SCIENCE SIFTINGS.

Auckland Star, Volume XLII, Issue 191, 12 August 1911, Page 15

SCIENCE SIFTINGS.

THE EARTH'S COKE. At a meeting of the Sekmological Association at The Hague, Prof. Weichert asserted that his studies of the varying velocity of earthquake tremors, passing through the interior of the globe, lead to the conclusion that the earth consists of a central core of iron or steel, about 5580 miles in diameter, surrounded with a stony shell 930 miles in thickness. Between the outer solid rind and the inner layer of rock, covering the metallic core, he thinks there is a layer of liquid, or plastic material, lying a little less than 20 miles below the surface of the earth. NEW ROADS TO DEFY MOTOR WEAR The reinforced macadam of a French engineer is expected to protect roads from excessive wear by motor-cars. In the test sections already laid down, the bottom layer is of concrete, on this is a layer of cement mortar, reinforced with iron rod, and a top layer is of mortar and crushed stone. Such a road is claimed to 'be more durable than ordinary macadam. The surface is elastic aDd easy to travel, and in France the cost is not greater than brick paving. PAPER TOWELS. There is now on the market a paper towel, and for iti many advantages are claimed. The paper towel is made oi a tough, soft, absorbent crepe tissue paper made up in long strips which are rolled. For use paper towels are carried on a roller fixture. The long, rolled strip is cross perforated at regular intervals, giving to each roll 150 sections or towels, each about a foot in width by a foot and a half long. When you want a towel you simply tear one off. A paper towel can, of course, be used but once, but it is not expensive. It is designed to provide a sanitary towel for hotels and clubs for schools and various institutions, for railroad stations, public buildings, stores and factories, and for domestic use—a clean towel for every one at every wash.

TENTH OF A SECOND. It is uncommon, in the experience of the "Scientific American," to find a person who can correctly estimate the lapse of a single second. But, in these days of speeding automobiles, the exact time when each of two colliding vehicles must have occupied particular spots may 'be a matter of great importance. In a recent experiment a car took nearly two seconds to stop after brakes were applied, and in that time it moved nineteen feet. So even fractions of a second are important. One can train himself to estimate even tenths of a second. Try it with a watch, and it will be found that rt is just possible to count ten in the lapse of a single second. But one must count very fast to do it.

THE SILKWORM'S TASK. If all the natural silk in the world (estimated at 110,000,000 lb) were extended in one single thread, such as is woven by the looms, it would make a line that would go over 1,250,000 times round .the earth at the equator, or 344 times the distance between the earth and the sun. The speed of light is 186,000 miles a second. But even at this enormous velocity, a ray of light would take about two days to travel a distance equal to the length of this thread. The work of the silkworm will be dimly appreciated when it is taken into account that about six filaments as spun by the worm in its cocoon go to form a single thread such as is spun into fabric by the loom. THE PALOLA WORMS. A very curious life history is exhibited by the Falola worms. These are green-ish-looking seaworms, found among the crevices of the coral rocks of Samoa, Fiji, and some of the Pacific Islands; while very similar species are also found in Florida and Japan. There is a breeding season twice a year, when the waters are thick as vermicelli soup with the little creatures; which, incidentally, are esteemed a great delicacy. The peculiar thing about them, however, is that they have no heads. They are simply the hinder segments of the worms laden with germ cells of both sexes, which are set free by the rupture of the body wall. The, head remains in its coral crevice. It has shaken off its long tail—the Atlantic species is about 10 inches in length—and proceeds to grow a new one. These worms thus afford a remarkable instance of regeneration of lost parts. The fact that reproduction by budding and fission is found among some other Polychaet worms at once suggests the origin of this peculiar characteristic

SOUND PROOF ROOM. The Physiological Institute of the University of Utrecht possesses one of the most remarkable rooms in the world, a chamber about seven and a half feet square, which is said to be absolutely noiseless, as far as the entrance of sounds from outside is concerned. This room is situated on the top storey of a laboratory building, and is an inside room, but so arranged that it can be ventilated and inundated with sunshine. The walls, floor and ceiling each consist of half a dozen layers of different substances, with air spaces and interstices filled with sound-deadening materials. Some persons when in the room experience a peculiar sensation in the ears. While every effort has 'been made to exclude sounds that arc not wanted, of course the object of constructing this singular room was to experiment with phenomena connected with sound. Some of the sounds employed are made in the room itself, others are introduced from outside by means of a copper tube, which is plugged with lead when not in use.

THE STONE AGE IN AMERICA. There is a good deal of scattered material in museums and elsewhere relative to the stone age in North America, but so far attempts to reduce it to any satisfactory chronological order have not been very successful; the objects, as a rule, are found on the surface or in mounds that cannot even be relatively dated. It is obvious that tribes of a thousand years ago used implements that can hardly be distinguished from those of the glacial period; while in the same tribe implement* representing various stages of culture appear to have been in use simultaneously. The distinctions of period are thug by no means so clearly marked as they generally are in Europe. Most authorities agree that there is little or no evidence for the presence of paleolithic man in North America: he had probably been well advanced in the neolithic stage before the migration from North-east Asia began. Even such a limit gives the historian of North America a good many thousand years to work in—much more ample ground than he is at present able to-cover.