Science Sittings

New Zealand Tablet, Volume XXXIII, Issue 40, 7 December 1905, Page 29

Science Sittings

By • Volt '

Insanity in Canada

The insane in the asylums of Canada number 16,662, an increase of 25 per cent, since 1891. One authority attributes the increase to immigration and lax medical inspection at ports, 3000 of the 699,500 immigrants of the last ten years having been at least partially insane

Using up Sawdust

An inteiesUug new material for using up sawdust is wood-stone. It. is a mixture of sawdust and calcined magnesia reduced to powder, the moistened ingredients being thoroughly mingled, pounded, ground, and submitted to moderate pressure for a number of hours. The finished products are further compressed in a hydraulic press. The material is incombustible, impermeable to water, and takes a high polish, being adapted for pavements, linings, coverings, and ornamental purposes.

A Cosmopolitan City

The most cosmopolitan city in the United States seems to be Chicago. Here is the census of its speak, ers of languages other than English : — German, 500,000; Polish, 125,000 ; Swedish, 100,000 , Bohemian, 90,000 ; Norwegian, 50,000'; Yiddish, 50,000 , Dutch, 30,000 ; Italian, 25,000 ; Danish, N20,000N 20,000 ; French, 15,000 ; Croatian and Servian, 10,000 ; Slovakian, 10,000 ; Lithuanian, 10,000 , Hungarian, 5000 ; Greek, 4000 ; Frisian, Roumanian, Slavonian, and Flemish, 1000 to 2000 ; Chinese and Spanish, 1000 ; Finnish, Scotch Gaelic and Irish Gaelic, 500 ; Russian, 7 000 ; Arabic, 250 ; Armenian, Manx, Icelandic, Albanian, 100 ; less than 100, Basque, Breton, Esthonian, .Gipsy, Japanese, Portuguese, Turkish.

Spectacles

It is hard to realise what our ancestors did .without the help of spectacles. The first mention of them seems to be toward the end of the thirteenth century, when convex spectacles were invented, it is supposed, by Roger Bacon Concave glasses were introduced soon afterward, but the Spectacle MakeiV Company of London was not incorporated until l(>30. It seems that the ancients knew nothing of these aids of vision, and it is more than hkelv that Homer and even Milton might have been spared their blindness had they understood the use of a powerful lens. Eyeglasses came m much later, when the spectacles were considered too cumbersome for fashionable wear, and lorgnettes came e\ en later when the great ladies wished an ornamental case for then eyeglasses. The eyeglasses of to-day fit on the nose with a spring; formerly they were held in place with the hand.

Path of Ocean Cables

Thou 1 seems to be no logical reason why cables cannot be laid acioss any section of the oceans ot the woild, no matter how gicat the depth. Some portions of the Atlantic cables arc three miles below the suiface, and this is not necessarily the extreme depth, for the cable- may and probably does pass from the top ol one .submarine Inll to another without (hooping matenally into the deep valleys between (says ' Lippincott's Magazine ') The gieatest known depth of the sea is 40,080 feet, oi 7 3-5 miles, found in the South Atlantic midway between the island of Tustan d'Acuhna and the mouth oi the Rio do la Plata Soundings have been made to the depth of 27,180 feet in the north Atlantic south of Newfoundland, and about 31,000 feet, or nearly Uh n lies, is reported south of the Beimudas. Even .such emrmous depths as these need not hinder cablelaying so far as the theory is concerned, but in practice, for reasons of economy in maintenance and otherwise, it. is found best to take advantage of favoring conditions in the ocean's bed To lllustiate, all of the cables between Hie United .Slates and Europe run up along oir coast until they reach the neighborhood of Newfoundland beioie starting acioss to their destination in [icland or France The leason for this is found in the range of .submarine tablelands, which lies between the three last-named countries.