Science Sittings

New Zealand Tablet, Volume XXXIII, Issue 39, 28 September 1905, Page 29

Science Sittings

By 'Volt'

Origin of the Metric System.

Some very ipteresthig faclis have 'lately been colleor ted about tihe foot, the most widely used measure of length in modern times. The measure is derived from the length of the human foot, but apparently has'varied more than that portion of the skeleton can possibly have done in. historic times. Tne ancient Welsh foot, for instance, was 9in long, whereas the Piedmont foot was 20in. Iti modern times it has varied from the Spanish foot of less than llin to the Venice foot of more than 13in. Almost every country has used a foot measure of a different length. It was this confusion which led the French to devise the metric system.

Dead Sea Disappearing.

A phenomenon of extraordinary geographical and historical interest is announced from the East. The recent notable perturbations that have taken place on our planet have bad a curious effect upon one of the earth's famous places. The geologists now announce that the Dead Sea is on the point oi disappearing. An English savant has just established the fact that the sinister lake of Biblical animals has been steadily diminishing year by, year, and that at the present time its greatest depth does not exceed three metres. The water, which is so rapidly evaporating, deposits chunks of salt upon the banks, and in tdme these salt heaps assume a picturesque and beautiful aspect, shining in the sun like gems and pearl. The conclusion which the scientists have reached from this phenomenon is that the Dead Sea is destined to become a desert of salt.

Wasting Soil.

The preservation of the soil itself as well as its fertility seems to be a problem to which man must give early attention. Professor N. S. Shaler, in calling attention to tMs, points out that under savage life the undisturbed roots and stems of the wild plants bound the soil 1 to the rocks, and the average washing away in four or five centuries would not equal the inoh that may be carried to the sea from a modern ploughed field by a single rain-storm. To this latter-day waste must be added cropping that takes away soluble minerals faster than they are formed. The soil is thus being reduced both irt 'quantity and in quality, and the results are to be seen 5n the lessened productiveness of lands in Italy, Greece, Spain, and most other parts of the world. The remodyf to be sought is some means of preventing the loss of the soil at a greater rate than the decay of the rocks restores it.

Floated 662 Days.

When Colonel 'Swalm, the American Consul at Southampton, was journeying from Montevideo to England via New York, in May, 1903, he placed his card, together with those of several other passengers on the steamship Tennyson, in a bottle, and stated that the finder, on returning it, would receive a reward of a sovereign. The bottle was thrown overboard in latitude 29 degrees', 30 minutes, morth, and longitude 68 degrees, 10 minutes, west. Nothing had since been heard of it until a few months ago, when Oolonel Swalm received word that it had been found on the Donegal Coast of Ireland, near Arranmore, by \x man named Call, who returned the cards. The bottle had evidently been carried by the Gulf Stream along the north of the American coast, then by that ' river of the sea ' across the Atlantic to the Irish Coast, to reach which point it had taken 062 days, the journey being made at an approximate rate of five miles a day.

Why Heat Reddens the Face

The effect of radiated heat on the nerves which control the small blood vessels of the skin makes the face flush. These tiny vessels, which are formally in a state of moderate contraction, under exposure to the heat relax and 'become distended with blood. In regard to exposure to direct heat, the retaining of the skin, together with the uncomfortably warm feeling accompanying it, ma? he looked upon as one of the useful little ' danger signals ' by which we are surrounded.

When from any cause a person has lost this suscepti'Mlity, as( fc4 somo forms of paralysis, he may expose a limb) to heat until serious injury results. The face flushes when near the fire because it is directly exposed to the rays of heat, while most of the body is protected by the clothing. Besides, the nerves of the face are particularly sensitive.and the skin there is most abundantly supplied with blood vessels*