena experimentally with great +ingenuity and perseverance. One hypothesis after another suggested +itself, seemed hopeful for a time, but ultimately had to be discarded. +Some died quickly, others lingered long. In the examination of one +electrical hypothesis which suggested itself we came across various +curious phenomena which we hope still to follow up.<a name="FNanchor_2" id="FNanchor_2"></a><a href="#Footnote_2"><sup>2</sup></a> It was some +months before what we now believe to be the true explanation began to +dawn upon us. Meanwhile we had acquired various new facts, and first +and foremost we found that the dark plane rising from a warm body was +only the upstreaming portion of a dust-free <i>coat</i> perpetually being +renewed on the surface of the body. Let me describe the appearance and +mode of seeing it by help of a diagram. (For full description see +<i>Philosophical Magazine</i> for March, 1884.)</p> + + +<p>Surrounding all bodies warmer than the air is a thin region free from +dust, which shows itself as a dark space when examined by looking +along a cylinder illuminated transversely, and with a dark background. +At high temperatures the coat is thick; at very low temperatures it is +absent, and dust then rapidly collects on the rod. On a warm surface +only the heavy particles are able to settle—there is evidently some +action tending to drive small bodies away. An excess of temperature of +a degree or two is sufficient to establish this dust-free coat, and it +is easy to see the dust-free plane rising from it. The appearances may +also be examined by looking along a cylinder <i>toward</i> the source of +light, when the dust-free spaces will appear brighter than the rest. A +rod of electric light carbon warmed and fixed horizontally across a +bell-jar full of dense smoke is very suitable for this experiment, and +by means of a lens the dust-free regions may be thus projected on to a +screen. Diminished pressure makes the coat thicker. Increased pressure +makes it thinner. In hydrogen it is thicker, and in carbonic acid +thinner, than in air. We have also succeeded in observing it in +liquids—for instance, in water holding fine rouge in suspension, the +solid body being a metal steam tube. Quantitative determinations are +now in progress.</p> + +<div class="figleft"><img src="./images/4a.png" alt="Fig. 1 and Fig. 2" /> +</div> + +<p>Fig. 1 shows the appearance when looking along a copper or carbon rod +laterally illuminated; the paths of the dust particles are roughly +indicated. Fig. 2 shows the coat on a semi-cylinder of sheet copper +with the concave side turned toward the light.</p> + +<p>It is difficult to give the full explanation of the dust free spaces +in a few words, but we may say roughly that there is a molecular +bombardment from all warm surfaces by means of which small suspended +bodies get driven outward and kept away from the surface. It is a sort +of differential bombardment of the gas molecules on the two faces of a +dust particle somewhat analogous to the action on Mr. Crookes' +radiometer vanes. Near cold surfaces the bombardment is very feeble, +and if they are cold enough it appears to act toward the body, driving +the dust inward—at any rate, there is no outward bombardment +sufficient to keep the dust away, and bodies colder than the +atmosphere surrounding them soon get dusty. Thus if I hold this piece +of glass in a magnesium flame, or in a turpentine or camphor flame, it +quickly gets covered with smoke—white in the one case, black in the +other. I take two conical flasks with their surfaces blackened with +camphor black, and filling one with ice, the other with boiling water, +I cork them and put a bell jar over them, under which I burn some +magnesium wire; in a quarter of an hour or so we find that the cold +one is white and hoary, the hot one has only a few larger specks of +dust on it, these being of such size that the bombardment was unable +to sustain their weight, and they have settled by gravitation. We thus +see that when the air in a room is warmer than the solids in it—as +will be the case when stoves, gas-burners, etc., are used—things will +get very dusty; whereas when walls and objects are warmer than the +air—as will be the case in sunshine, or when open fireplaces are +used, things will tend to keep themselves more free from dust. Mr. +Aitken points out that soot in a chimney is an illustration of this +kind of deposition of dust; and as another illustration it strikes me +as just possible that the dirtiness of snow during a thaw may be +partly due to the bombardment on to the cold surface of dust out of +the warmer air above. Mr. Aitken has indeed suggested a sort of +practical dust or smoke filter on this principle, passing air between +two surfaces—one hot and one cold—so as to vigorously bombard the +particles on to the cold surface and leave the air free.</p> + +<p>But we have found another and apparently much more effectual mode of +clearing air than this. We do it by discharging electricity into it. +It is easily possible to electrify air by means of a point or flame, +and an electrified body has this curious property, that the dust near +it at once aggregates together into larger particles. It is not +difficult to understand why this happens; each of the particles +becomes polarized by induction, and they then cling together end to +end, just like iron filings near a magnet. A feeble charge is often +sufficient to start this coagulating action. And when the particles +have grown into big ones, they easily and quickly fall. A stronger +charge forcibly drives them on to all electrified surfaces, where they +cling. A fine water fog in a bell jar, electrified, turns first into a +coarse fog or Scotch mist, and then into rain. Smoke also has its +particles coagulated, and a space can thus be cleared of it. I will +illustrate this action by making some artificial fogs in a bell-jar +furnished with a metal point. First burn some magnesium wire, +electrify it by a few turns of this small Voss machine, and the smoke +has become snow; the particles are elongated, and by pointing to the +charged rod indicate the lines of electrostatic force very +beautifully; electrify further, and the air is perfectly clear. Next +burn turpentine, and electrify gently; the dense black smoke +coagulates into black masses over an inch long; electrify further, and +the glass is covered with soot, but the air is clear. Turpentine smoke +acts very well, and can be tried on a larger scale; a room filled with +turpentine smoke, so dense that a gas-light is invisible inside it, +begins to clear in a minute or two after the machine begins to turn, +and in a quarter of an hour one can go in and find the walls thickly +covered with stringy blacks, notably on the gas-pipes and everything +most easily charged by induction. Next fill a bell-jar full of steam, +and electrify, paying attention to insulation of the supply point in +this case. In a few seconds the air looks clear, and turning on a beam +of light we see the globules of water dancing about, no longer fine +and impalpable, but separately visible and rapidly <a name="Page_7067" id="Page_7067"></a>falling. Finally, +make a London fog by burning turpentine and sulphur, adding a little +sulphuric acid, either directly as vapor or indirectly by a trace of +nitric oxide, and then blowing in steam. Electrify, and it soon +becomes clear, although it lakes a little longer than before; and on +removing the bell-jar we find that even the smell of SO<sub>2</sub> has +disappeared, and only a little vapor of turpentine remains. Similarly +we can make a Widnes fog by sulphureted hydrogen, chlorine, sulphuric +acid, and a little steam. Probably the steam assists the clearing when +gases have to be dealt with. It may be possible to clear the air of +tunnels by simply discharging electricity into the air—the +electricity being supplied by Holtz machines, driven say by small +turbines—a very handy form of power, difficult to get out of order. +Or possibly some hydro-electric arrangement might be devised for the +locomotive steam to do the work. I even hope to make some impression +on a London fog, discharging from lightning conductors or captive +balloons carrying flames, but it is premature to say anything about +this matter yet. I have, however, cleared a room of smoke very quickly +with a small hand machine.</p> + +<p>It will naturally strike you how closely allied these phenomena must +be to the fact of popular science that "thunder clears the air." Ozone +is undoubtedly generated by the flashes, and may have a beneficial +effect, but the dust-coagulating and dust-expelling power of the +electricity has a much more rapid effect, though it may not act till +the cloud is discharged. Consider a cloud electrified slightly; the +mists and clouds in its vicinity begin to coagulate, and go on till +large drops are formed, which may be held up by electrical action, the +drops dancing from one cloud to another and thus forming the very +dense thunder cloud. The coagulation of charged drops increases the +potential, as Prof. Tait points out, until at length—flash—the cloud +is discharged, and the large drops fall in a violent shower. Moreover, +the rapid excursion to and fro of the drops may easily have caused +them to evaporate so fast as to freeze, and hence we may get hail.</p> + +<p>While the cloud was electrified, it acted inductively on the earth +underneath, drawing up an opposite charge from all points, and thus +electrifying the atmosphere. When the discharge occurs this +atmospheric electrification engages with the earth, clearing the air +between, and driving the dust and germs on to all exposed surfaces. In +some such way also it may be that "thunder turns milk sour," and +exerts other putrefactive influences on the bodies which receive the +germs and dust from the air.</p> + +<p>But we are now no longer on safe and thoroughly explored territory. I +have allowed myself to found upon a basis of experimental fact, a +superstructure of practical application to the explanation of the +phenomena of nature and to the uses of man. The basis seems to me +strong enough to bear most of the superstructure, but before being +sure it will be necessary actually to put the methods into operation +and to experiment on a very large scale. I hope to do this when I can +get to a suitable place of operation. Liverpool fogs are poor affairs, +and not worth clearing off. Manchester fogs are much better and more +frequent, but there is nothing to beat the real article as found in +London, and in London if possible I intend to rig up some large +machines and to see what happens. The underground railway also offers +its suffocating murkiness as a most tempting field for experiment, and +I wish I were able already to tell you the actual result instead of +being only in a position to indicate possibilities. Whether anything +comes of it practically or not, it is an instructive example of how +the smallest and most unpromising beginnings may, if only followed up +long enough, lead to suggestions for large practical application. When +we began the investigation into the dust-free spaces found above warm +bodies, we were not only without expectation, but without hope or idea +of any sort, that anything was likely to come of it; the phenomenon +itself possessed its own interest and charm.</p> + +<p>And so it must ever be. The devotee of pure science never has +practical developments as his primary aim; often he not only does not +know, but does not in the least care whether his researches will ever +lead to any beneficial result. In some minds this passive ignoring of +the practical goes so far as to become active repulsion; so that some +singularly biased minds will not engage in anything which seems likely +to lead to practical use. I regard this as an error, and as the sign +of a warped judgment, for after all man is to us the most important +part of nature; but the system works well nevertheless, and the +division of labor accomplishes its object. One man investigates nature +impelled simply by his own genius, and because he feels he cannot help +it; it never occurs to him to give a reason for or to justify his +pursuits. Another subsequently utilizes his results, and applies them +to the benefit of the race. Meanwhile, however, it may happen that the +yet unapplied and unfruitful results evoke a sneer, and the question: +"Cui bono?" the only answer to which question seems to be: "No one is +wise enough to tell beforehand what gigantic developments may not +spring from the most insignificant fact."</p> + +<p><a name="Footnote_1" id="Footnote_1"></a><a href="#FNanchor_1">[1]</a></p> +<div class="note"><p>Lecture to the Royal Dublin Society by Dr. Oliver J. Lodge, April 2, 1884.</p></div> +<p><a name="Footnote_2" id="Footnote_2"></a><a href="#FNanchor_2">[2]</a></p> +<div class="note"><p>For instance, the electric properties of crystals can be readily examined in illuminated dusty air; the dust grows on them in little bushes and marks out their poles and neutral regions, without any need for an electrometer. Magnesia smoke answers capitally.</p></div> + +<hr /> + +<h2><a name="art14" id="art14"></a>TELEPHONY AND TELEGRAPHY ON THE SAME WIRES SIMULTANEOUSLY.</h2> + +<p>For the last eighteen months a system has been in active operation in +Belgium whereby the ordinary telegraph wires are used to convey +telephonic communications at the same time that they are being +employed in their ordinary work of transmitting telegraphic messages. +This system, the invention of M. Van Rysselberghe, whose previous +devices for diminishing the evil effects of induction in the telephone +service will be remembered, has lately been described in the <i>Journal +Telegraphique</i> of Berne, by M.J. Banneux of the Belgian Telegraph +Department. Our information is derived from this article and from +others by M. Hospitalier.</p> + +<p>The method previously adopted by Van Rysselberghe, to prevent +induction from taking place between the telegraph wires and those +running parallel to them used for telephone work, was briefly as +follows: The system of sending the dots and dashes of the +code—usually done by depressing and raising a key which suddenly +turns on the current and then suddenly turns it off—was modified so +that the current should rise gradually and fall gradually in its +strength by the introduction of suitable resistances. These were +introduced into the circuit at the moment of closing or opening by a +simple automatic arrangement worked exactly as before by a key. The +result, of the gradual opening and gradual closing of the circuit was +that the current attained its full strength gradually instead of +suddenly, and died away also gradually. And as induction from one wire +to another depends not on the strength of the current, but on the rate +at which the strength changes, this very simple modification had the +effect of suppressing induction. Later Van Rysselberghe changed these +arrangements for the still simpler device of introducing permanently +into the circuit either condensers or else electro-magnets having a +high coefficient of self-induction. These, as is well known to all +telegraphic engineers, retard the rise or fall of an electric current; +they fulfill the conditions required for the working of Van +Rysselberghe's method better than any other device.</p> + +<p>Having got thus far in his devices for destroying induction from one +line to another, Van Rysselberghe saw that, as an immediate +consequence, it might be concluded that, if the telegraph currents +were thus modified and graduated so that they produced no induction in +a neighboring telephone line, they would produce no sound in the +telephone if that instrument were itself joined up in the telegraph +line. And such was found to be case. Why this is so will be more +readily comprehended if it be remembered that a telephone is sensitive +to the changes in the strength of the current if those changes occur +with a frequency of some hundreds or in some cases thousands of times +<i>per second</i>. On the other hand, currents vibrating with such rapidity +as this are utterly incompetent to affect the moving parts of +telegraphic instruments, which cannot at the most be worked so as to +give more than 200 to 800 separate signals <i>per minute</i>.</p> + +<div class="figleft"><img src="./images/5a.png" alt="Fig. 1" /><br /> Fig. 1</div> + +<p>The simplest arrangement for carrying out this method is shown in Fig. +1, which illustrates the arrangements at one end of a line. M is the +Morse key for sending messages, and is shown as in its position of +rest for receiving. The currents arriving from the line pass first +through a "graduating" electromagnet, E<sub>2</sub>, of about 500 ohms +resistance, then through the key, thence through the electromagnet, R, +of the receiving Morse instrument, and so to the earth. A condenser, +C, of 2 microfarads capacity is also introduced between the key and +earth. There is a second "graduating" electromagnet, E<sub>1</sub>, of 500 +ohms resistance introduced between the sending battery, B, and the +key. When the key, M, is depressed in order to send a signal, the +current from the battery must charge the condenser, C, and must +magnetize the cores of the two electromagnets, E<sub>1</sub> and E<sub>2</sub>, and is +thereby retarded in rising to its full strength. Consequently no sound +is heard in a telephone, T, inserted in the line-circuit. Neither the +currents which start from one end nor those which start from the other +will affect the telephones inserted in the line. And, if these +currents do not affect telephones in the actual line, it is clear that +they will not affect telephones in neighboring lines. Also the +telephones so inserted in the main line might be used for speaking to +one another, though the arrangement of the telephones in the same +actual line would be inconvenient. Accordingly M. Van Rysselberghe has +devised a further modification in which a separate branch taken from +the telegraph line is made available for the telephone service. To +understand this matter, one other fact must be explained. Telephonic +conversation can be carried on, even though the actual metallic +communication be severed by the insertion of a condenser. Indeed, in +quite the early days of the Bell telephone, an operator in the States +used a condenser in the telegraph line to enable him to talk through +the wire. If a telephonic set at T<sub>1</sub> (Fig. 2) communicate through +the line to a distant station, T<sub>2</sub>, through a condenser, C, of a +capacity of half a microfarad, conversation is still perfectly +audible, provided the telephonic system is one that acts by induction +currents. And since in this case the interposition of the condenser +prevents any continuous flow of current through the line, no +perceptible weakening will be felt if a shunt S, of as high a +resistance as 500 ohms and of great electromagnetic rigidity, that is +to say, having a high coefficient of self-induction, be placed across +the circuit from line to earth. In this, as well as in the other +figures, the telephones indicated are of the Bell pattern, and if set +up as shown in Fig. 2, without any battery, would be used both as +transmitter and receiver on Bell's original plan. +<span class="figright"><img src="./images/5b.png" alt="Fig. 2" /><br /> Fig. 2</span> +But as a matter of fact any ordinary telephone might be used. In practice the Bell +telephone is not advantageous as a transmitter, and has been abandoned +except for receiving; the Blake, Ader, or some other modification of +the microphone being used in conjunction with a separate battery. To +avoid complication in the drawings, however, the simplest case is +taken. And it must be understood that instead of the single instrument +shown at T<sub>1</sub> or T<sub>2</sub>, a complete set of telephonic instruments, +including transmitter, battery, induction-coil, and receiver or +receivers, may be substituted. And if a shunt, S, of 500 ohms placed +across the circuit makes no difference to the talking in the +telephones because of the interposition of the separating condenser, +C, it will readily be understood that a telegraphic system properly +"graduated," and having also a resistance of 500 ohms, will not affect +the telephones if interposed in the place of S. This arrangement is +shown in Fig. 3, where the "graduated" telegraph-set from Fig. 1 is +intercalated into the telephonic system of Fig. 2, so that both work +simultaneously, but independently, through a single line. The combined +system at each end of the line will then consist of the telephone-set, +T<sub>1</sub>, the telegraph instruments (comprising battery, B<sub>1</sub>, key, +M<sub>1</sub> and Morse receiver, R<sub>1</sub>), the "graduating" electromagnets, +E<sub>1</sub>, and E<sub>2</sub>, the "graduating" condenser, C<sub>1</sub>, and the +"separating" condenser, C<sub>2</sub>. It was found by actual experiments that +the same arrangement was good for lines varying from 28 to 200 miles +in length. A single wire between Brussels, Ghent, and Ostend is now +regularly employed for transmission by telegraph of the ordinary +messages and of the telemeteorographic signals between the two +observatories at those places, and by telephone of verbal simultaneous +correspondence, for one of the Ghent newspapers. A still more +interesting arrangement is possible, and is indicated in Fig. 4. Here +a separating condenser is introduced at the intermediate station at +Ghent between earth and the line, which is thereby cut into two +independent sections for telephonic purposes, while remaining for +telegraphic purposes a single undivided line between Brussels and +Ostend. Brussels can telegraph to Ostend, or Ostend to Brussels, and +at the same time the wire can be used to telephone between Ghent and +Ostend, or between Ghent and Brussels, or both sections may be +simultaneously used.</p> + +<div class="figcenter"><a href="./images/5c.png"><img src="./images/5c_th.png" alt="Fig. 3" /></a><br />Fig. 3</div> + +<div class="figcenter"><img src="./images/5d.png" alt="Fig. 4" /><br />Fig. 4</div> + +<p>It would appear, then, that M. Van Rysselberghe has made an advance of +very extraordinary merit in devising these combinations. We have seen +in recent years how duplex telegraphy superseded single working, only +to be in turn superseded by the quadruplex system. Multiplex +telegraphy of various kinds has been actively pursued, but chiefly on +the other side of the Atlantic rather than in this country, where our +fast-speed automatic system has proved quite adequate hitherto. +Whether we shall see the adoption in the United Kingdom of Van +Rysselberghe's system is, however, by no means certain. The essence of +it consists in retarding the telegraphic signals to a degree quite +incompatible with the fast-speed automatic transmission of telegraphic +messages in which our Post Office system excels. We are not likely to +spoil our telegraphic system for the sake of simultaneous telephony, +unless there is something to be gained of much greater advantage than +as yet appears.—<i>Nature</i>.</p> + +<hr /> + +<h2><a name="art15" id="art15"></a>THE ELECTRIC MARIGRAPH.</h2> + +<p>For registering the height of the tide at every instant, hydrographic +services generally adopt quite a simple marigraph. The apparatus +consists in principle of a counterpoised float whose rising and +falling motion, reduced to a tenth, by means of a system of toothed +wheels, is transmitted to a pencil which moves in front of a vertical +cylinder. This cylinder itself moves around its axis by means of a +clockwork mechanism, and accomplishes one entire revolution every +twenty-four hours. By this means is obtained a curve of the tide in +which the times are taken for abscisses and the heights of the sea for +ordinates. However little such marigraphs have had to be used, great +defects have been recognized in them. When we come to change the sheet +on the cylinder (and such change should be made at least once every +fifteen days), there is an interruption in the curve. It is necessary, +besides, to perform office work of the most detailed kind in order to +refer to the same origin all these curves, which are intercrossed and +often superposed in certain parts upon the original sheet. In order to +render such a disentanglement possible, it is indispensable to mark by +hand, at least once every twenty-four hours, upon each curve, the date +of the day corresponding to it. It is equally useful to verify the +<a name="Page_7068" id="Page_7068"></a>exactness of the indications given by the apparatus by making +readings several times a day on a scale of tides placed alongside of +the float. Nine times out of ten the rise of the waves renders such +readings very difficult and the control absolutely illusory.</p> + +<p>All these conditions united, as well as others that we neglect in this +brief discussion, necessitate a surveillance at every instant. The +result is that these marigraphs must be installed in a special +structure, very near the bank, so as to be reachable at all times, and +that the indications that they give are always vitiated by error, +since the operation is performed upon a level at which are exerted +disturbing influences that are not found at a kilometer at sea. It +were to be desired that the float could be isolated by placing it a +certain distance from the shore, and transmit its indications, by +meant of a play of currents, to a registering apparatus situated upon +<i>terra firma</i>.</p> + +<p>In the course of one of his lectures published in the December number +(1883) of the <i>Elektrotechnische Zeitschrift</i>, Mr. Von Hefner-Alteneck +tells us that such a desideratum has been supplied by the firm of +Siemens & Halske. This marigraph, constructed on an order of the +German Admiralty, gives the level of the sea every ten minutes with an +approximation of 0.12 per cent., and that too for a difference of 8 +meters between the highest and lowest sea. The apparatus consists, as +we said above, of a float and registering device, connected with each +other by means of a cable. This latter is formed of three ordinary +conductors covered with gutta percha and surrounded with a leaden +sheath, which latter is itself protected against accident by means of +a strong covering of iron wire and hemp. The return is effected +through the earth. We shall enter into details concerning each of +these two apparatus in-succession, by beginning with the float, of +which Fig. 1 gives a general view, and Fig. 2 a diagrammatic sketch. +The float moves in a cast iron cylinder, having at its lower part a +large number of apertures of small diameter, so that the motion of the +waves does not perceptibly influence the level of the water in the +interior of the cylinder. It is attached to a copper ribbon, B, whose +other extremity is fixed to the drum, T. The ribbon winds around the +latter in the rising motion of the float, owing to a spiral spring +arranged so as to act upon the drum. The tension of this spring goes +on increasing in measure as the float descends.</p> + +<div class="center"><img src="./images/6a.png" alt="Fig. 1" /><br /><span class="smcap">Fig.</span> 1.—FLOAT OF SIEMENS AND HALSKE'S MARIGRAPH.</div> + +<p>This difference in tension is utilized for balancing at every instant +the weight of the ribbon unwound, and thus causing the float to +immerse itself in the water to a constant degree. The ribbon, B, is +provided throughout its length with equidistant apertures that exactly +correspond to tappets that project from the circumference of the +wheel, R. When the float moves its position, the wheel, R, begins to +turn and carries along in doing so the pinion, <i>w</i>, which revolves +over the toothed wheels, s<sub>1</sub>, s<sub>2</sub>, and s<sub>3</sub>. The thickness of w +is equal to that of the three wheels, s<sub>1</sub>, s<sub>2</sub>, and s<sub>3</sub>, and a +special spring secures at every instant an intimate contact between +the pinion and the said wheels. These latter are insulated from each +other and from the axle upon which they are keyed, and communicate, +each of them, with conductors, I., II., and III. They are so formed +and mounted that, in each of them, the tooth in one corresponds to the +interspace in the two others. As a result of this, in the motion of +the pinion, <i>w</i>, the latter is never in contact with but one of the +three wheels, s<sub>1</sub>, s<sub>2</sub>, and s<sub>3</sub>.</p> + +<div class="center"><img src="./images/6b.png" alt="Fig. 2." /><br /><span class="smcap">Fig.</span> 2.</div> + +<p>If we add that the lines, I., II., and III. are united at the shore +station with one of the poles of a pile whose other pole is connected +with the earth, and that w communicates with the earth through the +intermedium of R, and the body of the apparatus, it is easy to see +that in a vertical motion of the float in one direction we shall have +currents succeeding each other in the order I., II., III., I., II., +etc., while the order will become III., II., I., III., II., etc., if +the direction of the float's motion happen to change.</p> + +<div class="center"><img src="./images/6c.png" alt="Fig. 3." /><br /> <span class="smcap">Fig.</span> 3.</div> + +<div class="center"><img src="./images/6d.png" alt="Fig. 4." /><br /> <span class="smcap">Fig.</span> 4.</div> + +<p>In order to understand how a variation in currents of this kind can be +applied in general for producing a rotary motion in the two +directions, it will only be necessary to refer to Figs. 3 and 4. The +conductors, L<sub>1</sub>, L<sub>2</sub>, and L<sub>3</sub> communicate with the bobbins of +three electromagnets, E<sub>1</sub>, E<sub>2</sub>, and E<sub>3</sub>, whose poles are bent at +right angles to the circumference of the wheel, R. There is never but +one pole opposite a tooth. The distance between two consecutive poles +must be equal to a multiple of the pitch increased (Fig. 3) or +diminished (Fig. 4) by one-third thereof. It will be seen upon a +simple inspection of the figures that R will revolve in the direction +of the hands of a watch when the currents follow the order L<sub>1</sub>, +L<sub>2</sub>, L<sub>3</sub>, etc., in the case shown in Fig. 3, while in the case +shown in Fig. 4 the rotary motion will be in the contrary direction +for this same order of currents. But, in both cases, and this is the +important point, the direction of rotation changes when the order in +the succession of currents; is inverted. Fig. 6 gives a perspective +view of the registering apparatus, and Fig. 5 represents it in +diagram. It will be at once seen that, the toothed wheel, <i>r</i>, is +reduced to its simplest expression, since it consists of two teeth +only. The electro-magnets are arranged at an angle of 120°, and for a +<a name="Page_7069" id="Page_7069"></a>change of current the wheel, <i>r</i>, describes an angle of 60°, that is +to say, a sixth of a circumference. The motion of r is transmitted, by +means of the pinion, <i>d</i>, and the wheel, <i>e</i>, to the wheel, T. For a +one-meter variation in level the wheel, T, makes one complete +revolution. It is divided into 100 equal parts, and each arc therefore +corresponds to a difference of one centimeter in the level, and +carries, engraved in projection, the corresponding number. As a +consequence, there is upon the entire circumference a series of +numbers from to 99. The axle upon which the wheel, T, is keyed is +prolonged, on the side opposite <i>e</i>, by a threaded part, <i>a</i>, which +actuates a stylet, <i>g</i>. This latter is held above by a rod, I, which +is connected with a fork movable around a vertical axis, shown in Fig. +6. The rectilinear motion of g is 5 mm. for a variation of one meter +in level. Its total travel is consequently 40 mm. The sheet of paper +upon which the indications are taken, and which is shown of actual +size in Fig. 7, winds around the drum, P, and receives its motion from +the cylinder, W. This sheet is covered throughout its length with fine +prepared paper that permits of taking the imprints by impression.</p> + +<div class="center"> +<a href="./images/6e.png"><img src="./images/6e_th.png" alt="Fig. 5." title="" /></a><br /> +<span class="smcap">Fig.</span> 5.</div> + +<div class="center"> +<a href="./images/6f.png"><img src="./images/6f_th.png" alt="Fig. 6." title="" /></a><br /> + <span class="smcap">Fig.</span> 6—RECEIVER OF SIEMENS AND HALSKE'S MARIGRAPH.</div> + +<p>This stated, the play of the apparatus may be easily understood. Every +ten minutes a regulating clock closes the circuit of the local pile, +B<sub>2</sub>, and establishes a contact at C. The electro-magnet, E<sub>4</sub>, +attracts its armature, and thus acts upon the lever, <i>h</i>, which +presses the sheet of paper against the stylet in front that serves to +mark the level of the lowest waters, and against the stylet, <i>g</i>, and +the wheels, T and Z. In falling back, the lever, <i>h</i>, causes the +advance, by one notch, of the ratchet wheel that is mounted at the +extremity of the cylinder W, and thus displaces the sheet of paper a +distance of 5 mm. The wheel, Z, carries engraved in projection upon +its circumference the hours in Roman figures, and moves forward one +division every 60 minutes. The motion of this wheel is likewise +controlled by the cylinder, W.</p> + +<p>It will be seen upon referring to Fig. 7, that there is obtained a +very sharp curve marked by points. We have a general view on +considering the curve itself, and the height in meters is read +directly. The fractions of a meter, as well as the times, are in the +margin. Thus, at the point, <i>a</i>, the apparatus gives at 3 o'clock and +20 minutes a height of tide of 4.28 m. above the level of the lowest +water.</p> + +<div class="center"><img src="./images/6g.png" alt="Fig. 7." title="" /><br /> +<span class="smcap">Fig.</span> 7.</div> + +<p>This apparatus might possibly operate well, and yet not be in accord +with the real indications of the float, so it has been judged +necessary to add to it the following control.</p> + +<p>Every time the float reaches 3 meters above the level of the lowest +tide, the circuit of one of the lines that is open at this moment +(that of line I, for example) closes at C (Fig. 2), into this new +circuit there is interposed a considerable resistance, W, so that the +energy of the current is weakened to such a point that it in nowise +influences the normal travel of the wheel, <i>r</i>. At the shore station, +there is placed in deviation a galvanoscope, K, whose needle is +deflected. It suffices, then, to take datum points upon the +registering apparatus, upon the wheel, T, and the screw, <i>a</i>, in such +a way as to ascertain the moment at which the stylet, <i>g</i>, is going to +mark 3 meters. At this moment the circuit of the galvanoscope, K, is +closed, and we ascertain whether there is a deviation of the needle.</p> + +<p>As the sea generally rises to the height of 3 meters twice a day, it +is possible to control the apparatus twice a day, and this is fully +sufficient.</p> + +<p>It always belongs to practice to judge of an invention. Mr. Von +Hefner-Alteneck tells us that two of these apparatus have been set +up—one of them a year ago in the port of Kiel, and the other more +recently at the Isle of Wangeroog in the North Sea—and that both have +behaved excellently since the very first day of their installation. We +shall add nothing to this, since it is evidently the best eulogium +that can be accorded them.—<i>La Lumiere Electrique.</i></p> + +<hr /> + +<h2><a name="art16" id="art16"></a>DELUNE & CO.'S SYSTEM OF LAYING UNDERGROUND CABLES.</h2> + +<p>In recent times considerable attention has been paid to the subject of +laying telegraph cables underground, and various methods have been +devised. In some cases the cables have been covered with an armor of +iron, and in others they have been inclosed in cast-iron pipes. For +telephonic service they are generally inclosed in leaden tubes. What +this external envelope shall be that is to protect the wires from +injury is a question of the highest importance, since not only the +subject of protection is concerned, but also that of cost. It is +therefore interesting to note the efforts that are being made in this +line of electric industry.</p> + + +<div class="figleft"><img src="./images/7a-1.png" alt="Fig. 1. Section of the Pipe Open." /><br /><span class="smcap">Fig.</span> 1. Section of the Pipe Open.</div> +<div class="figright"><img src="./images/7a-2.png" alt="Fig. 2. Section of the Pipe Closed." /><br /> <span class="smcap">Fig.</span> 2. Section of the Pipe Closed.</div> +<div class="figcenter"><p> </p></div> + +<p>Messrs. Delune & Co. have recently taken out a patent for an +arrangement consisting of pipes made of beton. The annexed cuts, +borrowed from <i>L'Electricite</i>, represent this new system. The pipes, +which are provided with a longitudinal opening, are placed end to end +and coupled with a cement sleeve. The cables are put in place by +simply unwinding them as the work proceeds, and thus all that traction +is done away with that they are submitted to when cast iron pipes are +used. When once the cables are in place the longitudinal opening is +stopped up with cement mortar, and in this way a very tight conduit is +obtained whose hardness increases with time. The value of the system +therefore depends, as in all cement work, on the care with which the +manufacturing is done.</p> + +<p>Experiments have been made with the system at Toulouse, by the +Minister of Post Offices and Telegraphs, and at Lyons, by the General +Society of Telephones. Here, as with all similar questions, no opinion +can be pronounced until after a prolonged experience. But we cannot +help setting forth the advantages that the system offers. These are, +in the first place, a saving of about 50 per cent. over iron pipe, and +in the second, a better insulation, and consequently a better +protection of the currents against all kinds of disturbance, since a +non-conducting mass of cement is here substituted for metal.</p> + +<hr /> + +<h2><a name="art17" id="art17"></a>ELECTRICITY APPLIED TO HORSE-SHOEING.</h2> + +<p>"There is nothing new but what has been forgotten," said Marie +Antoinette to her milliner, Mdlle. Bertin, and what is true of fashion +is also somewhat so of science. Shoeing restive horses by the aid of +electricity is not new, experiments thereon having been performed as +long ago as 1879 by Mr. Defoy, who operated with a small magneto +machine.</p> + +<p>But the two photographs reproduced in Figs. 1 and 2 have appeared to +us curious enough to be submitted to our readers, as illustrating Mr. +Defoy's method of operating with an unruly animal.</p> + +<div class="figcenter"><a href="./images/7b.png"><img src="./images/7b_th.png" alt="Fig. 1.—THE HORSE RECEIVING THE CURRENT." /></a><br /> <span class="smcap">Fig.</span> 1.—THE HORSE RECEIVING THE CURRENT.</div> + +<p>The battery used was a small Grenet bichromate of potash pile, which +was easy to graduate on account of the depth to which the zinc could +be immersed. This pile was connected with the inductor of a small +Ruhmkorff coil, whose armature was connected with a snaffle-bit placed +in the horse's mouth.</p> + +<div class="figcenter"><a href="./images/7c.png"><img src="./images/7c_th.png" alt="Fig. 2.—THE HORSE CONQUERED." /></a><br /> <span class="smcap">Fig.</span> 2.—THE HORSE CONQUERED.</div> + +<p>This bit was arranged as follows (Fig. 3): The two conductors, which +were uncovered for a length of about three centimeters at their +extremity, were placed opposite each other on the two joints of the +snaffle, and about five or six centimeters apart. The mouth-pieces of +the bit had previously been inclosed in a piece of rubber tubing, in +order to insulate the extremities of the conductors and permit the +recomposition of the current to take place through the animal's tongue +or palate.</p> + +<p>Each of the bare ends of the conductors was provided, under a circular +brass ligature, with a small damp sponge, which, surrounding the +mouth-piece, secured a perfect contact of each end of the circuit with +the horse's mouth.</p> + +<div class="figcenter"><img src="./images/7d.png" alt="Fig. 3.—ARRANGEMENT OF THE BIT" /><br /> <span class="smcap">Fig.</span> 3.—ARRANGEMENT OF THE BIT</div> + +<p>The horse having been led in, defended himself vigorously as long as +an endeavor was made to remove his shoes by the ordinary method, but +the current had acted scarcely fifteen seconds when it became possible +to lift his feet and strike his shoes with the hammer.</p> + +<p>The experimenter having taken care during this experiment to place +the bobbin quite near the horse's ear, so that he could hear the +humming of the interrupter, undertook a second experiment in the +following way: Having detached the conductors from the armature, he +placed himself in front of the horse (as shown in Fig. 2), and began +to imitate the humming sound of the interrupter with his mouth. The +animal at once assumed the stupefied position that the action of the +current gave him in the first experiment, and allowed his feet to be +lifted and shod without his even being held by the snaffle.</p> + +<p>The horse was for ever after subdued, and yet his viciousness and his +repugnance to shoeing were such that he could only be shod previously +by confining his legs with a kicking-strap.</p> + +<p>It should be noted that the action of the induction coil, mounted as +this was, was very feeble and not very painful; and yet it was very +disagreeable in the mouth, and gave in this case a shock with a +sensation of light before the eyes, as we have found by experimenting +upon ourselves.</p> + +<p>From our own most recent experiments, we have ascertained the +following facts, which may guide every horse-owner in the application +of electricity to an animal that is opposed to being shod: (1) To a +horse that defends himself because he is irritable by temperament, and +nervous and impressionable (as happens with animals of pure or nearly +pure blood), the shock must be administered feebly and gradually +before an endeavor is made to take hold of his leg. The horse will +then make a jump, and try to roll over. The jump must be followed, +while an assistant holds the bridle, and the action of the current +must be at once arrested. After this the horse will not endeavor to +defend himself, and his leg may be easily handled.</p> + +<p>(2) Certain large, heavy, naturally ugly horses kick through sheer +viciousness. In this case, while the current is being given it should +be gradually increased in intensity, and the horse's foot must be +seized during its action. In most cases the passage of a current +through such horses (whose mucous membrane is less sensitive) produces +only <a name="Page_7070" id="Page_7070"></a>a slightly stupefied and contracted position of the head, +accompanied with a slight tremor. The current must be shut off as soon +as the horse's foot is well in one's hand, and be at once renewed if +he endeavors to defend himself again, as is rarely the case. It is a +mare of this nature that is represented in the annexed figures.</p> + +<p>We know that this same system has been applied for bringing to an +abrupt standstill runaway horses, harnessed to vehicles; but knowing +the effect of a sudden stoppage under such circumstances, we believe +that the remedy would prove worse than the disease, since the coachman +and vehicle, in obedience to the laws of inertia, would continue their +motion and pass over the animals, much to their detriment.—<i>Science +et Nature</i>.</p> + +<hr /> + +<h2><a name="art18" id="art18"></a>ESTEVE'S AUTOMATIC PILE.</h2> + +<p>Mr. Esteve has recently devised a generator of electricity which he +claims to be energetic, constant, and always ready to operate. The +apparatus is designed for the production of light and for actuating +electric motors, large induction bobbins, etc.</p> + +<p>We give a description of it herewith from data communicated by its +inventor.</p> + +<p>The accompanying cut represents a battery of 6 elements, with a +reservoir, R, for the liquid, provided at its lower part with a cock +for allowing the liquid to enter the pile. The vessels of the +different elements are of rectangular form. At the upper part, and in +the wider surfaces of each, there are two tubes. The first tube of the +first vessel receives the extremity of a safety-tube, A, whose other +extremity enters the upper part of the reservoir, R. This tube is +designed for regulating the flow of the liquid into the pile. When the +cock, <i>r</i>, is too widely open, the liquid might have a tendency to +flow over the edges of the vessel; but this would close the orifice of +the tube, A, and, as the air would then no longer enter the reservoir, +R, the flow would be stopped automatically. The second tube of the +first vessel is connected with a lead tube, 1, one of the extremities +of which enters the second vessel. The other tubes are arranged in the +same way in the other vessels. The renewal of the liquids is effected +by displacement, in flowing upward from one element over into another; +and the liquids make their exit from the pile at D, after having +served six times. The electrodes of the two first elements are +represented as renewed in the cut, in order to show the arrangement of +the tubes.</p> + +<div class="figcenter"><img src="./images/8a.png" alt="ESTEVE'S AUTOMATIC PILE." /><br /> ESTEVE'S AUTOMATIC PILE.</div> + +<p><i>Dimensions.</i>—The zinc, 2, has a superficies of 15×20 centimeters, +and is cut out of the ordinary commercial sheet metal. It may be +turned upside down when one end has become worn away, thus permitting +of its being entirely utilized. The negative electrode is formed of +four carbons, which have, each of them, a superficies of 8×21 +centimeters. These four carbons are less fragile and are more easily +handled than two having the same surface. Their arrangement is shown +at the left of the figure. They are fixed to a strip of copper, <i>a</i>, +to which is soldered another strip, L, bent at right angles. There are +thus two pairs of carbon per element, and these are simply suspended +from a piece of wood, as shown in the figure. Upon this wooden holder +will be seen the two strips, LL, that are designed to be put in +contact with the zinc of the succeeding element by means of pinchers +that connect the electrodes with one another. This arrangement permits +the pile to be taken apart very quickly.</p> + +<p><i>Charging, Work, and Duration of the Pile.</i>—The inventor has made a +large number of experiments with solutions of bichromate of potash of +various degrees of saturation, and has found the following to give the +best results:</p> + + + +<div class='center'> +<table border="0" cellspacing="0" width="40%" summary=""> +<tr><td align='left'>Bichromate of potash.</td><td align='right'>1</td><td align='center'>kilogramme.</td></tr> +<tr><td align='left'>Sulphuric acid</td><td align='right'>2</td><td align='center'>liters.</td></tr> +<tr><td align='left'>Water</td><td align='right'>8</td><td align='center'>"</td></tr> +</table></div> + +<p>When a larger quantity of the salt is used, crystallization occurs in +the pile.</p> + + +<div class='center'> +<table border="0" cellspacing="4" summary=""> +<tr><td align='left'></td><td align='right'>Constants and work<br />of an element having<br /> a zinc of 16×20 cm.</td><td align='right'>Constants and work<br /> of a round Bunsen<br />element, 20×30 cm.</td></tr> +<tr><td align='left'>Volts.</td><td align='right'>1.9</td><td align='right'>1.8</td></tr> +<tr><td align='left'>Resistance.</td><td align='right'>0.05</td><td align='right'>0.24</td></tr> +<tr><td align='left'>Work disposable in the external circuit.</td><td align='right'>1.839 k.</td><td align='right'>0.344 k.</td></tr> +</table></div> + +<p>The work disposable in the external circuit is deduced from the +formula:</p> + +<div class="center"><table summary="equation"> +<tr><td>T = </td><td>E²<br /><span class="over">(4R × 9.81)</span></td></tr> +</table></div> + +<p>It will be seen that an element thus charged gives as much energy as +5.3 large Bunsen elements.</p> + +<p>The battery is charged with 10 liters of solution, and is capable of +furnishing for 5 hours a current of 7 amperes with a difference of +potential of 9 volts at the pile terminals. The work, according to the +formula (EI)/<i>g</i>, equals 6.422 kilogram-meters; with a feebler +resistance in the external circuit it is capable of producing a +current of 19 amperes for an hour and an half. In this case the +resistance of the external circuit equals the interior resistance of +the pile. Upon immersing the electrodes in new liquid, and with no +resistance in the external circuit, the current may reach 100 amperes. +On renewing the liquids during the operation of the pile, a current of +7 amperes is kept up if about a liter of saturation per hour be +allowed to pass into the battery. For five hours, then, only 5 liters +are used instead of the 10 that are necessary when the liquid is not +renewed while the pile is in action.—<i>La Nature</i>.</p> + +<hr /> + +<h2><a name="art19" id="art19"></a>WOODWARD'S DIFFUSION MOTOR.</h2> + +<p>The energy produced by the phenomena of diffusion is exhibited in +lecture courses by placing a bell glass filled with hydrogen over a +porous vessel at whose base is fixed a glass tube that dips into +water. The hydrogen, in diffusing, enters the porous vessel, increases +the internal pressure, and a number of bubbles escapes from the tube. +On withdrawing the bell glass of hydrogen, the latter becomes diffused +externally, a lower pressure occurs in the porous vessel, and the +level of the water rises.</p> + +<p>The arrangement devised by Mr. C.J. Woodward, and recently presented +to the Physical Society of London, is an adaptation of this experiment +to the production of an oscillating motion by alternations in the +internal and external diffusion of the hydrogen.</p> + +<p>The apparatus, represented herewith, consists of a scale beam about +three feet in length that supports at one end a scale pan and weights, +and, at the other, a corked porous vessel that carries a glass tube, +<i>c</i>, which dips into a vessel containing either water or methylic +alcohol. Three or four gas jets, one of which is shown at E, are +arranged around the porous vessel, as close as possible, but in such a +way as not to touch it during the oscillation of the beam. These gas +jets communicate with a gasometer tilled with hydrogen, the bell of +which is so charged as to furnish a jet of sufficient strength. +Experience will indicate the best place to give the gas jets, but, in +general, it is well to locate them at near the center of the porous +vessel when the beam is horizontal.</p> + +<div class="figcenter"><img src="./images/8b.png" alt="" /></div> + +<p>It is now easy to see how the device operates. When the hydrogen comes +in presence of the porous vessel it becomes diffused therein, and the +pressure exerted in the interior then produces an ascent. When the +bottom of the porous vessel gets above the jets, the internal +diffusion ceases and the hydrogen becomes diffused externally, the +internal pressure diminishes, and the vessel descends. The vessel then +comes opposite the jets of hydrogen and the same motion occurs again, +and soon indefinitely. The work produced by this motor, which has +purely a scientific interest, is very feeble, and much below that +assigned to it by theory. In order to obtain a maximum, it would be +necessary to completely surround the porous vessel each time with +hydrogen, and afterward remove the jets to facilitate the access of +air. All the mechanical arrangements employed for obtaining such a +result have failed, because the friction introduced by the maneuvering +parts also introduces a resistance greater than the motor can +overcome. There is therefore a waste of energy due to the continuous +flow of hydrogen; but the apparatus, for all that, constitutes none +the less an original and interesting device.—<i>La Nature</i>.</p> + +<hr /> + +<h2><a name="art04" id="art04"></a>SOME RELATIONS OF HEAT TO VOLTAIC AND THERMO-ELECTRIC ACTION OF +METALS IN ELECTROLYTES.<a name="FNanchor_3" id="FNanchor_3"></a><a href="#Footnote_3"><sup>1</sup></a></h2> + + +<h3>By G. GORE, F.R.S., LL.D.</h3> + +<p>The experiments described in this paper throw considerable light upon +the real cause of the voltaic current. The results of them are +contained in twenty tables; and by comparing them with each other, and +also by means of additional experiments, the following general +conclusions and chief facts were obtained.</p> + +<p>When metals in liquids are heated, they are more frequently rendered +positive than negative in the proportion of about 2.8 to 1.0; and +while the proportion in weak solutions was about 2.29 to 1.0, in +strong ones it was about 3.27 to 1.0, and this accords with their +thermo-electric behavior as metals alone. The thermo-electric order of +metals in liquids was, with nearly every solution, whether strong or +weak, widely different from the thermo-electric order of the same +metals alone. A conclusion previously arrived at was also confirmed, +viz., that the liquids in which the hot metal was thermo-electro-positive +in the largest proportion of cases were those containing highly +electro-positive bases, such as the alkali metals. The thermo-electric +effect of <i>gradually</i> heating a metal in a liquid was sometimes +different from that of <i>suddenly</i> heating it, and was occasionally +attended by a reversal of the current.</p> + +<p>Degree of strength of liquid greatly affected the thermo-electric +order of metals. Increase of strength usually and considerably +increased the potential of metals thermo-electro-negative in liquids, +and somewhat increased that of those positive in liquids.</p> + +<p>The electric potential of metals, thermo-electro-positive in weak +liquids, was usually about 3.87 times, and in strong ones 1.87 times, +as great as of those which were negative. The potential of the +strongest thermo-electric couple, viz., that of aluminum in weak +solution of sodic phosphate, was 0.66 volt for 100° F. difference of +temperature, or about 100 times that of a bismuth and antimony couple.</p> + +<p>Heating one of the metals, either the positive or negative, of a +voltaic couple, usually increased their electric difference, making +most metals more positive, and some more negative; while heating the +second one also usually neutralized to a large extent the effect of +heating the first one. The electrical effect of heating a voltaic +couple is nearly wholly composed of the united effects of heating each +of the two metals separately, but is not however exactly the same, +because while in the former case the metals are dissimilar, and are +heated to the same temperature, in the latter they are similar, but +heated to different temperatures. Also, when heating a voltaic pair, +the heat is applied to two metals, both of which are previously +electro-polar by contact with each other as well as by contact with +the liquid; but when heating one junction of a metal and liquid +couple, the metal has not been previously rendered electro-polar by +contact with a different one, and is therefore in a somewhat different +state. When a voltaic combination, in which the positive metal is +thermo-negative, and the negative one is thermo-positive, is heated, +the electric potential of the couple diminishes, notwithstanding that +the internal resistance is decreased.</p> + +<p>Magnesium in particular, also zinc and cadmium, were greatly depressed +in electromotive force in electrolytes by elevation of temperature. +Reversals of position of two metals of a voltaic couple in the tension +series by rise of temperature were chiefly due to one of the two +metals increasing in electromotive force faster than the other, and in +many cases to one metal increasing and the other decreasing in +electromotive force, but only in a few cases was it a result of +simultaneous but unequal diminution of potential of the two metals. +With eighteen different voltaic couples, by rise of temperature from +60° to 160° F., the electromotive force in twelve cases was increased, +and in six decreased, and the average proportions of increase for the +eighteen instances was 0.10 volt for the 100° F. of elevation.</p> + +<p>A great difference in chemical composition of the liquid was attended +by a considerable change in the order of the volta-tension series, and +the differences of such order in two similar liquids, such as +solutions of hydric chloride and potassic chloride, were much greater +than those produced in either of those liquids by a difference of 100° +F. of temperature. Difference of strength of solution, like difference +of composition or of temperature, altered the order of such series +with nearly every liquid; and the amount of such alteration by an +increase of four or five times in the strength of the liquid was +rather less than that caused by a difference of 100° F. of +temperature. While also a variation of strength of liquid caused only +a moderate amount of change of order in the volta-tension series, it +produced more than three times that amount of change in the +thermo-electric tension series. The usual effect of increasing the +strength of the liquid upon the volta-electromotive force was to +considerably increase it, but its effect upon the thermo-electro-motive +force was to largely decrease it. The degree of potential of a metal +and liquid thermo-couple was not always exactly the same at the same +temperature during a rise as during a fall of temperature; this is +analogous to the variations of melting and solidifying points of +bodies under such conditions, and also to that of supersaturation of a +liquid by a salt, and is probably due to some hinderance to change of +molecular movement.</p> + +<p>The rate of ordinary chemical corrosion of each metal varied in every +different liquid; in each solution also it differed with every +different metal. The most chemically positive metals were usually the +most quickly corroded, and the corrosion of each metal was usually the +fastest with the most acid solutions. The rate of corrosion at any +given temperature was dependent both upon the nature of the metal and +upon that of the liquid, and was limited by the most feebly active of +the two, usually the electrolyte. The order of rate of corrosion of +metals also differed in every different liquid. The more dissimilar +the chemical characters of two liquids, the more diverse usually was +the order of rapidity of corrosion of a series of metals in them. The +order of rate of simple corrosion in any of the liquids examined +differed from that of chemico-electric and still more from that of +thermo-electric tension. Corrosion is not the cause of thermo-electric +action of metals in liquids.</p> + +<p>Out of fifty-eight cases of rise of temperature the rate of ordinary +corrosion was increased in every instance except one, and that was +only a feeble exception—the increase of corrosion from 60° to 160° F. +with different metals was extremely variable, and was from 1.5 to +321.6 times. Whether a metal increased or decreased in +thermo-electromotive force by being heated, it increased in rapidity +of corrosion. The proportions in which the most corroded metal was +also the most thermo-electro-positive one was 65.57 per cent. in +liquids at 60° F., and 69.12 in the same liquids at 160° F.; and the +proportion in which it was the most chemico-electro-positive at 60 F. +was 84.44 per cent, and at 160° F. 80.77 per cent. The proportion of +cases therefore in which the most chemico-electro-negative metal was +the most corroded one increased from 15.56 to 19.23 per cent, by a +rise of temperature of 100° F. Comparison of these proportions shows +that corrosion usually influenced in a greater degree chemico-electric +rather than thermo-electric actions of metals in liquids. Not only was +the relative number of cases in which the volta-negative metal was the +most corroded increased by rise of temperature, but also the average +relative loss by corrosion of the negative to that of the positive one +was increased from 3.11 to 6.32.</p> + +<p>The explanation most consistent with all the various results and +conclusions is a kinetic one: That metals and electrolytes are +throughout their masses in a state of molecular vibration. That the +molecules of those substances, being frictionless bodies in a +frictionless medium, and their motion not being dissipated by +conduction or radiation, continue incessantly in motion until some +cause arises to prevent them. That each metal (or electrolyte), when +unequally heated, has to a certain extent an unlike class of motions +in its differently heated parts, and behaves in those parts somewhat +like two metals (or electrolytes), and those unlike motions are +enabled, through the intermediate conducting portion of the substance, +to render those parts electro-polar. That every different metal and +electrolyte has a different class of motions, and in consequence of +this, they also, by contact alone with each other at the same +temperature, become electro-polar. The molecular motion of each +different substance also increases at a different rate by rise of +temperature.</p> + +<p>This theory is equally in agreement with the chemico-electric results. +In accordance with it, when in the case of a metal and an electrolyte, +the two classes of motions are sufficiently unlike, chemical corrosion +of the metal by the liquid takes place, and the voltaic current +originated by inherent molecular motion, under the condition of +contact, is maintained by the portions of motion lost by the metal and +liquid during the act of uniting together. Corrosion therefore is an +effect of molecular motion, and is one of the modes by which that +motion is converted into and produces electric current.</p> + +<p>In accordance with this theory, if we take a thermo-electric pair +consisting of a non-corrodible metal and an electrolyte (the two being +already electro-polar by mutual contact), <a name="Page_7071" id="Page_7071"></a>and heat one of their +points of contact, the molecular motions of the heated end of each +substance at the junction are altered; and as thermo-electric energy +in such combinations usually increases by rise of temperature, the +metal and liquid, each singly, usually becomes more electro polar. In +such a case the unequally heated metal behaves to some extent like two +metals, and the unequally heated liquid like two liquids, and so the +thermo-electric pair is like a feeble chemico-electric one of two +metals in two liquids, but without corrosion of either metal. If the +metal and liquid are each, when alone, thermo-electro-positive, and +if, when in contact, the metal increases in positive condition faster +than the liquid by being heated, the latter appears +thermo-electro-negative, but if less rapidly than the liquid, the +metal appears thermo-electro-negative.</p> + +<p>As also the proportion of cases is small in which metals that are +positive in the ordinary thermo-electric series of metals only become +negative in the metal and liquid ones (viz., only 73 out of 286 in +weak solutions, and 48 out of the same number in strong ones), we may +conclude that the metals, more frequently than the liquids, have the +greatest thermo-electric influence, and also that the relative +largeness of the number of instances of thermo-electro-positive metals +in the series of metals and liquids, as in the series of metals only, +is partly a consequence of the circumstance that rise of temperature +usually makes substances—metals in particular—electro-positive. +These statements are also consistent with the view that the elementary +substances lose a portion of their molecular activity when they unite +to form acids or salts, and that electrolytes therefore have usually a +less degree of molecular motion than the metals of which they are +partly composed.</p> + +<p>The current from a thermo-couple of metal and liquid, therefore, may +be viewed as the united result of difference of molecular motion, +first, of the two junctions, and second, of the two heated (or cooled) +substances; and in all cases, both of thermo- and chemico-electric +action, the immediate true cause of the current is the original +molecular vibrations of the substances, while contact is only a static +permitting condition. Also that while in the case of thermo-electric +action the sustaining cause is molecular motion, supplied by an +external source of heat, in the case of chemico-electric action it is +the motion lost by the metal and liquid when chemically uniting +together. The direction of the current in thermo-electric cases +appears to depend upon which of the two substances composing a +junction increases in molecular activity the fastest by rise of +temperature, or decreases the most rapidly by cooling.</p> + +<p><a name="Footnote_3" id="Footnote_3"></a><a href="#FNanchor_3">[1]</a></p> +<div class="note"><p>Read before the Royal Society, Nov., 1883.</p></div> + +<hr /> + +<h2><a name="art05" id="art05"></a>AIR REFRIGERATING MACHINE.</h2> + +<div class="figcenter"><a href="./images/9a.png"><img src="./images/9a_th.png" alt="IMPROVED AIR REFRIGERATING MACHINE." /></a><br /> IMPROVED AIR REFRIGERATING MACHINE.</div> + +<p>Messrs. J. & E. Hall, Dartford, exhibit at the International Health +Exhibition, London, in connection with a cold storage room, two sizes +of Ellis' patent air refrigerator, the larger one capable of +delivering 5,000 cubic feet of cold air per hour, when running at a +speed of 150 revolutions per minute; and the smaller one 2,000 cubic +feet of cold air per hour, at 225 revolutions per minute. The special +features in these machines are the arrangement of parts, by which +great compactness is secured, and the adoption of flat slides for the +compressor, instead of the ordinary beat valves, which permits of a +high rate of revolution without the objectionable noise which is +caused by clacks beating on their seats. The engraving shows the +general arrangement of the apparatus. Figs. 1 to 4 show details of the +compression and expansion valves, which are ordinary flat slides, +partly balanced, and held up to their faces by strong springs from +behind. The steam, compression, and expansion cylinders are severally +bolted to the end of a strong frame, which though attached to the +cooler box does not form part of it, the object being to meet the +strains between the cylinders and shaft in as direct a manner as +possible without allowing them to act on the cooler casting. Each +cylinder is double acting, the pistons being coupled to the shaft by +three connecting rods, the two outer ones working upon crank pins +fixed to overhung disks, and the center one on a crank formed in the +shaft. The slide valves for all the cylinders are driven from two +weigh shafts, the main valve shaft being actuated by a follow crank, +and the expansion and cut off valves from the crosshead pin of the +compressor. The machines may be used either in the vertical position +as exhibited, or may be fixed horizontally; and it is stated that the +construction is such as to admit of speeds of 200 and 300 revolutions +per minute respectively for the larger and smaller machines, under +which conditions the delivery of cold air may be taken at about 7,000 +and 2,600 cubic feet per hour. Messrs. Hall also make this class of +refrigerator without the steam cylinder, and arranged to be driven by +a belt from a gas engine or any existing motive power.</p> + +<hr /> + +<h2><a name="art06" id="art06"></a>A GAS RADIATOR AND HEATER.</h2> + +<div class="figcenter"><img src="./images/9b.png" alt="Fig. 1 & Fig. 2 A GAS RADIATOR AND HEATER." /><br />A GAS RADIATOR AND HEATER.</div> + +<p>There is now being introduced into Germany a gas radiator and heater, +the invention of Herr Wobbe. It consists, as will be seen in engraving +above, of a series of vertical U-shaped pipes, of wrought iron, 50 +millimeters (2 inches) in diameter. The two legs of the U are of +unequal length; the longer being about 5 feet, and the shorter 3 feet +(exclusive of the bend at the top). Beneath the open end of the +shorter leg of each pipe is placed a burner, attached to a horizontal +gas-pipe, which turns upon an axis. The object of having this pipe +rotate is to bring the burners into an inclined position—shown by the +dotted lines in Fig. 2—for lighting them. On turning them back to the +vertical position, the heated products of combustion pass up the +shorter tube and down the longer, where they enter a common +receptacle, from which they pass into the chimney or out of doors. +Surrounding the pipes are plates of sheet iron, inclined at the angle +shown in Fig. 2. The object of the plates is to prevent the heated air +of the room from passing up to the ceiling, and send it out into the +room. To prevent any of the pipes acting as chimneys, and bringing the +products of combustion back into the room, as well as to avoid any +back-pressure, a damper is attached to the outlet receptacle. The +heated gas becomes cooled so much (to about 100° Fahr.) that water is +condensed and precipitated, and collects in the vessel below the +outlet. Each burner has a separate cock, by which it may be kept +closed, half-open, or open. To obviate danger of explosion, there is a +strip of sheet iron in front of the burners, which prevents their +being lighted when in a vertical position; so that, in case any +unburned gas gets into the pipes, it cannot be ignited, for the +burners can only be lighted when inclined to the front. In starting +the stove the burners are lighted, in the inclined position; the chain +from the damper pulled up; the burners set vertical; and, as soon as +they are all drawing well into the tubes, the damper is closed. If +less heat is desired, the cocks are turned half off. It is not +permissible to entirely extinguish some of the burners, unless the +unused pipes are closed to prevent the products of combustion coming +back into the room. The consumption of gas per burner, full open, with +a pressure of 8/10, is said to be only 4-3/8 cubic feet per hour.</p> + +<hr /> + +<h2><a name="art07" id="art07"></a>CONCRETE WATER PIPES.</h2> + +<p>Concrete water pipes of small diameter, according to a foreign +contemporary, are used in parts of France, notably for water mains for +the towns of Coulommiers and Aix-en-Provence. The pipes were formed of +concrete in the trench itself. The mould into which the concrete was +stamped was sheet iron about two yards in length. The several pipes +were not specially joined to each other, the joints being set with +mortar. The concrete consisted of three parts of slow setting cement +and three parts of river sand, mixed with five parts of limestone +debris. The inner diameter of the pipes was nine inches; their +thickness, three inches. The average fall is given at one in five +hundred; the lowest speed of the current at one foot nine inches per +second. To facilitate the cleaning of the pipes, man-holes are +constructed every one hundred yards or so, the sides of which are also +made of concrete. The trenches are about five feet deep. The work was +done by four men, who laid down nearly two hundred feet of pipe in a +working day; the cost was about ninety-three cents per running yard. +It is claimed as an advantage for the new method that the pipes adhere +closely to the inequalities of the trench, and thus lie firmly on the +ground. When submitted to great pressure, however, they have not +proved effective, and the method, consequently, is only suitable for +pipes in which there is no pressure, or only a very trifling one.</p> + +<hr /> + +<h2><a name="art08" id="art08"></a><a name="Page_7072" id="Page_7072"></a>THE SELLERS STANDARD SYSTEM OF SCREW THREADS, NUTS, AND BOLT +HEADS.</h2> + +<div class="wide"> +<table summary="" cellspacing="0" cellpadding="0"> + +<tr><th colspan="9" align="center">SCREW THREADS.</th> +<th align="center" colspan="12">NUTS.</th> +<th align="center" colspan="12">BOLT HEADS.</th> +</tr> +<tr> +<th colspan="2">Diam.<br/>of<br />Screw.<br /><img src="./images/screw.png" width="50%" alt="" /></th> +<th colspan="2">Threads<br />per<br />inch.<br /><img src="./images/thread.png" width="50%" alt="" /></th> +<th align="center" colspan="3">Diameter<br />at root<br />of Thread.<br /><img src="./images/root.png" width="50%" alt="" /></th> +<th align="center">Area<br />of<br />Bolt<br />at<br />root<br />of<br />Thread.</th> +<th align="center">Width<br />of<br />Flat.<br /><img src="./images/flat.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Short<br />Diam.<br />Rough<br /><img src="./images/hex1.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Short<br />Diam.<br />Finish.<br /><img src="./images/hex2.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Long<br />Diam.<br />Rough.<br /><img src="./images/hex3.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Long<br />Diam.<br />Rough.<br /><img src="./images/dia.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Thick<br />ness<br />Rough.<br /><img src="./images/bolt1.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Thick<br />ness<br />Finish<br /><img src="./images/bolt2.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Short<br />Diam.<br />Rough<br /><img src="./images/hex1.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Short<br />Diam.<br />Finish.<br /><img src="./images/hex2.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Long<br />Diam.<br />Rough.<br /><img src="./images/hex3.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Long<br />Diam.<br />Rough.<br /><img src="./images/dia.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Thick<br />ness<br />Rough.<br /><img src="./images/bolt1.png" width="50%" alt="" /></th> +<th align="center" colspan="2">Thick<br />ness<br />Finish<br /><img src="./images/bolt2.png" width="50%" alt="" /></th> +</tr> + +<tr> +<td> </td><td align="center">1<br /><span class="over">4</span></td><td align="right">20</td><td> </td><td align="right">.185</td><td> </td><td align="center">13<br /><span class="over">64</span></td><td align="right">.026</td><td align="right">.0062</td> +<td> </td><td align="center">1<br /><span class="over">2</span></td><td> </td><td align="center">7<br /><span class="over">16</span></td> <td> </td><td align="center">37<br /><span class="over">64</span></td> <td> </td><td align="center">7<br /><span class="over">10</span></td> <td> </td><td align="center">1<br /><span class="over">4</span></td><td> </td><td align="center">3<br /><span class="over">16</span></td> +<td> </td><td align="center">1<br /><span class="over">2</span></td><td> </td><td align="center">7<br /><span class="over">16</span></td><td> </td><td align="center">37<br /><span class="over">64</span></td> <td> </td><td align="center">7<br /><span class="over">10</span></td> <td> </td><td align="center">1<br /><span class="over">4</span></td><td> </td><td align="center">3<br /><span class="over">16</span></td> +</tr> +<tr> +<td> </td><td align="center">5<br /><span class="over">16</span></td><td align="right">18</td><td> </td><td align="right">.240</td><td> </td><td align="center">15<br /><span class="over">64</span></td><td align="right">.045</td><td align="right">.0074</td> +<td> </td><td align="center">19<br /><span class="over">32</span></td><td> </td><td align="center">17<br /><span class="over">32</span></td> <td> </td><td align="center">11<br /><span class="over">16</span></td> <td> </td><td align="center">10<br /><span class="over">12</span></td> <td> </td><td align="center">5<br /><span class="over">16</span></td><td> </td><td align="center">1<br /><span class="over">4</span></td> +<td> </td><td align="center">19<br /><span class="over">32</span></td> <td> </td><td align="center">17<br /><span class="over">32</span></td> <td> </td><td align="center">11<br /><span class="over">16</span></td> <td> </td><td align="center">10<br /><span class="over">12</span></td> <td> </td><td align="center">19<br /><span class="over">64</span></td><td> </td><td align="center">1<br /><span class="over">4</span></td> +</tr> +<tr> +<td> </td><td align="center">3<br /><span class="over">8</span></td><td align="right">16</td><td> </td><td align="right">.294</td><td> </td><td align="center">19<br /><span class="over">64</span></td><td align="right">.067</td><td align="right">.0078</td> +<td> </td><td align="center">11<br /><span class="over">16</span></td><td> </td><td align="center">5<br /><span class="over">8</span></td><td> </td><td align="center">51<br /><span class="over">64</span></td> <td> </td><td align="center">63<br /><span class="over">64</span></td><td> </td><td align="center">3<br /><span class="over">8</span></td><td> </td><td align="center">5<br /><span class="over">16</span></td> +<td> </td><td align="center">11<br /><span class="over">16</span></td> <td> </td><td align="center">5<br /><span class="over">8</span></td> <td> </td><td align="center">51<br /><span class="over">64</span></td> <td> </td><td align="center">63<br /><span class="over">64</span></td> <td> </td><td align="center">11<br /><span class="over">32</span></td><td> </td><td align="center">5<br /><span class="over">16</span></td> +</tr> +<tr> +<td> </td><td align="center">7<br /><span class="over">16</span></td><td align="right">14</td><td> </td><td align="right">.344</td><td> </td><td align="center">11<br /><span class="over">32</span></td><td align="right">.092</td><td align="right">.0089</td> +<td> </td><td align="center">25<br /><span class="over">32</span></td><td> </td><td align="center">23<br /><span class="over">33</span></td> <td> </td><td align="center">9<br /><span class="over">10</span></td><td align="right">1</td><td align="center">7<br /><span class="over">64</span></td><td> </td><td align="center">7<br /><span class="over">16</span></td><td> </td><td align="center">3<br /><span class="over">8</span></td> +<td> </td><td align="center">25<br /><span class="over">32</span></td> <td> </td><td align="center">23<br /><span class="over">32</span></td> <td> </td><td align="center">9<br /><span class="over">16</span></td><td align="right">1</td><td align="center">7<br /><span class="over">64</span></td><td> </td><td align="center">25<br /><span class="over">64</span></td><td> </td><td align="center">3<br /><span class="over">8</span></td> +</tr> +<tr> +<td> </td><td align="center">1<br /><span class="over">2</span></td><td align="right">13</td><td> </td><td align="right">.400</td><td> </td><td align="center">13<br /><span class="over">32</span></td><td align="right">.125</td><td align="right">.0096</td> +<td> </td><td align="center">7<br /><span class="over">8</span></td><td> </td><td align="center">13<br /><span class="over">16</span></td><td align="right">1</td><td> </td><td align="right">1</td><td align="center">15<br /><span class="over">64</span></td><td> </td><td align="center">1<br /><span class="over">2</span></td><td> </td><td align="center">7<br /><span class="over">16</span></td> +<td> </td><td align="center">7<br /><span class="over">8</span></td> <td> </td><td align="center">13<br /><span class="over">16</span></td><td align="right">1</td><td> </td><td align="right">1</td><td align="center">15<br /><span class="over">64</span></td><td> </td><td align="center">7<br /><span class="over">16</span></td><td> </td><td align="center">7<br /><span class="over">16</span></td> +</tr> + +<tr> +<td> </td><td align="center">9<br /><span class="over">16</span></td><td align="right">12</td><td> </td><td align="right">.454</td><td> </td><td align="center">29<br /><span class="over">64</span></td><td align="right">.161</td><td align="right">.0104</td> +<td> </td><td align="center">31<br /><span class="over">32</span></td><td> </td><td align="center">29<br /><span