SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XXXVI, Issue 11056, 6 May 1899, Page 4 (Supplement)

SCIENCE, MECHANICAL INVENTIONS, ETC.

THE PHYSICS OF SMELL, The principal subject of Professor W. E. Anton's vice • presidential address on physics at the British Association was the physics of smell which was presented as a subject that had been but little studied. In testing the generally accepted idea that metals have smell, based on the fact that a smell is perceived with most of the commercial metals when handled, the author had observed that when these metals were cleaned or made outwardly pure the smell disappeared. Yet it is shown that these metals acquire smells, when they are handled or abraded by friction, which are characteristic and serve to distinguish them. This may be ascribed to chemical action, but not all chemical action in which metals may take part produces smell; for, when the'v are rubbed with soda or with sugar, no smell but that of soda or of sugar is perceived: nor is the metallic smell observed vhen dilute nitric acid is rubbed on certain metals, though chemical action is very marked with some. But mere breathing on certain metals, even when they have been rendered poetically odorless by cleaning, produces a veh- distinct smell, as also does touching them with the tongue. These smells have hitherto been attributed to the metals themselves, but Professor Ayrton looks for their sourco in the evolution of hydrogen which carries with it impurities, hydrocarbons, especially paraffin, and " it is probable that no metallic particles, even in the form of vapour, reach the nose or even leave the metal. While smells usually appear to lie diffused with great velocity, experiments prove that when tlio space through which they have to pass is free from draughts their progress is very slow, and it would therefore appear that the passage of a smell is far more due to the actual motion of the air containing it than to the diffusion of tile odoriferous substance through the air." The power of a smell to cling to a substance does not appear to depend on its intensity or oil the ease with which it travels through a closed space. Experiments to determine whether smells could pass through glass by transpiration either revealed flaws in the glass or ended in the breaking of the very thin bulbs and gave no answer. FmKPROOPIN'O OF TISSUES. At the Berlin exhibition of means and contrivances for the prevention of accidents n industries and otherwise, prizes were award"d for the following processes of fireproofing, respectively, diminishing the combustibility of tissues, curtain materials, and theatrical scenery, viz.—l. For light tissues: 8 liil. pure ammonium sulphate, 2J kil. pure ammonium carbonate, 2 kil. pure borax, 3 l.il. boric acid. 2 kil. starch, or 100 grammes dextrin, or 400 grammes gelatine, and 100 kil. water are mixed together, heated to ,'0 deg. C., and the material impregnated with the mixture, centrifugated and dried, and then ironed as usual. One liter of the mixture, costing about three or four cents, is enough to impregnate 15 yards of material. 2. For curtain materials, theatrical decorations, wood, furniture: 15 kil. ammonium chloride are mixed with so much floated chalk as to give the mass consistency; it is i lu-n heated to -60deg. C., and the material given one or two coats of it by means of a brush. A kilogramme of it, costing about four to five cents, is sufficient to cover five square yards. 3. For wood, cordage, >'"a./ matting, packing, cloth: 15 kil. amino chloride. 6 kil. boric acid, 3 kil. borax, are dissolved in 100 kil. water, the material laid down in the solution for 15-20 minutes at lOOdeg. C., squeezed and dried. One litre costs about five cents. 4. For paper, printed or not: 8 kil. ammonium sulphate. 3 kit. boric acid, 2 kil. borax, arc dissolved in 100 kil. water, and the solution applied at 50deg. C. phosphorus-copper castings.

Most brass founders know that nv the addition of a certain quantity of phosphorus to copper they are able to make a scud copper casting, but it is not every t>r i -•=- founder that knows the best, way in nl.i.h to mix this phosphorus in the copper. Phosphorus being such an extremely combustible substance, it hardly touches the molten met:-.! before it ignites, and is lost in flame and smoke. To get the full effects of the pbovphorus, it has to be quickly plunged to the bottom of the crucible. An ini/eninus method practiced by a New York city founder is to take a vcrv small crucible and bore several openings in it. The phosphorus is then put into this small pot, and the top is then covered over, and a piece of paper wound around tlio bottom where the pot has been punctured. When the copper has the right heat, the founder takes the small pot and plunges it quickly to the bottom of the crucible. Of course the paper is immediately burnt, which leaves an opening for the phosphorus, and it, having but one way to escape, runs out through the small holes, mixes thoroughly with the molten mass and plinsphorises the copper. The metal is then ready for pouring, and with this treatment a sound copper casting can be made. Such a method of adding, phosphorus to copper is especially good when the metal is to bo cast for electrical purposes.

HARPHNI.YG STEEL. The New York Herald announces that Mr. Thomas A. Edissn, jun., son of the great inventor, lias discovered a process of hardening steel which may revolutionise that industry. A six-inch plate, treated by tho new process, is superior in power of resistonce to 15-in Harvevised plates. Edison's is said to be much superior to the Krupp process. The steel rails. Mr. Edison declares, manufactured under his process will not spread. Tools and bearings aro made practically everlasting. The process is to be kept secret until after the Government have experimented with it on armour plates. Mr. Edison is 22 years old, and was brought up in his father's laboratory. SUGAR AS FOOD. lii an interesting paper recently published on the valuo of sugar as a food as compared with fat, M. Augusto Chauveru maintains that its nutritive valuo is considerably higher than that deduced from its heat of combustion, and that the calculation that 0.7561b of the former is equal to lib of tho latter is in many cases exceedel. The increase in relative nutritive valuo is due largely to the fact that sugar promotes assimilation of the prcteids and reduces dissimilation, and the value of a food must l eccssarilv depend not only upon the energy it is capable of supplying, but also on the indirect influence that it is capable of exerting in the renewal and formation of animal tissue. From whatever point of view tlio matter is regarded, the superiority of sugar over fat as a food, whether for men at rest or at work, is very distinct, and this is of til i greatest importance in a country like Great Britain, which has the largest consumers per head of population of any country in the world, due in a great measure, no doubt, to its being cheaper than in any other civilised country,

TOTAL ECLIPSE OF THE SUN. There will . bo a total Solar eclipse on May 28, 1900, plainly visible in Spain, Portugal, and Algiers, Speaking of the prospects at the British Astronomical Association, Mr. A. C. D. Comnielin said the shadow track ran through a popular country whore railways were numerous; there would therefore be every facility for the party to divide, and this should certainly be done, as the weather conditions were not so favourable nt any single station as to render success there a moral certainty. The steamer might remain at Algiers as a floating hotel to the party, and after the eclipse return by the same route, picking up the parties at the different points where they had been landed. SOURCES OP POWER, _ Latest official statistics of the " German Empire show that there is used by the German industries, including commerce and traffic, horticulture, and stock-breeding, a total of 3,421,194 horse-power. The various sources of power are given in tho table following: — Source of Power. Horse-power. & m . d 18.364 E atw 629, ° team 2,715.078 S s 53,841 Petroleum 7^94 Benzine, gasoline, etc. ... 3501 Hot-air 1298 Compressed-air Electricity was employed in 2245 establishments. In the mining and iron industry there were employed 994,050 horse-power or almost one-third of the total. In the manu-, facture of food-stuffs 686,279 horse-power were used, ip the textile industry 514,986, in the machine industry 182,767. and in the chemical industry 83,164* ■ ■ .. .: