NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XXVIII, Issue 8472, 24 January 1891, Page 4 (Supplement)

NOTES ON SCIENCE, MECHANICAL INVENTIONS, ETC.

THE DIAMOND.

Tut diamond has been so long regarded as a natural crystalline form of carbon that one remembers with surprise that this assumption rests on such slender scientific support as the similarity of atomic weight, and the property of its gaseous combustion product to cause a precipitate in baryta or lime water. As it appeared nob incompatible with this knowledgo that the diamond and carbon might bear the same relation to each other as nickel and cobalt, Professor Victor Meyer has suggested the further investigation of the subject. In order to obtain a derivative whose preparation entailed no loss of material and yet admitted of easy determination of its physical constituents, Herr Krause led the product of combustion in oxygen gas over red-hot copper oxide and then into ammonia water, from which solution he made the neutral sodium salt. This salt was found to correspond to the ch"mically pure carbonate in its crystalline form, water of crystallisation, solubility in water, melting point, and electrical conductivo power, so that there can remain no doubt as to the identity of the two substances.

STRENGTH OF MANGANESE BRONZE.

A manganese bronze tube similar to those used in hydraulic gun carriages was recently subjected to a severe test by Messrs. Armstrong, Mitchell, and Co., England. The tube wps 49 inches outside diameter, o*3 inch thick, and IS inches long. An internal pressure of 4000 {rounds per square inch was applied withoutincreaseof outside diameter; 5000 pounds pressure produced an enlargement of 0"03 inch ; COOO pounds pressure increased the diameter OOS inch. The testing pump could not go beyond this pressure, so the tube was turned off to an outside diameter of 4"55 inches, leaving it 0"125 inch in thickness. A pressure per square inch of 1000 pounds produced no change of diameter ; 2000 pounds pressure increased the diameter 0 - l inch; 2500 pounds pressure burst the tube. Two longitudinal specimens were taken from the tube and tested for tensile strength. They gave an ultimate strength of 315 tons per square inch and a stretch of 27£ per cent, in 3 inches. Some of the advantages of tubes made from this metal are freedom from the pitting and corrosion experienced with steel, and a strength when annealed double that of the best copper. For the same strength, manganese bronze tubes weigh about one-half that of copper or brass, and cost about one-third less per running foot. MICKOKKS IN HAILSTONES. Bacteria of various kinds have been found in snow and even in ice. Dr. Fontin, a Russian scientist, it is said, has demon- '■ strated that hailstones are not free from them. He has found that the water from melting of hailstones contains an average of 729 bacteria per cubic centimetre. Neither yeast fungus nor mould was present, but nine different kinds of bacteria were found. As the ordinary dwelling-place of the Bacillus mycoidesone of the species i found—is the earth, it appears that microbes of terrestrial origin may be carried up into the air, and thus rain, snow, and hail may be the direct means of conveying infection. SILVER REFINING BY ELECTRICITY.

The following method of refining silver electrically is described in the Engineering and Mining Journal :—The method is most suitable for the refining of auriferous silver containing about 11 percent, of gold, the cost in this case being only about 14 cents per pound. The principle upon which the process is based consists in using in an ordinary electrolytic bath anodes of an argentiferous matte, and a thin plate of pure silver as the cathode. The bath consists of a very weak solution of nitric acid containing about one per cent, of the acid. The anodes, which are about one-half inch thick, with a surface of about 13*5 square inches, are placed in muslin bates, which retain the gold, platinum, peroxide of lead, and similar foreign material contained in the matte. The current used is loOamperes, and the potential difference between the plates one volt. During the whole period of work brushes are kept moving up and down the silver plates, sweeping off the silver deposited into troughs put for the purpose at the bottom of the bath. These troughs are removed from time to time, and the silver taken out and sent to the furnace.

If the matte contains copper, this is dissolved by the nitric acid, bub is not deposited on the cathode.

A DISCOVERY.

It is not often that pala-ontological discoveries are made in railway cuttings, but an exceptional disinterment has been made at Wembley Park, on the London Metropolitan line. The remains of a hippopotamus, with some bones of an elephant and of a large ox, were lately unearthed at a depth of about 12 feet in a bed of clay, lying immediately beneath a thin stratum of clayey gravel. The remains include portions of the jaws, with several large teeth, in good preservation. An entire tusk, about 15 inches in length, projected from the clay, but it broke and crumbled into fragments, only a piece of the extremity about 4 incites in length having been well preserved. The surface strata all over London is rich in similar treasures, only a year ago an equally interesting discovery having been made at Charing Cross.

A DISCOVERY IX EVORAVINO,

The Papier Zeitung, of Berlin, announces that hi) important discovery has been made in the art of engraving:, and especially in photogravure. As usual the design to he engraved i* placed on a /,inc plate, either by photography or by an artist; this plate, backed by a coating of asphaltuin, is then placed in an acid bath. In the new process the plate is put into connection with a dynamo machine, and the current is led away by a wire placet! in the bath. As •soon as the circuit is established the acid attacks the metal with an astonishing rapidity, and a few minutes are sufficient to bite in .several millimetres deep.

PRINTING NKWSI'AI'iIKS BY PHOTOGRAPHY

Before the Hath Photographic Society (says the Photographic News) a machine has just been exhibited, by means of which machine positives from one negative have been turned out at the rate, it is stated, of three a second. This means 10,800 per hour, exclusive of the developing, washing, fixing, and drying operations, which, by means of suitable baths and mechanical appliances, need not take long. One picture turned out by the machine was of half-plate size, and slightly overdone in the high lights, which is a defect easily remedied ; in other respects, nearly all the prints on the long band were good. A long roll of highly sensitive bromide paper had been used. As the matter now stands, while only a fewhundred pictures have been turned out by the machine in early rough-and-ready experiments, it seems likely that it. will have an important bearing on book illustration. It would be something quite novel for a publisher to take a negative to a commercial firm, and in an hour or two to receive 10,000 dried and cut prints from it ready for binding.

MISCELLANEOUS.

In view of the greatly augmented demand for camphor for the now uses found for if, in the arts, with consequent enhancement of price, it is proposed to use naphthizin as a substitute for it in anti-moth applications. It is quite as effective as camphor, and, being also equally volatile, leaves no more permanent smell. A new clement, named " damaria," is said to have been discovered in the crater of an extinct volcano in Dnmarland. It is reported to have an atomic weight of only 0-5, or half that of hydrogen, and therefore it is the lightest known substance. Black Sea soundings are said to show that below the depth of 600 feet the water is so impregnated with sulphurated hydrogen gas emanating from decaying animal and vegetable matter that living organisms are not found there.

The explanation of the peculiar density of thunder clouds is said to lie in the fact that tho vapour is partially condensed into drop.-; by the electrical action. It is impossible to predict the boundary line of scientific discoveries, or the uses to which man may put them in r.he future. It was found some 50 years ago by Cagniard, Latour, and Schwann that the mysterious substance known to brewers as yeast or barm was really composed of a vast number of minute oval particles endowed with the powers of growth and multiplcation, and therefore undoubtedly living. There are four principal sources of heat : (1) physical, (2) chemical, (3) mechanical, and (4) physiological. The physical sources of heat are solar radiation, stellar radiation, terrestrial radiation, and electricity. A naturalist claims to have discovered in the river approach to Lake Nicaragua, and in the lake itself, the only fresh-water sharks known.