class="over">32</span></td><td align="right">1</td><td align="center">1<br /><span class="over">8</span></td><td align="right">1</td><td align="center">23<br /><span class="over">64</span></td><td> </td><td align="center">9<br /><span class="over">16</span></td><td> </td><td align="center">1<br /><span class="over">2</span></td> +<td> </td><td align="center">31<br /><span class="over">32</span></td> <td> </td><td align="center">29<br /><span class="over">32</span></td><td align="right">1</td><td align="center">1<br /><span class="over">8</span></td> <td align="right">1</td><td align="center">23<br /><span class="over">64</span></td><td> </td><td align="center">31<br /><span class="over">64</span></td><td> </td><td align="center">1<br /><span class="over">2</span></td> +</tr> + +<tr> +<td> </td><td align="center">5<br /><span class="over">8</span></td><td align="right">11</td><td> </td><td align="right">.507</td><td> </td><td align="center">33<br /><span class="over">64</span></td><td align="right">.201</td><td align="right">.0113</td> +<td align="right">1</td><td align="center">1<br /><span class="over">16</span></td><td align="right">1</td><td> </td><td align="right">1</td><td align="center">7<br /><span class="over">32</span></td> <td align="right">1</td><td align="center">1<br /><span class="over">2</span></td><td> </td><td align="center">5<br /><span class="over">8</span></td><td> </td><td align="center">9<br /><span class="over">16</span></td> +<td align="right">1</td><td align="center">1<br /><span class="over">16</span></td><td align="right">1</td><td> </td><td align="right">1</td><td align="center">7<br /><span class="over">32</span></td> <td align="right">1</td><td align="center">1<br /><span class="over">2</span></td><td> </td><td align="center">17<br /><span class="over">32</span></td><td> </td><td align="center">9<br /><span class="over">16</span></td> +</tr> + +<tr> +<td> </td><td align="center">3<br /><span class="over">4</span></td><td align="right">10</td><td> </td><td align="right">.620</td><td> </td><td align="center">5<br /><span class="over">8</span></td><td align="right">.301</td><td align="right">.0125</td> +<td align="right">1</td><td align="center">1<br /><span class="over">4</span></td><td align="right">1</td><td align="center">3<br /><span class="over">16</span></td><td align="right">1</td><td align="center">7<br /><span class="over">16</span></td><td align="right">1</td><td align="center">49<br /><span class="over">64</span></td><td> </td><td align="center">3<br /><span class="over">4</span></td><td> </td><td align="center">11<br /><span class="over">16</span></td> +<td align="right">1</td><td align="center">1<br /><span class="over">4</span></td> <td align="right">1</td><td align="center">3<br /><span class="over">16</span></td> <td align="right">1</td><td align="center">7<br /><span class="over">16</span></td> <td align="right">1</td><td align="center">49<br /><span class="over">64</span></td><td> </td><td align="center">5<br /><span class="over">8</span></td><td> </td><td align="center">11<br /><span class="over">16</span></td> +</tr> +<tr> +<td> </td><td align="center">7<br /><span class="over">8</span></td><td align="right">9</td><td> </td><td align="right">.731</td><td> </td><td align="center">47<br /><span class="over">64</span></td><td align="right">.419</td><td align="right">.0138</td> +<td align="right">1</td><td align="center">7<br /><span class="over">16</span></td><td align="right">1</td><td align="center">3<br /><span class="over">8</span></td><td align="right">1</td><td align="center">21<br /><span class="over">32</span></td><td align="right">2</td><td align="center">1<br /><span class="over">32</span></td><td> </td><td align="center">7<br /><span class="over">8</span></td><td> </td><td align="center">13<br /><span class="over">16</span></td> +<td align="right">1</td><td align="center">7<br /><span class="over">16</span></td> <td align="right">1</td><td align="center">3<br /><span class="over">8</span></td><td align="right">1</td><td align="center">21<br /><span class="over">32</span></td><td align="right">2</td><td align="center">1<br /><span class="over">32</span></td><td> </td><td align="center">23<br /><span class="over">32</span></td><td> </td><td align="center">13<br /><span class="over">16</span></td> +</tr> +<tr><td> </td> +</tr> +<tr> +<td align="right">1</td><td> </td> <td align="right">8</td><td> </td><td align="right">.837</td><td> </td><td align="center">27<br /><span class="over">32</span></td><td align="right">.550</td><td align="right">.0156</td> +<td align="right">1</td><td align="center">5<br /><span class="over">8</span></td><td align="right">1</td><td align="center">9<br /><span class="over">16</span></td><td align="right">1</td><td align="center">7<br /><span class="over">8</span></td><td align="right">2</td><td align="center">19<br /><span class="over">64</span></td><td align="right">1</td><td> </td><td> </td><td align="center">15<br /><span class="over">16</span></td> +<td align="right">1</td><td align="center">5<br /><span class="over">8</span></td> <td align="right">1</td><td align="center">9<br /><span class="over">16</span></td> <td align="right">1</td><td align="center">7<br /><span class="over">8</span></td> <td align="right">2</td><td align="center">19<br /><span class="over">64</span></td><td> </td><td align="center">13<br /><span class="over">16</span></td><td> </td><td align="center">15<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">1</td><td align="center">1<br /><span class="over">8</span></td><td align="right">7</td><td> </td><td align="right">.940</td><td> </td><td align="center">15<br /><span class="over">16</span></td><td align="right">.693</td><td align="right">.0178</td> +<td align="right">1</td><td align="center">13<br /><span class="over">16</span></td><td align="right">1</td><td align="center">3<br /><span class="over">4</span></td> <td align="right">2</td><td align="center">5<br /><span class="over">32</span></td> <td align="right">2</td><td align="center">9<br /><span class="over">16</span></td> <td align="right">1</td><td align="center">1<br /><span class="over">8</span></td><td align="right">1</td><td align="center">1<br /><span class="over">16</span></td> +<td align="right">1</td><td align="center">13<br /><span class="over">16</span></td> <td align="right">1</td><td align="center">3<br /><span class="over">4</span></td> <td align="right">2</td><td align="center">5<br /><span class="over">32</span></td> <td align="right">2</td><td align="center">7<br /><span class="over">16</span></td><td> </td><td align="center">29<br /><span class="over">32</span></td><td align="right">1</td><td align="center">1<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">1</td><td align="center">1<br /><span class="over">4</span></td><td align="right">7</td><td> </td><td align="right">1.065</td><td align="right">1</td><td align="center">1<br /><span class="over">16</span></td><td align="right">.890</td><td align="right">.0178</td> +<td align="right">2</td><td> </td><td align="right">1</td><td align="center">15<br /><span class="over">16</span></td><td align="right">2</td><td align="center">5<br /><span class="over">16</span></td><td align="right">2</td><td align="center">53<br /><span class="over">64</span></td><td align="right">1</td><td align="center">1<br /><span class="over">4</span></td><td align="right">1</td><td align="center">3<br /><span class="over">16</span></td> +<td align="right">2</td><td> </td><td align="right">1</td><td align="center">15<br /><span class="over">16</span></td> <td align="right">2</td><td align="center">5<br /><span class="over">16</span></td> <td align="right">2</td><td align="center">53<br /><span class="over">64</span></td><td align="right">1</td><td> </td><td align="right">1</td><td align="center">3<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">1</td><td align="center">3<br /><span class="over">8</span></td><td align="right">6</td><td> </td><td align="right">1.160</td><td align="right">1</td><td align="center">5<br /><span class="over">32</span></td><td align="right">1.056</td><td align="right">.0208</td> +<td align="right">2</td><td align="center">3<br /><span class="over">16</span></td><td align="right">2</td><td align="center">1<br /><span class="over">8</span></td><td align="right">2</td><td align="center">17<br /><span class="over">32</span></td><td align="right">3</td><td align="center">3<br /><span class="over">32</span></td> <td align="right">1</td><td align="center">3<br /><span class="over">8</span></td><td align="right">1</td><td align="center">5<br /><span class="over">16</span></td> +<td align="right">2</td><td align="center">3<br /><span class="over">16</span></td> <td align="right">2</td><td align="center">1<br /><span class="over">8</span></td> <td align="right">2</td><td align="center">17<br /><span class="over">32</span></td> <td align="right">3</td><td align="center">3<br /><span class="over">32</span></td> <td align="right">1</td><td align="center">3<br /><span class="over">32</span></td><td align="right">1</td><td align="center">5<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">1</td><td align="center">1<br /><span class="over">2</span></td><td align="right">6</td><td> </td><td align="right">1.284</td><td align="right">1</td><td align="center">9<br /><span class="over">32</span></td><td align="right">1.294</td><td align="right">.0208</td> +<td align="right">2</td><td align="center">3<br /><span class="over">8</span></td><td align="right">2</td><td align="center">5<br /><span class="over">16</span></td><td align="right">2</td><td align="center">3<br /><span class="over">4</span></td><td align="right">3</td><td align="center">23<br /><span class="over">64</span></td><td align="right">1</td><td align="center">1<br /><span class="over">2</span></td><td align="right">1</td><td align="center">7<br /><span class="over">16</span></td> +<td align="right">2</td><td align="center">3<br /><span class="over">8</span></td> <td align="right">2</td><td align="center">5<br /><span class="over">16</span></td> <td align="right">2</td><td align="center">3<br /><span class="over">4</span></td> <td align="right">3</td><td align="center">23<br /><span class="over">64</span></td> <td align="right">1</td><td align="center">3<br /><span class="over">16</span></td><td align="right">1</td><td align="center">7<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">1</td><td align="center">5<br /><span class="over">8</span></td> <td align="right">5</td><td align="center">1<br /><span class="over">2</span></td><td align="right">1.389</td><td align="right">1</td><td align="center">25<br /><span class="over">64</span></td><td align="right">1.515</td><td align="right">.0227</td> +<td align="right">2</td><td align="center">9<br /><span class="over">16</span></td><td align="right">2</td><td align="center">1<br /><span class="over">2</span></td><td align="right">2</td><td align="center">31<br /><span class="over">32</span></td><td align="right">3</td><td align="center">5<br /><span class="over">8</span></td><td align="right">1</td><td align="center">5<br /><span class="over">8</span></td><td align="right">1</td><td align="center">9<br /><span class="over">16</span></td> +<td align="right">2</td><td align="center">9<br /><span class="over">16</span></td> <td align="right">2</td><td align="center">1<br /><span class="over">2</span></td> <td align="right">2</td><td align="center">31<br /><span class="over">32</span></td> <td align="right">3</td><td align="center">5<br /><span class="over">8</span></td> <td align="right">1</td><td align="center">9<br /><span class="over">32</span></td><td align="right">1</td><td align="center">9<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">1</td><td align="center">3<br /><span class="over">4</span></td><td align="right">5</td><td> </td><td align="right">1.491</td><td align="right">1</td><td align="center">31<br /><span class="over">64</span></td><td align="right">1.746</td><td align="right">.0250</td> +<td align="right">2</td><td align="center">3<br /><span class="over">4</span></td><td align="right">2</td><td align="center">11<br /><span class="over">16</span></td><td align="right">3</td><td align="center">3<br /><span class="over">16</span></td><td align="right">3</td><td align="center">57<br /><span class="over">64</span></td><td align="right">1</td><td align="center">3<br /><span class="over">4</span></td><td align="right">1</td><td align="center">11<br /><span class="over">16</span></td> +<td align="right">2</td><td align="center">3<br /><span class="over">4</span></td> <td align="right">2</td><td align="center">11<br /><span class="over">16</span></td><td align="right">3</td><td align="center">3<br /><span class="over">16</span></td> <td align="right">3</td><td align="center">57<br /><span class="over">64</span></td> <td align="right">1</td><td align="center">3<br /><span class="over">8</span></td><td align="right">1</td><td align="center">11<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">1</td><td align="center">7<br /><span class="over">8</span></td><td align="right">5</td><td> </td><td align="right">1.616</td><td align="right">1</td><td align="center">39<br /><span class="over">64</span></td><td align="right">2.051</td><td align="right">.0250</td> +<td align="right">2</td><td align="center">15<br /><span class="over">16</span></td><td align="right">2</td><td align="center">7<br /><span class="over">8</span></td><td align="right">3</td><td align="center">13<br /><span class="over">32</span></td><td align="right">4</td><td align="center">5<br /><span class="over">32</span></td> <td align="right">1</td><td align="center">7<br /><span class="over">8</span></td><td align="right">1</td><td align="center">13<br /><span class="over">16</span></td> +<td align="right">2</td><td align="center">15<br /><span class="over">16</span></td> <td align="right">2</td><td align="center">7<br /><span class="over">8</span></td> <td align="right">3</td><td align="center">13<br /><span class="over">32</span></td> <td align="right">4</td><td align="center">5<br /><span class="over">32</span></td><td align="right">1</td><td align="center">15<br /><span class="over">32</span></td><td align="right">1</td><td align="center">13<br /><span class="over">16</span></td> +</tr> +<tr><td> </td> +</tr> +<tr> +<td align="right">2</td><td> </td><td align="right">4</td><td align="center">1<br /><span class="over">2</span></td><td align="right">1.742</td><td align="right">1</td><td align="center">23<br /><span class="over">32</span></td><td align="right">2.301</td><td align="right">.0277</td> +<td align="right">3</td><td align="center">1<br /><span class="over">8</span></td><td align="right">3</td><td align="center">1<br /><span class="over">16</span></td><td align="right">3</td><td align="center">5<br /><span class="over">8</span></td><td align="right">4</td><td align="center">27<br /><span class="over">64</span></td><td align="right">2</td><td> </td><td align="right">1</td><td align="center">15<br /><span class="over">16</span></td> +<td align="right">3</td><td align="center">1<br /><span class="over">8</span></td> <td align="right">3</td><td align="center">1<br /><span class="over">16</span></td> <td align="right">3</td><td align="center">5<br /><span class="over">8</span></td> <td align="right">4</td><td align="center">27<br /><span class="over">64</span></td> <td align="right">1</td><td align="center">9<br /><span class="over">16</span></td><td align="right">1</td><td align="center">15<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">2</td><td align="center">1<br /><span class="over">4</span></td> <td align="right">4</td><td align="center">1<br /><span class="over">2</span></td><td align="right">1.962</td><td align="right">1</td><td align="center">31<br /><span class="over">32</span></td><td align="right">3.023</td><td align="right">.0277</td> +<td align="right">3</td><td align="center">1<br /><span class="over">2</span></td><td align="right">3</td><td align="center">7<br /><span class="over">16</span></td><td align="right">4</td><td align="center">1<br /><span class="over">16</span></td><td align="right">4</td><td align="center">61<br /><span class="over">64</span></td><td align="right">2</td><td align="center">1<br /><span class="over">4</span></td><td align="right">2</td><td align="center">3<br /><span class="over">16</span></td> +<td align="right">3</td><td align="center">1<br /><span class="over">2</span></td> <td align="right">3</td><td align="center">7<br /><span class="over">16</span></td> <td align="right">4</td><td align="center">1<br /><span class="over">16</span></td> <td align="right">4</td><td align="center">61<br /><span class="over">64</span></td> <td align="right">1</td><td align="center">3<br /><span class="over">4</span></td><td align="right">2</td><td align="center">3<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">2</td><td align="center">1<br /><span class="over">2</span></td><td align="right">4</td><td> </td><td align="right">2.176</td><td align="right">2</td><td align="center">11<br /><span class="over">64</span></td><td align="right">3.718</td><td align="right">.0312</td> +<td align="right">3</td><td align="center">7<br /><span class="over">8</span></td><td align="right">3</td><td align="center">13<br /><span class="over">16</span></td><td align="right">4</td><td align="center">1<br /><span class="over">2</span></td><td align="right">5</td><td align="center">31<br /><span class="over">64</span></td><td align="right">2</td><td align="center">1<br /><span class="over">2</span></td><td align="right">2</td><td align="center">7<br /><span class="over">16</span></td> +<td align="right">3</td><td align="center">7<br /><span class="over">8</span></td><td align="right">3</td><td align="center">13<br /><span class="over">16</span></td><td align="right">4</td><td align="center">1<br /><span class="over">2</span></td> <td align="right">5</td><td align="center">31<br /><span class="over">64</span></td><td align="right">1</td><td align="center">15<br /><span class="over">16</span></td><td align="right">2</td><td align="center">7<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">2</td><td align="center">3<br /><span class="over">4</span></td><td align="right">4</td><td> </td><td align="right">2.426</td><td align="right">2</td><td align="center">27<br /><span class="over">64</span></td><td align="right">4.622</td><td align="right">.0312</td> +<td align="right">4</td><td align="center">1<br /><span class="over">4</span></td><td align="right">4</td><td align="center">3<br /><span class="over">16</span></td> <td align="right">4</td><td align="center">29<br /><span class="over">32</span></td><td align="right">6</td><td> </td><td align="right">2</td><td align="center">3<br /><span class="over">4</span></td><td align="right">2</td><td align="center">11<br /><span class="over">16</span></td> +<td align="right">4</td><td align="center">1<br /><span class="over">4</span></td> <td align="right">4</td><td align="center">3<br /><span class="over">16</span></td> <td align="right">4</td><td align="center">29<br /><span class="over">32</span></td><td align="right">6</td><td> </td><td align="right">2</td><td align="center">1<br /><span class="over">8</span></td><td align="right">2</td><td align="center">11<br /><span class="over">16</span></td> +</tr> +<tr><td> </td> +</tr> +<tr> +<td align="right">3</td><td> </td><td align="right">3</td><td align="center">1<br /><span class="over">2</span></td><td align="right">2.629</td><td align="right">2</td><td align="center">5<br /><span class="over">8</span></td><td align="right">5.428</td><td align="right">.0357</td> +<td align="right">4</td><td align="center">5<br /><span class="over">8</span></td><td align="right">4</td><td align="center">9<br /><span class="over">16</span></td><td align="right">5</td><td align="center">3<br /><span class="over">8</span></td><td align="right">6</td><td align="center">17<br /><span class="over">32</span></td><td align="right">3</td><td> </td><td align="right">2</td><td align="center">15<br /><span class="over">16</span></td> +<td align="right">4</td><td align="center">5<br /><span class="over">8</span></td> <td align="right">4</td><td align="center">9<br /><span class="over">16</span></td> <td align="right">5</td><td align="center">3<br /><span class="over">8</span></td> <td align="right">6</td><td align="center">17<br /><span class="over">32</span></td> <td align="right">2</td><td align="center">5<br /><span class="over">16</span></td><td align="right">2</td><td align="center">15<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">3</td><td align="center">1<br /><span class="over">4</span></td> <td align="right">3</td><td align="center">1<br /><span class="over">2</span></td><td align="right">2.879</td><td align="right">2</td><td align="center">7<br /><span class="over">8</span></td><td align="right">6.509</td><td align="right">.0357</td> +<td align="right">5</td><td> </td><td align="right">4</td><td align="center">15<br /><span class="over">16</span></td> <td align="right">5</td><td align="center">13<br /><span class="over">16</span></td><td align="right">7</td><td align="center">1<br /><span class="over">16</span></td> <td align="right">3</td><td align="center">1<br /><span class="over">4</span></td><td align="right">3</td><td align="center">3<br /><span class="over">16</span></td> +<td align="right">5</td><td> </td><td align="right">4</td><td align="center">15<br /><span class="over">16</span></td> <td align="right">5</td><td align="center">13<br /><span class="over">16</span></td> <td align="right">7</td><td align="center">1<br /><span class="over">16</span></td> <td align="right">2</td><td align="center">1<br /><span class="over">2</span></td><td align="right">3</td><td align="center">3<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">3</td><td align="center">1<br /><span class="over">2</span></td> <td align="right">3</td><td align="center">1<br /><span class="over">4</span></td><td align="right">3.100</td><td align="right">3</td><td align="center">3<br /><span class="over">32</span></td><td align="right">7.547</td><td align="right">.0384</td> +<td align="right">5</td><td align="center">3<br /><span class="over">8</span></td><td align="right">5</td><td align="center">5<br /><span class="over">16</span></td><td align="right">6</td><td align="center">7<br /><span class="over">32</span></td><td align="right">7</td><td align="center">39<br /><span class="over">64</span></td><td align="right">3</td><td align="center">1<br /><span class="over">2</span></td><td align="right">3</td><td align="center">7<br /><span class="over">16</span></td> +<td align="right">5</td><td align="center">3<br /><span class="over">8</span></td> <td align="right">5</td><td align="center">5<br /><span class="over">16</span></td> <td align="right">6</td><td align="center">7<br /><span class="over">32</span></td> <td align="right">7</td><td align="center">39<br /><span class="over">64</span></td><td align="right">2</td><td align="center">11<br /><span class="over">16</span></td><td align="right">3</td><td align="center">7<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">3</td><td align="center">3<br /><span class="over">4</span></td><td align="right">3</td><td> </td><td align="right">3.317</td><td align="right">3</td><td align="center">5<br /><span class="over">16</span></td><td align="right">8.614</td><td align="right">.0413</td> +<td align="right">5</td><td align="center">3<br /><span class="over">4</span></td><td align="right">5</td><td align="center">11<br /><span class="over">16</span></td> <td align="right">6</td><td align="center">21<br /><span class="over">32</span></td><td align="right">8</td><td align="center">1<br /><span class="over">8</span></td> <td align="right">3</td><td align="center">3<br /><span class="over">4</span></td><td align="right">3</td><td align="center">11<br /><span class="over">16</span></td> +<td align="right">5</td><td align="center">3<br /><span class="over">4</span></td><td align="right">5</td><td align="center">11<br /><span class="over">16</span></td><td align="right">6</td><td align="center">21<br /><span class="over">32</span></td> <td align="right">8</td><td align="center">1<br /><span class="over">8</span></td> <td align="right">2</td><td align="center">7<br /><span class="over">8</span></td><td align="right">3</td><td align="center">11<br /><span class="over">16</span></td> +</tr> +<tr><td> </td> +</tr> +<tr> +<td align="right">4</td><td> </td> <td align="right">3</td><td> </td><td align="right">3.567</td><td align="right">3</td><td align="center">9<br /><span class="over">16</span></td><td align="right">9.993</td><td align="right">.0413</td> +<td align="right">6</td><td align="center">1<br /><span class="over">8</span></td><td align="right">6</td><td align="center">1<br /><span class="over">16</span></td><td align="right">7</td><td align="center">3<br /><span class="over">32</span></td><td align="right">8</td><td align="center">41<br /><span class="over">64</span></td><td align="right">4</td><td> </td><td align="right">3</td><td align="center">15<br /><span class="over">16</span></td> +<td align="right">6</td><td align="center">1<br /><span class="over">8</span></td> <td align="right">6</td><td align="center">1<br /><span class="over">16</span></td> <td align="right">7</td><td align="center">3<br /><span class="over">32</span></td> <td align="right">8</td><td align="center">41<br /><span class="over">64</span></td> <td align="right">3</td><td align="center">1<br /><span class="over">16</span></td><td align="right">3</td><td align="center">15<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">4</td><td align="center">1<br /><span class="over">4</span></td> <td align="right">2</td><td align="center">7<br /><span class="over">8</span></td><td align="right">3.798</td><td align="right">3</td><td align="center">51<br /><span class="over">64</span></td><td align="right">11.329</td><td align="right">.0435</td> +<td align="right">6</td><td align="center">1<br /><span class="over">2</span></td><td align="right">6</td><td align="center">7<br /><span class="over">16</span></td><td align="right">7</td><td align="center">9<br /><span class="over">16</span></td> <td align="right">9</td><td align="center">3<br /><span class="over">16</span></td> <td align="right">4</td><td align="center">1<br /><span class="over">4</span></td><td align="right">4</td><td align="center">3<br /><span class="over">16</span></td> +<td align="right">6</td><td align="center">1<br /><span class="over">2</span></td> <td align="right">6</td><td align="center">7<br /><span class="over">16</span></td> <td align="right">7</td><td align="center">9<br /><span class="over">16</span></td> <td align="right">9</td><td align="center">3<br /><span class="over">16</span></td> <td align="right">3</td><td align="center">1<br /><span class="over">4</span></td><td align="right">4</td><td align="center">3<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">4</td><td align="center">1<br /><span class="over">2</span></td> <td align="right">2</td><td align="center">3<br /><span class="over">4</span></td><td align="right">4.028</td><td align="right">4</td><td align="center">1<br /><span class="over">32</span></td><td align="right">12.742</td><td align="right">.0454</td> +<td align="right">6</td><td align="center">7<br /><span class="over">8</span></td><td align="right">6</td><td align="center">13<br /><span class="over">16</span></td> <td align="right">7</td><td align="center">31<br /><span class="over">32</span></td><td align="right">9</td><td align="center">3<br /><span class="over">4</span></td> <td align="right">4</td><td align="center">1<br /><span class="over">2</span></td><td align="right">4</td><td align="center">7<br /><span class="over">16</span></td> +<td align="right">6</td><td align="center">7<br /><span class="over">8</span></td><td align="right">6</td><td align="center">13<br /><span class="over">16</span></td><td align="right">7</td><td align="center">31<br /><span class="over">32</span></td> <td align="right">9</td><td align="center">3<br /><span class="over">4</span></td> <td align="right">3</td><td align="center">7<br /><span class="over">16</span></td><td align="right">4</td><td align="center">7<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">4</td><td align="center">3<br /><span class="over">4</span></td> <td align="right">2</td><td align="center">5<br /><span class="over">8</span></td><td align="right">4.256</td><td align="right">4</td><td align="center">1<br /><span class="over">4</span></td><td align="right">14.226</td><td align="right">.0476</td> +<td align="right">7</td><td align="center">1<br /><span class="over">4</span></td><td align="right">7</td><td align="center">3<br /><span class="over">16</span></td> <td align="right">8</td><td align="center">13<br /><span class="over">32</span></td><td align="right">10</td><td align="center">1<br /><span class="over">4</span></td> <td align="right">4</td><td align="center">3<br /><span class="over">4</span></td><td align="right">4</td><td align="center">11<br /><span class="over">16</span></td> +<td align="right">7</td><td align="center">1<br /><span class="over">4</span></td> <td align="right">7</td><td align="center">3<br /><span class="over">16</span></td> <td align="right">8</td><td align="center">13<br /><span class="over">32</span></td> <td align="right">10</td><td align="center">1<br /><span class="over">4</span></td> <td align="right">3</td><td align="center">5<br /><span class="over">8</span></td><td align="right">4</td><td align="center">11<br /><span class="over">16</span></td> +</tr> +<tr><td> </td> +</tr> +<tr> +<td align="right">5</td><td> </td><td align="right">2</td><td align="center">1<br /><span class="over">2</span></td><td align="right">4.480</td><td align="right">4</td><td align="center">31<br /><span class="over">64</span></td><td align="right">15.763</td><td align="right">.0500</td> +<td align="right">7</td><td align="center">5<br /><span class="over">8</span></td><td align="right">7</td><td align="center">9<br /><span class="over">16</span></td> <td align="right">8</td><td align="center">27<br /><span class="over">32</span></td><td align="right">10</td><td align="center">49<br /><span class="over">64</span></td><td align="right">5</td><td> </td><td align="right">4</td><td align="center">15<br /><span class="over">16</span></td> +<td align="right">7</td><td align="center">5<br /><span class="over">8</span></td><td align="right">7</td><td align="center">9<br /><span class="over">16</span></td><td align="right">8</td><td align="center">27<br /><span class="over">32</span></td><td align="right">10</td><td align="center">49<br /><span class="over">64</span></td><td align="right">3</td><td align="center">13<br /><span class="over">16</span></td><td align="right">4</td><td align="center">15<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">5</td><td align="center">1<br /><span class="over">4</span></td> <td align="right">2</td><td align="center">1<br /><span class="over">2</span></td><td align="right">4.730</td><td align="right">4</td><td align="center">47<br /><span class="over">64</span></td><td align="right">17.570</td><td align="right">.0500</td> +<td align="right">8</td><td> </td><td align="right">7</td><td align="center">15<br /><span class="over">16</span></td><td align="right">9</td><td align="center">9<br /><span class="over">32</span></td><td align="right">11</td><td align="center">23<br /><span class="over">64</span></td><td align="right">5</td><td align="center">1<br /><span class="over">4</span></td><td align="right">5</td><td align="center">3<br /><span class="over">16</span></td> +<td align="right">8</td><td> </td><td align="right">7</td><td align="center">15<br /><span class="over">16</span></td> <td align="right">9</td><td align="center">9<br /><span class="over">32</span></td><td align="right">11</td><td align="center">23<br /><span class="over">64</span></td><td align="right">4</td><td> </td><td align="right">5</td><td align="center">3<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">5</td><td align="center">1<br /><span class="over">2</span></td> <td align="right">2</td><td align="center">3<br /><span class="over">8</span></td><td align="right">4.953</td><td align="right">4</td><td align="center">61<br /><span class="over">64</span></td><td align="right">19.267</td><td align="right">.0526</td> +<td align="right">8</td><td align="center">3<br /><span class="over">8</span></td><td align="right">8</td><td align="center">5<br /><span class="over">16</span></td> <td align="right">9</td><td align="center">23<br /><span class="over">32</span></td><td align="right">11</td><td align="center">7<br /><span class="over">8</span></td> <td align="right">5</td><td align="center">1<br /><span class="over">2</span></td><td align="right">5</td><td align="center">7<br /><span class="over">16</span></td> +<td align="right">8</td><td align="center">3<br /><span class="over">8</span></td><td align="right">8</td><td align="center">5<br /><span class="over">16</span></td><td align="right">9</td><td align="center">23<br /><span class="over">32</span></td> <td align="right">11</td><td align="center">7<br /><span class="over">8</span></td> <td align="right">4</td><td align="center">3<br /><span class="over">16</span></td><td align="right">5</td><td align="center">7<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">5</td><td align="center">3<br /><span class="over">4</span></td> <td align="right">2</td><td align="center">3<br /><span class="over">8</span></td><td align="right">5.203</td><td align="right">5</td><td align="center">13<br /><span class="over">64</span></td><td align="right">21.261</td><td align="right">.0526</td> +<td align="right">8</td><td align="center">3<br /><span class="over">4</span></td><td align="right">8</td><td align="center">11<br /><span class="over">16</span></td><td align="right">10</td><td align="center">5<br /><span class="over">32</span></td><td align="right">12</td><td> </td><td align="right">5</td><td align="center">3<br /><span class="over">4</span></td><td align="right">5</td><td align="center">11<br /><span class="over">16</span></td> +<td align="right">8</td><td align="center">3<br /><span class="over">4</span></td><td align="right">8</td><td align="center">11<br /><span class="over">16</span></td><td align="right">10</td><td align="center">5<br /><span class="over">32</span></td> <td align="right">12</td><td align="center">3<br /><span class="over">8</span></td> <td align="right">4</td><td align="center">3<br /><span class="over">8</span></td><td align="right">5</td><td align="center">11<br /><span class="over">16</span></td> +</tr> +<tr> +<td align="right">6</td><td> </td><td align="right">2</td><td align="center">1<br /><span class="over">4</span></td><td align="right">5.423</td><td align="right">5</td><td align="center">27<br /><span class="over">64</span></td><td align="right">23.097</td><td align="right">.0555</td> +<td align="right">9</td><td align="center">1<br /><span class="over">8</span></td><td align="right">9</td><td align="center">1<br /><span class="over">16</span></td><td align="right">10</td><td align="center">19<br /><span class="over">32</span></td><td align="right">12</td><td align="center">15<br /><span class="over">16</span></td><td align="right">6</td><td> </td><td align="right">5</td><td align="center">15<br /><span class="over">16</span></td> +<td align="right">9</td><td align="center">1<br /><span class="over">8</span></td><td align="right">9</td><td align="center">1<br /><span class="over">16</span></td><td align="right">10</td><td align="center">19<br /><span class="over">32</span></td><td align="right">12</td><td align="center">15<br /><span class="over">16</span></td><td align="right">4</td><td align="center">9<br /><span class="over">16</span></td><td align="right">5</td><td align="center">15<br /><span class="over">16</span></td> +</tr> +</table> + +<p class="center"><a href="./images/10-table.png"><i>Original table</i></a></p> +</div> + +<p>The dimensions given for diameter at root of threads are also those +for diameter of hole in nuts and diameter of lap drills. All bolts and +studs 3/4 in. diameter and above, screwed into boilers, have 12 +threads per inch, sharp thread, a taper of 1/16 in. per 1 inch; tap +drill should be 9/64 in. less than normal diameter of bolts.</p> + +<p>The table is based upon the following general formulæ for certain +dimensions:</p> + +<div class="center"> +<table border="0" cellspacing="2" summary=""> +<tr><td align='left'>Short diam. rough nut or head</td><td align='left'>=</td><td align='left'>11/2 diam. of bolt + 1/8.</td></tr> +<tr><td align='left'>Short diam. finished nut or head</td><td align='left'>=</td><td align='left'>11/2 diam. of bolt + 1/16.</td></tr> +<tr><td align='left'>Thickness rough nut</td><td align='left'>=</td><td align='left'>diameter of bolt.</td></tr> +<tr><td align='left'>Thickness finished nut</td><td align='left'>=</td><td align='left'>diameter of bolt - 1/16.</td></tr> +<tr><td align='left'>Thickness rough head</td><td align='left'>=</td><td align='left'>1/2 short diameter.</td></tr> +<tr><td align='left'>Thickness finished head</td><td align='left'>=</td><td align='left'>diameter of bolt - 1/16.</td></tr> +</table> +</div> + +<hr /> + +<h2><a name="art09" id="art09"></a>AN ENGLISH RAILWAY FERRY BOAT.</h2> + +<div class="figcenter"><a href="./images/10b.png"><img src="./images/10b_th.png" alt="AN ENGLISH RAILWAY FERRY BOAT." /></a><br />AN ENGLISH RAILWAY FERRY BOAT.</div> + +<p>The illustrations above represent a double screw steam ferry boat for +transporting railway carriages, vehicles, and passengers, etc., +designed and constructed by Messrs. Edwards and Symes, of Cubitt Town, +London. The hull is constructed of iron, and is of the following +dimensions: Length 60 ft.; beam 16 ft.; over sponsons 25 ft. The +vessel was fitted with a propeller, rudder, and steering gear at each +end, to enable it to run in either direction without having to turn +around. The boat was designed for the purpose of working the train +service across the bay of San Juan, in the island of Puerto Rico, and +for this purpose a single line of steel rails, of meter gauge, is laid +along the center of the deck, and also along the hinged platforms at +each end. In the engraving these platforms are shown, one hoisted up, +and the other lowered to the level of the deck. When the boat is at +one of the landing stages, the platform is lowered to the level of the +rails on the pier, and the carriages and trucks are run on to the deck +by means of the small hauling engine, which works an endless chain +running the whole length of the deck. The trucks, etc., being on +board, the platform is raised by means of two compact hand winches +worked by worm and worm-wheels in the positions shown; thus these two +platforms form the end bulwarks to the boat when crossing the bay. On +arriving at the opposite shore the operation is repeated, the other +platform is lowered, and the hauling engine runs the trucks, etc., on +to the shore. With a load of 25 tons the draught is 4 ft.