VOLUME XV. AND POPULAR SCIENCE REVIEW. BOSTON, JULY, 1881. the ether, how illustrate them in any experi73 mental way? 74 75 75 NUMBER 7. Every portion of the ring is continually roll This can be done very simply, ing round on its circular core The particles on 74 and the experiments are well worth trying, 76 76 The only apparatus that we need is a cu- 76 78 80 tightly stretched cloth for one side, and a round hole au inch or so in diameter in the opposite 8 side. On the bottom of this box put a saucer 8containing a little strong muriatic acid, and an79 other containing some strong ammonia water. 79 The vapors from these liquids will fill the box, 80 and the chlorine of the acid will unite with the So hypothetical ammonium of the ammonia to form solid particles of ammonium chloride (sal am81 moniac), which will fill the box like a white smoke. If now we strike the cloth side of the 82 box a sudden blow, a ring of this smoke will issue from the opening, as shown in Figure 1. 80 81 The Sick Premier and the East Wind. Morphia with Chloroform as an Anæsthetic.. 83 83 Summer Drinks. - Select Formulæ.. Therapeutical Hints.. Familiar Science. MATTER IN A WHIRL. WE really know nothing of the ultimate constitution of matter, and it is hardly conceivable Fig. 1. we find that they manifest a variety of curious that we ever shall understand it perfectly. The Let us start several of these rings, and watch The rings will move through the air as if they were solid bodies. When two of them come into collision they are thrown into energetic vibration. If two happen to be moving in the same direction, with their centres on the same Of the speculations as to the nature of the line, and their faces perpendicular to this line, atoms, that which is known as the "vortex the- the one in front expands and goes slower, and ory" devised by Sir William Thompson, is now the one behind contracts and goes faster, till it received with most favor by leading scientific overtakes and passes through the one in front; men, and a brief outline of it may be of interest it will then begin to expand and to move slower, to our readers. and allow the other one to pass through it in turn; and so on alternately. In all these changes of form each ring preserves its individuality. Each, as it floats through the atmosphere, is all the time made up of precisely the same particles of air and smoke, and these are precisely the same particles of air and smoke that were driven out of the box by the blow on its back. It is not merely particles of sal ammoniac which are moving through the air, but A strange notion this, you may say, that all a portion of the air has become, as it were, a solids, liquids, and gases, all the varied sub- different substance from the surrounding air, stances and forms of substances in the material through which it moves very much like a solid universe, are made up of nothing but rotating body. If we attempt to cut one of these rings, ring-like portions of a subtle imponderable fluid! it either recedes from the knife or wriggles How can we get a clear notion of such forms in around it, so as to escape without injury. According to this theory the atoms are minute whirling rings in the ether, or the highly rarefied and elastic fluid which is supposed to fill the entire universe and to permeate all bodies. It is by means of this ether that light and heat are transmitted through space. They are supposed to be waves or undulations in the ether, just as the atoms are supposed to be whirling motious in it. Fig. 2. the inside of the ring are moving forward, and those on the outside moving backward, as shown by the arrows in Figure 2. Helmholtz has shown by mathematical investigation that were such vortex rings once started in a perfect fluid, such as the ether is assumed to be, they would always retain their individual character, and would be absolutely indestructible except by the power which created them. No process at our disposal could either start such a vortex ring in the ether, or destroy one which was already in existence. These vortex rings might be either circular in form, or have any conceivable number of knots and windings upon them. Prof. A. E. Dolbear has been studying these rings, and has noted several new and curious phenomena which he describes in a recent number of Science. If two holes are made about two inches apart in the side of the box, two rings may be started at once, having the same rate of rotation. Two such rings, if not too far apart, will sometimes approach each other and combine to form one ring, which continues to move in the same direction. "The combination is effected by the breaking of each at the point of contact, and the welding of the opposite parts of each ring to form one ring with twice the diameter." Two of these rings may in like manner combine to form a new one. We may suppose that we have here an illustration of what occurs when the different substances unite to form a chemical compound, as in the case of the chlorine and ammonium which furnish the material for the illustration. The whirling rings of the two gases