Science Siftings

New Zealand Tablet, Volume XXXVII, Issue 14, 8 April 1909, Page 555

Science Siftings

BY 'VOLT

The Panama Canal.

Colonel Gothals has promised Mr.- Taft that ships shall be passing through the canal oh January 1, 1915- Mr. Taft, after his trip -through the Culebra cut with the engineers, expressed himself as delighted with the progress that has been made. He was jparticularly, interested in the rock cut, 350 feet deep', through the mountain, only 95 feet remaining to be done. Mr. Taft went the entire nine miles and received a great ovation from the laborers.

The Magnetic Pole.

The South Magnetic Pole located by the Shaekleton exploration party (says an exchange) is just about a thousand miles from the South Geographical Pole. The earth is a magnet, and like every magnet it has two 'poles.' But it is not uniformly magnetised. If it were a uniformly magnetised globe, its magnetic poles would correspond with its geographical poles. If a number of people were to start from different places on the earth an.d move north by the "compass, they ~ would eventually assemble in a land called Boothia. This is where the North Magnetic Pole is situated. Sir James Ross located the North Magnetic Pole in 1831, and in the winter of 1903-4 Amundsen, the Norwegian explorer, spent some months in Boothia studying the Magnetic Pole. There is a similar Pole in the southern hemisphere. We adopt the geographical terms to describe these two Poles. But as a matter of fact, if a freely moving magnet is suspended, its south pole dips towards the South Pole of the earth, and as the north pole of one magnet attracts the south pole of another, it follows tliat the Magnetic Pole of the southern hemisphere of the earth must be, strictly speaking, its north magnetic pole.

A Mystery of Nature.

The work done by Mr. J. Murray, biologist to the Antarctic expedition, is of an intensely valuable and interesting character, states the Lyttelton Times. Mr. Mxirray was stationed at the Cape Royds base and his time was spent in observing, collecting, and photographing the animal life of the region. Most wonderful of the many mysteries of Nature which Mr. Murray unravelled was the life history of a marvellous rotifer. These creatures, which are of a family ~of microscopic water insects, were found fifteen feet deep in ice. The lake in which the rotifera lived had not thawed for two summers, so that the little creatures had been at least three years in ice when they were discovered. Half an hour after it had been thawed out," the;; rotifera commenced to feed voraciously, and made a hearty meal of minute vegetable matter. They were then frozen and thawed again each week and seemed to accept the process with unvarying equanimity. Mr. Murray has obtained vast mnnbers < f rotifera, which he will distribute amongst scientists in New Zealand, Australia, and Great Britain.

A yMonster Spider.

Travellers in the mountains of Ceylon and India speak of a gigantic spider that is to be found there. It measures about six inches across and is quite handsome — if a spider^ can be that. The under part of the body is either bright gold or scarlet, and the upper part is covered with a delicate slate-colored fur. The web spun by it is like yellowsilk, with a central net five feet in length. The web is strong enough to catch and hold a good-sized bird. Sometimes a man rides into one of them without seeing it, and ■ the threads wrap about his face like the silk cords of a real net. Having spun' its web the spider sits motionless, waiting for its victim- • Presently some large insect or perhaps a bird comes flying against it, and is at once caught in the meshes. Then the monster runs fast across the net and begins throwing the coils around the captive. It works rapidly and soon has the head completely wrappedup, so that the captive is first blinded and then choked. ' The bite of this spider is not poisonous, like that of the tarantula, but a man who ran into one of these webs and got nipped in the nose by the watchful owner says its jaws are as strong as the beak of a bird. Here and there in the forest may be found skeletons of birds hanging in the webs, the threads of which are strong enough to retain the bones after the weather has destroyed the flesh and blown, away' the feathers.- -'