</p> + +<p>The seats shown on the deck are for the convenience of foot +passengers, and the whole of the deck is protected from the sun of +that tropical climate by a canvas awning. The steering of the vessel +is effected from the bridge at the center, which extends from side to +side of the vessel, and there are two steering wheels with independent +steering gear for each end, with locking gear for the forward rudder +when in motion. The man at the wheel communicates with the engineer by +means of a speaking tube at the wheel. There is a small deck house for +the use of deck stores, on one side of which is the entrance to the +engine room. The cross battens, shown between the rails, are for the +purpose of horse traffic, when horses are used for hauling the trucks, +or for ordinary carts or wagons. The plan below deck shows the +arrangement of the bulkheads, with a small windlass at each end for +lifting the anchors, and a small hatch at each side for entrance to +these compartments. The central compartment contains the machinery, +which consists of a pair of compound surface condensing engines, with +cylinders 11 in. and 20 in. in diameter; the shafting running the +whole length of the vessel, with a propeller at each end. Steam is +generated in a steel boiler of locomotive form, so arranged that the +funnel passes through the deck at the side of the vessel; and it is +designed for a working pressure of 100 lb. per square inch. This +boiler also supplies steam for the small hauling engine fixed on the +bulkhead. Light to this compartment is obtained by means of large side +scuttles along each side of the boat and glass deck lights, and the +iron grating at the entrance near the deck house. This boat was +constructed in six pieces for shipment, and the whole put together in +the builders' yard. The machinery was fixed, and the engine driven by +steam from its own boiler, then the whole was marked and taken +asunder, and shipped to the West Indies, where it was put together and +found to answer the purpose intended.—<i>Engineering</i>.</p> + +<hr /> + +<div class="center">[For <span class="smcap">The Scientific American.</span>]</div> + +<h2><a name="art10" id="art10"></a>THE PROBLEM OF FLIGHT, AND THE FLYING MACHINE.</h2> + +<p>As a result of reading the various communications to the +<span class="smcap">Scientific American</span> and <span class="smcap">Supplement</span>, and <i>Van +Nostrand's Engineering Magazine</i>, including descriptions of proposed +and tested machines, and the reports of the British Aeronautical +Society, the writer of the following concludes:</p> + +<p>That, as precedents for the construction of a successful flying +machine, the investigation of some species of birds as a base of the +principles of all is correct only in connection with the species and +habits of the bird; that the <i>general mechanical principles</i> of flight +applicable to the <i>operation</i> of the <i>same unit</i> of wing in <i>all</i> +species are alone applicable to the flying machine.</p> + +<p>That these principles of <i>operation</i> do not demand the principles of +<i>construction</i> of the bird.</p> + +<p>That as the wing is in its stroke an arc of a screw propeller's +operation, and in its angle a screw propeller blade, its animal +operation compels its reciprocation instead of rotation.</p> + +<p>That the swifter the wing beat, the more efficient its effect per unit +of surface, the greater the load carried, and the swifter the flight.</p> + +<p>That the screw action being, in full flight, that of a screw propeller +whose axis of rotation forms a slight angle with the vertical, the +distance of flight per virtual "revolution" of "screw" wing far +exceeds the pitch distance of said "screw."</p> + +<p>That consequently a bird's flight answers to an iceboat close hauled; +the wing <i>force</i> answering to the <i>wind</i>, the wing <i>angle</i> to the +<i>sail</i>, the bird's <i>weight</i> to the leeway fulcrum of the <i>ice</i>, and +the passage across direction of the <i>wing</i> flop to the fresh <i>moving</i> +"inertia" of the wind, both yielding a maximum of force to bird or +iceboat.</p> + +<p>That the speed of <i>reciprocation</i> of a fly's <i>wing</i> being equivalent +to a <i>screw rotation</i> of 9,000 per minute, proves that a <i>screw</i> may +be run at this speed without losing efficiency by centrifugal vacuum.</p> + +<p>That as the <i>object</i> of wing or screw is to mount upon the inertia of +the particles of a mobile fluid, and as the rotation of steamship +propellers in water—a fluid of many times the inertia of air—is +<i>already</i> in <i>excess</i> of the highest speed heretofore tried in the +propellers of moderately successful flying machines, it is plain that +the speed employed in <i>water</i> must be many times exceeded in <i>air</i>.</p> + +<p>That with a <i>sufficient</i> speed of rotation, the supporting power of +the inertia of air must <i>equal</i> that of <i>water</i>.</p> + +<p>That as mere speed of rotation of propeller <i>shaft</i>, minus blades, +must absorb but a small proportion of power of engine, the addition of +blades will not cause more resistance than that actually encountered +from inertia of air.</p> + +<p>That this must be the measure of load lifted.</p> + +<p>That without <i>slip</i> of screw, the actual <i>power</i> expended, will be +little in <i>excess</i> of that required to support the machine in <i>water</i>, +with a slower rotation of screw.</p> + +<p>That in case the same <i>power</i> is expended in water or air, the only +difference will lie in the sizes and speed of engines or screws.</p> + +<p>That the <i>greater</i> the speed, the <i>less</i> weight of engine, boiler, and +screw must be, and the stronger their construction.</p> + +<p>That, in consequence, solid metal worked down, instead of bolts and +truss work, must be used.</p> + +<p>That as the bird wing is a screw in action, and acts <i>directly</i> +between the inertias of the load and the air, the position and +operation of the screw, to the load, must imitate it.</p> + +<p>That, in consequence, machines having wing planes, driven <i>against</i> +one inertia of air by screws acting in the line, of flight against +another inertia of air, lose fifty per cent. of useful effect, besides +exposing to a head wind the cross section of the stationary screw wing +planes and the rotating screw discs; and supporting the dead weight of +the wing planes, and having all the screw slip in the line of flight, +and carrying slow and heavy engines.</p> + +<p>That as a result of these conclusions, the supporting and propelling +power should be expressed in the rotation of screws combining both +functions, the position of whose planes of rotation to a fixed +horizontal line of direction determines the progress and speed of +machine upon other lines.</p> + +<p>That the whole weight carried by the screws should be at all times +exactly below the center of gravity of the plane of support, whether +it be horizontal or inclined.</p> + +<p>That while the <i>permanently</i> positioned weight, such as the engines, +frame, holding screws, etc., may be rigidly connected to or around the +screw plane of support, the variable positioned weight, such as the +passenger and the car, should be connected by a <i>flexible joint</i> to +the said plane of support.</p> + +<p>Consequently, the car may oscillate without altering its weight +position under center of supporting plane, thus avoiding an +involuntary alteration of speed or direction of flight.</p> + +<p>That to steer a machine so constructed, it is merely necessary <a name="Page_7073" id="Page_7073"></a>to +move the point of attachment of car to <i>machine</i> proper, out of the +center of plane of support in the desired direction, and thus cause +the plane of support or rotation of propellers to incline in that +direction.</p> + +<p>That the reservoir of power, the boiler, etc., should be placed in the +<i>car</i>, and steam carried to engines through joint connecting car with +machine.</p> + +<p>That at present material exists, and power also, of sufficient +lightness and strength to admit of a machine construction capable of a +limited successful flight in any fair wind and direction.</p> + +<p>That such <i>machine</i> once built, the finding of a <i>power</i> for long +flights will be easy, if not already close at hand in <i>electricity</i>.</p> + +<p>That the <i>easiest</i> design for such <i>actual machine</i> should be adopted, +leaving the adaptation of the principles involved to the making of +more perfect machines, to a time after the success of the <i>first</i>.</p> + +<p>That such design may be a propeller, and its engine at each end of a +steel frame tube, supporting tube horizontally, a car to be supported +by a universal joint from center of said tube, and the joint apparatus +movable along the tube or a short distance transverse to it, to alter +position of center of gravity.</p> + +<p>That the machine so built might traverse the water as well as air.</p> + +<hr /> + +<h2><a name="art21" id="art21"></a>THE LONGHAIRED POINTER MYLORD.</h2> + +<p>Pointers are trained to search for game, and to indicate that they +have found the same by standing motionless in front of it, and, when +it has been shot, to carry the game to the huntsman. Several kinds of +pointers are known, such as smooth, longhaired, and bushyhaired +pointers. The smoothhaired pointers are better for hunting on high +land, whereas the longhaired or bushyhaired dogs are better for low, +marshy countries, crossed by numerous streams, etc. Mylord, the dog +represented in the annexed cut taken from the <i>Illustrirte Zeitung</i>, +is an excellent specimen of the longhaired pointer, and is owned by +Mr. G. Borcher, of Braunschweig, Germany.</p> + +<div class="figcenter"><a href="./images/11a.png"><img src="./images/11a_th.png" alt="THE LONGHAIRED POINTER, "MYLORD."" /></a><br /> THE LONGHAIRED POINTER, "MYLORD."</div> + +<p>The longhaired pointer is generally above the medium size, powerful, +somewhat longer than the normal dog, the body is narrower and not +quite as round as that of the smoothhaired dog, and the muscles of the +shoulders and hind legs are not as well developed and not as +prominent. The head and neck are erect, the head being specially long, +and the tail is almost horizontal to the middle, and then curves +upward slightly. The long hair hangs in wavy lines on both sides of +his body. The expression of his face is intelligent, bright, and +good-natured, and his step is light and almost noiseless.</p> + +<p>The pointer is specially valuable, as it can be employed for many +different purposes; he is an excellent dog for the woods, for the +woodsman and hunter who uses only one dog for different kinds of game. +The intelligence of the German pointer is very great, but he does not +develop as rapidly as the English dog, which has been raised for +generations for one purpose only. The German pointer hunts very +slowly, but surely. It is not difficult to train this dog, but he +cannot be trained until he has reached a certain age.</p> + +<hr /> + +<h2><a name="art20" id="art20"></a>LUNAR HEAT.</h2> + +<h3>By Professor C.A. YOUNG.</h3> + +<p>One of the most interesting inquiries relating to the moon is that +which deals with the heat she sends us, and the probable temperature +of her surface. The problem seems to have been first attacked by +Tschirnhausen and La Hire, about 1700; and they both found, that even +when the moon's rays were concentrated by the most powerful +burning-lenses and mirrors they could obtain, its heat was too small +to produce the slightest perceptible effect on the most delicate +thermometers then known. For more than a hundred years, this was all +that could be made out, though the experiment was often repeated.</p> + +<p>It was not until 1831 that Melloni, with his newly-invented +"thermopile," <a name="FNanchor_4" id="FNanchor_4"></a><a href="#Footnote_4"><sup>1</sup></a> succeeded in making the lunar heat sensible; and in +1835, taking his apparatus to the top of Vesuvius, he obtained not +only perceptible, but measurable, results, getting a deviation of four +or five divisions of his galvanometer.</p> + +<p>Others repeated the experiment several times between this time and +1856, with more or less success; but, so far as I know, the first +quantitative result was that obtained in 1856 by Piazzi Smyth during +his Teneriffe expedition. On the top of the mountain, at an elevation +of ten thousand feet, he found that the moon's rays affected his +thermopile to the same extent as a standard candle ten feet away. +Marie Davy has since shown that this corresponds to a heating effect +of about 1/1300 of a Centigrade degree.</p> + +<p>The subject was resumed in 1868 by Lord Rosse in Ireland; and a long +series of observations, running through several years, was made by the +aid of his three-foot reflector (not the great <i>six</i>-foot instrument, +which is too unwieldy for such work). The results of his work have, +until very recently, been accepted as authoritative. It should be +mentioned that, at about the same time, observations were also made at +Paris by Marie Davy and Martin; but they are generally looked upon +merely as corroborative of Rosse's work, which was more elaborate and +extensive. Rosse considered that his results show that the heat from +the moon is mainly <i>obscure, radiated</i> heat; the <i>reflected</i> heat, +according to him, being much less in amount.</p> + +<p>A moment's thought will show that the moon's heat must consist of two +portions. First, there will be <i>reflected solar heat</i>. The amount and +character of this will depend in no way upon the temperature of the +moon's surface, but solely upon its reflecting power. And it is to be +noted that moon-<i>light</i> is only a part of this reflected radiant +energy, differing from the invisible portion of the same merely in +having such a wave-length and vibration period as to bring it within +the range of perception of the human eye.</p> + +<p>The second portion of the heat sent us by the moon is that which she +emits on her own account as a warm body—warmed, of course, mainly, if +not entirely, by the action of the sun. The amount of <i>this</i> heat will +depend upon the temperature of the moon's surface and its radiating +power; and the temperature will depend upon a number of things +(chiefly heat-absorbing power of the surface, and the nature and +density of the lunar atmosphere, as well as the supply of heat +received from the sun), being determined by a balance between give and +take. So long as more heat is received in a second than is thrown off +in the same time, the temperature will rise, and <i>vice versa</i>.</p> + +<p>It is to be noted, further, that this second component of the moon's +thermal radiance must be mainly what is called "obscure" or dark heat, +like that from a stove or teakettle, and characterized by the same +want of penetrative power. No one knows why at present; but it is a +fact that the heat-radiations from bodies at a low +temperature—radiations of which the vibrations are relatively slow, +and the wave-length great—have no such power of penetrating +transparent media as the higher-pitched vibrations which come from +incandescent bodies. A great part, therefore, of this contingent of +the lunar heat is probably stopped in the upper air, and never reaches +the surface of the earth at all.</p> + +<p>Now, the thermopile cannot, of course, discriminate directly between +the two portions of the lunar heat; but to some extent it does enable +us to do so indirectly, since they vary in quite a different way with +the moon's age. The simple <i>reflected</i> heat must follow the same law +as moonlight, and come to its maximum at full moon. The <i>radiated</i> +heat, on the other hand, will reach its maximum when the average +temperature of that part of the moon's surface turned toward the earth +is highest; and this must be some time after full moon, for the same +sort of reasons that make the hottest part of a summer's day come two +or three hours after noon.</p> + +<p>The conclusion early reached by Lord Rosse was that nearly all the +lunar heat belonged to the second category—dark heat <i>radiated</i> from +the moon's warmed surface, the <i>reflected</i> portion being comparatively +small—and he estimated that the temperature of the hottest parts of +the moon's surface must run as high as 500° F.; well up toward the +boiling-point of mercury. Since the lunar day is a whole month long, +and there are never any clouds in the lunar sky, it is easy to imagine +that along toward two or three o'clock in the lunar afternoon (if I +may use the expression), the weather gets pretty hot; for when the sun +stands in the lunar sky as it does at Boston at two P.M., it has been +shining continuously for more than two hundred hours. On the other +hand, the coldest parts of the moon's surface, when the sun has only +just risen after a night of three hundred and forty hours, must have a +temperature more than a hundred degrees below zero.</p> + +<p>Lord Rosse's later observations modified his conclusions, to some +extent, showing that he had at first underestimated the percentage of +simple reflected heat, but without causing him to make any radical +change in his ideas as to the maximum heat of the moon's surface.</p> + +<p>For some time, however, there has been a growing skepticism among +astronomers, relating not so much to the correctness of his measures +as to the computations by which he inferred the high percentage of +obscure radiated beat compared with the reflected heat, and so deduced +the high temperature of lunar noon.</p> + +<p>Professor Langley, who is now engaged in investigating the subject, +finds himself compelled to believe that the lunar surface never gets +even comfortably warm—because it has no blanket. It receives heat, it +is true, from the sun, and probably some twenty-five or thirty per +cent. more than the earth, since there are no clouds and no air to +absorb a large proportion of the incident rays; but, at the same time, +there is nothing to retain the heat, and prevent the radiation into +space as soon as the surface begins to warm. We have not yet the data +to determine exactly how much the temperature of the lunar rocks would +have to be raised above the absolute zero (-273° C. or -459° F.) in +order that they might throw off into space as much heat in a second as +they would get from the sun in a second. But Professor Langley's +observations, made on Mount Whitney at an elevation of fifteen +thousand feet, when the barometer stood at seventeen inches +(indicating that about fifty-seven per cent. of the air was still +above him), showed that rocks exposed to the perpendicular rays of the +sun were not heated to any such extent as those at the base of the +mountain similarly exposed; and the difference was so great as to make +it almost certain that a mass of rock not covered by a reasonably +dense atmosphere could never attain a temperature of even 200° or 300° +F. under solar radiation, however long continued.</p> + +<p>It must, in fact, be considered at present extremely doubtful whether +any portion of the moon's surface ever reaches a temperature as high +as -100°.</p> + +<p>The subject, undoubtedly, needs further investigation, and it is now +receiving it. Professor Langley is at work upon it with new and +specially constructed apparatus, including a "bolometer" so sensitive +that, whereas previous experimenters have thought themselves fortunate +if they could get deflections of ten or twelve galvanometric divisions +to work with, he easily obtains three or four hundred. We have no time +or space here to describe Professor Langley's <a name="Page_7074" id="Page_7074"></a>"bolometer;" it must +suffice to say that it seems to stand to the thermopile much as that +does to the thermometer. There is good reason to believe that its +inventor will be able to advance our knowledge of the subject by a +long and important step; and it is no breach of confidence to add that +so far, although the research is not near completion yet, everything +seems to confirm the belief that the radiated heat of the moon, +instead of forming the principal part of the heat we get from her, is +relatively almost insignificant, and that the lunar surface now never +experiences a <i>thaw</i> under any circumstances.</p> + +<p>Since the superstition as to the moon's influence upon the wind and +weather is so widespread and deep seated, a word on that subject may +be in order. In the first place, since the total heat received from +the moon, even according to the highest determination (that of Smyth), +is not so much as 0.00001 of that received from the sun, and since the +only hold the moon has on the earth's weather is through the heat she +sends us (I ignore here the utterly insignificant atmospheric <i>tide</i>), +it follows necessarily that her influence <i>must</i> be very trifling. In +the next place, all carefully collated observations show that it <i>is</i> +so, and not only trifling, but generally absolutely insensible.</p> + +<p>For example, different investigators have examined the question of +nocturnal cloudiness at the time of full moon, there being a prevalent +belief that the full moon "eats up" light clouds. On comparing thirty +or forty years' observations at each of several stations (Greenwich. +Paris, etc.), it is found that there is no ground for the belief. And +so in almost every case of imagined lunar meteorological influence. As +to the coincidence of weather changes with changes of the moon, it is +enough to say that the idea is absolutely inconsistent with that +progressive movement of the "weather" across the country from west to +east, with which the Signal Service has now made us all so familiar.</p> + +<p>Princeton, April 12, 1884.</p> + +<p><a name="Footnote_4" id="Footnote_4"></a><a href="#FNanchor_4">[1]</a></p> +<div class="note"><p>Probably most of our readers know that the thermopile +consists of a number of little bars of two different metals, connected +in pairs, and having the ends joined in a conducting circuit with a +galvanometer. If, now, one set of the junctures is heated more than +the other set, a current of electricity will be generated, which will +affect the galvanometer. The bars are usually made of bismuth and +antimony though iron and German silver answer pretty well. They are +commonly about half or three-quarters of an inch long, and about half +as large as an ordinary match. The "pile" is made of from +fifty to a hundred such bars packed closely, but insulated by thin +strips of mica, except just at the soldered junctions. With an +instrument of this kind and a very delicate galvanometer, Professor +Henry found that the heat from a person's face could be perceived at a +distance of several hundred feet. There is however, some doubt whether +he was not mistaken in respect to this extreme +sensitiveness.</p></div> + +<hr /> + +<h2><a name="art22" id="art22"></a>APPLE TREE BORERS.</h2> + +<p>The apple tree borers have destroyed thousands of trees in New +England, and are likely to destroy thousands more. There are three +kinds of borers which assail the apple tree. The round headed or two +striped apple tree borer, <i>Saperda candida</i>, is a native of this +country, infesting the native crabs, thorn bushes, and June berry. It +was first described by Thomas Say, in 1824, but was probably widely +distributed before that. In his "Insects Injurious to Fruit," Prof. +Saunders thus describes the borer:</p> + +<p>"In its perfect state it is a very handsome beetle, about +three-quarters of an inch long, cylindrical in form, of a pale brown +color, with two broad, creamy white stripes running the whole length +of its body; the face and under surface are hoary white, the antennæ +and legs gray. The females are larger than the males, and have shorter +antennæ. The beetle makes its appearance during the months of June and +July, usually remaining in concealment during the day, and becoming +active at dusk. The eggs are deposited late in June and during July, +one in a place, on the bark of the tree, near its base. Within two +weeks the young worms are hatched, and at once commence with their +sharp mandibles to gnaw their way through the outer bark to the +interior. It is generally conceded that the larvæ are three years in +reaching maturity. The young ones lie for the first year in the +sapwood and the inner bark, excavating flat, shallow cavities, about +the size of a silver dollar, which are filled with their sawdust-like +castings. The holes by which they enter being small are soon filled +up, though not until a few grains of castings have fallen from them. +Their presence may, however, often be detected in young trees from the +bark becoming dark colored, and sometimes dry and dead enough to +crack."</p> + +<p>On the approach of winter, it descends to the lower part of its +burrow, where it remains inactive until spring. The second season it +continues its work in the sapwood, and in case two or three are at +work in the same tree may completely girdle it, thus destroying it. +The third year it penetrates to the heart of the tree, makes an +excavation, and awaits its transformation. The fourth spring it comes +forth a perfect beetle, and lays its eggs for another generation.</p> + +<h3>THE FLAT-HEADED BORER.</h3> + +<p>The flat-headed apple tree borer, <i>Chrysobothris femorata</i>, is also a +native of this country. It is a very active insect, delights to bask +in the hot sunshine; runs up and down the tree with great rapidity, +but flies away when molested. It is about half an inch in length. "It +is of a flattish, oblong form, and of a shining, greenish black color, +each of its wing cases having three raised lines, the outer two +interrupted by two impressed transverse spots of brassy color dividing +each wing cover into three nearly equal portions. The under side of +the body and legs shine like burnished copper; the feet are shining +green." This beetle appears in June and July, and does not confine its +work to the base of the tree, but attacks the trunk in any part, and +sometimes the larger branches. The eggs are deposited in cracks or +crevices of the bark, and soon hatch. The young larva eats its way +through the bark and sapwood, where it bores broad and flat channels, +sometimes girdling and killing the tree. As it approaches maturity, it +bores deeper into the tree, working upward, then eats out to the bark, +but not quite through the bark, where it changes into a beetle, and +then cuts through the bark and emerges to propagate its kind. This +insect is sought out when just beneath the bark, and devoured by +woodpeckers and insect enemies.</p> + +<p>Another borer, the long-horned borer, <i>Leptostylus aculifer</i>, is +widely distributed, but is not a common insect, and does not cause +much annoyance to the fruit grower. It appears in August, and deposits +its eggs upon the trunks of apple trees. The larvæ soon hatch, eat +through the bark, and burrow in the outer surface of the wood just +under the bark.</p> + +<h3>PROTECTION AGAINST BORERS.</h3> + +<p>The practical point is, What remedies can be used to prevent the +ravages of the borers? The usual means of fighting the borers is, to +seek after them in the burrows, and try to kill them by digging them +out, or by reaching them with a wire. This seems to be the most +effectual method of dealing with them after they have once entered the +tree, but the orchardist should endeavor to prevent the insects from +entering the tree. For this purpose, various washes have been +recommended for applying to the tree, either for destroying the young +larvæ before they enter the bark, or for preventing the beetles +depositing their eggs. It has been found that trees which have been +coated with alkaline washes are avoided by beetles when laying their +eggs. Prof. Saunders recommends that soft soap be reduced to the +consistency of a thick paint, by the addition of a strong solution of +washing soda in water, and be applied to the bark of the tree, +especially about the base or collar, and also extended upward to the +crotches where the main branches have their origin. It should be +applied in the evening of a warm day, so that it may dry and form a +coating not easily dissolved by the rain. This affords a protection +against all three kinds of borers. It should be applied early in June, +before the beetles begin to lay their eggs, and again in July, so as +to keep the tree well protected.</p> + +<p>Hon. T.S. Gold, of Connecticut, at a meeting of the Massachusetts +State Board of Agriculture, in regard to preventing the ravages of the +borer, said:</p> + +<p>"A wash made of soap, tobacco water, and fresh cow manure mingled to +the consistency of cream, and put on early with an old broom, and +allowed to trickle down about the roots of the tree, has proved with +me a very excellent preventive of the ravages of the borer, and a +healthful wash for the trunk of the tree, much to be preferred to the +application of lime or whitewash, which I have often seen applied, but +which I am inclined to think is not as desirable an application as the +potash, or the soda, as this mixture of soft soap and manure."</p> + +<p>J.B. Moore, of Concord, Mass., at the same meeting said, in regard to +the destruction of the borer:</p> + +<p>"I have found, I think, that whale oil soap can be used successfully +for the destruction of that insect. It is a very simple thing; it will +not hurt the tree if you put it on its full strength. You can take +whale oil soap and dilute until it is about as thick as paint, and put +a coating of it on the tree where the holes are, and I will bet you +will never see a borer on that tree until the new crop comes. I feel +certain of it, because I have done it."</p> + +<p>For borers, tarred paper 1 or 2 feet wide has been recommended to be +wrapped about the base of the trunk of the tree, the lower edge being +1 or 2 inches below the surface of the soil. This prevents the +two-striped borer from laying its eggs in the tree, but would not be +entirely effectual against the flat-headed borer, which attacks any +part of the trunk and the branches. By the general use of these means +for the prevention of the ravages of the borers, the damages done by +these insects could be brought within very narrow limits, and hundreds +of valuable apple trees saved.</p> + +<p class="signature">H. REYNOLDS, M.D.</p> + +<p>Livermore Falls, Me.</p> + +<hr /> + +<h2><a name="art23" id="art23"></a>KEFFEL'S GERMINATING APPARATUS.</h2> + +<p>The apparatus represented in the annexed cut is designed to show the +quality of various commercial seeds, and make known any fraudulent +adulterations that they may have undergone. It is based upon a direct +observation, of the germination of the seeds to be studied.</p> + +<div class="figcenter"><img src="./images/12a.png" alt="KEFFEL'S GERMINATING APPARATUS." /><br /> KEFFEL'S GERMINATING APPARATUS.</div> + +<p>The apparatus consists of a cylindrical vessel containing water to the +height of 0.07 m. Above the water is a germinating disk containing 100 +apertures for the insertion of the seeds to be studied, the +germinating end of the latter being directed toward the water. After +the seeds are in place the disk is filled with damp sand up to the top +of its rim, and the apparatus is closed with a cover which carries in +its center a thermometer whose bulb nearly reaches the surface of the +water.</p> + +<p>The apparatus is then set in a place where the temperature is about +18°, and where there are no currents of air. An accurate result is +reached at the end of about twenty or twenty-four hours. As the +germinating disk contains 100 apertures for as many seeds, it is only +necessary to count the number of seeds that have germinated in order +to get the percentage of fresh and stale ones.</p> + +<p>The aqueous vapor that continuously moistens all the seeds, under +absolutely identical conditions for each, brings about their +germination under good conditions for accuracy and comparison. If it +be desired to observe the starting of the leaves, it is only necessary +to remove the cover after the seeds have germinated.</p> + +<p>This ingenious device is certainly capable of rendering services to +brewers, distillers, seedsmen, millers, farmers, and gardeners, and it +may prove useful to those who have horses to feed, and to amateur +gardeners, since it permits of ascertaining the value and quality of +seeds of every nature.—<i>La Nature</i>.</p> + +<hr /> + +<h2><a name="art24" id="art24"></a>MILLET.</h2> + +<p>The season is now at hand when farmers who have light lands, and who +may possibly find themselves short of fodder for next winter feeding, +should prepare for a crop of millet. This is a plant that rivals corn +for enduring a drought, and for rapid growth. There are three popular +varieties now before the public, besides others not yet sufficiently +tested for full indorsement—the coarse, light colored millet, with a +rough head, Hungarian millet, with a smooth, dark brown head, yielding +seeds nearly black, and a newer, light colored, round seeded, and +later variety, known as the golden millet.</p> + +<p>Hungarian millet has been the popular variety with us for many years, +although the light seeded, common millet is but slightly different in +appearance or value for cultivation. They grow in a short time, eight +weeks being amply sufficient for producing a forage crop, though a +couple of weeks more would be required for maturing the seed. Millet +should not be sown in early spring, when the weather and ground are +both cold. It requires the hot weather of June and July to do well; +then it will keep ahead of most weeds, while if sown in April the +weeds on foul land would smother it.</p> + +<p>Millet needs about two months to grow in, but if sowed late in July it +will seem to "hurry up," and make a very respectable showing in less +time. We have sown it in August, and obtained a paying crop, but do +not recommend it for such late seeding, as there are other plants that +will give better satisfaction. Golden millet has been cultivated but a +few years in this country, and as yet is but little known, but from a +few trials we have been quite favorably impressed with it. It is +coarser than the other varieties, but cattle appear to be very fond of +it nevertheless. It resembles corn in its growth nearly as much as +grass, and, compared with the former, it is fine and soft, and it +cures readily, like grass, and may be packed away in hay mows with +perfect safety. It is about two weeks later than the other millets, +and consequently cannot be grown in quite so short a time, although it +may produce as much weight to the acre, in a given period, as either +of the other more common varieties. A bushel of seed per acre is not +too much for either variety of millet.—<i>N.E. Farmer</i>.</p> + +<hr /> + +<p>A <span class="smcap">Catalogue</span> containing brief notices of many important +scientific papers heretofore published in the <span class="smcap">Supplement</span>, may be had +gratis at this office.</p> + +<hr /> + +<h3>THE</h3> + +<h2>Scientific American Supplement.</h2> + +<p class="center"><b>PUBLISHED WEEKLY.</b></p> + +<p class="center"><b>Terms of Subscription, $5 a Year.</b></p> + +<p>Sent by mail, postage prepaid, to subscribers in any part of the +United States or Canada. 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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. 443, June 28, 1884 + +Author: Various + +Release Date: September 29, 2005 [EBook #16773] + +Language: English + +Character set encoding: ASCII + +*** 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. 443. + + + + +NEW YORK, JUNE 28, 1884. + +Scientific American Supplement. Vol. XVII., No. 443. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + * * * * * + + + + +TABLE OF CONTENTS. + + +I. CHEMISTRY AND METALLURGY.--Beeswax and its Adulterations. + --Chemical ingredients.--Detection of adulterations. 7064 + + Phenol in the Stem, Leaves, and Cones of Pinus Sylvestris. + --A discovery bearing on the flora of the Carboniferous + epoch and the formation of petroleum. 7065 + + The School of Physics and Chemistry of Paris.--With + engraving of laboratory. 7065 + + Some Relations of Heat to Voltaic and Thermo Electric + Action of Metals in Electrolysis.--By G. GORE. 7070 + +II. ENGINEERING, MECHANICS, ETC.--Air Refrigerating + Machine.--5 figures. 7071 + + A Gas Radiator and Heater. 7071 + + Concrete Water Pipes. 7071 + + The Sellers Standard System of Screw Threads. Nuts, and + Bolt Heads.--A table. 7072 + + An English Railway Ferry Boat.--3 figures. 7072 + + The Problem of Flight and the Flying Machine. 7072 + +III. TECHNICAL.--Concrete Buildings for Farms.--How to construct + them. 7063 + + What Causes Paint to Blister and Peel?--How to prevent it. 7063 + + Olive Oil.--Difficulties encountered in raising an olive + crop.--Process of making Oil. 7064 + +IV. ELECTRICITY. ETC.--Telephony and Telegraphy on the Same + Wires Simultaneously.--4 figures. 7067 + + The Electric Marigraph.--An apparatus for measuring the + height of the tide.--With engravings and diagrams showing + the Siemens and Halske marigraph and the operation of the + same. 7068 + + Delune & Co.'s System of Laying Underground Cables.--2 + figures. 7069 + + Electricity Applied to Horseshoeing.--Quieting an unruly + animal.--3 engravings. 7069 + + Esteve's Automatic Pile.--1 figure. 7070 + + Woodward's Diffusion Motor. 7070 + +V. ASTRONOMY.--Lunar Heat.--Its reflected and obscure + heat.--Trifling influence of the moon upon wind and + weather.--By Prof. C.A. YOUNG. 7073 + +VI. NATURAL HISTORY.--The Long-haired Pointer "Mylord." + --With engraving. 7073 + +VII. HORTICULTURE, ETC.--Apple Tree Borers.--Protection + against the same. 7074 + + Keffel's Germinating Apparatus.--With engraving. 7074 + + Millet.--Its Cultivation. 7074 + +VIII. MISCELLANEOUS.--Puerta del Sol, Madrid, Spain.--With + engraving. 7063 + + Dust-free Spaces.--A lecture delivered by Dr. OLIVER J. + LODGE before the Royal Dublin Society. 