combine, and the result of the combination is a new set of rings which have new properties. The following are a few of the other phenomena noticed by Professor Dolbear: If one vortex-ring strikes another vortex-ring upon the edge, the two rings will bound away from each other as though they were solid elastic bodies, each one vibrating as it recedes. If a vortex-ring passes near any light object, as, for instance, a silk thread suspended, or better still a small cloud of smoke or ammonium chloride dust, the latter will be seen to be apparently repelled from the front of it, but attracted and drawn into the ring from the rear. If a vortex-ring be projected parallel with any surface, and at not too great a distance from the surface, the ring will move in a curved path toward it and strike it. The structure of the vortex-ring is concentric; that is, a cross-section of a ring generally shows a series of several concentric circles, with a hollow centre. The middle of the ring appears to be a cylindrical unoccupied space. Most of these phenomena are best shown by having only one hole in the side of the box; and if we wish to exhibit the rings to a room full of people, the hole should be about three inches in diameter. The rings can then be projected with force enough to carry them ten or fifteen feet from the box. To make one ring overtake another, hit the cloth a harder blow. In order that two rings should combine, it is necessary that they have the same rate of rotation, and this is best secured by the use of two holes, the rings being produced by a single blow. All these experiments are pretty and interesting in themselves, aside from the theoretical inferences that have been drawn from them; and, as will be seen, they require no apparatus except such as any one can make for himself, and no special skill in manipulation. WHAT IS GLUCOSE? In the manufacture of beer and spirits from beck, has proved that a bitter substance resemgrain of any sort the first operation consists in bling colchicine is sometimes formed during ferconverting the starch of the grain into grape mentation. He has even succeeded in separating sugar, which is most readily accomplished by al- and crystallizing this bitter substance, and has lowing the grain to germinate. The diastase described its reactions. then produced effects the desired conversion. Dilute acids have the same action on starch, and while almost any acid can be employed, even carbonic acid, glucose manufacturers generally prefer sulphuric acid. Some chemists claim to have discovered all sorts of poisonous substances in glucose, such as lead, tin, sulphuric acid, etc. We have not been so fortunate as to make any such startling discoveries. Of course, like every other manufactured The first part of the operation is essentially article, much depends on the care taken in its the same as in the manufacture of starch. The preparation. The presence of sulphate of lime corn is soaked in water or dilute alkali, then in very small quantities might be expected. Dexcrushed and washed on sieves as long as the wa- trine is often present in considerable quantity, ter runs off milky. The starch is then allowed but this is both sweet and wholesome, in fact to settle, and the supernatant water drawn off. highly nutritious. The next operation in making starch consists in The uses of glucose are very numerous, aldrying it, but where the starch is to be converted though it is seldom sold to the public under its into glucose this part of the operation can of real name; but under the alias of "golden drips," GLUCOSE is the sugar of the future. Oppose course be omitted. The starch is next subjected" sugar-house syrup," "strained honey," and even it as you will, it is daily increasing in importance to the action of very dilute sulphuric acid, in Vermont maple syrup, its sale is very extensive. and in the number of its uses. In climates the proportion of two pounds of acid to 100 It is largely employed by confectioners for makwhere the sugar-cane will not grow, and in coun- pounds of starch, and 300 to 400 of water. The ing candies, by wine-dealers for strengthening tries where the sugar-beet cannot be cultivated water is first heated to boiling; the acid, diluted wine, by brewers to add body to their beer. Dr. with profit, there is a wide field for glucose. with three times its weight of water, is then Kedzie, of the Michigan Board of Health, reWherever corn, grain, or potatoes thrive, there poured in; and afterwards the milky mixture of ports that of seventeen samples of table syrup glucose factories will flourish. Glucose differs starch suspended in water is allowed to flow into tested by him, fifteen contained glucose. Of as much from cane sugar as tallow from lard, or the boiling acid. The first change that the twenty samples analyzed in Chicago, only one butter from oleomargarine. Both kinds of sugar starch undergoes is a conversion into dextrine. was unadulterated. are sweet, although in a very different degree, By long-continued boiling this is changed into and for many purposes one can be substituted glucose. When