LIQUID AIR.

Timaru Herald, Volume LXXV, Issue 11577, 12 October 1901, Page 1 (Supplement)

LIQUID AIR.

The most sensational thing in the scientific world to-day is liquid air. Yet it has taken a long time to achieve popularity, for it was in 1883 that it was first made by Professor Wrobleski, at Cracow.

No one needs reminding to-day that air is, roughly speaking, merely a mixture of oxygen and nitrogen, and liquid air is therefore the reduction of both these ga3esto the more solid state to which all bodies can eventually "be brought. Pure liquid air, when first formed," is almost colourless, .but as the nitrogen, which is much more volatile than the oxygen, evaporates>it get's a bluish tinge, something like that seenin a bucket of sea water. This intensifies until, when so much of the nitrogen has evaporated that the liquid contains about .80 per cent, of oxygen, it is as blue as the sky, that being the colour of liquid oxygen. To liquid oiygen, indeed, most of the phenomena to be observed with liquid air are due. In America, and on i the Continent, where liquid air has also been prepared on a practically commercial scale, it is transported from place to place in a bucket covered with felt to lessen evaporation, for all the world as if it were really water, and a small quantity is dipped cut for use as required. _ In the laboratory, however, where it is treated with more ceremony, it was first collected in a double flask, the space between the two surfaces being converted into a vacuum, and the inner surface silvered to still further lessen the evaporation by heat from the outside. If out of a bucket of liquid air some is taken with a tin ladle, the mere action so chills the tinth!)t it becomes as brittle as Venetian glass, and if dropped on to the floor shivers into a thousand pieces, like the little glass toys which are commonly known as Prince Rupert's drops. An indiarubber ball put for a moment into liquid air becomes so brittle that if taken out and thrown against a wall it falls-to the ground in thousands of splinters. Alcohol, which as no one can forget,, is used for measuring degrees of extreme cold, as it does not freeze until about 150deg. C, is easily converted _ into what is practically alcoholic ice when liquid air is poured into it. First of all, however, it. becomes as thick as treacle, and when lifted out of the containing vessel can be still further frozen stiff into icicles.