Science Siftings

New Zealand Tablet, Volume LII, Issue 16, 6 May 1925, Page 62

Science Siftings

(Bt Volt)

Forests of Floating ;; Seaweed.

The "greatest seagoing expedition - ever organised is . about to start from New York to explore the Sargasso Sea. Discovered by Columbus, this remarkable sea is covered by a huge gathering of seaweeds, a floating mass of vegetable growth extending ' for nearly 260,000 square miles, around which the " North Atlantic slowly revolves. Numerous air bladders, like small berries,, keep the ; plants - afloat. ;

Seaweeds thrive chiefly in . the 100 fathom limit—within 600 ft of the surfacebut small and almost invisible forms are found everywhere •in the ocean. Round ; British coasts a primitive variety is. seen in the bright green and hair-like “crow-silks”; but no essential difference exists between the small weeds and* the immense growths found in Pacific waters. ‘ ~' ' . ' “

Thicker than the trunk of a large tree, the gigantic stems 'of seaweed near Tierra del Fuego attain the astonishing length of 400 ft. Huge fronds resemble the spreading leaves of tropical palms.; There are extensive sub-ocean .forests ; of kelp, and floating islands of weeds swarming with live , animals often measuring Bft from base to tip. .,

Seaweeds multiply chiefly by means of spores, " but, near land ; the ' .waves; render unique assistance. ; In rough weather, numerous small pieces of weed are stripped from their moorings by the;; sea and are carried away-until they become entangled and held fast. Then," if - not dislodged 2 and other circumstances are favorable, the pieces -of * weed settle down and become fresh plants. ;

X-Ray Negatives Advantages to Surgery.

A cablemessage from New York to. the. daily papers, - under date April 15 says:.— An X-ray negative of a person's hand, which was sent by wire from New York to Chicasp. has been f examined by prominent - medical men, who assert, that this successful experiment demohstaftes that the' time is near when X-ray diagnosis of an V; injury or , aliment by specialists can be made' at a great : distance : from ihe.patienK ' The picture : was; received in Chicago set en minute? after, it had been sent from ~ New Yorfs. Specialists state that the negative is as clear and distinct as the average plate, ond could readily; be used for the purpose of diagnosis. Leading physicians in' New York and Chicago declare that the process will prove most Valuable in helping to eliminate the time element which is frequently of the utmost iinpoitance in the* diagnosis of a case. ,-. ; The Beginning of; Gas-Lights ;: '■;;- Those who have reached middle-age can remember the time when "gas-light-was provided merely by gas-jets, each consuming six cubic feet of gas an hour and providing no more light than, three common candles. r ? ~', .: T Forty» years (ago; electric light began to. supplant gas, and most people made up their minds that gas lighting was doomed. Experiments 7 ; were.; mode .with the' object of fi improving coal gas-r-thatj is, giving it ! greater.

power of illumination —but these proved fu- , tile. ' ' " •" : ’• "•.■■■■■'■■•■ -'v “ ’ ■•;-■■;

Then Baroh Auer von Walsbach came--to • ; the .rescue. : He, discovered■ that cotton fabric, : if soaked in -a: nitrate- solution composed of r v ninety-nine - parts of .: thorium r. and ( one : -oijgf cerium, . and then v; placed ~ over a , hot flame ' to burn out all impurities, would : glow with a white incandescence, r giving out' a ;pure white light of- astonishing power. (-

By making a clone of this fabric he produced the incandescent gas mantle, which, if placed over a gas-jet, cut the consumption of gas by . half, mud at the same . time gave ten times more light. This invention saved the gas-lighting industry, and is to-day being used extensively upon oil ms well as gas lights. .I-- ‘ '

. Thorium, the principal • material in the * composition of the gas mantle, is a rare earth found in very few places. • Almost the whole of the world’s supply comes from, Brazil. ; -