one part of the liquid mixed for the other without the consumer being aware with six parts of absolute alcohol no longer gives any precipitate of dextrine, the boiling is stopped. of the fact. 66 The manufacturers limit the term "glucose" to the thick syrup which neither solidifies nor crystallizes on long standing. The same substance in a solid state is called "grape sugar," but there is no chemical difference between the two. The name grape sugar" owes its origin to the fact that a kind of sugar found in grapes and other sweet fruits has the same chemical composition as that made from starch by methods that we shall presently describe. This real grape sugar is often seen as an incrustation on raisins and figs. Honey also contains grape sugar, and it was there it was first discovered by Lowitz in 1792. We give below the result of our own analyses of two specimens of American grape sugar obtained in New York city, and of two samples of candy obtained in Boston, one of which, usually called French candy, contains about eight per cent. of glucose. The next step in the operation is to neutral- The syrup is now evaporated in shallow pans sired. into alcohol and carbon dioxide. It possesses ing of glucose, because it ferments so quickly in the power of reducing copper, silver, and other the stomach, as might have been expected. A Glucose can be made from any of the carbohydrates, starch, dextrine, cellulose, etc., but is generally prepared from starch. In this country corn starch is used, while abroad potato starch is preferred-because it is cheaper. Ash. Sulphuric acid found to be nearly free from glucose. We do not believe that pure glucose is an injurious substance when properly made, but to sell it under the name of cane sugar, when it is but one third as sweet, is a fraud; and to charge the price of cane sugar, when it costs but three cents a pound to make it, is a swindle. That it pays to make it is evident from the fact that there are more than twenty glucose factories in this country turning out over one million pounds per day of grape sugar and glucose. COOKERY FOR INVALIDS. THE following, from a recent English journal, contains some hints which form a suggestive appendix to former articles that have appeared in our columns on this important subject: Give the distasteful food the semblance of something that is particularly palatable to the patient, and your efforts will be rewarded by your soon be of pastry. holding him eating with an appetite. For instance, you are bound to give mince, and equally bound not to give pastry. Your patient, however, is fond What you must then do is this: You must make a vol-au-vent case, and fill it with minced chicken or lamb. Then, though your patient may not eat a single mouthful of the crust, the look of the whole thing calls up the pleasurable feelings associated with the vol-au-vent, in lieu of the feeling of disgust excited by a dish of mince. On this day you will find that he enjoys his meal; on another occasion you can surround the mince with a wall of mashed potatoes or boiled rice. Again, you may send up your mince in the guise of a "cottager's pie." This, as every one knows, is just a layer of minced meat placed at the bottom of a small pie dish, covered with a three-inch layer of potatoes, put in the oven and nicely browned. Yet, again, you may put the mince into rissoles, or roll it up inside batter, or, failing all these, can make threecornered sandwiches with it. In this last case the mince should be of chicken, and, instead of buttering both pieces of the bread, you might spread the faintest soupçon of potted ham on one of them. SCIENTIFIC BREVITIES. THE TELEPHONE THROUGH WATER. duced. AMMONIA EVERYWHERE. — Dr. Angus Smith, tricité states that M. Dohrn has introduced the telein a parliamentary report, comments upon the uni- phone in connection with his scientific explorations versal presence of ammonia, which he has found of the bed of the Bay of Naples. By its use the upon every object he has examined, indoors and diver and the boatman overhead are able to comout-of-doors, in the town and in the country. Am- municate with each other quickly and intelligibly. monia, it is believed, may be an index of decayed CONVERTING SOUND INTO LIGHT. A French matter. By suspending a piece of glass anywhere, scientist claims that he has succeeded in reversing and after a while washing the outer surface with the result obtained by Professor Bell, in producing He has described an experiing a Nessler solution to the washing, the presence pure water by means of a spray bottle, and apply- light from sound. ment to the French Academy, by which he conand quantity of ammonia are ascertained. This tends a transformation of sound into light is proDr. Smith hopes to make "a ready popular test for air, - -a test for sewer gases, for overcrowding, for cleanliness of habitations and even of furniture, as well as for smoke and all the sources of ammonia." In a part of the report dealing with the effect of gases upon vegetation, he quotes a German man of science, named Mohr, as saying that thirty-six years had done more to destroy the Luxor obelisk in Paris than as many centuries in Egypt, and that the climate of London will be still more destructive to Cleopatra's Needle. "This," adds Dr. Smith, "we may readily agree to, as we see already a change, so far as color is concerned, and the black always contains the acid" (sulphuric acid). In conclusion The doctor has ordered the professor speaks of the "enormous value of the burning bituminous wood. The change of volume In catering for such an invalid as we have in view, our aim is to get him to take a stipulated amount of meat per diem. him so many ounces a day, to be given in any form (save the solid) in which he can be induced to swallow it. As long, then, as this quantity gets taken, our object is secured. We may give it, if we like, through the medium of soup, or through that of meat-jellies. It is quite possible, therefore, to let two, or even three, days in the week pass without mince in any one of its Protean shapes being present. We can make a chicken panada, and put as much as is equivalent to the specified number of ounces into a plate of soup; or, again, we can make some strong ox-tail jelly, and administer a couple of glasses to him; and then, when we have given the We can ammonia obtainable from the fifteen millions of coal SOMETHING NEW IN OPTICS. CARBONIZATION OF WOOD Under Pressure. At a recent meeting of the Silesian Society for National Culture, Herr Göppert exhibited a halfcarbonized piece of pine wood which had lain two years under a steam-pipe of 250 cwt. at a mine near Schoppinitz. It had been compressed to a fourth part of its thickness, and had come into the halfcarbonized state through the action of pressure alone, as little moisture had access, and the temperature was never above that of the surrounding atmosphere. It had quite the look of a dark browncolored bituminous wood of the tertiary brown coal formation, but it was without the smell observed in was at the cost of the water contents of the wood. A considerable amount of oxygen and hydrogen had come off as water, and the composition approximated to that of peat of the older peat formations. SANITARY AND HYGIENIC NOTES. PURE AIR IN WORKSHOPS. A correspondent of a Montreal journal remarks: "Some workmen According to think themselves tired' when they are only poiM. Trève, the flame of a lamp appears brighter, and soned. They labor in factories, breathe air without a vertical shaft, a post, or mast is seen more dis- oxygen, and in an atmosphere of death. They are tinctly, through a vertical than through a horizontal too often allowed to smoke, and thus add fuel to the slit, while a house, a landscape, or the disk of the sun flame that is consuming them. They knock off work or moon is perceived more clearly through a hori-tired' and listless, when they are merely weakened zontal slit. He finds similar differences in photo- by foul air, and made dull and heavy by an atmosgraphs, according as the light passes from the object phere charged with disease. They keep the winto the plate through a vertical or a horizontal slit, and dows shut and close the door on health, while they ascribes the results to the action of diffused light. lift the gratings of the tomb by breathing and rebreathing the poison from their own lungs, and the floating particles of matter about them. Open the windows, let in the sunshine and the breeze, stop smoking, and you will soon find that it is the poison of confinement, and not labor, that wearies and tires." AN IMPROVED RESPIRATOR. A new respirator due allowance of meat, we are able to include in that day's menu things which are more appetizing, though less nourishing, than the mince. give him a souffle flavored with vanilla, served in a smoking tin, with a snowy white napkin round it. Charlotte russe, macaroni with sweet sauces, roast THE WORK DONE BY THE HEART. An Engapples (to be eaten with baked milky rice pudding), lish writer says: "We may form some conception of stewed pears covered with cream, and innumerable the enormous energy of the human heart when we other puddings can be given with great benefit, reflect that a good climber can ascend only 9000 ft. since, by causing your invalid to derive pleasure in nine hours, that is, can raise his own weight only from some portion at least of his meal, you prevent 1000 ft. in an hour, that is, of course, continuously him from regarding all eating as distasteful. for any length of time, while the work done by the for use in impure air, invented by Dr. Rennecke, But, above all, it must be remembered that the heart is equivalent to raising its own weight (10 has the peculiarity that separate air-passages are way in which things are served is the most impor- oz.) 13,860 ft. high. And we may put this even afforded for inhalation and for exhalation. A light tant element in the matter. The trays should be more strikingly by pointing out that the most pow-mask of gutta-percha, covering the nose and neighcovered with the freshest of cloths, and even be erful engine ever made by man, the Bavaria' loco- boring parts, has before the point of the