SCIENCE, MECHANICAL INVENTIONS, ETC.

New Zealand Herald, Volume XLI, Issue 12609, 25 June 1904, Page 4 (Supplement)

SCIENCE, MECHANICAL INVENTIONS, ETC.

Eli.- ; - . . _' j _~_..__ ~- "vessels, have attracted moie ' : than tis.nal ICE-BREAKER^ fact that ;-B»*Mnw& '-vessels have attracted more .n ntmal interest owing to the fact that P.-. I . '\ihey form part of. the system of the Trans- '*; .Bibenaai railway. A' recent paper read before.tbe Society. of Arts,by Mr. Arthur _ul**oii gives * ivA\ account of the vessel now in use in the »ort* ■ Sea, «>* Lake Baikal, and. elsewhere. As a type of Wg» r:i which are in general use in -porta, subject 4o being blocked by ice, we may take the j Sampo "which is now, in the port, of Haago. j in Finland, c She- was built on the lyne, and is 202ffc long, with a <*M*c*ment _ of 2000 tors, and » draught of 18ft., She ha« a propeller at each end, and her two.engines '■ - : have between them 2560 horse-power. She can forge her way through field-ice at the rate of eight knots an hour, the ice being ■ from a foot to a foot and a-h&lf in thickness. In drift-ice. from Bft to 10ft thick her rate-is reduced to two Or three knots an hour. The finest of these vessels afloat is the Ernuk, which can ran at niae knots ■through ice 2ft thick, with a foot of snow an top. ' She makes very short work of ■•° packs of ice from 20iu to coin thick. She lias 8000 tons displacement, and draws 22ft. She is 335 ft long. The Baikal, which - serves oh "the lake of that name, has »_ dis- '■ '-"-"= placement of 4200 tons, and is nearly 300 ft , in ? length. She is fitted with three lines of rails for the engines and the carriages of tl»«. trains, and panders so far to the requirements of civilisation as totarry, * f>rom«ni>dc deck for the use of the-passengcrs While crossinir the lake. Although the fieldice on Lake! Baikal is 3ft thick, there has been no undue delay in carrying passengers and mails before the outbreak of the war. j The how-angles and . lines of vessels such j jis these are designed so that when they -have mounted the ice and their, weight-is «V■■■"-' breaking it down they will not jam when returning to he carried forward again by the. 1 water. The broken ice passes either ....d'.? the vessel or under the field-it®. Were it to lie on the surface of the water it would -have.' a tendency to jam the ■ breaker sideways. . The vest-el has therefore -to break more lee than is necessary? for its mien: passajje/ . How strong the bows awl jsidea have to be made may he imagined it' 'we" remember that: for most of the time they are in use they are in a state of perpetual collision. .. . ■ ,''.. ,•' ' _____ .-•". ■,;*■, ' l

