SCIENCE NOTES.

Otago Witness, Issue 2006, 4 August 1892, Page 44

SCIENCE NOTES.

— But a very short time ago, comparatively speaking, both aluminium and magnesium were regarded as purely chemical wonders. O.ving, however, to the vast improvement which has been effected in the manufacture of these metals, and tke energy with which such manufacture has been pursued, they are utilised to-day for nearly every kind of manufacturing purpose. In many parts of the world there are established important aluminium and magnesium factories, but perhaps one of the most extensive and successful i 3 that known as the Hemelingen Fabrik, situated near Bremen, in Germany. At this establishment, aluminium and magnesium are made for every purpose to which they can be adapted, and a representative of Machinery, who lately finding hiinpolf at Bremen, writes to say that he went all over the works belonging to this important firm, being shown every part of the important manufacture fromits very beginning. Notonly h ive aluminium and magnesium a distinct technical ralue in their pure state, bufc they are extremely useful for bleuding with otrwr metalF. Magnesium ha? always been in special favour for lighting and optical purposes in signaling, fireworks and photoyaphy, but now that its value is raised as si blending agont, its s-ile and demand are likely to be considerably increa-ei. One of its principal recommendations is that it cleanses the rosral with v/h'ch il. is b'rr.cL'l fr r <m all impure parts, which effect c:"H>ol be procured" without its assistance, and u-rv--c;ii!ly when casting is resorted to. For this purpose, then, magnesium is vow added to r.opper, and owing to thn eminc-.Hy s-tis-fa..lcr\ r .-raits attained, the Kemeliugon

Fabrik has been further induced to try the experiment of adding magnesium to a quantiiy of German silver, brass and nickel, with Ilie result that the experiment, has proved surprisingly satisfactory. The proprietors have discovered a 'so thac a slight addition of magnesium to Geinmn silver prevents the oil of zjjC Mid nickel oxide from remainiutr. 'ihe same effect, we understand, is obtained by the addition of magnesium to nickel, while at the eainu time the addition considerably promotes the value of the metal. It is also known that nickel treated in this manner is much easier to handle while the hammering, turning and drawing processes aie btiug earned out. Must of the leading Geirm.n nickel manufactuiiug firms are already pmchasing large quantities of magnesium from the Hemelingen Fabrik, the resuit of the experiment being known to have been thoroughly paii.-.fd.utoiy. From what the correspondent say.*, (he Aluminium and Magnesium Fabiik t\>n fairly claim to have rendered a gre.ih technical and industrial service by reason r f its discovery, a fact which has be'-n duly recognised by the highest German Stato anthoritic-e.

— - Tie imnißiise consumption of oysters *.nd clama iri a::d aruim'i toe city oi: New York has led to t-n L-dustjy of which, perLiap a , it ''ou'l h-> ijiryOfsiblc to find a counterpaifc elviiii -c Instead of allowing iht» shells *o -tycuinuhits in heaps, like t ; ic kitchen iai Wns of r.i<;hi~tor\c f&vngei, th*y are rn«unf.ictmcd i-.to quicklime, and t'.j ir !".->tr\' i>- !y no trc <n a:: uiiimpoirant. o-;C. Thz hhe'lt- ..ic burnt in huye kilns of ovjl r< ' : cr>, J'!i»- :% -i- r. at the bottom. U t jon U.id i-> lir t of all staiteda coke iitj, tb..vo v-'hich it> pl.tcci afitratn-n of shells :ih-"1 cne font in fhioknc oa . Over this is placed a iayer of coal dust, then shells again

and so on up to the top of the kiln. The initial fire gradually creeps through the porous mass, until in about 17 hours it reaches the top, when the resulting quicklime is withdrawn from below, and is ultimately used for gas purification, aa well as by farmers and soap manufacturers. Seven different firms in New York City and Brooklyn turn out them between four and five million bushels of this shell lime yearly. We glean the foregoing particulars from the Scientific American.

— Satisfactory results havo been obtained from experiments in the welding of tramsvay rails by electricity made at tho works of the Johnson Eail Company, Johnstown, Pa. It has been found practicable to weld together two pieces of steel of 25 square inch sectional area, thus doing away with the need of fishplates, and enabling a solid steel rail of practically any length to be used. The experiments show that the necessity for stated and frequent joints to allow for contraction and expansion has been much overrated.

— A German inventor has devised a means of producing a light superior in strength to either oil or electricity. It is by means of driven^air through pumice stone, the latter having been impregnated with benzine. The benzine gas thus obtained is then carried through a fine magnesium powder, and proceeds upward through a pipe to be consumed in a small flame of a claimed 400,000 candle power. The apparatus for producing this light consists of a blast engine for driving the air through the pumice, and a number of other accessories, all of which take up but a small space, and which are enclosed in a glass cate for protection from the elements, as the light is specially designed for coast illumination. The arrangement is especially adapted for giving an intermittent light, the consumption of magnesium being small, depending od the power of the light required.

— Pending the cheapening of aluminium processes of manufacture to the extent which shall render that remarkable metal available for important, purposes which at present are commercially out of the question, there are, even now, instances of its being employed for special purposes which only a short time ago were thought equally removed irom ttie practicable. Small steam and naphtha launches, both in Great Britain and on the Continent, are being constructed of this as yet high-priced metal ; the advantages attaching to its employment amply compensating for extra first-cost. Its great strength enatles a reduction of from 30 to 40 per cent, to be made on the weight of the hull alone from what it would be if steel or wood were employed. Its non-corrosive properties enable special preservative coating and cleaning of the shell to be dispensed with. Ths metal, white almost as silver, is t-imply polished, and remains so; the consequent smoothness gi"ing the craft a considerably greater speed tbau could be obtained from a steel or wooden launch of the same dimeu?ions and engine power.

— Finely divided aluminium has previously been suggested as a substitute for magnesium as an actinic light for photo graphic purposes. Now, that ifc is cheaper than magnesium, the following formula, for a mixture, which is recommended by a French contemporary as giving a powerful flash, may be ot use to those of our readers •who are interested in photography — 100 parts aluminium powder, 25 parts lvcopodium, 5 parts ammonium nitrate. This powder can be used for flashing in an ordinary spirit lamp, but givo3 a brighter and more powerful light if the powder be flashed into the flame by means of a jet of oxygen gas. — Amid the not unfrequent groans of those bewailing the vast mass of knowledge with which modern science is overloading poor humanity it is (writes a B. So. in the Adelaide Observer) well to bo palled up for a change with suipiise at sorm- of cur nineteenth century ignorance; in each science a long list could be drawii up cf items cf surprising i^noranco, hut the most surprising to ihe general community would be the list in physiology. It is indeed strange, seeing that physiology is the scientific babis ot medicine, that there -are glands in the human body whose very function is unknown, the most striking being the thyroid. Some recent work suggests that the function is to destroy some poi3on that would otherwise accumulate in the blood. In man destruction of the thyroid gland is attended with terrible results, a burning fever beyond all ordinary fever is established, to be terminated only by death with a form of epileptic seizure. Experiments on dogs have proved that if the whole of the thyroid is removed death must ensne, but that if a little is left behind the animal can survive anil get along all right, and it has even been proved by experiment that after the whole gland has been removed from an animal a portion can be grafted on from another and save its life, or if the juice of the thyroids of other animala is injected into its veins it can survive. These results aud similar lecenl ones aie most easily explained by assuming that the thyroid produces an antidote to a poison accumulating in the blood, but there is no certainty in the matter till the poi-on is actually produced and shown to work the mischief. Meanwhile thia is about all we know of an o:gan whose removal means certain death.