nose a prorendered bright by a vase of flowers. You should motive of the Vienna and Trieste railway, can only longation containing wadding (pure or saturated never set a plate before an invalid containing the raise itself through 2700 ft. in an hour; that is, its exact quantity of meat, fish, or pudding you want energy is less than one fifth of that of the human him to eat. If you do, he will be sure to leave half, heart. Of course, the actual amount of work done, with the complaint that he has no appetite. He both by engine and climber, is much greater than should always have every thing served on small dishes, that done by the heart; but relative to weight, the energy of the heart far exceeds that of the other and should be allowed to assist himself. His vege tables and sauces should never be heaped on his plate, but should come up in tiny vegetable dishes and pretty sauce-boats. Above all, he should never be told beforehand what he may expect, so that his meals have all the charm of a surprise. In short, an invalid's meals should be so managed that he should look forward to them with pleasure as to a break in the day's monotony, instead of turning from them with disgust, as from some disagreeable ordeal to be undergone with all the resolution he can muster. A TEACHER was explaining to a little girl the meaning of the word "cuticle." "What is that all over my face and hands?" said he. "It's freckles, sir," answered the little cherub. two." with a suitable substance), between two pieces of wire-gauze, and having an aperture below, covered by a hard rubber valve which opens outwards. The inspired air must pass through the wadding, while the expired air preferably passes out through the aperture, so that no precipitation of the products of expiration takes place in the wadding. THE BEARD IN ETHNOLOGY. - Mr. C. S. Wake, THE BRAIN WORKER. So long, says a medical in the Revue d'Anthropologie, remarks that but few authority, as the brain worker is able to sleep well, writers on ethnology have recognized the beard as eat well, and take a fair proportion of out-door exeran important race character, and many travellers cise, it is not necessary to impose any special limits have been so careless as to make no observations as on the actual number of hours he devotes to his to the presence or absence of the beard among the labors. peoples whom they have visited. Mr. Wake, after an elaborate ethnological survey, concludes that the hair on the face is a character of much value to the anthropologist. It is curious that the most highly civilized races are those most plentifully supplied with beard; and, in fact, the beardless peoples may be compared to the children, and the bearded to the adults, of the human race. But when what is generally known as worry steps in to complicate matters, when cares connected with family arrangements or with those numerous personal details which we can seldom escape intervenes, or when the daily occupation of life is in itself a fertile source of anxiety, then we find one or the other of these three safeguards broken down. Probably the man of business or the successful lawyer fails to shake himself free from his anxieties at night, and slumber becomes fitful or disturbed. The nervous system, unsettled by the mental strain, brings about various defects in nutrition, and then we meet that depression which is the chief misery of the overworked. Sulphur Carbonaceous matter 64.47 26.68 0.59 trace 5.79 1.92 99.45 Under the microscope he detected particles of pyrites and stone coal. ing one part of sulphur, and stirring in two parts good pickle can be made with it. Here are two napp analyzed a piece of the commercial metal rules: Slice and boil until tender three heads of and found it contained, cabbage, as for coldslaw; add a little salt and vinegar to the water in which they are to be boiled. When done take out and spread on plates, and drain CARE OF THE EYES. It is well settled that off the vinegar and water. Then put in a jar, and the eyes are benefited by an amount of systematic pour warm, fresh vinegar over. Sweeten to taste; use which preserves the tone of their muscles and the celery seed and mustard are good to season with. regularity of their blood supply. Acuteness of sight For the other kind of pickle select a nice firm head is aided by the attention bestowed upon objects of cabbage. After removing the outside leaves, and within the range of vision. In people who cannot inspecting it carefully to see that there are no worms read the sight is far from acute. The wives of such or bugs, shave it very fine, and put it in a jar. Sprinmen are often indebted to their household needle-kle salt and pepper over it, and spices if you choose; work for the maintenance of a higher standard of a red pepper sliced and put in is good. Pour over vision than that of their husbands. Idleness of the it enough cold vinegar to cover it. This will be eyes, if one may use such an expression, is in every ready for use in about three days." way hurtful to them, and proper and varied employ- DYEING BLACK. - Four ounces copperas and