7067 + + * * * * * + + + + +PUERTA DEL SOL, MADRID. + + +Puerta del Sol, or Gate of the Sun, Madrid, is the most famous and +favorite public square in the Spanish city of Madrid. It was the +eastern portal of the old city. From this square radiate several of +the finest streets, such as Alcala, one of the handsomest +thoroughfares in the world, Mayor, Martera, Carretas, Geronimo. In our +engraving the post office is seen on the right. Large and splendid +buildings adorn the other sides, which embrace hotels, cafes, reading +rooms, elegant stores, etc. From this square the street railway lines +traverse the city in all directions. The population of the city is +about 400,000. It contains many magnificent buildings. Our engraving +is from _Illustrirte Zeitung_. + +[Illustration: THE PUERTA DEL SOL, MADRID, SPAIN (From a Photograph.)] + + * * * * * + + + + +CONCRETE BUILDINGS FOR FARMS. + + +Buildings made of concrete have never received the attention in this +country that they deserve. They have the merit of being durable and +fire-proof, and of not being liable to be blown down by violent winds. +It is very easy to erect them in places where sand and gravel are near +at hand and lime is comparatively cheap. Experiments made in England +show that coal screenings may be employed to good advantage in the +place of sand and gravel. Mr. Samuel Preston, of Mount Carroll, Ill., +has a dwelling and several other buildings made of concrete and +erected by himself. They were put up in 1851, and are in excellent +condition. In _The Farmers' Review_ he gives the following directions +for building concrete walls: + +First, secure a good stone foundation, the bottom below frost, the top +about one foot above ground. Near the top of the foundation bed in 2x4 +scantling edgewise transversely with the walls, at such distances +apart as the length of the planks that form the boxes to hold the +concrete may require, the ends of the scantling to run six inches +beyond the outside and inside of the wall. Now take 2x6 studding, one +foot longer than the height of the concrete walls are to be, bolt in +an upright position in pairs to each end of the 2x4 scantling, and, if +a foot wall is to be built, sixteen inches apart, as the box plank +will take up four inches. To hold the studding together at the top, +take pieces of 2x6 lumber, make two mortises in each piece large +enough to slip easily up and down on the studding, forming a tie. Make +one mortise long enough to insert a key, so that the studding can be +opened at the top when the box plank are to be raised. When the box +plank are in position, nail cleats with a hole in each of them on each +side of the studding, and corresponding holes in the studding, into +which insert a pin to hold the plank to the studding. Bore holes along +up in the studding, to hold the boxes when raised. + +To make the walls hollow, and I would do it in a building for any +purpose, use inch boards the same width of the box plank, one side +planed; put the two rough sides together with shingles between, +nailing them together with six-penny nails; place them in the middle +of the wall, the thin end of the shingle down. That gives them a bevel +and can be easily raised with the boxes. To tie the wall together, at +every third course place strips of boards a little shorter than the +thickness of the wall; cut notches in each so that the concrete will +fill in, holding all fast. The side walls being up, place two inch +planks on top of the wall upon which to rest the upper joists, put on +joist and rafters, remove the box plank, take inch boards for boxes, +cut to fit between joists and rafters, and fill with concrete to upper +side of rafters, which makes walls that will keep out cold and damp, +all kinds of vermin, and a roof which nothing but a cyclone can +remove. In making door and window frames, make the jambs two inches +narrower than the thickness of the walls, nailing on temporary two +inch strips. + +Make the mortar bed large enough to hold the material for one course; +put in unslaked quicklime in proportion to 1 to 20 or 30 of other +material; throw into it plenty of water, and don't have that +antediluvian idea that you can drown it; put in clean sand and gravel, +broken stone, making it thin enough, so that when it is put into boxes +the thinner portion will run in, filling all interstices, forming a +solid mass. A brick trowel is necessary to work it down alongside the +boxing plank. One of the best and easiest things to carry the concrete +to the boxes is a railroad wheelbarrow, scooping it in with a scoop +shovel. Two courses a week is about as fast as it will be safe to lay +up the walls. + + * * * * * + +The _Medical Summary_ recommends the external use of buttermilk to +ladies who are exposed to tan or freckles. + + * * * * * + + + + +WHAT CAUSES PAINT TO BLISTER AND PEEL? + +HOW TO PREVENT IT. + + +This subject has been treated by many, but out of the numerous ideas +that have been brought to bear upon it, the writers have failed to +elucidate the question fully, probably owing to the fact that in most +parts they were themselves dubious as to the real cause. Last year +W.S. gave a lengthy description in the _Building News_, in which he +classified blistering and peeling of paint into one of blistering +only. He stated in the beginning of his treatise the following: + +"The subject of blistering of paint has from time to time engrossed +the attention of practical men; but so far as we can follow it in the +literature pertaining to the building trade, its cause has never been +clearly laid down, and hence it is a detail enshrouded in mystery." + +W.S. dwells mostly, in his following explanations on blistering +paints, on steam raised in damp wood. Also an English painter, +according to the _Painters' Journal_, lately reiterates the same +theory, and gives sundry reasons how water will get into wood through +paint, but is oblivious that the channels which lead water into wood +are open to let it out again. He lays great stress on boiled oil +holding water in suspense to cause blistering, which is merely a +conjecture. Water boils at 212 deg. F. and linseed oil at 600 deg. F., +consequently no water can possibly remain after boiling, and a drop of +water put into boiling oil would cause an explosion too dangerous to +be encountered. + +It will be shown herewith that boiled oil, though in general use, is +unfit for durable painting, that it is the cause of most of the +troubles painters have to contend with, and that raw linseed oil +seasoned by age is the only source to bind pigments for durable +painting; but how to procure it is another trouble to overcome, as all +our American raw linseed oil has been heated by the manufacturers, to +qualify it for quick drying and an early market, thereby impairing its +quality. After linseed oil has been boiled, it becomes a poor varnish; +it remains soft and pliable when used in paint, giving way to air +pressure from the wood in hot weather, forming blisters. Turpentine +causes no blistering; it evaporates upon being exposed, and leaves the +paint in a porous condition for the gas in the wood to escape; but all +painters agree that blistering is caused by gas, and on investigation +we find two main sources from which gas is generated to blister +paint--one from the wood, the other from the ingredients of the paint. +The first named source of gas is started in hot weather by expansion +of air confined in painted wood, which presses against the paint and +raises blisters when the paint is too soft to resist. Tough, +well-cemented paint resists the pressure and keeps the air back. These +blisters mostly subside as soon as the air cools and returns to the +pores, but subsequently peel off. + +W.S. and others assert that damp in painted wood turns into steam when +exposed to sun heat, forming blisters, which cannot be possible when +we know that water does not take a gaseous form (steam) at less than +212 deg. F. They have very likely been deluded by the known way of +distilling water with the aid of sunshine without concentrating the +rays of the sun, based upon the solubility of water in air, viz.: Air +holds more water in solution (or suspension) in a warmer than in a +cooler degree of temperature; by means of a simple apparatus +sun-heated air is guided over sun-heated water, when the air saturated +with water is conducted into a cooler, to give up its water again. But +water has an influence toward hastening to blister paint; it holds the +unhardened woodsap in solution, forming a slight solvent of the oil, +thereby loosening the paint from the wood, favoring blistering and +peeling. There is a certain kind of blister which appears in certain +spots or places only, and nowhere else, puzzling many painters. The +explanation of this is the same as before--soft paint at these spots, +caused by accident or sluggish workmen having saturated the wood with +coal oil, wax, tar, grease, or any other paint-softening material +before the wood was painted, which reacts on the paint to give way to +air pressure, forming blisters. + +The second cause of paint blistering from the ingredients of the paint +happens between any layer of paint or varnish on wood, iron, stone, or +any other substance. Its origin is the gaseous formation of volatile +oils during the heated season, of which the lighter coal oils play the +most conspicuous part; they being less valuable than all other +volatile oils, are used in low priced japan driers and varnishes. +These volatile oils take a gaseous form at different temperatures, lie +partly dormant until the thermometer hovers at 90 deg. F. in the shade, +when they develop into gas, forming blisters in airtight paint, or +escape unnoticed in porous paint. This is the reason why coal-tar +paint is so liable to blister in hot weather; an elastic, soft +coal-tar covering holds part of its volatile oil confined until heated +to generate into gas; a few drops only of such oil is sufficient to +spoil the best painted work, and worse, when it has been applied in +priming, it settles into the pores of the wood, needing often from two +to three repetitions of scraping and repainting before the evil is +overcome. Now, inasmuch as soft drying paint is unfit to answer the +purpose, it is equally as bad when paint too hard or brittle has been +used, that does not expand and contract in harmony with the painted +article, causing the paint to crack and peel off, which is always the +case when either oil or varnish has been too sparingly and turpentine +too freely used. Intense cold favors the action, when all paints +become very brittle, a fact much to be seen on low-priced vehicles in +winter time. Damp in wood will also hasten it, as stated in +blistering, the woodsap undermining the paint. + +To avoid peeling and blistering, the paint should be mixed with raw +linseed oil in such proportions that it neither becomes too brittle +nor too soft when dry. Priming paint with nearly all oil and hardly +any pigment is the foundation of many evils in painting; it leaves too +much free oil in the paint, forming a soft undercoat. For durable +painting, paint should be mixed with as much of a base pigment as it +can possibly be spread with a brush, giving a thin coat and forming a +chemical combination called soap. To avoid an excess of oil, the +following coats need turpentine to insure the same proportion of oil +and pigment. As proof of this, prime a piece of wood and a piece of +iron with the same paint; when the wood takes up part of the oil from +the paint and leaves the rest in proportion to harden well, where at +the same time the paint on iron remains soft. To be more lucid, it +need be explained, linseed oil boiled has lost its oleic acid and +glycerine ether, which form with the bases of pigments the insoluble +soap, as well as its albumen, which in boiling is thrown out. It +coagulates at 160 deg. F. heat; each is needed to better withstand the +action of wind and weather, preventing the dust from attaching itself +to a painted surface, a channel for ammonia in damp weather to +dissolve and wash off the paint. In later years linseed oil has been +extracted from linseed meal by the aid of naphtha and percolation, the +product of a very clear, quick drying oil, but lacking in its binding +quality, no doubt caused by the naphtha dissolving the fatty matter +only, leaving the glycerine and albumen in the meal. + +All pigments of paint group according to their affinity to raw linseed +oil into three classes. First, those that form chemical combinations, +called soap. This kind is the most durable, is used for priming +purposes, and consists of lead, zinc, and iron bases, of which red +lead takes up the most oil; next, white lead, the pure carbonate Dutch +process made, following with zinc white and iron carbonates, as iron +ore paint, Turkey umber, yellow ocher; also faintly the chromates of +lead--chrome-green and chrome-yellow, finishing with the poorest of +all, modern white lead, made by the wet or vinegar process. The second +class being neutrals have no chemical affinity to linseed oil; they +need a large quantity of drier to harden the paint, and include all +blacks, vermilion, Prussian, Paris, and Chinese blue, also terra di +Sienna, Vandyke brown, Paris green, verdigris, ultramarine, genuine +carmine, and madderlake. The last seven are, on account of their +transparency, better adapted for varnish mixtures--glazing. The third +class of pigments act destructively to linseed oil; they having an +acid base (mostly tin salt, hydrochloride of tin, and redwood dye), +form with the gelatinous matter of the oil a jelly that will neither +work well under the brush nor harden sufficiently, and can be used in +varnish for glazing only; they are not permanent in color, and among +the most troublesome are the lower grades of so-called carmines, +madderlakes, rose pinks, etc., which contain more or less acidous +dyes, forming a soft paint with linseed oil that once dry on a job can +be twisted or peeled off like the skin of a ripe peach. All these +combinations of paint have to be closely observed by the painter to +insure his success. + +Twenty-five years ago a house needed to be painted outside but once in +from five to seven years; it looked well all the time, as no dust +settled in the paint to make it unsightly. Painters then used the +Dutch-process-made white-lead, a base and raw linseed oil, a fat acid, +which formed the insoluble soap. They also put turpentine in the +following coats, to keep up the proportions of oil and pigment. All +held out well against wind and weather. Now they use the +wet-process-made white lead, neutralized by vinegar, with oil +neutralized by boiling, from the first to the last coat, and--fail in +making their work permanent. + +W.S., in the _Building News_, relates an unaccountable mysterious +blistering in a leaky house, where the rainwater came from above on a +painted wood wall, blistering the paint in streaks and filled at the +lower ends with water, which no doubt was caused by the water soaking +the wood at the upper ends where there was no paint, and following it +down through the fibers, pushed and peeled off the soft, inadhesive +paint. Green, sappy, and resinous wood is unfit for durable painting, +and to avoid blistering and peeling wood should be well seasoned and +primed with all raw linseed oil, some drier, to insure a moderately +slow drying, and as much of a base pigment as the painter can possibly +spread (much drier takes up too much oil acid, needed for the pigment +base to combine with), which insures a tough paint that never fails to +stand against blistering or peeling, as well as wind, weather, and +ammonia. + +The coach, car, and house painter can materially improve his painting +where his needs lie by first oiling the wood with raw oil, then +smoothing the surface down with lump pumicestone, washing it with a +mixture of japan drier or, better yet, gold sizing and turpentine, +wiping dry, and following it up with a coat of white lead, oil, and +turpentine. The explanation is: the raw oil penetrates the wood and +raises the wood fibers on the surface to be rubbed down with +pumicestone, insuring the best surface for the following painting: to +harden the oil in the wood it receives a coat of japan drier, which +follows into the pores and there forms a tough, resinous matter, +resisting any air pressure that might arise from within, and at the +same time reacts on the first coat of lead as a drier. This mode +insures the smoothest and toughest foundation for the following +painting, and may be exposed to the hottest July sun without fear of +either blistering or peeling. + +LOUIS MATERN. + +Bloomington, Ill. + + * * * * * + + + + +OLIVE OIL. + + +The following particulars with regard to the production of olive oil +in Tuscany have been furnished to Mr. Consul Inglis by one of the +principal exporters in Leghorn: + +The olive oil produced in Tuscany from the first pressing of the fruit +is intended for consumption as an article of food. Hence, great +attention is paid both to the culture of the olive tree and the +process of making oil. + +The olive crop is subject to many vicissitudes, and is an uncertain +one. It may be taken as a rule that a good crop does not occur more +frequently than once in three years. A prolonged drought in summer may +cause the greater part of the small fruit to fall off the trees. A +warm and wet autumn will subject the fruit to the ravages of a maggot +or worm, which eats its way into it. Fruit thus injured falls to the +ground prematurely, and the oil made from it is of very bad quality, +being nauseous in taste and somewhat thick and viscous. Frost +following immediately on a fall of snow or sleet, when the trees are +still wet, will irretrievably damage the fruit, causing it to shrivel +up and greatly diminishing the yield of oil, while the oil itself has +a dark color, and loses its delicate flavor. + +The olive tree in Tuscany generally blossoms in April. By November the +fruit has attained its full size, though not full maturity, and the +olive harvest generally commences then. The fruit, generally speaking, +is gathered as it falls to the ground, either from ripeness or in +windy weather. In some districts, however, and when the crop is short, +the practice is to strip the fruit from the trees early in the season. +When there is a full crop the harvest lasts many months, and may not +be finished till the end of May, as the fruit does not all ripen +simultaneously. + +Oil made early in the season has a deeper color, and is distinguished +by a fruity flavor, with a certain degree of pungency; while as the +season advances it becomes lighter in color, thinner in body, and +milder and sweeter in taste. Oil made toward the close of the harvest +in April or May from extremely ripe fruit is of a very pale straw +color, mild and sweet to the taste, though sometimes, if the fruit has +remained too long on the trees, it may be slightly rancid. Oil very +light in color is much prized in certain countries, notably France, +and hence, if it also possesses good quality, commands a higher price +in the Tuscan markets. + +The fruit of the olive tree varies just as much in quality as does the +grape, according to the species of the tree itself, the nature of the +soil, exposure, and climate of the locality where it grows. Some +varieties of the olive tree largely grown, because thought to be +better suited to the special conditions of some districts, yield a +fruit which imparts a bitter taste to the oil made from it; such oil, +even when otherwise perfect, ranks as a second rate quality. + +The highest quality of oil can only be obtained when the fruit is +perfectly and uniformly sound, well ripened, gathered as soon as it +has dropped from the trees, and crushed immediately with great +attention. Should the fruit remain any time on the ground, +particularly during wet weather, it deteriorates fast and gets an +earthy taste; while if allowed to remain an undue length of time in +the garners it heats, begins to decompose, and will yield only bad +oil. + +The process of making oil is as follows: The fruit is crushed in a +stone mill, generally moved by water power; the pulp is then put into +bags made of fiber, and a certain number of these bags, piled one upon +another, are placed in a press, most frequently worked by hand; when +pressure is applied, the oil flows down into a channel by which it is +conveyed to a receptacle or tank. + +When oil ceases to flow, tepid water is poured upon the bags to carry +off oil retained by the bags. The pulp is then removed from the bags, +ground again in the mill, then replaced in the bags, and pressed a +second time. The water used in the process of making oil must be quite +pure; the mill, press, bags, and vessels sweet and clean, as the least +taint would ruin the quality of the oil produced. + +The oil which has collected in the tank or receptacle just mentioned +is removed day by day, and the water also drained off, as oil would +suffer in quality if left in contact with water; the water also, which +necessarily contains some oil mingled with it, is sent to a deposit +outside, and at some distance from the crushing house, which is called +the "Inferno," where it is allowed to accumulate, and the oil which +comes to the surface is skimmed off from time to time. It is fit only +for manufacturing purposes. + +After the second pressing the olive-pulp is not yet done with; it is +beaten up with water by mechanical agitators moved by water-power, and +then the whole discharged into open-air tanks adjoining the crushing +house. There the crushed olive kernels sink to the bottom, are +gathered up and sold for fuel, fetching about 12 francs per 1,000 +kilos, while the _debris_ of the pulp is skimmed off the surface of +the tank and again pressed in bags, yielding a considerable quantity +of inferior oil, called "olio lavato," or washed oil, which, if +freshly made, is even used for food by the poorer classes. The pulp +then remaining has still further use. It is sold for treatment in +factories by the sulphide of carbon process, and by this method yields +from seven to nine per cent. of oil, of course suitable only for +manufacturing purposes. Only the first two pressings yield oil which +ranks as first quality, subject of course to the condition of the +fruit being unexceptionable. New oil is allowed to rest a while in +order to get rid of sediment; it is then clarified by passing through +clean cotton wool, when it is fit for use. + +The highest quality of olive oil for eating purposes should not only +be free from the least taint in taste or smell, but possessed of a +delicate, appetizing flavor. When so many favorable conditions are +needed as to growth, maturity, and soundness of the fruit, coupled +with great attention during the process of oil-making, it is not to be +wondered at that by no means all or even the greater part of the oil +produced in the most favored districts of Tuscany is of the highest +quality. On the contrary, the bulk is inferior and defective. + +These defective oils are largely dealt in both for home consumption +and export, when price and not quality is the object. + +In foreign countries there is always a market for inferior, defective +olive oil for cooking purposes, etc., provided the price be low. Price +and not quality is the object, so much so that when olive oil is dear, +cotton-seed, ground-nut, and other oils are substituted, which bear +the same relation to good olive oil that butterine and similar +preparations do to real butter. + +The very choicest qualities of pure olive oil are largely shipped from +Leghorn to England, along with the very lowest qualities, often also +adulterated. + +The oil put into Florence flasks is of the latter kind. Many years +back this was not the case, but now it is a recognized fact that +nothing but the lowest quality of oil is put into these flasks; oil +utterly unfit for food, and so bad that it is a mystery to what use it +is applied in England. Importers in England of oil in these flasks +care nothing, however, about quality; cheapness is the only +desideratum. + +The best quality of Tuscan olive oil is imported in London in casks, +bottled there, and bears the name of the importers alone on the label. +There is no difficulty in procuring in England the best Tuscan oil, +which nothing produced elsewhere can surpass; but consumers who wish +to get, and are willing to pay for, the best article must look to the +name and reputation of the importers and the general excellence of all +the articles they sell, which is the best guarantee they can have of +quality. + + * * * * * + + + + +BEESWAX AND ITS ADULTERATIONS. + + +Beeswax is a peculiar waxy substance secreted only by bees, and +consisting of 80.2 per cent. carbon, 13.4 per cent. hydrogen, and 6.4 +per cent. oxygen. It is a mixture of myricine, cerotic acid, and +cerolein, the first of which is insoluble in boiling alcohol, the +second is soluble in hot alcohol and crystallizes out on cooling, +while the third remains dissolved in cold alcohol. + +Although we are unable to produce real beeswax artificially, there are +many imitations which are made use of to adulterate the genuine +article, and their detection is a matter of considerable difficulty. +Huebl says (_Dingl. Jour._, p. 338) that the most reliable method of +estimating the adulteration of beeswax is that proposed by Becker, and +known as the saponification method. + +The quantity of potassic hydrate required to saponify one gramme or 15 +grains of pure beeswax varies from 97 to 107 milligrammes. Other kinds +of wax and its substitutes require in some cases more and in others +less of the alkali. This method would, however, lead to very erroneous +conclusions if applied to a mixture of which some of the constituents +have higher saponification numbers than beeswax and others higher, as +one error would balance the other. + +To avoid this, the quantity of alkali required to saponify the +myricine is first ascertained, and then that required to saturate the +free cerotic acid. In this way two numbers are obtained; and in an +investigation of twenty samples of Austrian yellow beeswax, the author +found these numbers stood to each other almost in the constant ratio +of 1 to 3.70. Although this ratio cannot be considered as definitely +established by so few experiments, it may serve as a guide in judging +of the purity of beeswax. + +The experiment is carried out as follows: 3 or 4 grammes of the wax +that has been melted in water are put in 20 c.c. of neutral 95 per +cent, alcohol, and warmed until the wax melts, when phenolphthaleine +is added, and enough of an alcoholic solution of potash run in from a +burette until on shaking it retains a faint but permanent red color. +The burette used by the author is divided in 0.05 c.c. After adding 20 +c.c. more of a half normal potash solution, it is heated on a water +bath for 3/4 hour. Then the uncombined excess of alkali is titrated with +half normal hydrochloric acid. The alcohol must be tested as to its +reaction before using it, and carefully neutralized with the acid of +phenolphthalein. + +To saturate the free acid in 1 gramme of wax requires 19 to 21 +milligrammes of potassic hydrate, while 73 to 76 milligrammes more are +necessary to saponify the myricine ether. The lower numbers in the one +usually occur with low numbers for the other, so that the proportions +remain 1 to 3.6 or 1 to 3.8. + +For comparison he gives the following numbers obtained with one gramme +of the more common adulterants: + + + ----------------+----------+----------+---------+--------+ + | To | To | Total | | + |neutralize| convert |saponifi-| | + | the acid.|the ether.| cation. | Ratio. | + ----------------+----------+----------+---------+--------+ + Japanese wax | 20 | 200 | 220 | 10 | + Carnauba wax | 4 | 75 | 79 | 19 | + Tallow | 4 | 176 | 180 | 44 | + Stearic acid | 195 | 0 | 195 | 0/195 | + Rosin | 110 | 1.6 | 112 | 0.015 | + Paraffine | 0 | 0 | 0 | 0 | + Ceresine | 0 | 0 | 0 | 0 | + Yellow beeswax | 20 | 75 | 95 | 3.75 | + ----------------+----------+----------+---------+--------+ + + +The author deduces the following conclusions as the results of these +investigations: + +1. If the numbers obtained lie between these limits, 19 to 21, 73 to +76, 92 to 97, and 3.6 to 3.8 respectively, it may be assumed that the +beeswax is pure, provided it also corresponds to beeswax in its +physical properties. + +2. If the saponification figures fall below 92 and yet the ratio is +correct, it is adulterated with some neutral substance like paraffine. + +3. If the ratio is above 3.8, it is very probable that Japanese or +carnauba wax or grease has been added. + +4. If the ratio falls below 3.6, stearic acid or resin has been used +as the adulterant. + + * * * * * + + + + +PHENOL IN THE STEM, LEAVES, AND CONES OF PINUS SYLVESTRIS. + +A DISCOVERY BEARING ON THE FLORA OF THE CARBONIFEROUS EPOCH AND THE +FORMATION OF PETROLEUM. + +By A.B. GRIFFITHS, Ph.D., F.C.S. Membre de la Societe Chimique de +Paris, Medallist in Chemistry and Botany, etc. + + +Having found, in small quantities, alcohols of the C_{n}H_{2n-7} +series, last summer, in the stem, acicular leaves, and cones of _Pinus +sylvestris_, I wish in this paper to say a few words on the subject. + +First of all, I took a number of cones, cut them up into small pieces, +and placed them in a large glass beaker, then nearly filled it with +distilled water, and heated to about 80 deg. C., keeping the decoction at +this temperature for about half an hour, I occasionally stirred with a +glass rod, and then allowed it to cool, and filtered. This filtrate +was then evaporated nearly to dryness, when a small quantity of +six-sided prisms crystallized out, which subsequently were found to be +the hydrate of phenol (C_{6}H_{5}HO)_{2}H_{2}O. Its melting point was +found to be 17.2 deg. C. Further, the crystals already referred to were +dissolved in ether, and then allowed to evaporate, when long colorless +needles were obtained, which, on being placed in a dry test tube and +the tube placed in a water bath kept at 42 deg. C., were found to melt; +and on making a careful combustion analysis of these crystals, the +following composition was obtained: + + Carbon 76.6 + Hydrogen 6.4 + Oxygen 17.0 + ----- + 100.0 + +This gives C_{6}H_{6}O, which is the formula for phenol. + +On dissolving some of these crystals in water (excess) and adding +ferric chloride, a beautiful violet color was imparted to the +solution. To another aqueous solution of the crystals was added +bromine water, and a white precipitate was obtained, consisting of +tribromophenol. An aqueous solution of the crystals immediately +coagulated albumen. + +All these reactions show that the phenol occurs in the free state in +the cones of this plant. In the same manner I treated the acicular +leaves, and portions of the stem separately, both being previously cut +up into small pieces, and from both I obtained phenol. + +I have ascertained the relative amount of phenol in each part of the +plant operated upon; by heating the stem with water at 80 deg. C., and +filtering, and repeating this operation until the aqueous filtrate +gave no violet color with ferric chloride and no white precipitate +with bromine water. + +I found various quantities according to the age of the stem. The older +portions yielding as much as 0.1021 per cent, while the young portions +only gave 0.0654 per cent. The leaves yielding according to their age, +0.0936 and 0.0315 per cent.; and the cones also gave varying amounts, +according to their maturity, the amounts varying between 0.0774 and +0.0293. + +Two methods were used in the quantitative estimation of the amount of +phenol. The first was the new volumetric method of M. Chandelon +(_Bulletin de la Societe Chemique de Paris_, July 20, 1882; and +_Deutsch-Americanishe Apotheker Zeitung_, vol. iii., No. 12, September +1, 1882), which I have found to be very satisfactory. The process +depends on the precipitation of phenol by a dilute aqueous solution of +bromine as tribromophenol. The second method was to extract, as +already staled, a known weight of each part of the plant with water, +until the last extract gives _no_ violet color with ferric chloride, +and no white precipitate with the bromine test (which is capable of +detecting in a solution the 1/60000 part of phenol). The aqueous +extract is at this point evaporated, then ether is added, and finally +the ethereal solution is allowed to evaporate. The residue (phenol) is +weighed directly, and from this the percentage can be ascertained. By +this method of extraction, the oil of turpentine, resins, etc., +contained in _Pinus sylvestris_ do not pass into solution, because +they are insoluble in water, even when boiling; what passes into +solution besides phenol is a little tannin, which is practically +insoluble in ether. + +From this investigation it will be seen that phenol exists in various +proportions in the free state in the leaves, stem, and cones of _Pinus +sylvestris_, and as this compound is a product in the distillation of +coal, and as geologists have to a certain extent direct evidence that +the flora of the Carboniferous epoch was essentially crytogamous, the +only phaenogamous plants which constituted any feature in "the coal +forests" being the coniferae, and as coal is the fossil remains of that +gigantic flora which contained phenol, I think my discovery of phenol +in the coniferae of the present day further supports, from a chemical +point of view, the views of geologists that the coniferae existed so +far back in the world's history as the Carboniferous age. + +I think this discovery also supports the theory that the origin of +petroleum in nature is produced by moderate heat on coal or similar +matter of a vegetable origin. For we know from the researches of +Freund and Pebal (_Ann. Chem. Pharm._, cxv. 19), that petroleum +contains phenol and its homologues, and as I have found this organic +compound in the coniferae of to-day, it is probable that petroleum in +certain areas has been produced from the conifers and the flora +generally of some primaeval forests. It is stated by numerous chemists +that "petroleum almost always contains solid paraffin" and similar +hydrocarbons. Professors Schorlemmer and Thorpe have found heptane in +Pinus, which heptane yielded primary heptyl-alcohol, and +methyl-pentyl-carbinol, exactly as the heptane obtained from petroleum +does (_Annalen de Chemie_, ccxvii., 139, and clxxxviii., 249; and +_Berichte der Deutschen Chemischen Gesellschaft_, viii., 1649); and, +further, petroleum contains a large number of hydrocarbons which are +found in coal. Again, Mendelejeff, Beilstein, and others (_Bulletin de +la Societe Chemique de Paris_, No. 1, July 5, 1883), have found +hydrocarbons of the-- + + C_{n}H_{2n2+}, C_{n}H_{2n-6}, + +also hydrocarbons of the C_{n}H_{2n} series in the petroleum of Baku, +American petroleum containing similar hydrocarbons. + +I think all these facts give very great weight to the theory that +petroleum is of organic origin. + +On the other hand, Berthelot, from his synthetic production of +hydrocarbons, believes that the interior of the globe contains +alkaline metals in the _free_ state, which yield acetylides in the +presence of carbonic anhydride, which are decomposed into acetylene by +aqueous vapor. But it has been already proved that acetylene may be +polymerized, so as to produce aromatic carbides, or the derivatives of +marsh gas, by the absorption of hydrogen. Berthelot's view, therefore, +is too imaginative; for the presence of _free_ alkaline metals in the +earth's interior is an unproved and very improbable hypothesis. +Byasson states that petroleum is formed by the action of water, +carbonic anhydride, and sulphureted hydrogen upon incandescent iron. +Mendelejeff thinks it is formed by the action of aqueous vapor upon +carbides of iron; and in his article, "Petroleum, the Light of the +Poor" (in this month's--February--number of _Good Words_), Sir Lyon +Playfair, K.C.B., F.R.S., etc., holds opinions similar to those of +Mendelejeff. + +Taking in consideration the facts that solid paraffin is found in +petroleum and is also found in coal, and from my own work that phenol +exists in _Pinus sylvestris_, and has been found by others in coal +which is produced from the decomposition of a flora containing +numerous gigantic coniferae allied to Pinus, and that petroleum +contains phenol, and each (i.e., petroleum and coal) contains a number +of hydrocarbons common to both, I am inclined to think that the +balance of evidence is in favor of the hypothesis that petroleum has +been produced in nature from a vegetable source in the interior of the +globe. Of course, there can be no practical or direct evidence as to +the origin of petroleum; therefore "theories are the only lights with +which we can penetrate the obscurity of the unknown, and they are to +be valued just as far as they illuminate our path." + +In conclusion, I think that there is a connecting link between the old +pine and fir forest of bygone ages and the origin of petroleum in +nature.--_Chemical News._ + + * * * * * + + + + +THE SCHOOL OF PHYSICS AND CHEMISTRY OF PARIS. + + +Recently we paid a visit to the New Municipal School of Physics and +Chemistry that the city of Paris founded in 1882, and that is now in +operation in the large building of the old Rollin College. This +establishment is one of those that supply a long-felt want of our +time, and we are happy to make it known to our readers. The object for +which it was designed was, in the intention of its founders, to give +young people who have just graduated from the higher primary schools +special instruction which shall be at once scientific and practical, +and which shall fit them to become engineers or superintendents in +laboratories connected with chemical and physical industries. To reach +such a result it has been necessary to give the teaching an +essentially practical character, by permitting the pupils to proceed +of themselves in manipulations in well fitted laboratories. It is upon +this important point that we shall now more particularly dwell; but, +before making known the general mode of teaching, we wish to quote a +few passages from the school's official programme: + + "Many questions and problems, in physics as well as in chemistry, + find their solution only with the aid of mathematics and + mechanics. It therefore became necessary, through lectures + bearing upon the useful branches of mathematics, to supplement + the too limited ideas that pupils brought with them on entering + the school. Mathematics and mechanics are therefore taught here + at the same time with physics and chemistry, but they are merely + regarded in the light of auxiliaries to the latter. + + "The studies extend over three years. Each of the three divisions + (1st, 2d, and 3d years) includes thirty pupils. + + "During the three first semesters, pupils of the same grade + attend lectures and go through manipulations in chemistry, + physics, mathematics, and draughting in common. + + "At the end of the third semester they are divided into 10 + physical and 20 chemical students. + + "From this moment, although certain courses still remain wholly + or partially common to the two categories of pupils (physical and + chemical), the same is no longer the case with regard to the + practical exercises, for the physical students thereafter + manipulate only in the physical laboratories, and the chemical + only in the chemical laboratories; moreover, the manipulations + acquire a greater importance through the time that is devoted to + them. + + "At each promotion the three first semesters are taken up with + general and scientific studies. Technical applications are the + subject of the lectures and exercises of the three last + semesters. At the end of the third year certificates are given to + those pupils who have undergone examination in a satisfactory + manner, and diplomas to such as have particularly distinguished + themselves." + +When pupils have been received at the school, after passing the +necessary examination, their time of working is divided up between +lectures and questionings and different laboratory manipulations. + +The course of lectures on general and applied physics comprises +hydrostatics and heat (Prof. Dommer), electricity and magnetism (Prof. +Hospitalier), and optics and acoustics (Prof. Baille). Lectures on +general chemistry are delivered by Profs. Schultzenberger and +Henninger, on analytical chemistry by Prof. Silva, on chemistry +applied to the industries by Prof. Henninger (for inorganic) and Prof. +Schultzenberger (for organic). The lectures on pure and applied +mathematics and mechanics are delivered by Profs. Levy and Roze. + +[Illustration: GENERAL VIEW OF A LABORATORY AT THE PARIS SCHOOL OF +PHYSICS AND CHEMISTRY.] + +The pupils occupy themselves regularly every day, during half the time +spent at the school, with practical work in analytical and applied +chemistry and physics and general chemistry. This practical work is a +complement to the various lectures, and has reference to what has been +taught therein. Once or twice per week the pupils spend three hours in +a shop devoted to wood and metal working, and learn how to turn, +forge, file, adjust, etc. + +The school's cabinets are now provided with the best instruments for +study, and are daily becoming richer therein. The chemical +laboratories are none the less remarkably organized. In the +accompanying cut we give a view of one of these--the one that is under +the direction of Mr. Schultzenberger, professor of chemistry and +director of the new school. Each pupil has his own place in front of a +large table provided with a stand whereon he may arrange all the +products that he has to employ. Beneath the work-table he has at his +disposal a closet in which to place his apparatus after he is through +using them. Each pupil has in front of him a water-faucet, which is +fixed to a vertical column and placed over a sink. Alongside of this +faucet there is a double gas burner, which may be connected with +furnaces and heating apparatus by means of rubber tubing. A special +hall, with draught and ventilation, is set apart for precipitations by +sulphureted hydrogen and the preparation of chlorine and other +ill-smelling and deleterious gases. The great amount of light and +space provided secure the best of conditions of hygiene to this fine +and vast laboratory, where young people have all the necessary +requisites for becoming true chemists.--_La Nature._ + + * * * * * + + + + +DUST-FREE SPACES.