HOW ALUMINIUM WAS FOUND. Al::niinium is found in clay, felspar'; slat*, and iii other minerals and rocks. Trior to Its discovery by a. chemist named Waaler {» German) it had been known to exist, but the difficulty wa* to obtain it from natural sources. Tin* difficulty was overcome by Wohler more by accident than design.' Ho had just been soixingsotac chloride of aluminium and sodium together, and,-not requiring the compound at «o;.nent» put it uside on a stove. Presently he ticked it -up; when, to his agreeable surprise, he fouud that tie had.obtained the metal in minute giob.es or beads through tie compound havnig become heated. At the present day- it seems feasible to suppose -hat the period is not very-far distant when aluminium will oust iron, lead, and copper from their high position "in: the world of metals. •'■;:;::■•£::>■ V-^ l^^ -<>■'■■ > ■■■■'■ .» ~-'■' ■* -—_— .-- -■•.-'■ • ■-.•.' ABOUT THE MAXIM GUN. TV. best known of ad automatic guns is that associate*} with th« name of Mr. Hir.rn .#. Maxim. It depends no; on I lie operation "tf ?-,';"•/ the gflms, but is -vroirkeJ by .the recoil which <.'•/•' is. set up by each explosion. If you lire a fe.^Hfle r |fin it "butts' against the shoulder, and it is this power which is ingeniously utij'> - -'■ lised by Maxim to feed and explode the next cartridges, „ The ft iat ridge iis fired by hand, and then the machine, being set motion, does ; the rest. : The. barrel 1 of this gun is ootircly different from that of the Sailing, the Ilotcbkiss, and the Colt. The [r." ,f : narrow {suite] is net inside a case which holds i;;£.-;' seven Van's.'a-hair pints of "water,' intended j&jp.to keep it fool while the firing goes en. \ But ;.;-■/■ eo rapidly is beat generated that when six Qil'l hundred rounds have been fired in a minute. ''{.. {i.ijtlvbalf the wat is already at boiling ■V- point. ;■" Indeed, in firing one thousand shots one and a-haif ] pints of water will be '.on-. ;i. ; .verted \ into steiiuV, and lost?through ; a rent !; wliicb 'v. left open for the escape of steam, but not of .wat«t. In a dry Jesert the use ;]||fiof Madeiras may be incommoded by. lack of water, lr«it there ii this compensation, that a j /.:'; thousand round* fired into an enemy in a J'f couple of minutes will do a vast amount of i execution. ' Even though the r bullets, are Boiall. the Maxim can cut down trees arid j ?•■ demolish brick Vails in "a.wonderful wav by • ' theTofrctntration of its fire. :All you nave ;'_ j .to do iaizr put in the first cartridge by hand and.fire; ( !V*Pi''s. on ' r hand .on the trigger, | and the hands with 250 cartridger each will pmas ,' through v automatically. The weapon V.J. is sighted 2500 yards, it can fire six huu- ■ d**d arid twenty shots amimrte, and weighs ; J«|!y,;S)l|4o 661b. It can be fitted fo* any kind of rifle or cartridges. Td make mai} r , chine ijuts a practicably weapai it is rieces- . Gary to use smokeless powder, such as cor- j *? ditte, for with the old black po.vder the gun j ■■'■. would soon be enveloped in a i loud of smoke ■:*%\ ';*^s woafd tide the enemy from, the gunner. | ; '-r.' .s.: :*. •';' l "''•■/ ; " -• ' i QUEER EFFECTS OF SUNSHINE. ' v :■'.;,•- Everyone kno-srs that the heat of the sun *riil ■ ejtpaad iron and steel. Stevenson's toMdar bridge over the Menai Straits is 400 feet long The heaviest train passing over it bends it just half an inch, yet ou a July " day, after the "sun has been shining on it for several hours, it is found to be bent an inch and a-haif below its usual horizontal line. ,3.Tie heat of s -the sun acts on stone as ! well j as metal, a fact , which is proved by the Wash - ■ ingtou monument. It is 655 feet high, it will eb found to be about two , inches higher in the evening in the, mornihg of.a sunny day. A strange effect "of sun-, ..' . shine was noted' at, Plymouth, 'where to lay ~ this foundations of a sea' wall the workmen had to descend ima diving bell. These bells had stupidly been fitted with convex circu- ■ lar glasses at ; the top. The sea was very' ; calm and the glosses so -concentrated the* rays of the ; sun that the clothes of one "of i', 1 Ike -workmen vem set on fire; and that at : f?-1»jlio leas than twenty-five feet below the sur- I ; ;iace,of the water. mM^MiOM"£ s : : v? ?s ..;-■■>",' I

THE PANAMA CANAL.- ' ' : ■: •,- In the important element of natural harbours the Panama route has met all the requirements -of commerce during the four centuries since its discovery; On the Pacific when the canal reaches deep, water no works of harbour improvements .'will ever be reQuired. v! On the Atlantic the natural depth now meets the needs of ordinary commercial steamers, and when morels required it may ye secured, by dredging, without fear of deterioration, since there are no moving sands to br combated. The merits of theinland roate ire equally . conspicuous. The; distance is only, about 45 miles from ocean, to ocean, or only one' quarter as long as that by Nicaragua, and the summit level may be fixed at about 65 feet, or a little more than half that at Nicaragua. The route is swept by no strong winds; the curvature is ex- ' ■ ceptionally favourable as compared with ex- . isting ship canals; the annual rainfall, -'ranges from about 14C inches on the. Atlantic voilst to about 93 inches in the iuterior, and about 60 near the shores of the Pacific, "with a well-defined '■'. dry season of fully ; three months; * and with judicious regulation it harbour improvements will ever by rc©bjrctioriablc currents in anj part of the i*-*«te. 'Die transit ocean to ocean may he made in" a single day without en crouching upon night, - but night passages can be made easy and safe by a (system of electric lighting supplied by water-power at the Pl ; two dam* on the Cliagres. The floods of the '11./ river may be readily controlled, and ample . provision to meet "th» low-water requirements of the canal may easily be made. In m word, an excellent canal well snitch to the needs of navigation in av. be const runted ; i«thjre;are "no technical difficulties that will not yield : : - to '-the ordinary resources of Modern engineering, if judicious measures ' arc 'adopt.ed in preparing the final plans, j Jt is'true that five lock'.' will be required, gllftTOltoi reach the summit level, two to de- , eceud, and one to overcomei the "large tidal oscillation on the Pacific coast, but e:cjieri«nc* on the Manchester Ship Canal ■ has demonstrated that they will entail no seri©:ir difficulties in navigation.—The Engiw«rii»- Magazine. : ' ; '"' '■- '•'■■