ment is eminently conducive to their preservation one ounce logwood extract to each pound of goods; and efficiency. dissolve the copperas in water sufficient to cover the cloth; wet it in clean water before putting it in copperas water, to prevent spotting; boil it in the copperas water about 20 minutes; take it out, rinse in clear water first, then wash in soap-suds till it seems soft as before it was put in the copperas water; then put into the logwood dye and let it boil about 20 minutes; take out, and let it dry; wash before it dries, or after, as is most convenient. It will neither crock, fade, nor grow rusty. HOUSEHOLD HINTS. THE REMOVAL OF GREASE SPOTS. Fatty oils have a greater surface tension than oil of turpentine, benzole, or other oils. Hence, if a grease spot on a piece of cloth be moistened on the reverse side with one of these solvents, the tension on the greasy side is larger, and therefore the mixture of benzole and fat or grease will tend to move toward the main grease spot. If we were to moisten the centre of this spot with benzole, we should not remove it, but drive the grease upon the clean portion of the cloth. It is therefore necessary to distribute the benzole first over a circle surrounding the grease spot, to approach the latter gradually, at the same time having blotting paper in contact with the spot to absorb the fat immediately. WASHING MIXTURE. A correspondent of The Country Gentleman says: “I send you a recipe for a washing preparation that I have used in my family for some time, and find very valuable, as it saves time and labor, and does not injure the clothes in any way, but keeps them of a clean and beautiful color. To make 15 pounds of the soap, take 7 pounds of firm, tough soap (home-made hard soap will answer), cut into thin slices, 2 pounds of sal soda, and 1 pound of unslacked lime. Put the lime and soda into a dish, pour over it two gallons of boiling soft water, stir it well, and let it settle. Pour off the clear water into a dish containing the soap; put it on the fire, and let it remain there until the soap is dissolved. Dissolve 1 ounce of alum and 2 ounces of borax, and put them into the soap as it is taken from the fire. Let the soap cool a little, and then add 1 ounce of benzine. When the soap is perfectly cool it can be cut into bars. Soak the clothes over night. Cut 1 pound of this soap into 7 gallons of water, put the clothes in, and boil without rubbing. Wash them enough after boiling to get the soap out, and rinse thoroughly. Use the same water for second boil." TO RESTORE BLACK MERINO. Soak the goods which gives a blue picture with a pure white CLEANSING SILVER-WARE. - - Dr. B. F. Davenport recommends the use of hyposulphite of soda for cleansing tarnished silver-ware. A saturated solution is employed, applied by a cloth or brush. It is well to preserve the salt in a dry state, as the solution decomposes readily. NEARLY two years ago an Englishman named Spence noticed that when metallic sulphides were mixed with melted sulphur they seemed to comTO WASH LACE. A Canada correspondent bine and form a homogeneous mass. On account gives the following method: Mix a teaspoonful of powdered borax in a basin of strong white Castile of its low melting point and the property of exsoapsuds. Baste the lace to be washed very care- panding on cooling, it was particularly well fully with fine thread upon two thicknesses of flannel. adapted for making casts and connecting gas and Soak the lace thus arranged in the suds mixture water pipes, and being able to resist the action of It soon betwenty-four hours, or longer if very dirty, changing acids would take the place of lead. the suds two or three times. Then let it lie a couple came a commercial article in England, but we hear of hours in clean water to rinse, changing the water little of it in this country. A moment's consideraSqueeze it out (do not wring it), and when tion will show us that its remarkable properties partly dry place the flannel, with the lace on it, lace differ very little from those of sulphur. In color downward, on two thicknesses of dry flannel laid it resembles cast iron; its melting point (255° When on a table, and smooth it with a hot iron. F.) is a little higher than that of sulphur; its the lace is quite dry rip it off. It is considerable specific gravity is from 3 to 3.5, that of sulphur trouble, but the lace looks beautiful. SUMMER PICKLES. An exchange gives the fol- only 2. We need hardly add that it is neither a metal lowing hint to housekeepers whose stock of homemade pickles may give out before the "new crop" nor a chemical compound. It might more propcomes in: "If cabbage can be procured, a really erly be called "adulterated sulphur." Glasse once. Well-sized paper is painted over with a brush with the following solution, freshly prepared: 30 volumes of gum Arabic solution (1 to 5), 8 volumes solution of citrate of iron and ammonia (1 to 2), 5 volumes solution of perchloride of iron (1 to 2). The mixture appears limpid at first, but soon grows thicker. The paper is dried in the dark, then exposed for a few minutes