SCIENCE OF THE DAY.

New Zealand Herald, Volume LXVII, Issue 20554, 3 May 1930, Page 5 (Supplement)

SCIENCE OF THE DAY.

CREATURES OF UNDERSEAS. Self-defenco as a science lias been developed to an amazing extent by some of tho undersea creatures. The cuttlolish, for instance, developed a smoko screen of its own long before the World War. From a special sac it shoots ont a dense black ink —used in the preparation of tho colour sepia—which, mixing with tho sea water, forms a very efficient screen.

Some of the sea cucumbers, those cylindrical animals about a foot long and of a darkish colour, use a method dissimilar from any yet tried in human warfaro. They possess special organs filled with a peculiar substance; this is shot out in the form of very fine threads, which bocomo exceedingly sticky on coming into contact with water. Any animal entangled in these cannot escape. Sea anemones, being soft and jelly-like, would have a very bad timo of it were it not for the numerous small "guns" they can discharge when attacked. These "guns" are long threads, coiled round in special cells which contain a liquid, sometimes poisonous: .a small trigger juts out from the cell. When this is touched the pressure inside increases and forces tho thread into tho body of the enemy. There aro hundreds of these "guns" capablo of paralysing other small animals. Tho success of this method is shown by tho fact that some animals, themselves incapablo of making weapons, uso those of others. In each of its nippers a certain kind of crab carries an anemone. Thus, when attacked, it is protected by tho anemone's "guns." Some sea slugs havo improved even on this. They uso tho weapons of sea anemones they have overpowered and eaten; (he "guns" migrate to the ends of their tentacles in an unexploded condition, where they work in the same way as when in their original owners. SILK FROM THE AIR. Illimitable supplies of cellulose—tho raw material of paper, artificial silk, explosives, and other substances—will before long be obtained from tho air by synthetic methods instead of from tho forests of tho world. This striking prediction was made by Dr. Herbert Levinstein, president of the Society of Chemical Industry, in an address to members of the Institution of Chemical Engineers in London. Research had shown, said Dr. Levinstein, that sugar and cellulose camo from tho same fundamental chemical " bricks" or units, and as sugar had already been prepared sya-

thetically from tho carbon dioxide existing in a small amount in tho atmosphere and tho water vapour everywhere present, it was not unreasonable to expect that before long tho paper for our newspapers and many other products of cellplose might bo similarly obtained. Tho percentage of carbon dioxide in the air was certainly small, but having regard to tho billions of tons of air availablo, and to the fact that the proportions of carbon dioxide and water vapour were being continually renewed through tho normal operation of natural processes, it was possible to envisage the air around jis as a reservoir of " wood pulp" for newsprint and all other paper requirements, much more inexhaustible than the Norwegian and Canadian forests, which were at present being consumed at such an alarming rate.

TREE THAT " SEES." Trees liavo almost as wonderful a senso of direction as birds, says a recent writer. Should tlicro be a leak in an underground wator-pipo in a park or garden, a neighbouring tree is almost stiro to find it out, and, extending its roots in that direction, project a shoot through the break into the pipo. Even rnoro extraordinary is the performance of tho rattan, a climbing palm common in tropical countries. When it has climbed a treo, it goes over the top and comes down again to tho ground. Then, growing at tho rate of a foot every twenty-four hours it sots out straight for tho next tree, winch may bo over fifty yards away.

ELECTRICITY MARCHING ON. It seems that out of tho ten millions houses in Britain only about a quarter are wirod for electricity. In a speech recontly, Sir John Brooke, the Electricity Commissioner, said ho expected that there would be an increnso of 3000 million units in the sale of electricity in the next five years. Of this tho domestic demand would probably equal 800 million units.