Science Siftings

New Zealand Tablet, 16 July 1908, Page 35

Science Siftings

BY 'VOLT'

A Curiosity About Eclipses.

The average number of total and partial eclipses in any one year (says an exchange) is four, the maximum seven and the minimum two. There is nothing really peculiar in this except the fact that where only two occur they are always both of the sun.

India Rubber.

Few articles seem more strangely named than India rubber. It gets the ' rubber ' from the first use to which it was put — that of erasing pencil marks by rubbing. Nor should it be associated with India.- The tree was first mentioned by an explorer among the Mexican Indians three centuries ago, and the first account of the substance occurs in connection with Columbus' visit to Hayti on his second voyage. Most of our present importation comes from Brazil. But Columbus and those explorers who followed him were searching for a short passage to India, and they supposed that the land they discovered was India. The name India rubber is therefore a permanent sign of their mistake.

Atmosphere of the Sun

If some of the latest results of astronomical investigation are to be accepted, the atmosphere of the sun is 5000 miles deep, and is composed of various gases and vapors of metals. Then, as observed through the telescope, its surface is covered with minute white forms, apparently floating in an ocean of greyish fluid, these being clouds, composed not of water, but chiefly of carbon, and it is argued that, just as the electrician uses carbon for producing the brightest of artificial lights, so the sun employs the same agent in the production of its transcendent light and heat, the sun clouds being, in fact, made-up ot drops of liquid carbon, which have a radiance vastly exceeding that of the well-known glow of the filament in an electric lamp.

Panama Hats

The Panama is a leaf hat made in Colombia, Ecuador, and Peru from the undeveloped leaf of the ' bombonaje,' which is a screw pine rather than a palm. The trunk of the plant is only a yard in height, but the leaf stalks are two yards long. The leaf before it has opened is prepared for the manufacture of hats. It then consists of a bundle of plaits about two feet long and an inch in diameter called a ' cogollo.' The green outside is stripped off, and by means of a forked instrument it is cut into narrow strips of uniform size. The cogollo is next boiled to toughen the fibre and hung in the sun to dry and bleach, when the strips shrivel into cordlike strands ready for use. It takes sixteen cogollos for an ordiary hat and twenty-four for the finest, and a single hat is plaited in from four days to as many months, according to its texture and quality.

Genesis of the Hailstone.

If it were not for the countless trillions of dust particles that float separately invisible in the atmosphere, there could be no rain drops, snow crystals, or hailstones. From a perfectly dustless atmosphere the moisture would descend in ceaseless rain without drops. The dust particles serve as nuclei about which the vapor gathers. The snow crystal is the most beautiful creation of the aerial moisture, and the hailstone is the most extraordinary. The heart of every hailstone is a tiny speck of dust. Such a speck, with a little moisture condensed about it, is the germ from which may be formed a hailstone capable of felling a man or smashing a window. But first it must be caught up by the current of the air and carried to the level of the lofty cirrus clouds, five or six or even ten miles high. Then, continually growing by fresh accessions of moisture, it begins its long plunge to the earth, spinning through the clouds and flashing in the sun like' a diamond bolt shot from a rainbow.