under a negative or drawing, and developed with a solution of one part ferro cyanide of potassium in 5 parts of water applied with a brush. It is fixed with dilute bydrochloric acid, 1 to 10, washed thoroughly, and dried. INDUSTRIAL MEMORANDA. PREPARATION OF A CLEAR SOLUTION of CaOutDr. Eder and V. Tóth give the following directions : Inclose 30 grams of finely cut caoutchouc in a capacious linen bag, and suspend this within a flask containing 1 liter of benzine by means of a thread held fast by the stopper, so that the bag remains near the surface of the liquid. the course of 6 or 8 days the soluble portion of the caoutchouc, about 40 to 60%, will pass into the benzine, while the contents of the bag will swell to an enormous size. The clear limpid solution, which is quite viscous and contains 1.2 to 1.5% of In caoutchouc, is then carefully separated. The swelled contents of the bag retain to of the benzine used, and may be utilized for the preparation of an inferior grade of caoutchouc varnish. The authors also state that a solution of caoutchouc in benzine, kept in half-full bottles, is decomposed on exposure to light, which may be seen by the change of the solution from a viscous to a thin fluidbut it requires about three times as much time. condition. Even in the dark this change goes on, ICE IN THE DISTILLATION OF ALCOHOL. ice will be required. The cost of production will include only the coal for working the steam-engine which drives the air-pump, and the sulphuric acid, the evaporation of which produces the ice. M. Pictet declares that this will notably diminish the expense of distillation. THE BRUSH LIGHT AT THE LONDON POSTOFFICE. The English Mechanic says: "The electric light at the post-office, St. Martin's-leGrand, has pleased the authorities, and is welcomed by the sorters. A large room, in which there are usually 400 to 500 persons at work, is well illuminated by sixteen Brush lamps, replacing 400 gasburners; and the temperature of the atmosphere, which was often up to 85° F., and higher, has been reduced to about 70°, an improvement that is highly 'appreciated by the workers." A RAILWAY ACROSS AUSTRALIA. A movement is on foot for constructing a railway across Australia, but the difficulty is the arid nature of the centre of that large island. There are good reasons, however, for believing that, at all events, sufficient water is to be had by sinking wells; for, although there is none visible, it is a fact that gum-trees flourish, and there is abundance of scrub which must obtain water somehow. It is known that the underlying rock is an almost level bed of sandstone, which is believed to be saturated with water; for rivers are known which lose themselves in the waterless plain, and never reach the sea. METALLIC BELT. An inventor in Hartford, Conn., has patented a belt which is made of iron wire, the selvages being brass and copper. The weft is of cotton, several threads being woven in without being twisted together. A double fabric is made, between which, or inside of which, a number of single heavier wires are inclosed to take the tensile strain of the belt. A BERLIN LOCOMOTIVE FACTORY. The works of Börsig, of Berlin, for construction of locomotives, employ at present 3000 workmen, and turn out 200 to 250 engines annually. The first locomotive was made in 1842. In 1846, Börsig completed his 100th locomotive, in 1854 his 500th, and in 1858 his 1000th. A NEW CELLULOID. This new product is said to be obtained from well-peeled potatoes, which are treated for 36 hours with a solution of 8 parts of sulphuric acid in 100 parts of water. The mass is dried between blotting paper, and then pressed. It is further stated that in France smoking-pipes are manufactured out of this new material which are quite equal in appearance to the meerschaum. By heavy pressure the material acquires such a hardness that billiard balls can be manufactured from it. AN ELECTRIC TRICYCLE.- A tricycle driven by electricity appeared lately in one of the streets of Paris. M. Trouvé writes of it to La Nature, stating that the tricycle was of English make, and very heavy (55 kilo.), and that he had adapted to it two of his small electric motors, fed by three secondary elements or accumulators of electricity. The vehicle, mounted by a friend of his, ran several times along the Rue de Valois as fast, at least, as a good ordinary cab. The total weight of the vehicle, with its rider, was about 160 kilograms, and the effective force produced by the two motors was 7 kilogrammeters. The experiment lasted an hour and a half. In view of the results, M. Trouvé has set about the construction of a motor which will produce as much as the two others, so as to obtain a greater velocity, say 20 to 30 kilometers an hour. actly made. The wear of the implement, even after through it, and cinnabar red when seen by reflec- ANALYTICAL NOTES. TEST FOR TARTARIC ACID. To a solution of tartaric acid, or an alkaline tartrate, Fenton adds a small quantity of an iron salt, then a few drops of peroxide of hydrogen, and finally an excess of caustic soda. A beautiful violet color