[1] + + [Footnote 1: Lecture to the Royal Dublin Society by Dr. Oliver J. + Lodge, April 2, 1884.] + + +Within the last few years a singular interest has arisen in the +subject of dust, smoke, and fog, and several scientific researches +into the nature and properties of these phenomena have been recently +conducted. It so happened that at the time I received a request from +the secretary of this society to lecture here this afternoon I was in +the middle of a research connected with dust, which I had been +carrying on for some months in conjunction with Mr. J.W. Clark, +Demonstrator of Physics in University College, Liverpool, and which +had led us to some interesting results. It struck me that possibly +some sort of account of this investigation might not be unacceptable +to a learned body such as this, and accordingly I telegraphed off to +Mr. Moss the title of this afternoon's lecture. But now that the time +has come for me to approach the subject before you, I find myself +conscious of some misgivings, and the misgivings are founded upon this +ground: that the subject is not one that lends itself easily to +experimental demonstration before an audience. Many of the experiments +can only be made on a small scale, and require to be watched closely. +However, by help of diagrams and by not confining myself too closely +to our special investigation, but dealing somewhat with the wider +subject of dust in general, I may hope to render myself and my subject +intelligible if not very entertaining. + +First of all, I draw no distinction between "dust" and "smoke." It +would be possible to draw such a distinction, but it would hardly be +in accordance with usage. Dust might be defined as smoke which had +settled, and the term smoke applied to solid particles still suspended +in the air. But at present the term "smoke" is applied to solid +particles produced by combustion only, and "dust" to particles owing +their floating existence to some other cause. This is evidently an +unessential distinction, and for the present I shall use either term +without distinction, meaning by dust or smoke, solid particles +floating in the air. Then "fog"; this differs from smoke only in the +fact that the particles are liquid instead of solid. And the three +terms dust, smoke, and fog, come to much the same thing, only that the +latter term is applied when the suspended particles are liquid. I do +not think, however, that we usually apply the term "fog" when the +liquid particles are pure water; we call it then mostly either mist or +cloud. The name "fog," at any rate in towns, carries with it the idea +of a hideous, greasy compound, consisting of smoke and mist and +sulphur and filth, as unlike the mists on a Highland mountain as a +country meadow is unlike a city slum. Nevertheless, the finest cloud +or mist that ever existed consists simply of little globules of water +suspended in air, and thus for our present purpose differs in no +important respect from fog, dust, and smoke. A cloud or mist is, in +fact, fine water-dust. Rain is coarse water-dust formed by the +aggregation of smaller globules, and varying in fineness from the +Scotch mist to the tropical deluge. It has often been asked how it is +that clouds and mists are able to float about when water is so much +heavier (800 times heavier) than air. The answer to this is easy. It +depends on the resistance or viscosity of fluids, and on the smallness +of the particles concerned. Bodies falling far through fluids acquire +a "terminal velocity," at which they are in stable equilibrium--their +weight being exactly equal to the resistance--and this terminal +velocity is greater for large particles than for small; consequently +we have all sorts of rain velocity, depending on the size of the +drops; and large particles of dust settle more quickly than small. +Cloud-spherules are falling therefore, but falling very slowly. + +To recognize the presence of dust in air there are two principal +tests; the first is, the obvious one of looking at it with plenty of +light, the way one is accustomed to look for anything else; the other +is a method of Mr. John Aitken's, viz., to observe the condensation of +water vapor. + +Take these in order. When a sunbeam enters a darkened room through a +chink, it is commonly said to be rendered visible by the motes or dust +particles dancing in it; but of course really it is not the motes +which make the sunbeam visible, but the sunbeam the motes. A dust +particle is illuminated like any other solid screen, and is able to +send a sufficient fraction of light to our eyes to render itself +visible. If there are no such particles in the beam--nothing but +clear, invisible air--then of course nothing is seen, and the beam +plunges on its way quite invisible to us unless we place our eyes in +its course. In other words, to be visible, light must enter the eye. +(A concentrated beam was passed through an empty tube, and then +ordinary air let in.) + +The other test, that of Mr. Aitken, depends on the condensation of +steam. When a jet of steam finds itself in dusty air, it condenses +around each dust particle as a nucleus, and forms the white visible +cloud popularly called steam. In the absence of nuclei Mr. Aitken has +shown that the steam cannot condense until it is highly +supersaturated, and that when it does it condenses straight into +rain--that is, into large drops which fall. The condensation of steam +is a more delicate test for dust than is a beam of light. A curious +illustration of the action of nuclei in condensing moisture has just +occurred to me, in the experiment--well known to children--of writing +on a reasonably clean window-pane with, say, a blunt wooden point, and +then breathing on the glass; the condensation of the breath renders +the writing legible. No doubt the nuclei are partially wiped away by +the writing, and the moisture will condense into larger drops with +less light-scattering power along the written lines than over the +general surface of the pane where the nuclei are plentiful, and the +drops therefore numerous and minute. Mr. Aitken points out that if the +air were ever quite dustless, vapor could not condense, but the air +would gradually get into a horribly supersaturated condition, soaking +all our walls and clothes, dripping from every leaf, and penetrating +everywhere, instead of falling in an honest shower, against which +umbrellas and slate roofs are some protection. But let us understand +what sort of dust it is which is necessary for this condensing +process. It is not the dust and smoke of towns, it is not the dust of +a country road; all such particles as these are gross and large +compared with those which are able to act as condensers of moisture. +The fine dust of Mr. Aitken exists everywhere, even in the upper +regions of the atmosphere; many of its particles are of +ultra-microscopic fineness, one of them must exist in every raindrop, +nay, even in every spherule of a mist or cloud, but it is only +occasionally that one can find them with the microscope. It is to such +particles as these that we owe the blue of the sky, and yet they are +sufficiently gross and tangible to be capable of being filtered out of +the air by a packed mass of cotton-wool. Such dust as this, then, we +need never be afraid of being without. Without it there could be no +rain, and existence would be insupportable, perhaps impossible; but it +is not manufactured in towns; the sea makes it; trees and wind make +it; but the kind of dust made in towns rises only a few hundred yards +or so into the atmosphere, floating as a canopy or pall over those +unfortunate regions, and sinks and settles most of it as soon as the +air is quiet, but scarcely any of it ever rises into the upper regions +of the atmosphere at all. + +Dust, then, being so universally prevalent, what do I mean by +dust-free spaces? How are such things possible? And where are they to +be found? In 1870 Dr. Tyndall was examining dusty air by means of a +beam of light in which a spirit-lamp happened to be burning, when he +noticed that from the flame there poured up torrents of apparently +thick black smoke. He could not think the flame was really smoky, but +to make sure he tried, first a Bunsen gas flame and then a hydrogen +flame. They all showed the same effect, and smoke was out of the +question. He then used a red-hot poker, a platinum wire ignited by an +electric current, and ultimately a flask of hot water, and he found +that from all warm bodies examined in dusty air by a beam of light the +upstreaming convection currents were dark. Now, of course smoke would +behave very differently. Dusty air itself is only a kind of smoke, and +it looks bright, and the thicker the smoke the brighter it looks; the +blackness is simply the utter absence of smoke; there is nothing at +all for the light to illuminate, accordingly we have the blankness of +sheer invisibility. Here is a flame burning under the beam, and, to +show what real smoke looks like, I will burn also this spirit lamp +filled with turpentine instead of alcohol. _Why_ the convention +currents were free from dust was unknown; Tyndall thought the dust was +burnt and consumed; Dr. Frankland thought it was simply evaporated. + +In 1881 Lord Rayleigh took the matter up, not feeling satisfied with +these explanations, and repeated the experiment very carefully. He +noted several new points, and hit on the capital idea of seeing what a +cold body did. From the cold body the descending current was just as +dark and dust-free as from a warm body. Combustion and evaporation +explanations suffered their death-blow. But he was unable to suggest +any other explanation in their room, and so the phenomenon remained +curious and unexplained. + +In this state Mr. Clark and I took the matter up last summer, and +critically examined all sorts of hypotheses that suggested themselves, +Mr. Clark following up the phenomena experimentally with great +ingenuity and perseverance. One hypothesis after another suggested +itself, seemed hopeful for a time, but ultimately had to be discarded. +Some died quickly, others lingered long. In the examination of one +electrical hypothesis which suggested itself we came across various +curious phenomena which we hope still to follow up.[2] It was some +months before what we now believe to be the true explanation began to +dawn upon us. Meanwhile we had acquired various new facts, and first +and foremost we found that the dark plane rising from a warm body was +only the upstreaming portion of a dust-free _coat_ perpetually being +renewed on the surface of the body. Let me describe the appearance and +mode of seeing it by help of a diagram. (For full description see +_Philosophical Magazine_ for March, 1884.) + + [Footnote 2: For instance, the electric properties of crystals + can be readily examined in illuminated dusty air; the dust grows + on them in little bushes and marks out their poles and neutral + regions, without any need for an electrometer. Magnesia smoke + answers capitally.] + +Surrounding all bodies warmer than the air is a thin region free from +dust, which shows itself as a dark space when examined by looking +along a cylinder illuminated transversely, and with a dark background. +At high temperatures the coat is thick; at very low temperatures it is +absent, and dust then rapidly collects on the rod. On a warm surface +only the heavy particles are able to settle--there is evidently some +action tending to drive small bodies away. An excess of temperature of +a degree or two is sufficient to establish this dust-free coat, and it +is easy to see the dust-free plane rising from it. The appearances may +also be examined by looking along a cylinder _toward_ the source of +light, when the dust-free spaces will appear brighter than the rest. A +rod of electric light carbon warmed and fixed horizontally across a +bell-jar full of dense smoke is very suitable for this experiment, and +by means of a lens the dust-free regions may be thus projected on to a +screen. Diminished pressure makes the coat thicker. Increased pressure +makes it thinner. In hydrogen it is thicker, and in carbonic acid +thinner, than in air. We have also succeeded in observing it in +liquids--for instance, in water holding fine rouge in suspension, the +solid body being a metal steam tube. Quantitative determinations are +now in progress. + +[Illustration: Fig. 1 and Fig. 2] + +Fig. 1 shows the appearance when looking along a copper or carbon rod +laterally illuminated; the paths of the dust particles are roughly +indicated. Fig. 2 shows the coat on a semi-cylinder of sheet copper +with the concave side turned toward the light. + +It is difficult to give the full explanation of the dust free spaces +in a few words, but we may say roughly that there is a molecular +bombardment from all warm surfaces by means of which small suspended +bodies get driven outward and kept away from the surface. It is a sort +of differential bombardment of the gas molecules on the two faces of a +dust particle somewhat analogous to the action on Mr. Crookes' +radiometer vanes. Near cold surfaces the bombardment is very feeble, +and if they are cold enough it appears to act toward the body, driving +the dust inward--at any rate, there is no outward bombardment +sufficient to keep the dust away, and bodies colder than the +atmosphere surrounding them soon get dusty. Thus if I hold this piece +of glass in a magnesium flame, or in a turpentine or camphor flame, it +quickly gets covered with smoke--white in the one case, black in the +other. I take two conical flasks with their surfaces blackened with +camphor black, and filling one with ice, the other with boiling water, +I cork them and put a bell jar over them, under which I burn some +magnesium wire; in a quarter of an hour or so we find that the cold +one is white and hoary, the hot one has only a few larger specks of +dust on it, these being of such size that the bombardment was unable +to sustain their weight, and they have settled by gravitation. We thus +see that when the air in a room is warmer than the solids in it--as +will be the case when stoves, gas-burners, etc., are used--things will +get very dusty; whereas when walls and objects are warmer than the +air--as will be the case in sunshine, or when open fireplaces are +used, things will tend to keep themselves more free from dust. Mr. +Aitken points out that soot in a chimney is an illustration of this +kind of deposition of dust; and as another illustration it strikes me +as just possible that the dirtiness of snow during a thaw may be +partly due to the bombardment on to the cold surface of dust out of +the warmer air above. Mr. Aitken has indeed suggested a sort of +practical dust or smoke filter on this principle, passing air between +two surfaces--one hot and one cold--so as to vigorously bombard the +particles on to the cold surface and leave the air free. + +But we have found another and apparently much more effectual mode of +clearing air than this. We do it by discharging electricity into it. +It is easily possible to electrify air by means of a point or flame, +and an electrified body has this curious property, that the dust near +it at once aggregates together into larger particles. It is not +difficult to understand why this happens; each of the particles +becomes polarized by induction, and they then cling together end to +end, just like iron filings near a magnet. A feeble charge is often +sufficient to start this coagulating action. And when the particles +have grown into big ones, they easily and quickly fall. A stronger +charge forcibly drives them on to all electrified surfaces, where they +cling. A fine water fog in a bell jar, electrified, turns first into a +coarse fog or Scotch mist, and then into rain. Smoke also has its +particles coagulated, and a space can thus be cleared of it. I will +illustrate this action by making some artificial fogs in a bell-jar +furnished with a metal point. First burn some magnesium wire, +electrify it by a few turns of this small Voss machine, and the smoke +has become snow; the particles are elongated, and by pointing to the +charged rod indicate the lines of electrostatic force very +beautifully; electrify further, and the air is perfectly clear. Next +burn turpentine, and electrify gently; the dense black smoke +coagulates into black masses over an inch long; electrify further, and +the glass is covered with soot, but the air is clear. Turpentine smoke +acts very well, and can be tried on a larger scale; a room filled with +turpentine smoke, so dense that a gas-light is invisible inside it, +begins to clear in a minute or two after the machine begins to turn, +and in a quarter of an hour one can go in and find the walls thickly +covered with stringy blacks, notably on the gas-pipes and everything +most easily charged by induction. Next fill a bell-jar full of steam, +and electrify, paying attention to insulation of the supply point in +this case. In a few seconds the air looks clear, and turning on a beam +of light we see the globules of water dancing about, no longer fine +and impalpable, but separately visible and rapidly falling. Finally, +make a London fog by burning turpentine and sulphur, adding a little +sulphuric acid, either directly as vapor or indirectly by a trace of +nitric oxide, and then blowing in steam. Electrify, and it soon +becomes clear, although it lakes a little longer than before; and on +removing the bell-jar we find that even the smell of SO2 has +disappeared, and only a little vapor of turpentine remains. Similarly +we can make a Widnes fog by sulphureted hydrogen, chlorine, sulphuric +acid, and a little steam. Probably the steam assists the clearing when +gases have to be dealt with. It may be possible to clear the air of +tunnels by simply discharging electricity into the air--the +electricity being supplied by Holtz machines, driven say by small +turbines--a very handy form of power, difficult to get out of order. +Or possibly some hydro-electric arrangement might be devised for the +locomotive steam to do the work. I even hope to make some impression +on a London fog, discharging from lightning conductors or captive +balloons carrying flames, but it is premature to say anything about +this matter yet. I have, however, cleared a room of smoke very quickly +with a small hand machine. + +It will naturally strike you how closely allied these phenomena must +be to the fact of popular science that "thunder clears the air." Ozone +is undoubtedly generated by the flashes, and may have a beneficial +effect, but the dust-coagulating and dust-expelling power of the +electricity has a much more rapid effect, though it may not act till +the cloud is discharged. Consider a cloud electrified slightly; the +mists and clouds in its vicinity begin to coagulate, and go on till +large drops are formed, which may be held up by electrical action, the +drops dancing from one cloud to another and thus forming the very +dense thunder cloud. The coagulation of charged drops increases the +potential, as Prof. Tait points out, until at length--flash--the cloud +is discharged, and the large drops fall in a violent shower. Moreover, +the rapid excursion to and fro of the drops may easily have caused +them to evaporate so fast as to freeze, and hence we may get hail. + +While the cloud was electrified, it acted inductively on the earth +underneath, drawing up an opposite charge from all points, and thus +electrifying the atmosphere. When the discharge occurs this +atmospheric electrification engages with the earth, clearing the air +between, and driving the dust and germs on to all exposed surfaces. In +some such way also it may be that "thunder turns milk sour," and +exerts other putrefactive influences on the bodies which receive the +germs and dust from the air. + +But we are now no longer on safe and thoroughly explored territory. I +have allowed myself to found upon a basis of experimental fact, a +superstructure of practical application to the explanation of the +phenomena of nature and to the uses of man. The basis seems to me +strong enough to bear most of the superstructure, but before being +sure it will be necessary actually to put the methods into operation +and to experiment on a very large scale. I hope to do this when I can +get to a suitable place of operation. Liverpool fogs are poor affairs, +and not worth clearing off. Manchester fogs are much better and more +frequent, but there is nothing to beat the real article as found in +London, and in London if possible I intend to rig up some large +machines and to see what happens. The underground railway also offers +its suffocating murkiness as a most tempting field for experiment, and +I wish I were able already to tell you the actual result instead of +being only in a position to indicate possibilities. Whether anything +comes of it practically or not, it is an instructive example of how +the smallest and most unpromising beginnings may, if only followed up +long enough, lead to suggestions for large practical application. When +we began the investigation into the dust-free spaces found above warm +bodies, we were not only without expectation, but without hope or idea +of any sort, that anything was likely to come of it; the phenomenon +itself possessed its own interest and charm. + +And so it must ever be. The devotee of pure science never has +practical developments as his primary aim; often he not only does not +know, but does not in the least care whether his researches will ever +lead to any beneficial result. In some minds this passive ignoring of +the practical goes so far as to become active repulsion; so that some +singularly biased minds will not engage in anything which seems likely +to lead to practical use. I regard this as an error, and as the sign +of a warped judgment, for after all man is to us the most important +part of nature; but the system works well nevertheless, and the +division of labor accomplishes its object. One man investigates nature +impelled simply by his own genius, and because he feels he cannot help +it; it never occurs to him to give a reason for or to justify his +pursuits. Another subsequently utilizes his results, and applies them +to the benefit of the race. Meanwhile, however, it may happen that the +yet unapplied and unfruitful results evoke a sneer, and the question: +"Cui bono?" the only answer to which question seems to be: "No one is +wise enough to tell beforehand what gigantic developments may not +spring from the most insignificant fact." + + * * * * * + + + + +TELEPHONY AND TELEGRAPHY ON THE SAME WIRES SIMULTANEOUSLY. + + +For the last eighteen months a system has been in active operation in +Belgium whereby the ordinary telegraph wires are used to convey +telephonic communications at the same time that they are being +employed in their ordinary work of transmitting telegraphic messages. +This system, the invention of M. Van Rysselberghe, whose previous +devices for diminishing the evil effects of induction in the telephone +service will be remembered, has lately been described in the _Journal +Telegraphique_ of Berne, by M.J. Banneux of the Belgian Telegraph +Department. Our information is derived from this article and from +others by M. Hospitalier. + +The method previously adopted by Van Rysselberghe, to prevent +induction from taking place between the telegraph wires and those +running parallel to them used for telephone work, was briefly as +follows: The system of sending the dots and dashes of the +code--usually done by depressing and raising a key which suddenly +turns on the current and then suddenly turns it off--was modified so +that the current should rise gradually and fall gradually in its +strength by the introduction of suitable resistances. These were +introduced into the circuit at the moment of closing or opening by a +simple automatic arrangement worked exactly as before by a key. The +result, of the gradual opening and gradual closing of the circuit was +that the current attained its full strength gradually instead of +suddenly, and died away also gradually. And as induction from one wire +to another depends not on the strength of the current, but on the rate +at which the strength changes, this very simple modification had the +effect of suppressing induction. Later Van Rysselberghe changed these +arrangements for the still simpler device of introducing permanently +into the circuit either condensers or else electro-magnets having a +high coefficient of self-induction. These, as is well known to all +telegraphic engineers, retard the rise or fall of an electric current; +they fulfill the conditions required for the working of Van +Rysselberghe's method better than any other device. + +Having got thus far in his devices for destroying induction from one +line to another, Van Rysselberghe saw that, as an immediate +consequence, it might be concluded that, if the telegraph currents +were thus modified and graduated so that they produced no induction in +a neighboring telephone line, they would produce no sound in the +telephone if that instrument were itself joined up in the telegraph +line. And such was found to be case. Why this is so will be more +readily comprehended if it be remembered that a telephone is sensitive +to the changes in the strength of the current if those changes occur +with a frequency of some hundreds or in some cases thousands of times +_per second_. On the other hand, currents vibrating with such rapidity +as this are utterly incompetent to affect the moving parts of +telegraphic instruments, which cannot at the most be worked so as to +give more than 200 to 800 separate signals _per minute_. + +[Illustration: Fig. 1] + +[Illustration: Fig. 2] + +The simplest arrangement for carrying out this method is shown in Fig. +1, which illustrates the arrangements at one end of a line. M is the +Morse key for sending messages, and is shown as in its position of +rest for receiving. The currents arriving from the line pass first +through a "graduating" electromagnet, E2, of about 500 ohms +resistance, then through the key, thence through the electromagnet, R, +of the receiving Morse instrument, and so to the earth. A condenser, +C, of 2 microfarads capacity is also introduced between the key and +earth. There is a second "graduating" electromagnet, E1, of 500 ohms +resistance introduced between the sending battery, B, and the key. +When the key, M, is depressed in order to send a signal, the current +from the battery must charge the condenser, C, and must magnetize the +cores of the two electromagnets, E1 and E2, and is thereby retarded in +rising to its full strength. Consequently no sound is heard in a +telephone, T, inserted in the line-circuit. Neither the currents which +start from one end nor those which start from the other will affect +the telephones inserted in the line. And, if these currents do not +affect telephones in the actual line, it is clear that they will not +affect telephones in neighboring lines. Also the telephones so +inserted in the main line might be used for speaking to one another, +though the arrangement of the telephones in the same actual line would +be inconvenient. Accordingly M. Van Rysselberghe has devised a further +modification in which a separate branch taken from the telegraph line +is made available for the telephone service. To understand this +matter, one other fact must be explained. Telephonic conversation can +be carried on, even though the actual metallic communication be +severed by the insertion of a condenser. Indeed, in quite the early +days of the Bell telephone, an operator in the States used a condenser +in the telegraph line to enable him to talk through the wire. If a +telephonic set at T1 (Fig. 2) communicate through the line to a +distant station, T2, through a condenser, C, of a capacity of half a +microfarad, conversation is still perfectly audible, provided the +telephonic system is one that acts by induction currents. And since in +this case the interposition of the condenser prevents any continuous +flow of current through the line, no perceptible weakening will be +felt if a shunt S, of as high a resistance as 500 ohms and of great +electromagnetic rigidity, that is to say, having a high coefficient of +self-induction, be placed across the circuit from line to earth. In +this, as well as in the other figures, the telephones indicated are of +the Bell pattern, and if set up as shown in Fig. 2, without any +battery, would be used both as transmitter and receiver on Bell's +original plan. But as a matter of fact any ordinary telephone might be +used. In practice the Bell telephone is not advantageous as a +transmitter, and has been abandoned except for receiving; the Blake, +Ader, or some other modification of the microphone being used in +conjunction with a separate battery. To avoid complication in the +drawings, however, the simplest case is taken. And it must be +understood that instead of the single instrument shown at T1 or T2, a +complete set of telephonic instruments, including transmitter, +battery, induction-coil, and receiver or receivers, may be +substituted. And if a shunt, S, of 500 ohms placed across the circuit +makes no difference to the talking in the telephones because of the +interposition of the separating condenser, C, it will readily be +understood that a telegraphic system properly "graduated," and having +also a resistance of 500 ohms, will not affect the telephones if +interposed in the place of S. This arrangement is shown in Fig. 3, +where the "graduated" telegraph-set from Fig. 1 is intercalated into +the telephonic system of Fig. 2, so that both work simultaneously, but +independently, through a single line. The combined system at each end +of the line will then consist of the telephone-set, T1, the telegraph +instruments (comprising battery, B1, key, M1 and Morse receiver, R1), +the "graduating" electromagnets, E1, and E2, the "graduating" +condenser, C1, and the "separating" condenser, C2. It was found by +actual experiments that the same arrangement was good for lines +varying from 28 to 200 miles in length. A single wire between +Brussels, Ghent, and Ostend is now regularly employed for transmission +by telegraph of the ordinary messages and of the telemeteorographic +signals between the two observatories at those places, and by +telephone of verbal simultaneous correspondence, for one of the Ghent +newspapers. A still more interesting arrangement is possible, and is +indicated in Fig. 4. Here a separating condenser is introduced at the +intermediate station at Ghent between earth and the line, which is +thereby cut into two independent sections for telephonic purposes, +while remaining for telegraphic purposes a single undivided line +between Brussels and Ostend. Brussels can telegraph to Ostend, or +Ostend to Brussels, and at the same time the wire can be used to +telephone between Ghent and Ostend, or between Ghent and Brussels, or +both sections may be simultaneously used. + +[Illustration: Fig. 3] + +[Illustration: Fig. 4] + +It would appear, then, that M. Van Rysselberghe has made an advance of +very extraordinary merit in devising these combinations. We have seen +in recent years how duplex telegraphy superseded single working, only +to be in turn superseded by the quadruplex system. Multiplex +telegraphy of various kinds has been actively pursued, but chiefly on +the other side of the Atlantic rather than in this country, where our +fast-speed automatic system has proved quite adequate hitherto. +Whether we shall see the adoption in the United Kingdom of Van +Rysselberghe's system is, however, by no means certain. The essence of +it consists in retarding the telegraphic signals to a degree quite +incompatible with the fast-speed automatic transmission of telegraphic +messages in which our Post Office system excels. We are not likely to +spoil our telegraphic system for the sake of simultaneous telephony, +unless there is something to be gained of much greater advantage than +as yet appears.--_Nature._ + + * * * * * + + + + +THE ELECTRIC MARIGRAPH. + + +For registering the height of the tide at every instant, hydrographic +services generally adopt quite a simple marigraph. The apparatus +consists in principle of a counterpoised float whose rising and +falling motion, reduced to a tenth, by means of a system of toothed +wheels, is transmitted to a pencil which moves in front of a vertical +cylinder. This cylinder itself moves around its axis by means of a +clockwork mechanism, and accomplishes one entire revolution every +twenty-four hours. By this means is obtained a curve of the tide in +which the times are taken for abscisses and the heights of the sea for +ordinates. However little such marigraphs have had to be used, great +defects have been recognized in them. When we come to change the sheet +on the cylinder (and such change should be made at least once every +fifteen days), there is an interruption in the curve. It is necessary, +besides, to perform office work of the most detailed kind in order to +refer to the same origin all these curves, which are intercrossed and +often superposed in certain parts upon the original sheet. In order to +render such a disentanglement possible, it is indispensable to mark by +hand, at least once every twenty-four hours, upon each curve, the date +of the day corresponding to it. It is equally useful to verify the +exactness of the indications given by the apparatus by making readings +several times a day on a scale of tides placed alongside of the float. +Nine times out of ten the rise of the waves renders such readings very +difficult and the control absolutely illusory. + +All these conditions united, as well as others that we neglect in this +brief discussion, necessitate a surveillance at every instant. The +result is that these marigraphs must be installed in a special +structure, very near the bank, so as to be reachable at all times, and +that the indications that they give are always vitiated by error, +since the operation is performed upon a level at which are exerted +disturbing influences that are not found at a kilometer at sea. It +were to be desired that the float could be isolated by placing it a +certain distance from the shore, and transmit its indications, by +meant of a play of currents, to a registering apparatus situated upon +_terra firma_. + +In the course of one of his lectures published in the December number +(1883) of the _Elektrotechnische Zeitschrift_, Mr. Von Hefner-Alteneck +tells us that such a desideratum has been supplied by the firm of +Siemens & Halske. This marigraph, constructed on an order of the +German Admiralty, gives the level of the sea every ten minutes with an +approximation of 0.12 per cent., and that too for a difference of 8 +meters between the highest and lowest sea. The apparatus consists, as +we said above, of a float and registering device, connected with each +other by means of a cable. This latter is formed of three ordinary +conductors covered with gutta percha and surrounded with a leaden +sheath, which latter is itself protected against accident by means of +a strong covering of iron wire and hemp. The return is effected +through the earth. We shall enter into details concerning each of +these two apparatus in-succession, by beginning with the float, of +which Fig. 1 gives a general view, and Fig. 2 a diagrammatic sketch. +The float moves in a cast iron cylinder, having at its lower part a +large number of apertures of small diameter, so that the motion of the +waves does not perceptibly influence the level of the water in the +interior of the cylinder. It is attached to a copper ribbon, B, whose +other extremity is fixed to the drum, T. The ribbon winds around the +latter in the rising motion of the float, owing to a spiral spring +arranged so as to act upon the drum. The tension of this spring goes +on increasing in measure as the float descends. + +[Illustration: FIG. 1.--FLOAT OF SIEMENS AND HALSKE'S MARIGRAPH.] + +[Illustration: FIG. 2.] + +This difference in tension is utilized for balancing at every instant +the weight of the ribbon unwound, and thus causing the float to +immerse itself in the water to a constant degree. The ribbon, B, is +provided throughout its length with equidistant apertures that exactly +correspond to tappets that project from the circumference of the +wheel, R. When the float moves its position, the wheel, R, begins to +turn and carries along in doing so the pinion, w, which revolves +over the toothed wheels, s1, s2, and s3. The thickness of w +is equal to that of the three wheels, s1, s2, and s3, and a +special spring secures at every instant an intimate contact between +the pinion and the said wheels. These latter are insulated from each +other and from the axle upon which they are keyed, and communicate, +each of them, with conductors, I., II., and III. They are so formed +and mounted that, in each of them, the tooth in one corresponds to the +interspace in the two others. As a result of this, in the motion of +the pinion, w, the latter is never in contact with but one of the +three wheels, s1, s2, and s3. + +If we add that the lines, I., II., and III. are united at the shore +station with one of the poles of a pile whose other pole is connected +with the earth, and that w communicates with the earth through the +intermedium of R, and the body of the apparatus, it is easy to see +that in a vertical motion of the float in one direction we shall have +currents succeeding each other in the order I., II., III., I., II., +etc., while the order will become III., II., I., III., II., etc., if +the direction of the float's motion happen to change. + +[Illustration: FIG. 3.] + +[Illustration: FIG. 4.] + +In order to understand how a variation in currents of this kind can be +applied in general for producing a rotary motion in the two +directions, it will only be necessary to refer to Figs. 3 and 4. The +conductors, L1, L2, and L3 communicate with the bobbins of +three electromagnets, E1, E2, and E3, whose poles are bent at +right angles to the circumference of the wheel, R. There is never but +one pole opposite a tooth. The distance between two consecutive poles +must be equal to a multiple of the pitch increased (Fig. 3) or +diminished (Fig. 4) by one-third thereof. It will be seen upon a +simple inspection of the figures that R will revolve in the direction +of the hands of a watch when the currents follow the order L1, +L2, L3, etc., in the case shown in Fig. 3, while in the case +shown in Fig. 4 the rotary motion will be in the contrary direction +for this same order of currents. But, in both cases, and this is the +important point, the direction of rotation changes when the order in +the succession of currents; is inverted. Fig. 6 gives a perspective +view of the registering apparatus, and Fig. 5 represents it in +diagram. It will be at once seen that, the toothed wheel, r, is +reduced to its simplest expression, since it consists of two teeth +only. The electro-magnets are arranged at an angle of 120 deg., and for a +change of current the wheel, r, describes an angle of 60 deg., that is +to say, a sixth of a circumference. The motion of r is transmitted, by +means of the pinion, d, and the wheel, e, to the wheel, T. For a +one-meter variation in level the wheel, T, makes one complete +revolution. It is divided into 100 equal parts, and each arc therefore +corresponds to a difference of one centimeter in the level, and +carries, engraved in projection, the corresponding number. As a +consequence, there is upon the entire circumference a series of +numbers from to 99. The axle upon which the wheel, T, is keyed is +prolonged, on the side opposite e, by a threaded part, a, which +actuates a stylet, g. This latter is held above by a rod, I, which +is connected with a fork movable around a vertical axis, shown in Fig. +6. The rectilinear motion of g is 5 mm. for a variation of one meter +in level. Its total travel is consequently 40 mm. The sheet of paper +upon which the indications are taken, and which is shown of actual +size in Fig. 7, winds around the drum, P, and receives its motion from +the cylinder, W. This sheet is covered throughout its length with fine +prepared paper that permits of taking the imprints by impression. + +[Illustration: FIG. 5] + +[Illustration: FIG. 6--RECEIVER OF SIEMENS AND HALSKE'S MARIGRAPH.] + +[Illustration: FIG. 7] + +This stated, the play of the apparatus may be easily understood. Every +ten minutes a regulating clock closes the circuit of the local pile, +B2, and establishes a contact at C. The electro-magnet, E4, +attracts its armature, and thus acts upon the lever, h, which +presses the sheet of paper against the stylet in front that serves to +mark the level of the lowest waters, and against the stylet, g, and +the wheels, T and Z. In falling back, the lever, h, causes the +advance, by one notch, of the ratchet wheel that is mounted at the +extremity of the cylinder W, and thus displaces the sheet of paper a +distance of 5 mm. The wheel, Z, carries engraved in projection upon +its circumference the hours in Roman figures, and moves forward one +division every 60 minutes. The motion of this wheel is likewise +controlled by the cylinder, W. + +It will be seen upon referring to Fig. 7, that there is obtained a +very sharp curve marked by points. We have a general view on +considering the curve itself, and the height in meters is read +directly. The fractions of a meter, as well as the times, are in the +margin. Thus, at the point, a, the apparatus gives at 3 o'clock and +20 minutes a height of tide of 4.28 m. above the level of the lowest +water. + +This apparatus might possibly operate well, and yet not be in accord +with the real indications of the float, so it has been judged +necessary to add to it the following control. + +Every time the float reaches 3 meters above the level of the lowest +tide, the circuit of one of the lines that is open at this moment +(that of line I, for example) closes at C (Fig. 2), into this new +circuit there is interposed a considerable resistance, W, so that the +energy of the current is weakened to such a point that it in nowise +influences the normal travel of the wheel, r. At the shore station, +there is placed in deviation a galvanoscope, K, whose needle is +deflected. It suffices, then, to take datum points upon the +registering apparatus, upon the wheel, T, and the screw, a, in such +a way as to ascertain the moment at which the stylet, g, is going to +mark 3 meters. At this moment the circuit of the galvanoscope, K, is +closed, and we ascertain whether there is a deviation of the needle. + +As the sea generally rises to the height of 3 meters twice a day, it +is possible to control the apparatus twice a day, and this is fully +sufficient. + +It always belongs to practice to judge of an invention. Mr. Von +Hefner-Alteneck tells us that two of these apparatus have been set +up--one of them a year ago in the port of Kiel, and the other more +recently at the Isle of Wangeroog in the North Sea--and that both have +behaved excellently since the very first day of their installation. We +shall add nothing to this, since it is evidently the best eulogium +that can be accorded them.