SCIENCE OF THE DAY.

New Zealand Herald, Volume LXV, Issue 20028, 18 August 1928, Page 5 (Supplement)

SCIENCE OF THE DAY.

THE DEPTH OF THE SEA. In the course of a recent address on Admiralty charts, Admiral H. P. Douglas, the Hydrographer of the British Navy, made an allusion to the echosounding apparatus now used for ascertaining ocean depths. In the last three years navigators have been extremely interested to see on revised Admiralty charts, which are used by seamen of all nations, the plotting of unfamiliar sea depths. Admiral Douglas, explaining this said that the new method is adding greatly to our knowledge of the sea. Three years ago, when the wire leadj, apparatus was still being used, the greatest depth which had been plumbed was five miles, and this, indeed, is what the geography books state is the greatest known sea depth. It was clear that in many places the sea was deeper than could be penetrated by the wire, but how much could not be discovered. By the new method there is no limit to the depths which can bo ascertained, and German American, and Japanese snips 1 are constantly reporting colossal depths, i'hese are marked on tho Admiralty charts.

There was a tune when no plottings were made which had not been backed by a specimen oi' the bottom of the sea, but with the new method there is no need to doubt the accuracy of the depths reported. The greatest up to the present have been reported by the German survey ship, Emden, iu the Eastern Archipelago. They vary between seven and eight miles. " The German ship, Meteor," said Admiral Douglas, " has recently done somo extraordinary work in the South Atlantic, re-charting the whole of tiie area and totallj revising our ideas as to the depths of the ocean and the configuration of the land under it. ,We have always known that in parts the sea is deeper than the highest mountain, and by the use of the new method we hope to ascertain exactly how much."

THE BEE'S BUSINESS. An important instance of the balance of Nature is involved in the fact that most flowers are dependent for pollination on the visits of appropriate insects. If cer-

tain insects fail to visit them the crop of seeds fails; if tliey keep their appointment the crop succeeds. These visits depend somewhat on the weather, but sometimes disastrous results occur through the depletion of these friends of the (lowers. Several hundreds of flower species, too, depend not upon insects, but upon the visits of honcybirds, hum-, ming-btrds, and sun-birds, and if these are " killed or driven away ' it. is a disaster for the plants. It is believed that the keepjng of bees on fruit and in orchards increases the chances of the fruit trees. NOVEL TADPOLE TEST. Hot water causes female tadpoles to turn into males if they are kept in it too long. A scientist kept two sets of tadpoles from the egg stage until he was able to determine the sex. In one set, in which the temperature of the water was natural, the sex ratio was normal, about 100 females to 96 males. In tho other set the temperature of the water was jumped suddenly to nearly ninety degrees Fahrenheit when the tadpoles were five weeks old. The sex glands of the females in this set gradually assumed a masculine character, and the frogs emerged as males. THE POTATO-TOMATO. An extraordinary plant that produces tomatoes above the ground and potatoes under the ground has been grown at the Missouri Botanical Garden, The plants that bear potatoes and tomatoes are closely related, though different in their development. Tho potato is merely a swollen bud on a underground stem; the tomato is tho seed-bearing organ of tho plant, and although tomato plants never bear tubers on their roots, potatoes; often go to seed and produce fruits that look not unlike small green tomatoes. By grafting the shoots off one plant to the mot of the other, it has been possible to produce a plant whoso fruits are edible, and whose roots bear potato-like tubers.