Science Siftings

New Zealand Tablet, 9 February 1911, Page 259

Science Siftings

‘VOLT 1

Telephone Service on Trains, One of the railroads running between New York and Buffalo is considering the advisability of installing a telephone service on its trains, so that passengers may send and receive messages when at the several stations.

Steel Encased in Cement.

In tearing down a skyscraper building that had stood fourteen years, it was found that the parts where the steel had been encased in cement there was no rust, but where a paint made of pure linseed oil had been used to preserve the steel the paint had entirely disappeared, and there was more or less rust.

Automatic Enunciators.

A Chicago hotel has introduced a new method for calling out the name of a guest who is wanted at the office or elsewhere. Instead of sending a bell boy through the corridors to shout out the name in unintelligible tones, they have placed automatic enunciators in different parts of the house, all operated from one station, that clearly call out the name.

The Turkey.

The turkey is the only specimen of the native fauna of America which has ever been reduced to domestication. The deer, the antelope, the lordly bison, and the many birds which are used for food have all remained untamed, or have disappeared from the face of the earth, with the exception of the turkey. Just when or how this bird was reduced to subjection to man is now unknown. Even in name it is credited to an Asiatic country. The name probably came through the way the bird was introduced into England. It is supposed to have come by way of Spain, and was called a Turkish bird because of a notion that it was introduced into Spain by the Moors, who, in the common language of England at that time, were called Turks.

Protection of Electric Workers.

A rubber shield has been introduced recently with a view to protecting electric workers, especially ‘ linemen,’ from contact with live wires. It is made of rubber, and is about the size of an automobile tyre, terminating at each end in two small tubes. It is hollow, and is slit all the way along one side so that it may be opened out and slipped down over a wire. At the shoulder between the small tube and the body, tube is a hard-rubber ring, which fits closely around the small tube and clamps it upon the wire. This ring has a slot so located as to admit the wire. Each shield is subjected, before it leaves the factory, to a f treasure of 30,000 volts, so after putting shields over the ive wires the lineman need have v no fear of accidental shock. He can also throw the shields, spread out, over the crossarms, to sit or stand upon. Then, as he works upon a wire, the current cannot pass through his body to the ground by way of the pole. In trimming or repairing arc-lamps there is also danger of shock, so the lamp man may take one of the shields with him on his rounds and stand in it as he would in a snow-shoe. Still another application is in tunnels or subways carrying live conductors. When the lineman is slicing or repairing these cables he makes use of one or more of the shields to sit or stand upon w'hile at his work.

The Teeth of Mammals.

In shape and size, as well as in number, the teeth of mammals are very clearly related to the nature of their food in the first place, and to their use as weapons of attack or of defence. "When the surface of the cheek-teeth is broad, with low and numerous tubercles, the food of the animal is of a rather soft substance, which yields to a grinding action. Such are fruits, nuts, roots* or leaves, which are ' triturated ' and mixed with the saliva during the process of mastication. Where the vegetable food is coarse grass or tree twigs, requiring long and thorough grinding, transverse ridges of enamel are present on the cheek-teeth, as in cattle, deer, and rabbits. Truly carnivorous animals, which eat the raw carcases of other animals, have a different shape of teeth. Not only do they have large and dagger-like ' dog-teeth,' as weapons of attack, but the cheek-teeth (very few in number) present a long, sharp-edged ridge running parallel to the length of the jaw, the edges of which in corresponding tipper and lower teeth fit and work together like the blades of a f>air of scissors. The cats (including the lions, tigers, and eopards) have this, arrangement in perfection. They cut the bones and muscles of their prey into great lumps with the scissor-like cheek-teeth, and swallow the great pieces whole without mastication. Insect-eating mammals have cheek-teeth, with three or four sharp-pointed tubercles standing up on the surface. They break the hard-shelled insects and swallow them rapidly. The fish-eating whales have an immense number of peg-like pointed teeth only. These serve as do those of the sealsmerely to catch and grip the fish, which are swallowed whole. '•' : '""i