--_La Lumiere Electrique._ + + * * * * * + + + + +DELUNE & CO.'S SYSTEM OF LAYING UNDERGROUND CABLES. + + +In recent times considerable attention has been paid to the subject of +laying telegraph cables underground, and various methods have been +devised. In some cases the cables have been covered with an armor of +iron, and in others they have been inclosed in cast-iron pipes. For +telephonic service they are generally inclosed in leaden tubes. What +this external envelope shall be that is to protect the wires from +injury is a question of the highest importance, since not only the +subject of protection is concerned, but also that of cost. It is +therefore interesting to note the efforts that are being made in this +line of electric industry. + +[Illustration: FIG. 1. Section of the Pipe Open.] + +[Illustration: FIG. 2. Section of the Pipe Closed.] + +Messrs. Delune & Co. have recently taken out a patent for an +arrangement consisting of pipes made of beton. The annexed cuts, +borrowed from _L'Electricite_, represent this new system. The pipes, +which are provided with a longitudinal opening, are placed end to end +and coupled with a cement sleeve. The cables are put in place by +simply unwinding them as the work proceeds, and thus all that traction +is done away with that they are submitted to when cast iron pipes are +used. When once the cables are in place the longitudinal opening is +stopped up with cement mortar, and in this way a very tight conduit is +obtained whose hardness increases with time. The value of the system +therefore depends, as in all cement work, on the care with which the +manufacturing is done. + +Experiments have been made with the system at Toulouse, by the +Minister of Post Offices and Telegraphs, and at Lyons, by the General +Society of Telephones. Here, as with all similar questions, no opinion +can be pronounced until after a prolonged experience. But we cannot +help setting forth the advantages that the system offers. These are, +in the first place, a saving of about 50 per cent. over iron pipe, and +in the second, a better insulation, and consequently a better +protection of the currents against all kinds of disturbance, since a +non-conducting mass of cement is here substituted for metal. + + * * * * * + + + + +ELECTRICITY APPLIED TO HORSE-SHOEING. + + +"There is nothing new but what has been forgotten," said Marie +Antoinette to her milliner, Mdlle. Bertin, and what is true of fashion +is also somewhat so of science. Shoeing restive horses by the aid of +electricity is not new, experiments thereon having been performed as +long ago as 1879 by Mr. Defoy, who operated with a small magneto +machine. + +But the two photographs reproduced in Figs. 1 and 2 have appeared to +us curious enough to be submitted to our readers, as illustrating Mr. +Defoy's method of operating with an unruly animal. + +[Illustration: FIG. 1.--THE HORSE RECEIVING THE CURRENT.] + +The battery used was a small Grenet bichromate of potash pile, which +was easy to graduate on account of the depth to which the zinc could +be immersed. This pile was connected with the inductor of a small +Ruhmkorff coil, whose armature was connected with a snaffle-bit placed +in the horse's mouth. + +[Illustration: FIG. 2.--THE HORSE CONQUERED.] + +This bit was arranged as follows (Fig. 3): The two conductors, which +were uncovered for a length of about three centimeters at their +extremity, were placed opposite each other on the two joints of the +snaffle, and about five or six centimeters apart. The mouth-pieces of +the bit had previously been inclosed in a piece of rubber tubing, in +order to insulate the extremities of the conductors and permit the +recomposition of the current to take place through the animal's tongue +or palate. + +Each of the bare ends of the conductors was provided, under a circular +brass ligature, with a small damp sponge, which, surrounding the +mouth-piece, secured a perfect contact of each end of the circuit with +the horse's mouth. + +[Illustration: FIG. 3.--ARRANGEMENT OF THE BIT] + +The horse having been led in, defended himself vigorously as long as +an endeavor was made to remove his shoes by the ordinary method, but +the current had acted scarcely fifteen seconds when it became possible +to lift his feet and strike his shoes with the hammer. + +The experimenter having taken care during this experiment to place the +bobbin quite near the horse's ear, so that he could hear the humming +of the interrupter, undertook a second experiment in the following +way: Having detached the conductors from the armature, he placed +himself in front of the horse (as shown in Fig. 2), and began to +imitate the humming sound of the interrupter with his mouth. The +animal at once assumed the stupefied position that the action of the +current gave him in the first experiment, and allowed his feet to be +lifted and shod without his even being held by the snaffle. + +The horse was for ever after subdued, and yet his viciousness and his +repugnance to shoeing were such that he could only be shod previously +by confining his legs with a kicking-strap. + +It should be noted that the action of the induction coil, mounted as +this was, was very feeble and not very painful; and yet it was very +disagreeable in the mouth, and gave in this case a shock with a +sensation of light before the eyes, as we have found by experimenting +upon ourselves. + +From our own most recent experiments, we have ascertained the +following facts, which may guide every horse-owner in the application +of electricity to an animal that is opposed to being shod: (1) To a +horse that defends himself because he is irritable by temperament, and +nervous and impressionable (as happens with animals of pure or nearly +pure blood), the shock must be administered feebly and gradually +before an endeavor is made to take hold of his leg. The horse will +then make a jump, and try to roll over. The jump must be followed, +while an assistant holds the bridle, and the action of the current +must be at once arrested. After this the horse will not endeavor to +defend himself, and his leg may be easily handled. + +(2) Certain large, heavy, naturally ugly horses kick through sheer +viciousness. In this case, while the current is being given it should +be gradually increased in intensity, and the horse's foot must be +seized during its action. In most cases the passage of a current +through such horses (whose mucous membrane is less sensitive) produces +only a slightly stupefied and contracted position of the head, +accompanied with a slight tremor. The current must be shut off as soon +as the horse's foot is well in one's hand, and be at once renewed if +he endeavors to defend himself again, as is rarely the case. It is a +mare of this nature that is represented in the annexed figures. + +We know that this same system has been applied for bringing to an +abrupt standstill runaway horses, harnessed to vehicles; but knowing +the effect of a sudden stoppage under such circumstances, we believe +that the remedy would prove worse than the disease, since the coachman +and vehicle, in obedience to the laws of inertia, would continue their +motion and pass over the animals, much to their detriment.--_Science +et Nature._ + + * * * * * + + + + +ESTEVE'S AUTOMATIC PILE. + + +Mr. Esteve has recently devised a generator of electricity which he +claims to be energetic, constant, and always ready to operate. The +apparatus is designed for the production of light and for actuating +electric motors, large induction bobbins, etc. + +We give a description of it herewith from data communicated by its +inventor. + +The accompanying cut represents a battery of 6 elements, with a +reservoir, R, for the liquid, provided at its lower part with a cock +for allowing the liquid to enter the pile. The vessels of the +different elements are of rectangular form. At the upper part, and in +the wider surfaces of each, there are two tubes. The first tube of the +first vessel receives the extremity of a safety-tube, A, whose other +extremity enters the upper part of the reservoir, R. This tube is +designed for regulating the flow of the liquid into the pile. When the +cock, r, is too widely open, the liquid might have a tendency to +flow over the edges of the vessel; but this would close the orifice of +the tube, A, and, as the air would then no longer enter the reservoir, +R, the flow would be stopped automatically. The second tube of the +first vessel is connected with a lead tube, 1, one of the extremities +of which enters the second vessel. The other tubes are arranged in the +same way in the other vessels. The renewal of the liquids is effected +by displacement, in flowing upward from one element over into another; +and the liquids make their exit from the pile at D, after having +served six times. The electrodes of the two first elements are +represented as renewed in the cut, in order to show the arrangement of +the tubes. + +[Illustration: ESTEVE'S AUTOMATIC PILE.] + +_Dimensions._--The zinc, 2, has a superficies of 15x20 centimeters, +and is cut out of the ordinary commercial sheet metal. It may be +turned upside down when one end has become worn away, thus permitting +of its being entirely utilized. The negative electrode is formed of +four carbons, which have, each of them, a superficies of 8x21 +centimeters. These four carbons are less fragile and are more easily +handled than two having the same surface. Their arrangement is shown +at the left of the figure. They are fixed to a strip of copper, a, +to which is soldered another strip, L, bent at right angles. There are +thus two pairs of carbon per element, and these are simply suspended +from a piece of wood, as shown in the figure. Upon this wooden holder +will be seen the two strips, LL, that are designed to be put in +contact with the zinc of the succeeding element by means of pinchers +that connect the electrodes with one another. This arrangement permits +the pile to be taken apart very quickly. + +_Charging, Work, and Duration of the Pile._--The inventor has made a +large number of experiments with solutions of bichromate of potash of +various degrees of saturation, and has found the following to give the +best results: + + + Bichromate of potash. 1 kilogramme. + Sulphuric acid 2 liters. + Water 8 " + + +When a larger quantity of the salt is used, crystallization occurs in +the pile. + + Constants and work Constants and work + of an element of a round Bunsen + having a zinc of element, 20x30 cm. + 16x20 cm. + + Volts. 1.9 1.8 + Resistance. 0.05 0.24 + Work disposable in the + external circuit. 1.839 k. 0.344 k. + + +The work disposable in the external circuit is deduced from the +formula: + + T = E squared/(4R x 9.81) + +It will be seen that an element thus charged gives as much energy as +5.3 large Bunsen elements. + +The battery is charged with 10 liters of solution, and is capable of +furnishing for 5 hours a current of 7 amperes with a difference of +potential of 9 volts at the pile terminals. The work, according to the +formula (EI)/g, equals 6.422 kilogram-meters; with a feebler +resistance in the external circuit it is capable of producing a +current of 19 amperes for an hour and an half. In this case the +resistance of the external circuit equals the interior resistance of +the pile. Upon immersing the electrodes in new liquid, and with no +resistance in the external circuit, the current may reach 100 amperes. +On renewing the liquids during the operation of the pile, a current of +7 amperes is kept up if about a liter of saturation per hour be +allowed to pass into the battery. For five hours, then, only 5 liters +are used instead of the 10 that are necessary when the liquid is not +renewed while the pile is in action.--_La Nature._ + + * * * * * + + + + +WOODWARD'S DIFFUSION MOTOR. + + +The energy produced by the phenomena of diffusion is exhibited in +lecture courses by placing a bell glass filled with hydrogen over a +porous vessel at whose base is fixed a glass tube that dips into +water. The hydrogen, in diffusing, enters the porous vessel, increases +the internal pressure, and a number of bubbles escapes from the tube. +On withdrawing the bell glass of hydrogen, the latter becomes diffused +externally, a lower pressure occurs in the porous vessel, and the +level of the water rises. + +The arrangement devised by Mr. C.J. Woodward, and recently presented +to the Physical Society of London, is an adaptation of this experiment +to the production of an oscillating motion by alternations in the +internal and external diffusion of the hydrogen. + +The apparatus, represented herewith, consists of a scale beam about +three feet in length that supports at one end a scale pan and weights, +and, at the other, a corked porous vessel that carries a glass tube, +c, which dips into a vessel containing either water or methylic +alcohol. Three or four gas jets, one of which is shown at E, are +arranged around the porous vessel, as close as possible, but in such a +way as not to touch it during the oscillation of the beam. These gas +jets communicate with a gasometer tilled with hydrogen, the bell of +which is so charged as to furnish a jet of sufficient strength. +Experience will indicate the best place to give the gas jets, but, in +general, it is well to locate them at near the center of the porous +vessel when the beam is horizontal. + +[Illustration] + +It is now easy to see how the device operates. When the hydrogen comes +in presence of the porous vessel it becomes diffused therein, and the +pressure exerted in the interior then produces an ascent. When the +bottom of the porous vessel gets above the jets, the internal +diffusion ceases and the hydrogen becomes diffused externally, the +internal pressure diminishes, and the vessel descends. The vessel then +comes opposite the jets of hydrogen and the same motion occurs again, +and soon indefinitely. The work produced by this motor, which has +purely a scientific interest, is very feeble, and much below that +assigned to it by theory. In order to obtain a maximum, it would be +necessary to completely surround the porous vessel each time with +hydrogen, and afterward remove the jets to facilitate the access of +air. All the mechanical arrangements employed for obtaining such a +result have failed, because the friction introduced by the maneuvering +parts also introduces a resistance greater than the motor can +overcome. There is therefore a waste of energy due to the continuous +flow of hydrogen; but the apparatus, for all that, constitutes none +the less an original and interesting device.--_La Nature._ + + * * * * * + + + + +SOME RELATIONS OF HEAT TO VOLTAIC AND THERMO-ELECTRIC ACTION OF METALS +IN ELECTROLYTES.[1] + + [Footnote 1: Read before the Royal Society, Nov., 1883.] + +By G. GORE, F.R.S., LL.D. + + +The experiments described in this paper throw considerable light upon +the real cause of the voltaic current. The results of them are +contained in twenty tables; and by comparing them with each other, and +also by means of additional experiments, the following general +conclusions and chief facts were obtained. + +When metals in liquids are heated, they are more frequently rendered +positive than negative in the proportion of about 2.8 to 1.0; and +while the proportion in weak solutions was about 2.29 to 1.0, in +strong ones it was about 3.27 to 1.0, and this accords with their +thermo-electric behavior as metals alone. The thermo-electric order of +metals in liquids was, with nearly every solution, whether strong or +weak, widely different from the thermo-electric order of the same +metals alone. A conclusion previously arrived at was also confirmed, +viz., that the liquids in which the hot metal was thermo-electro-positive +in the largest proportion of cases were those containing highly +electro-positive bases, such as the alkali metals. The thermo-electric +effect of _gradually_ heating a metal in a liquid was sometimes +different from that of _suddenly_ heating it, and was occasionally +attended by a reversal of the current. + +Degree of strength of liquid greatly affected the thermo-electric +order of metals. Increase of strength usually and considerably +increased the potential of metals thermo-electro-negative in liquids, +and somewhat increased that of those positive in liquids. + +The electric potential of metals, thermo-electro-positive in weak +liquids, was usually about 3.87 times, and in strong ones 1.87 times, +as great as of those which were negative. The potential of the +strongest thermo-electric couple, viz., that of aluminum in weak +solution of sodic phosphate, was 0.66 volt for 100 deg. F. difference of +temperature, or about 100 times that of a bismuth and antimony couple. + +Heating one of the metals, either the positive or negative, of a +voltaic couple, usually increased their electric difference, making +most metals more positive, and some more negative; while heating the +second one also usually neutralized to a large extent the effect of +heating the first one. The electrical effect of heating a voltaic +couple is nearly wholly composed of the united effects of heating each +of the two metals separately, but is not however exactly the same, +because while in the former case the metals are dissimilar, and are +heated to the same temperature, in the latter they are similar, but +heated to different temperatures. Also, when heating a voltaic pair, +the heat is applied to two metals, both of which are previously +electro-polar by contact with each other as well as by contact with +the liquid; but when heating one junction of a metal and liquid +couple, the metal has not been previously rendered electro-polar by +contact with a different one, and is therefore in a somewhat different +state. When a voltaic combination, in which the positive metal is +thermo-negative, and the negative one is thermo-positive, is heated, +the electric potential of the couple diminishes, notwithstanding that +the internal resistance is decreased. + +Magnesium in particular, also zinc and cadmium, were greatly depressed +in electromotive force in electrolytes by elevation of temperature. +Reversals of position of two metals of a voltaic couple in the tension +series by rise of temperature were chiefly due to one of the two +metals increasing in electromotive force faster than the other, and in +many cases to one metal increasing and the other decreasing in +electromotive force, but only in a few cases was it a result of +simultaneous but unequal diminution of potential of the two metals. +With eighteen different voltaic couples, by rise of temperature from +60 deg. to 160 deg. F., the electromotive force in twelve cases was increased, +and in six decreased, and the average proportions of increase for the +eighteen instances was 0.10 volt for the 100 deg. F. of elevation. + +A great difference in chemical composition of the liquid was attended +by a considerable change in the order of the volta-tension series, and +the differences of such order in two similar liquids, such as +solutions of hydric chloride and potassic chloride, were much greater +than those produced in either of those liquids by a difference of 100 deg. +F. of temperature. Difference of strength of solution, like difference +of composition or of temperature, altered the order of such series +with nearly every liquid; and the amount of such alteration by an +increase of four or five times in the strength of the liquid was +rather less than that caused by a difference of 100 deg. F. of +temperature. While also a variation of strength of liquid caused only +a moderate amount of change of order in the volta-tension series, it +produced more than three times that amount of change in the +thermo-electric tension series. The usual effect of increasing the +strength of the liquid upon the volta-electromotive force was to +considerably increase it, but its effect upon the thermo-electro-motive +force was to largely decrease it. The degree of potential of a metal +and liquid thermo-couple was not always exactly the same at the same +temperature during a rise as during a fall of temperature; this is +analogous to the variations of melting and solidifying points of +bodies under such conditions, and also to that of supersaturation of a +liquid by a salt, and is probably due to some hinderance to change of +molecular movement. + +The rate of ordinary chemical corrosion of each metal varied in every +different liquid; in each solution also it differed with every +different metal. The most chemically positive metals were usually the +most quickly corroded, and the corrosion of each metal was usually the +fastest with the most acid solutions. The rate of corrosion at any +given temperature was dependent both upon the nature of the metal and +upon that of the liquid, and was limited by the most feebly active of +the two, usually the electrolyte. The order of rate of corrosion of +metals also differed in every different liquid. The more dissimilar +the chemical characters of two liquids, the more diverse usually was +the order of rapidity of corrosion of a series of metals in them. The +order of rate of simple corrosion in any of the liquids examined +differed from that of chemico-electric and still more from that of +thermo-electric tension. Corrosion is not the cause of thermo-electric +action of metals in liquids. + +Out of fifty-eight cases of rise of temperature the rate of ordinary +corrosion was increased in every instance except one, and that was +only a feeble exception--the increase of corrosion from 60 deg. to 160 deg. F. +with different metals was extremely variable, and was from 1.5 to 321.6 +times. Whether a metal increased or decreased in thermo-electromotive +force by being heated, it increased in rapidity of corrosion. The +proportions in which the most corroded metal was also the most +thermo-electro-positive one was 65.57 per cent. in liquids at 60 deg. F., +and 69.12 in the same liquids at 160 deg. F.; and the proportion in which +it was the most chemico-electro-positive at 60 F. was 84.44 per cent, +and at 160 deg. F. 80.77 per cent. The proportion of cases therefore in +which the most chemico-electro-negative metal was the most corroded +one increased from 15.56 to 19.23 per cent, by a rise of temperature +of 100 deg. F. Comparison of these proportions shows that corrosion +usually influenced in a greater degree chemico-electric rather than +thermo-electric actions of metals in liquids. Not only was the +relative number of cases in which the volta-negative metal was the +most corroded increased by rise of temperature, but also the average +relative loss by corrosion of the negative to that of the positive one +was increased from 3.11 to 6.32. + +The explanation most consistent with all the various results and +conclusions is a kinetic one: That metals and electrolytes are +throughout their masses in a state of molecular vibration. That the +molecules of those substances, being frictionless bodies in a +frictionless medium, and their motion not being dissipated by +conduction or radiation, continue incessantly in motion until some +cause arises to prevent them. That each metal (or electrolyte), when +unequally heated, has to a certain extent an unlike class of motions +in its differently heated parts, and behaves in those parts somewhat +like two metals (or electrolytes), and those unlike motions are +enabled, through the intermediate conducting portion of the substance, +to render those parts electro-polar. That every different metal and +electrolyte has a different class of motions, and in consequence of +this, they also, by contact alone with each other at the same +temperature, become electro-polar. The molecular motion of each +different substance also increases at a different rate by rise of +temperature. + +This theory is equally in agreement with the chemico-electric results. +In accordance with it, when in the case of a metal and an electrolyte, +the two classes of motions are sufficiently unlike, chemical corrosion +of the metal by the liquid takes place, and the voltaic current +originated by inherent molecular motion, under the condition of +contact, is maintained by the portions of motion lost by the metal and +liquid during the act of uniting together. Corrosion therefore is an +effect of molecular motion, and is one of the modes by which that +motion is converted into and produces electric current. + +In accordance with this theory, if we take a thermo-electric pair +consisting of a non-corrodible metal and an electrolyte (the two being +already electro-polar by mutual contact), and heat one of their points +of contact, the molecular motions of the heated end of each substance +at the junction are altered; and as thermo-electric energy in such +combinations usually increases by rise of temperature, the metal and +liquid, each singly, usually becomes more electro polar. In such a +case the unequally heated metal behaves to some extent like two +metals, and the unequally heated liquid like two liquids, and so the +thermo-electric pair is like a feeble chemico-electric one of two +metals in two liquids, but without corrosion of either metal. If the +metal and liquid are each, when alone, thermo-electro-positive, and if, +when in contact, the metal increases in positive condition faster than +the liquid by being heated, the latter appears thermo-electro-negative, +but if less rapidly than the liquid, the metal appears +thermo-electro-negative. + +As also the proportion of cases is small in which metals that are +positive in the ordinary thermo-electric series of metals only become +negative in the metal and liquid ones (viz., only 73 out of 286 in +weak solutions, and 48 out of the same number in strong ones), we may +conclude that the metals, more frequently than the liquids, have the +greatest thermo-electric influence, and also that the relative +largeness of the number of instances of thermo-electro-positive metals +in the series of metals and liquids, as in the series of metals only, +is partly a consequence of the circumstance that rise of temperature +usually makes substances--metals in particular--electro-positive. +These statements are also consistent with the view that the elementary +substances lose a portion of their molecular activity when they unite +to form acids or salts, and that electrolytes therefore have usually a +less degree of molecular motion than the metals of which they are +partly composed. + +The current from a thermo-couple of metal and liquid, therefore, may +be viewed as the united result of difference of molecular motion, +first, of the two junctions, and second, of the two heated (or cooled) +substances; and in all cases, both of thermo- and chemico-electric +action, the immediate true cause of the current is the original +molecular vibrations of the substances, while contact is only a static +permitting condition. Also that while in the case of thermo-electric +action the sustaining cause is molecular motion, supplied by an +external source of heat, in the case of chemico-electric action it is +the motion lost by the metal and liquid when chemically uniting +together. The direction of the current in thermo-electric cases +appears to depend upon which of the two substances composing a +junction increases in molecular activity the fastest by rise of +temperature, or decreases the most rapidly by cooling. + + * * * * * + + + + +AIR REFRIGERATING MACHINE. + + +[Illustration: IMPROVED AIR REFRIGERATING MACHINE.] + +Messrs. J. & E. Hall, Dartford, exhibit at the International Health +Exhibition, London, in connection with a cold storage room, two sizes +of Ellis' patent air refrigerator, the larger one capable of +delivering 5,000 cubic feet of cold air per hour, when running at a +speed of 150 revolutions per minute; and the smaller one 2,000 cubic +feet of cold air per hour, at 225 revolutions per minute. The special +features in these machines are the arrangement of parts, by which +great compactness is secured, and the adoption of flat slides for the +compressor, instead of the ordinary beat valves, which permits of a +high rate of revolution without the objectionable noise which is +caused by clacks beating on their seats. The engraving shows the +general arrangement of the apparatus. Figs. 1 to 4 show details of the +compression and expansion valves, which are ordinary flat slides, +partly balanced, and held up to their faces by strong springs from +behind. The steam, compression, and expansion cylinders are severally +bolted to the end of a strong frame, which though attached to the +cooler box does not form part of it, the object being to meet the +strains between the cylinders and shaft in as direct a manner as +possible without allowing them to act on the cooler casting. Each +cylinder is double acting, the pistons being coupled to the shaft by +three connecting rods, the two outer ones working upon crank pins +fixed to overhung disks, and the center one on a crank formed in the +shaft. The slide valves for all the cylinders are driven from two +weigh shafts, the main valve shaft being actuated by a follow crank, +and the expansion and cut off valves from the crosshead pin of the +compressor. The machines may be used either in the vertical position +as exhibited, or may be fixed horizontally; and it is stated that the +construction is such as to admit of speeds of 200 and 300 revolutions +per minute respectively for the larger and smaller machines, under +which conditions the delivery of cold air may be taken at about 7,000 +and 2,600 cubic feet per hour. Messrs. Hall also make this class of +refrigerator without the steam cylinder, and arranged to be driven by +a belt from a gas engine or any existing motive power. + + * * * * * + + + + +A GAS RADIATOR AND HEATER. + + +[Illustration: Fig. 1 & Fig. 2 A GAS RADIATOR AND HEATER.] + +There is now being introduced into Germany a gas radiator and heater, +the invention of Herr Wobbe. It consists, as will be seen in engraving +above, of a series of vertical U-shaped pipes, of wrought iron, 50 +millimeters (2 inches) in diameter. The two legs of the U are of +unequal length; the longer being about 5 feet, and the shorter 3 feet +(exclusive of the bend at the top). Beneath the open end of the +shorter leg of each pipe is placed a burner, attached to a horizontal +gas-pipe, which turns upon an axis. The object of having this pipe +rotate is to bring the burners into an inclined position--shown by the +dotted lines in Fig. 2--for lighting them. On turning them back to the +vertical position, the heated products of combustion pass up the +shorter tube and down the longer, where they enter a common +receptacle, from which they pass into the chimney or out of doors. +Surrounding the pipes are plates of sheet iron, inclined at the angle +shown in Fig. 2. The object of the plates is to prevent the heated air +of the room from passing up to the ceiling, and send it out into the +room. To prevent any of the pipes acting as chimneys, and bringing the +products of combustion back into the room, as well as to avoid any +back-pressure, a damper is attached to the outlet receptacle. The +heated gas becomes cooled so much (to about 100 deg. Fahr.) that water is +condensed and precipitated, and collects in the vessel below the +outlet. Each burner has a separate cock, by which it may be kept +closed, half-open, or open. To obviate danger of explosion, there is a +strip of sheet iron in front of the burners, which prevents their +being lighted when in a vertical position; so that, in case any +unburned gas gets into the pipes, it cannot be ignited, for the +burners can only be lighted when inclined to the front. In starting +the stove the burners are lighted, in the inclined position; the chain +from the damper pulled up; the burners set vertical; and, as soon as +they are all drawing well into the tubes, the damper is closed. If +less heat is desired, the cocks are turned half off. It is not +permissible to entirely extinguish some of the burners, unless the +unused pipes are closed to prevent the products of combustion coming +back into the room. The consumption of gas per burner, full open, with +a pressure of 8/10, is said to be only 4-3/8 cubic feet per hour. + + * * * * * + + + + +CONCRETE WATER PIPES. + + +Concrete water pipes of small diameter, according to a foreign +contemporary, are used in parts of France, notably for water mains for +the towns of Coulommiers and Aix-en-Provence. The pipes were formed of +concrete in the trench itself. The mould into which the concrete was +stamped was sheet iron about two yards in length. The several pipes +were not specially joined to each other, the joints being set with +mortar. The concrete consisted of three parts of slow setting cement +and three parts of river sand, mixed with five parts of limestone +debris. The inner diameter of the pipes was nine inches; their +thickness, three inches. The average fall is given at one in five +hundred; the lowest speed of the current at one foot nine inches per +second. To facilitate the cleaning of the pipes, man-holes are +constructed every one hundred yards or so, the sides of which are also +made of concrete. The trenches are about five feet deep. The work was +done by four men, who laid down nearly two hundred feet of pipe in a +working day; the cost was about ninety-three cents per running yard. +It is claimed as an advantage for the new method that the pipes adhere +closely to the inequalities of the trench, and thus lie firmly on the +ground. When submitted to great pressure, however, they have not +proved effective, and the method, consequently, is only suitable for +pipes in which there is no pressure, or only a very trifling one. + + * * * * * + + + + +THE SELLERS STANDARD SYSTEM OF SCREW THREADS, NUTS, AND BOLT HEADS. + + + _____________________________________________________ + | | + | SCREW THREADS. | + |_____________________________________________________| + | | | | | | + | Diam. |Threads | Diameter | Area of | Width | + | of | per | at root of | Bolt at | of | + | Screw. | inch. | Thread. | root of | Flat. | + | | | | Thread. | | + |________|________|_________________|_________|_______| + | | | | | | | + | 1/4 | 20 | .185 | 13/64 | .026 | .0062 | + | 5/16 | 18 | .240 | 15/64 | .045 | .0074 | + | 3/8 | 16 | .294 | 19/64 | .067 | .0078 | + | 7/16 | 14 | .344 | 11/32 | .092 | .0089 | + | 1/2 | 13 | .400 | 13/32 | .125 | .0096 | + | 9/16 | 12 | .454 | 29/64 | .161 | .0104 | + | 5/8 | 11 | .507 | 33/64 | .201 | .0113 | + | 3/4 | 10 | .620 | 5/8 | .301 | .0125 | + | 7/8 | 9 | .731 | 47/64 | .419 | .0138 | + | | | | | | | + | 1 | 8 | .837 | 27/32 | .550 | .0156 | + | 1-1/8 | 7 | .940 | 15/16 | .693 | .0178 | + | 1-1/4 | 7 | 1.065 | 1- 1/16 | .890 | .0178 | + | 1-3/8 | 6 | 1.160 | 1- 5/32 | 1.056 | .0208 | + | 1-1/2 | 6 | 1.284 | 1- 9/32 | 1.294 | .0208 | + | 1-5/8 | 5-1/2 | 1.389 | 1-25/64 | 1.515 | .0227 | + | 1-3/4 | 5 | 1.491 | 1-31/64 | 1.746 | .0250 | + | 1-7/8 | 5 | 1.616 | 1-39/64 | 2.051 | .0250 | + | | | | | | | + | 2 | 4-1/2 | 1.742 | 1-23/32 | 2.301 | .0277 | + | 2-1/4 | 4-1/2 | 1.962 | 1-31/32 | 3.023 | .0277 | + | 2-1/2 | 4 | 2.176 | 2-11/64 | 3.718 | .0312 | + | 2-3/4 | 4 | 2.426 | 2-27/64 | 4.622 | .0312 | + | | | | | | | + | 3 | 3-1/2 | 2.629 | 2- 5/8 | 5.428 | .0357 | + | 3-1/4 | 3-1/2 | 2.879 | 2- 7/8 | 6.509 | .0357 | + | 3-1/2 | 3-1/4 | 3.100 | 3- 3/32 | 7.547 | .0384 | + | 3-3/4 | 3 | 3.317 | 3- 5/16 | 8.614 | .0413 | + | | | | | | | + | 4 | 3 | 3.567 | 3- 9/16 | 9.993 | .0413 | + | 4-1/4 | 2-7/8 | 3.798 | 3-51/64 | 11.329 | .0435 | + | 4-1/2 | 2-3/4 | 4.028 | 4- 1/32 | 12.742 | .0454 | + | 4-3/4 | 2-5/8 | 4.256 | 4- 1/4 | 14.226 | .0476 | + | | | | | | | + | 5 | 2-1/2 | 4.480 | 4-31/64 | 15.763 | .0500 | + | 5-1/4 | 2-1/2 | 4.730 | 4-47/64 | 17.570 | .0500 | + | 5-1/2 | 2-3/8 | 4.953 | 4-61/64 | 19.267 | .0526 | + | 5-3/4 | 2-3/8 | 5.203 | 5-13/64 | 21.261 | .0526 | + | 6 | 2-1/4 | 5.423 | 5-27/64 | 23.097 | .0555 | + |________|________|_________________|_________|_______| + _____________________________________________________________ + | | + | NUTS. | + |___________________ __________________________________________| + | | | | | | | + | Short | Short | Long | Long | Thick- | Thick- | + | Diam. | Diam. | Diam. | Diam. | ness | ness | + | Rough. | Finish. | Rough. | Rough. | Rough. | Finish. | + | | | | | | | + | (Hex.) | (Hex.) | (Hex.) | (Square) | | | + |_________|_________ |__________|__________|_________|_________| + | | | | | | | + | 1/2 | 7/16 | 37/64 | 7/10 | 1/4 | 3/16 | + | 19/32 | 17/32 | 11/16 | 10/12 | 5/16 | 1/4 | + | 11/16 | 5/8 | 51/64 | 63/64 | 3/8 | 5/16 | + | 25/32 | 23/33 | 9/10 | 1- 7/64 | 7/16 | 3/8 | + | 7/8 | 13/16 | 1 | 1-15/64 | 1/2 | 7/16 | + | 31/32 | 29/32 | 1- 1/8 | 1-23/64 | 9/16 | 1/2 | + | 1-1/16 | 1 | 1- 7/32 | 1- 1/2 | 5/8 | 9/16 | + | 1-1/4 | 1-3/16 | 1- 7/16 | 1-49/64 | 3/4 | 11/16 | + | 1-7/16 | 1-3/8 | 1-21/32 | 2- 1/32 | 7/8 | 13/16 | + | | | | | | | + | 1- 5/8 | 1-9/16 | 1- 7/8 | 2-19/64 | 1 | 15/16 | + | 1-13/16| 