results, which is destroyed by chlorine or hypochlorites. Chlorine water may, however, be employed instead of peroxide of hydrogen, if care is taken to avoid any excess. NITRIC ACID IN WATER. Williams reduces the nitric acid to ammonia by the use of zinc which has been covered with a film of copper by immersion in a dilute solution of sulphate of copper. The temperature is maintained at 30° C. or higher, and the presence of neutral salts aids the operation. The ammonia is subsequently determined by Nessler's solution. DELICATE TEST FOR CAUSTIC ALKALIES. Bachmeyer recommends a solution of tannin, which is colored red or reddish-brown by the slightest trace of caustic alkali. In a short time the reddish color passes into a dirty green. NITROUS ACID IN WATER. Griess's test is so delicate as to detect one part in 1,000,000,000 of water. The water is acidified, and some sulphanilic acid with some hydrochlorate of naphthylamine added. If nitrous acid is present a rose-red tint is developed. ALBUMEN IN URINE. Bodecker adds to the urine a slight excess of acetic acid and then a few drops of a solution of ferrocyanide of potassium. The mixture is now warmed, and the smallest trace of albumen causes a turbidity. DIRECT SYNTHESIS OF AMMONIA. - Johnson has obtained ammonia by passing a mixture of hydrogen and nitrogen over spongy platinum, both hot and cold. The greatest quantity obtained was 24 milligrams per hour. If the nitrogen was prepared by passing air over hot copper, or if the nitrogen from other sources was heated strongly, no ammonia was obtained. Johnson thinks that nitrogen, like phosphorus, exists in an active and inactive state, the latter produced by heat. GLUCOSE IN Bread. - Bernbeck analyzed some bread which had a peculiar taste, and found 4.2 per cent. of glucose and 16.8 of dextrine in it. The wheat from which the flour was made had suffered a kind of malting due to the damp weather in the harvest during the fall of 1880. PRACTICAL RECIPES. To INSTANTANEOUS SILVERING MIXTURE. coat copper or brass objects with silver without difficulty or loss of time, the following process is given : Mix 3 parts of chloride of silver with 20 parts of powdered cream of tartar and 15 parts of powdered common salt. Moisten a suitable quantity of the mixture with water, and rub it with a piece of blotting paper upon the metallic object, which must be thoroughly clean. The latter is afterwards rubbed with a piece of cotton upon which precipitated chalk is dusted; then washed with water, and polished with a dry cloth. DRESSING FOR LEATHER. - To three pounds of boiling water add, with continual stirring, a half pound of white wax, an ounce of transparent glue, two ounces of gum senegal, one and a half ounces white soap, and two ounces of brown candy. Finally add two and a half ounces of alcohol, and, after the whole is cooled, three ounces of fine Frankfort black. It is generally admitted that fertilizers should be made only from materials for which no other DETERMINATION OF CHICORY IN GROUND COF-use can be found, substances which have already FEE.-M. Prunier weighs out 2 grams, and sep- served their purpose in the animal economy, and arates the finer powder by sifting through fine silk. have become waste products. On the other hand, This powder, which, as microscopic examination no substance should actually be allowed to go to proves, is composed entirely of pure coffee, is set waste that contains any of the essential elements aside. That which remains on the sieve is macer- of plant food, whether it be phosphoric acid, potated with a few grams of water in a test glass. After some hours it is thrown upon a piece of cloth ash, or nitrogenous matter capable of conversion stretched out and is crushed with the fingers. The into ammonia. The utilization, then, of the waste grains of coffee resist the pressure, whilst those of as dried blood, offal, refuse chicory, reduced to a paste by soaking in water, pen- portions of hides, hoofs, or horn, as well as of etrate into the cloth, and adhere to it. On drying night soil and sewage becomes an interesting the cloth it is easy to detach the coffee, which, after topic to consider. desiccation at 100° and addition of the fine powder separated at first, gives the weight of pure coffee. The chicory is calculated as loss. A COLOR REACTION OF OIL OF PEPPERMINT. CUTTING HOLES IN GLASS. The firm of served by M. C. Roucher. It appears that when to Richter & Co., in Chemnitz, have found a way of acetic acid of 10 degrees' strength about 1-20th of from the abattoirs Some of these, if applied in their crude state, will undergo decomposition too slowly; others are too volatile, and the more valuable constituents escape into the air. In the last named the quantity of water present, the danger of contagious germs, and the unpleasant odors are seriAn apparatus invented by Mr. ous objections. William Plumer for utilizing all kinds of refuse, including night soil and garbage, has been set up in this city. This apparatus we have examined with interest, and as its operations have some novelty it may be worth considering. |