1- 3/4 | 2- 5/32 | 2- 9/16 | 1-1/8 | 1- 1/16 | + | 2 | 1-15/16 | 2- 5/16 | 2-53/64 | 1-1/4 | 1- 3/16 | + | 2- 3/16| 2- 1/8 | 2-17/32 | 3- 3/32 | 1-3/8 | 1- 5/16 | + | 2- 3/8 | 2- 5/16 | 2- 3/4 | 3-23/64 | 1-1/2 | 1- 7/16 | + | 2- 9/16| 2- 1/2 | 2-31/32 | 3- 5/8 | 1-5/8 | 1- 9/16 | + | 2- 3/4 | 2-11/16 | 3- 3/16 | 3-57/64 | 1-3/4 | 1-11/16 | + | 2-15/16| 2- 7/8 | 3-13/32 | 4- 5/32 | 1-7/8 | 1-13/16 | + | | | | | | | + | 3-1/8 | 3- 1/16 | 3- 5/8 | 4-27/64 | 2 | 1-15/16 | + | 3-1/2 | 3- 7/16 | 4- 1/16 | 4-61/64 | 2-1/4 | 2- 3/16 | + | 3-7/8 | 3-13/16 | 4- 1/2 | 5-31/64 | 2-1/2 | 2- 7/16 | + | 4-1/4 | 4- 3/16 | 4-29/32 | 6 | 2-3/4 | 2-11/16 | + | | | | | | | + | 4-5/8 | 4- 9/16 | 5- 3/8 | 6-17/32 | 3 | 2-15/16 | + | 5 | 4-15/16 | 5-13/16 | 7- 1/16 | 3-1/4 | 3- 3/16 | + | 5-3/8 | 5- 5/16 | 6- 7/32 | 7-39/64 | 3-1/2 | 3- 7/16 | + | 5-3/4 | 5-11/16 | 6-21/32 | 8- 1/8 | 3-3/4 | 3-11/16 | + | | | | | | | + | 6-1/8 | 6- 1/16 | 7- 3/32 | 8-41/64 | 4 | 3-15/16 | + | 6-1/2 | 6- 7/16 | 7- 9/16 | 9- 3/16 | 4-1/4 | 4- 3/16 | + | 6-7/8 | 6-13/16 | 7-31/32 | 9- 3/4 | 4-1/2 | 4- 7/16 | + | 7-1/4 | 7- 3/16 | 8-13/32 | 10- 1/4 | 4-3/4 | 4-11/16 | + | | | | | | | + | 7-5/8 | 7- 9/16 | 8-27/32 | 10-49/64 | 5 | 4-15/16 | + | 8 | 7-15/16 | 9- 9/32 | 11-23/64 | 5-1/4 | 5- 3/16 | + | 8-3/8 | 8- 5/16 | 9-23/32 | 11- 7/8 | 5-1/2 | 5- 7/16 | + | 8-3/4 | 8-11/16 | 10- 5/32 | 12- 3/8 | 5-3/4 | 5-11/16 | + | 9-1/8 | 9- 1/16 | 10-19/32 | 12-15/16 | 6 | 5-15/16 | + |_________|__________|__________|__________|_________|_________| + _____________________________________________________________ + | | + | BOLT HEADS. | + |_____________________________________________________________| + | | | | | | | + | Short | Short | Long | Long | Thick- | Thick- | + | Diam. | Diam. | Diam. | Diam. | ness | ness | + | Rough. | Finish. | Rough. | Rough. | Rough. | Finish. | + | | | | | | | + | (Hex.) | (Hex.) | (Hex.) | (Square) | | | + |_________|_________|__________|__________|_________|_________| + | | | | | | | + | 1/2 | 7/16 | 37/64 | 7/10 | 1/4 | 3/16 | + | 19/32 | 17/32 | 11/16 | 10/12 | 19/64 | 1/4 | + | 11/16 | 5/8 | 51/64 | 63/64 | 11/32 | 5/16 | + | 25/32 | 23/32 | 9/16 | 1-7/64 | 25/64 | 3/8 | + | 7/8 | 13/16 | 1 | 1-15/64 | 7/16 | 7/16 | + | 31/32 | 29/32 | 1- 1/8 | 1-23/64 | 31/64 | 1/2 | + | 1- 1/16 | 1 | 1- 7/32 | 1- 1/2 | 17/32 | 9/16 | + | 1- 1/4 | 1- 3/16 | 1- 7/16 | 1-49/64 | 5/8 | 11/16 | + | 1- 7/16 | 1- 3/8 | 1-21/32 | 2- 1/32 | 23/32 | 13/16 | + | | | | | | | + | 1- 5/8 | 1- 9/16 | 1- 7/8 | 2-19/64 | 13/16 | 15/16 | + | 1-13/16 | 1- 3/4 | 2- 5/32 | 2- 7/16 | 29/32 | 1- 1/16 | + | 2 | 1-15/16 | 2- 5/16 | 2-53/64 | 1 | 1- 3/16 | + | 2- 3/16 | 2- 1/8 | 2-17/32 | 3- 3/32 | 1- 3/32 | 1- 5/16 | + | 2- 3/8 | 2- 5/16 | 2- 3/4 | 3-23/64 | 1- 3/16 | 1- 7/16 | + | 2- 9/16 | 2- 1/2 | 2-31/32 | 3- 5/8 | 1- 9/32 | 1- 9/16 | + | 2- 3/4 | 2-11/16 | 3- 3/16 | 3-57/64 | 1- 3/8 | 1-11/16 | + | 2-15/16 | 2- 7/8 | 3-13/32 | 4- 5/32 | 1-15/32 | 1-13/16 | + | | | | | | | + | 3- 1/8 | 3- 1/16 | 3- 5/8 | 4-27/64 | 1- 9/16 | 1-15/16 | + | 3- 1/2 | 3- 7/16 | 4- 1/16 | 4-61/64 | 1- 3/4 | 2- 3/16 | + | 3- 7/8 | 3-13/16 | 4- 1/2 | 5-31/64 | 1-15/16 | 2- 7/16 | + | 4- 1/4 | 4- 3/16 | 4-29/32 | 6 | 2- 1/8 | 2-11/16 | + | | | | | | | + | 4- 5/8 | 4- 9/16 | 5- 3/8 | 6-17/32 | 2- 5/16 | 2-15/16 | + | 5 | 4-15/16 | 5-13/16 | 7- 1/16 | 2- 1/2 | 3- 3/16 | + | 5- 3/8 | 5- 5/16 | 6- 7/32 | 7-39/64 | 2-11/16 | 3- 7/16 | + | 5- 3/4 | 5-11/16 | 6-21/32 | 8- 1/8 | 2- 7/8 | 3-11/16 | + | | | | | | | + | 6- 1/8 | 6- 1/16 | 7- 3/32 | 8-41/64 | 3- 1/16 | 3-15/16 | + | 6- 1/2 | 6- 7/16 | 7- 9/16 | 9- 3/16 | 3- 1/4 | 4- 3/16 | + | 6- 7/8 | 6-13/16 | 7-31/32 | 9- 3/4 | 3- 7/16 | 4- 7/16 | + | 7- 1/4 | 7- 3/16 | 8-13/32 | 10- 1/4 | 3- 5/8 | 4-11/16 | + | | | | | | | + | 7- 5/8 | 7- 9/16 | 8-27/32 | 10-49/64 | 3-13/16 | 4-15/16 | + | 8 | 7-15/16 | 9- 9/32 | 11-23/64 | 4 | 5- 3/16 | + | 8- 3/8 | 8- 5/16 | 9-23/32 | 11- 7/8 | 4- 3/16 | 5- 7/16 | + | 8- 3/4 | 8-11/16 | 10- 5/32 | 12- 3/8 | 4- 3/8 | 5-11/16 | + | 9- 1/8 | 9- 1/16 | 10-19/32 | 12-15/16 4- 9/16 | 5-15/16 | + |_________|_________|__________|__________|_________|_________| + + +The dimensions given for diameter at root of threads are also those +for diameter of hole in nuts and diameter of lap drills. All bolts and +studs 3/4 in. diameter and above, screwed into boilers, have 12 +threads per inch, sharp thread, a taper of 1/16 in. per 1 inch; tap +drill should be 9/64 in. less than normal diameter of bolts. + +The table is based upon the following general formulae for certain +dimensions: + + Short diam. rough nut or head = 11/2 diam. of bolt + 1/8. + " finished nut or head = 11/2 diam. of bolt + 1/16. + Thickness rough nut = diameter of bolt. + Thickness finished nut = diameter of bolt - 1/16. + Thickness rough head = 1/2 short diameter. + Thickness finished head = diameter of bolt - 1/16. + + * * * * * + + + + +AN ENGLISH RAILWAY FERRY BOAT. + + +[Illustration: AN ENGLISH RAILWAY FERRY BOAT.] + +The illustrations above represent a double screw steam ferry boat for +transporting railway carriages, vehicles, and passengers, etc., +designed and constructed by Messrs. Edwards and Symes, of Cubitt Town, +London. The hull is constructed of iron, and is of the following +dimensions: Length 60 ft.; beam 16 ft.; over sponsons 25 ft. The +vessel was fitted with a propeller, rudder, and steering gear at each +end, to enable it to run in either direction without having to turn +around. The boat was designed for the purpose of working the train +service across the bay of San Juan, in the island of Puerto Rico, and +for this purpose a single line of steel rails, of meter gauge, is laid +along the center of the deck, and also along the hinged platforms at +each end. In the engraving these platforms are shown, one hoisted up, +and the other lowered to the level of the deck. When the boat is at +one of the landing stages, the platform is lowered to the level of the +rails on the pier, and the carriages and trucks are run on to the deck +by means of the small hauling engine, which works an endless chain +running the whole length of the deck. The trucks, etc., being on +board, the platform is raised by means of two compact hand winches +worked by worm and worm-wheels in the positions shown; thus these two +platforms form the end bulwarks to the boat when crossing the bay. On +arriving at the opposite shore the operation is repeated, the other +platform is lowered, and the hauling engine runs the trucks, etc., on +to the shore. With a load of 25 tons the draught is 4 ft. + +The seats shown on the deck are for the convenience of foot +passengers, and the whole of the deck is protected from the sun of +that tropical climate by a canvas awning. The steering of the vessel +is effected from the bridge at the center, which extends from side to +side of the vessel, and there are two steering wheels with independent +steering gear for each end, with locking gear for the forward rudder +when in motion. The man at the wheel communicates with the engineer by +means of a speaking tube at the wheel. There is a small deck house for +the use of deck stores, on one side of which is the entrance to the +engine room. The cross battens, shown between the rails, are for the +purpose of horse traffic, when horses are used for hauling the trucks, +or for ordinary carts or wagons. The plan below deck shows the +arrangement of the bulkheads, with a small windlass at each end for +lifting the anchors, and a small hatch at each side for entrance to +these compartments. The central compartment contains the machinery, +which consists of a pair of compound surface condensing engines, with +cylinders 11 in. and 20 in. in diameter; the shafting running the +whole length of the vessel, with a propeller at each end. Steam is +generated in a steel boiler of locomotive form, so arranged that the +funnel passes through the deck at the side of the vessel; and it is +designed for a working pressure of 100 lb. per square inch. This +boiler also supplies steam for the small hauling engine fixed on the +bulkhead. Light to this compartment is obtained by means of large side +scuttles along each side of the boat and glass deck lights, and the +iron grating at the entrance near the deck house. This boat was +constructed in six pieces for shipment, and the whole put together in +the builders' yard. The machinery was fixed, and the engine driven by +steam from its own boiler, then the whole was marked and taken +asunder, and shipped to the West Indies, where it was put together and +found to answer the purpose intended.--_Engineering._ + + * * * * * + +[For THE SCIENTIFIC AMERICAN.] + + + + +THE PROBLEM OF FLIGHT, AND THE FLYING MACHINE. + + +As a result of reading the various communications to the SCIENTIFIC +AMERICAN and SUPPLEMENT, and _Van Nostrand's Engineering Magazine_, +including descriptions of proposed and tested machines, and the +reports of the British Aeronautical Society, the writer of the +following concludes: + +That, as precedents for the construction of a successful flying +machine, the investigation of some species of birds as a base of the +principles of all is correct only in connection with the species and +habits of the bird; that the _general mechanical principles_ of flight +applicable to the _operation_ of the _same unit_ of wing in _all_ +species are alone applicable to the flying machine. + +That these principles of _operation_ do not demand the principles of +_construction_ of the bird. + +That as the wing is in its stroke an arc of a screw propeller's +operation, and in its angle a screw propeller blade, its animal +operation compels its reciprocation instead of rotation. + +That the swifter the wing beat, the more efficient its effect per unit +of surface, the greater the load carried, and the swifter the flight. + +That the screw action being, in full flight, that of a screw propeller +whose axis of rotation forms a slight angle with the vertical, the +distance of flight per virtual "revolution" of "screw" wing far +exceeds the pitch distance of said "screw." + +That consequently a bird's flight answers to an iceboat close hauled; +the wing _force_ answering to the _wind_, the wing _angle_ to the +_sail_, the bird's _weight_ to the leeway fulcrum of the _ice_, and +the passage across direction of the _wing_ flop to the fresh _moving_ +"inertia" of the wind, both yielding a maximum of force to bird or +iceboat. + +That the speed of _reciprocation_ of a fly's _wing_ being equivalent +to a _screw rotation_ of 9,000 per minute, proves that a _screw_ may +be run at this speed without losing efficiency by centrifugal vacuum. + +That as the _object_ of wing or screw is to mount upon the inertia of +the particles of a mobile fluid, and as the rotation of steamship +propellers in water--a fluid of many times the inertia of air--is +_already_ in _excess_ of the highest speed heretofore tried in the +propellers of moderately successful flying machines, it is plain that +the speed employed in _water_ must be many times exceeded in _air_. + +That with a _sufficient_ speed of rotation, the supporting power of +the inertia of air must _equal_ that of _water_. + +That as mere speed of rotation of propeller _shaft_, minus blades, +must absorb but a small proportion of power of engine, the addition of +blades will not cause more resistance than that actually encountered +from inertia of air. + +That this must be the measure of load lifted. + +That without _slip_ of screw, the actual _power_ expended, will be +little in _excess_ of that required to support the machine in _water_, +with a slower rotation of screw. + +That in case the same _power_ is expended in water or air, the only +difference will lie in the sizes and speed of engines or screws. + +That the _greater_ the speed, the _less_ weight of engine, boiler, and +screw must be, and the stronger their construction. + +That, in consequence, solid metal worked down, instead of bolts and +truss work, must be used. + +That as the bird wing is a screw in action, and acts _directly_ +between the inertias of the load and the air, the position and +operation of the screw, to the load, must imitate it. + +That, in consequence, machines having wing planes, driven _against_ +one inertia of air by screws acting in the line, of flight against +another inertia of air, lose fifty per cent. of useful effect, besides +exposing to a head wind the cross section of the stationary screw wing +planes and the rotating screw discs; and supporting the dead weight of +the wing planes, and having all the screw slip in the line of flight, +and carrying slow and heavy engines. + +That as a result of these conclusions, the supporting and propelling +power should be expressed in the rotation of screws combining both +functions, the position of whose planes of rotation to a fixed +horizontal line of direction determines the progress and speed of +machine upon other lines. + +That the whole weight carried by the screws should be at all times +exactly below the center of gravity of the plane of support, whether +it be horizontal or inclined. + +That while the _permanently_ positioned weight, such as the engines, +frame, holding screws, etc., may be rigidly connected to or around the +screw plane of support, the variable positioned weight, such as the +passenger and the car, should be connected by a _flexible joint_ to +the said plane of support. + +Consequently, the car may oscillate without altering its weight +position under center of supporting plane, thus avoiding an +involuntary alteration of speed or direction of flight. + +That to steer a machine so constructed, it is merely necessary to move +the point of attachment of car to _machine_ proper, out of the center +of plane of support in the desired direction, and thus cause the plane +of support or rotation of propellers to incline in that direction. + +That the reservoir of power, the boiler, etc., should be placed in the +_car_, and steam carried to engines through joint connecting car with +machine. + +That at present material exists, and power also, of sufficient +lightness and strength to admit of a machine construction capable of a +limited successful flight in any fair wind and direction. + +That such _machine_ once built, the finding of a _power_ for long +flights will be easy, if not already close at hand in _electricity_. + +That the _easiest_ design for such _actual machine_ should be adopted, +leaving the adaptation of the principles involved to the making of +more perfect machines, to a time after the success of the _first_. + +That such design may be a propeller, and its engine at each end of a +steel frame tube, supporting tube horizontally, a car to be supported +by a universal joint from center of said tube, and the joint apparatus +movable along the tube or a short distance transverse to it, to alter +position of center of gravity. + +That the machine so built might traverse the water as well as air. + + * * * * * + + + + +THE LONGHAIRED POINTER MYLORD. + + +Pointers are trained to search for game, and to indicate that they +have found the same by standing motionless in front of it, and, when +it has been shot, to carry the game to the huntsman. Several kinds of +pointers are known, such as smooth, longhaired, and bushyhaired +pointers. The smoothhaired pointers are better for hunting on high +land, whereas the longhaired or bushyhaired dogs are better for low, +marshy countries, crossed by numerous streams, etc. Mylord, the dog +represented in the annexed cut taken from the _Illustrirte Zeitung_, +is an excellent specimen of the longhaired pointer, and is owned by +Mr. G. Borcher, of Braunschweig, Germany. + +[Illustration: THE LONGHAIRED POINTER, "MYLORD."] + +The longhaired pointer is generally above the medium size, powerful, +somewhat longer than the normal dog, the body is narrower and not +quite as round as that of the smoothhaired dog, and the muscles of the +shoulders and hind legs are not as well developed and not as +prominent. The head and neck are erect, the head being specially long, +and the tail is almost horizontal to the middle, and then curves +upward slightly. The long hair hangs in wavy lines on both sides of +his body. The expression of his face is intelligent, bright, and +good-natured, and his step is light and almost noiseless. + +The pointer is specially valuable, as it can be employed for many +different purposes; he is an excellent dog for the woods, for the +woodsman and hunter who uses only one dog for different kinds of game. +The intelligence of the German pointer is very great, but he does not +develop as rapidly as the English dog, which has been raised for +generations for one purpose only. The German pointer hunts very +slowly, but surely. It is not difficult to train this dog, but he +cannot be trained until he has reached a certain age. + + * * * * * + + + + +LUNAR HEAT. + +By Professor C.A. YOUNG. + + +One of the most interesting inquiries relating to the moon is that +which deals with the heat she sends us, and the probable temperature +of her surface. The problem seems to have been first attacked by +Tschirnhausen and La Hire, about 1700; and they both found, that even +when the moon's rays were concentrated by the most powerful +burning-lenses and mirrors they could obtain, its heat was too small +to produce the slightest perceptible effect on the most delicate +thermometers then known. For more than a hundred years, this was all +that could be made out, though the experiment was often repeated. + +It was not until 1831 that Melloni, with his newly-invented +"thermopile," [1] succeeded in making the lunar heat sensible; and in +1835, taking his apparatus to the top of Vesuvius, he obtained not +only perceptible, but measurable, results, getting a deviation of four +or five divisions of his galvanometer. + + [Footnote 1: Probably most of our readers know that the + thermopile consists of a number of little bars of two different + metals, connected in pairs, and having the ends joined in a + conducting circuit with a galvanometer. If, now, one set of the + junctures is heated more than the other set, a current of + electricity will be generated, which will affect the + galvanometer. The bars are usually made of bismuth and antimony + though iron and German silver answer pretty well. They are + commonly about half or three-quarters of an inch long, and about + half as large as an ordinary match. The "pile" is made of from + fifty to a hundred such bars packed closely, but insulated by + thin strips of mica, except just at the soldered junctions. With + an instrument of this kind and a very delicate galvanometer, + Professor Henry found that the heat from a person's face could be + perceived at a distance of several hundred feet. There is + however, some doubt whether he was not mistaken in respect to + this extreme sensitiveness.] + +Others repeated the experiment several times between this time and +1856, with more or less success; but, so far as I know, the first +quantitative result was that obtained in 1856 by Piazzi Smyth during +his Teneriffe expedition. On the top of the mountain, at an elevation +of ten thousand feet, he found that the moon's rays affected his +thermopile to the same extent as a standard candle ten feet away. +Marie Davy has since shown that this corresponds to a heating effect +of about 1/1300 of a Centigrade degree. + +The subject was resumed in 1868 by Lord Rosse in Ireland; and a long +series of observations, running through several years, was made by the +aid of his three-foot reflector (not the great _six_-foot instrument, +which is too unwieldy for such work). The results of his work have, +until very recently, been accepted as authoritative. It should be +mentioned that, at about the same time, observations were also made at +Paris by Marie Davy and Martin; but they are generally looked upon +merely as corroborative of Rosse's work, which was more elaborate and +extensive. Rosse considered that his results show that the heat from +the moon is mainly _obscure, radiated_ heat; the _reflected_ heat, +according to him, being much less in amount. + +A moment's thought will show that the moon's heat must consist of two +portions. First, there will be _reflected solar heat_. The amount and +character of this will depend in no way upon the temperature of the +moon's surface, but solely upon its reflecting power. And it is to be +noted that moon-_light_ is only a part of this reflected radiant +energy, differing from the invisible portion of the same merely in +having such a wave-length and vibration period as to bring it within +the range of perception of the human eye. + +The second portion of the heat sent us by the moon is that which she +emits on her own account as a warm body--warmed, of course, mainly, if +not entirely, by the action of the sun. The amount of _this_ heat will +depend upon the temperature of the moon's surface and its radiating +power; and the temperature will depend upon a number of things +(chiefly heat-absorbing power of the surface, and the nature and +density of the lunar atmosphere, as well as the supply of heat +received from the sun), being determined by a balance between give and +take. So long as more heat is received in a second than is thrown off +in the same time, the temperature will rise, and _vice versa_. + +It is to be noted, further, that this second component of the moon's +thermal radiance must be mainly what is called "obscure" or dark heat, +like that from a stove or teakettle, and characterized by the same +want of penetrative power. No one knows why at present; but it is a fact +that the heat-radiations from bodies at a low temperature--radiations +of which the vibrations are relatively slow, and the wave-length +great--have no such power of penetrating transparent media as the +higher-pitched vibrations which come from incandescent bodies. A great +part, therefore, of this contingent of the lunar heat is probably +stopped in the upper air, and never reaches the surface of the earth +at all. + +Now, the thermopile cannot, of course, discriminate directly between +the two portions of the lunar heat; but to some extent it does enable +us to do so indirectly, since they vary in quite a different way with +the moon's age. The simple _reflected_ heat must follow the same law +as moonlight, and come to its maximum at full moon. The _radiated_ +heat, on the other hand, will reach its maximum when the average +temperature of that part of the moon's surface turned toward the earth +is highest; and this must be some time after full moon, for the same +sort of reasons that make the hottest part of a summer's day come two +or three hours after noon. + +The conclusion early reached by Lord Rosse was that nearly all the +lunar heat belonged to the second category--dark heat _radiated_ from +the moon's warmed surface, the _reflected_ portion being comparatively +small--and he estimated that the temperature of the hottest parts of +the moon's surface must run as high as 500 deg. F.; well up toward the +boiling-point of mercury. Since the lunar day is a whole month long, +and there are never any clouds in the lunar sky, it is easy to imagine +that along toward two or three o'clock in the lunar afternoon (if I +may use the expression), the weather gets pretty hot; for when the sun +stands in the lunar sky as it does at Boston at two P.M., it has been +shining continuously for more than two hundred hours. On the other +hand, the coldest parts of the moon's surface, when the sun has only +just risen after a night of three hundred and forty hours, must have a +temperature more than a hundred degrees below zero. + +Lord Rosse's later observations modified his conclusions, to some +extent, showing that he had at first underestimated the percentage of +simple reflected heat, but without causing him to make any radical +change in his ideas as to the maximum heat of the moon's surface. + +For some time, however, there has been a growing skepticism among +astronomers, relating not so much to the correctness of his measures +as to the computations by which he inferred the high percentage of +obscure radiated beat compared with the reflected heat, and so deduced +the high temperature of lunar noon. + +Professor Langley, who is now engaged in investigating the subject, +finds himself compelled to believe that the lunar surface never gets +even comfortably warm--because it has no blanket. It receives heat, it +is true, from the sun, and probably some twenty-five or thirty per +cent. more than the earth, since there are no clouds and no air to +absorb a large proportion of the incident rays; but, at the same time, +there is nothing to retain the heat, and prevent the radiation into +space as soon as the surface begins to warm. We have not yet the data +to determine exactly how much the temperature of the lunar rocks would +have to be raised above the absolute zero (-273 deg. C. or -459 deg. F.) in +order that they might throw off into space as much heat in a second as +they would get from the sun in a second. But Professor Langley's +observations, made on Mount Whitney at an elevation of fifteen +thousand feet, when the barometer stood at seventeen inches +(indicating that about fifty-seven per cent. of the air was still +above him), showed that rocks exposed to the perpendicular rays of the +sun were not heated to any such extent as those at the base of the +mountain similarly exposed; and the difference was so great as to make +it almost certain that a mass of rock not covered by a reasonably +dense atmosphere could never attain a temperature of even 200 deg. or 300 deg. +F. under solar radiation, however long continued. + +It must, in fact, be considered at present extremely doubtful whether +any portion of the moon's surface ever reaches a temperature as high +as -100 deg.. + +The subject, undoubtedly, needs further investigation, and it is now +receiving it. Professor Langley is at work upon it with new and +specially constructed apparatus, including a "bolometer" so sensitive +that, whereas previous experimenters have thought themselves fortunate +if they could get deflections of ten or twelve galvanometric divisions +to work with, he easily obtains three or four hundred. We have no time +or space here to describe Professor Langley's "bolometer;" it must +suffice to say that it seems to stand to the thermopile much as that +does to the thermometer. There is good reason to believe that its +inventor will be able to advance our knowledge of the subject by a +long and important step; and it is no breach of confidence to add that +so far, although the research is not near completion yet, everything +seems to confirm the belief that the radiated heat of the moon, +instead of forming the principal part of the heat we get from her, is +relatively almost insignificant, and that the lunar surface now never +experiences a _thaw_ under any circumstances. + +Since the superstition as to the moon's influence upon the wind and +weather is so widespread and deep seated, a word on that subject may +be in order. In the first place, since the total heat received from +the moon, even according to the highest determination (that of Smyth), +is not so much as 0.00001 of that received from the sun, and since the +only hold the moon has on the earth's weather is through the heat she +sends us (I ignore here the utterly insignificant atmospheric _tide_), +it follows necessarily that her influence _must_ be very trifling. In +the next place, all carefully collated observations show that it _is_ +so, and not only trifling, but generally absolutely insensible. + +For example, different investigators have examined the question of +nocturnal cloudiness at the time of full moon, there being a prevalent +belief that the full moon "eats up" light clouds. On comparing thirty +or forty years' observations at each of several stations (Greenwich. +Paris, etc.), it is found that there is no ground for the belief. And +so in almost every case of imagined lunar meteorological influence. As +to the coincidence of weather changes with changes of the moon, it is +enough to say that the idea is absolutely inconsistent with that +progressive movement of the "weather" across the country from west to +east, with which the Signal Service has now made us all so familiar. + +Princeton, April 12, 1884. + + * * * * * + + + + +APPLE TREE BORERS. + + +The apple tree borers have destroyed thousands of trees in New +England, and are likely to destroy thousands more. There are three +kinds of borers which assail the apple tree. The round headed or two +striped apple tree borer, _Saperda candida_, is a native of this +country, infesting the native crabs, thorn bushes, and June berry. It +was first described by Thomas Say, in 1824, but was probably widely +distributed before that. In his "Insects Injurious to Fruit," Prof. +Saunders thus describes the borer: + +"In its perfect state it is a very handsome beetle, about +three-quarters of an inch long, cylindrical in form, of a pale brown +color, with two broad, creamy white stripes running the whole length +of its body; the face and under surface are hoary white, the antennae +and legs gray. The females are larger than the males, and have shorter +antennae. The beetle makes its appearance during the months of June and +July, usually remaining in concealment during the day, and becoming +active at dusk. The eggs are deposited late in June and during July, +one in a place, on the bark of the tree, near its base. Within two +weeks the young worms are hatched, and at once commence with their +sharp mandibles to gnaw their way through the outer bark to the +interior. It is generally conceded that the larvae are three years in +reaching maturity. The young ones lie for the first year in the +sapwood and the inner bark, excavating flat, shallow cavities, about +the size of a silver dollar, which are filled with their sawdust-like +castings. The holes by which they enter being small are soon filled +up, though not until a few grains of castings have fallen from them. +Their presence may, however, often be detected in young trees from the +bark becoming dark colored, and sometimes dry and dead enough to +crack." + +On the approach of winter, it descends to the lower part of its +burrow, where it remains inactive until spring. The second season it +continues its work in the sapwood, and in case two or three are at +work in the same tree may completely girdle it, thus destroying it. +The third year it penetrates to the heart of the tree, makes an +excavation, and awaits its transformation. The fourth spring it comes +forth a perfect beetle, and lays its eggs for another generation. + + +THE FLAT-HEADED BORER. + +The flat-headed apple tree borer, _Chrysobothris femorata_, is also a +native of this country. It is a very active insect, delights to bask +in the hot sunshine; runs up and down the tree with great rapidity, +but flies away when molested. It is about half an inch in length. "It +is of a flattish, oblong form, and of a shining, greenish black color, +each of its wing cases having three raised lines, the outer two +interrupted by two impressed transverse spots of brassy color dividing +each wing cover into three nearly equal portions. The under side of +the body and legs shine like burnished copper; the feet are shining +green." This beetle appears in June and July, and does not confine its +work to the base of the tree, but attacks the trunk in any part, and +sometimes the larger branches. The eggs are deposited in cracks or +crevices of the bark, and soon hatch. The young larva eats its way +through the bark and sapwood, where it bores broad and flat channels, +sometimes girdling and killing the tree. As it approaches maturity, it +bores deeper into the tree, working upward, then eats out to the bark, +but not quite through the bark, where it changes into a beetle, and +then cuts through the bark and emerges to propagate its kind. This +insect is sought out when just beneath the bark, and devoured by +woodpeckers and insect enemies. + +Another borer, the long-horned borer, _Leptostylus aculifer_, is +widely distributed, but is not a common insect, and does not cause +much annoyance to the fruit grower. It appears in August, and deposits +its eggs upon the trunks of apple trees. The larvae soon hatch, eat +through the bark, and burrow in the outer surface of the wood just +under the bark. + + +PROTECTION AGAINST BORERS. + +The practical point is, What remedies can be used to prevent the +ravages of the borers? The usual means of fighting the borers is, to +seek after them in the burrows, and try to kill them by digging them +out, or by reaching them with a wire. This seems to be the most +effectual method of dealing with them after they have once entered the +tree, but the orchardist should endeavor to prevent the insects from +entering the tree. For this purpose, various washes have been +recommended for applying to the tree, either for destroying the young +larvae before they enter the bark, or for preventing the beetles +depositing their eggs. It has been found that trees which have been +coated with alkaline washes are avoided by beetles when laying their +eggs. Prof. Saunders recommends that soft soap be reduced to the +consistency of a thick paint, by the addition of a strong solution of +washing soda in water, and be applied to the bark of the tree, +especially about the base or collar, and also extended upward to the +crotches where the main branches have their origin. It should be +applied in the evening of a warm day, so that it may dry and form a +coating not easily dissolved by the rain. This affords a protection +against all three kinds of borers. It should be applied early in June, +before the beetles begin to lay their eggs, and again in July, so as +to keep the tree well protected. + +Hon. T.S. Gold, of Connecticut, at a meeting of the Massachusetts +State Board of Agriculture, in regard to preventing the ravages of the +borer, said: + +"A wash made of soap, tobacco water, and fresh cow manure mingled to +the consistency of cream, and put on early with an old broom, and +allowed to trickle down about the roots of the tree, has proved with +me a very excellent preventive of the ravages of the borer, and a +healthful wash for the trunk of the tree, much to be preferred to the +application of lime or whitewash, which I have often seen applied, but +which I am inclined to think is not as desirable an application as the +potash, or the soda, as this mixture of soft soap and manure." + +J.B. Moore, of Concord, Mass., at the same meeting said, in regard to +the destruction of the borer: + +"I have found, I think, that whale oil soap can be used successfully +for the destruction of that insect. It is a very simple thing; it will +not hurt the tree if you put it on its full strength. You can take +whale oil soap and dilute until it is about as thick as paint, and put +a coating of it on the tree where the holes are, and I will bet you +will never see a borer on that tree until the new crop comes. I feel +certain of it, because I have done it." + +For borers, tarred paper 1 or 2 feet wide has been recommended to be +wrapped about the base of the trunk of the tree, the lower edge being +1 or 2 inches below the surface of the soil. This prevents the +two-striped borer from laying its eggs in the tree, but would not be +entirely effectual against the flat-headed borer, which attacks any +part of the trunk and the branches. By the general use of these means +for the prevention of the ravages of the borers, the damages done by +these insects could be brought within very narrow limits, and hundreds +of valuable apple trees saved. + +H. REYNOLDS, M.D. + +Livermore Falls, Me. + + * * * * * + + + + +KEFFEL'S GERMINATING APPARATUS. + + +The apparatus represented in the annexed cut is designed to show the +quality of various commercial seeds, and make known any fraudulent +adulterations that they may have undergone. It is based upon a direct +observation, of the germination of the seeds to be studied. + +[Illustration: KEFFEL'S GERMINATING APPARATUS.] + +The apparatus consists of a cylindrical vessel containing water to the +height of 0.07 m. Above the water is a germinating disk containing 100 +apertures for the insertion of the seeds to be studied, the +germinating end of the latter being directed toward the water. After +the seeds are in place the disk is filled with damp sand up to the top +of its rim, and the apparatus is closed with a cover which carries in +its center a thermometer whose bulb nearly reaches the surface of the +water. + +The apparatus is then set in a place where the temperature is about +18 deg., and where there are no currents of air. An accurate result is +reached at the end of about twenty or twenty-four hours. As the +germinating disk contains 100 apertures for as many seeds, it is only +necessary to count the number of seeds that have germinated in order +to get the percentage of fresh and stale ones. + +The aqueous vapor that continuously moistens all the seeds, under +absolutely identical conditions for each, brings about their +germination under good conditions for accuracy and comparison. If it +be desired to observe the starting of the leaves, it is only necessary +to remove the cover after the seeds have germinated. + +This ingenious device is certainly capable of rendering services to +brewers, distillers, seedsmen, millers, farmers, and gardeners, and it +may prove useful to those who have horses to feed, and to amateur +gardeners, since it permits of ascertaining the value and quality of +seeds of every nature.--_La Nature._ + + * * * * * + + + + +MILLET. + + +The season is now at hand when farmers who have light lands, and who +may possibly find themselves short of fodder for next winter feeding, +should prepare for a crop of millet. This is a plant that rivals corn +for enduring a drought, and for rapid growth. There are three popular +varieties now before the public, besides others not yet sufficiently +tested for full indorsement--the coarse, light colored millet, with a +rough head, Hungarian millet, with a smooth, dark brown head, yielding +seeds nearly black, and a newer, light colored, round seeded, and +later variety, known as the golden millet. + +Hungarian millet has been the popular variety with us for many years, +although the light seeded, common millet is but slightly different in +appearance or value for cultivation. They grow in a short time, eight +weeks being amply sufficient for producing a forage crop, though a +couple of weeks more would be required for maturing the seed. Millet +should not be sown in early spring, when the weather and ground are +both cold. It requires the hot weather of June and July to do well; +then it will keep ahead of most weeds, while if sown in April the +weeds on foul land would smother it. + +Millet needs about two months to grow in, but if sowed late in July it +will seem to "hurry up," and make a very respectable showing in less +time. We have sown it in August, and obtained a paying crop, but do +not recommend it for such late seeding, as there are other plants that +will give better satisfaction. Golden millet has been cultivated but a +few years in this country, and as yet is but little known, but from a +few trials we have been quite favorably impressed with it. It is +coarser than the other varieties, but cattle appear to be very fond of +it nevertheless. It resembles corn in its growth nearly as much as +grass, and, compared with the former, it is fine and soft, and it +cures readily, like grass, and may be packed away in hay mows with +perfect safety. It is about two weeks later than the other millets, +and consequently cannot be grown in quite so short a time, although it +may produce as much weight to the acre, in a given period, as either +of the other more common varieties. A bushel of seed per acre is not +too much for either variety of millet.--_N.E. Farmer._ + + * * * * * + + +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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