LIQUID AIR.

Hawke's Bay Tribune, Volume XIV, Issue 234, 10 September 1924, Page 3

LIQUID AIR.

ROTARY CLUB LECTURE. President Edmundson, of the Napier Rotary Club, was the speaker at yesterday’s luncheon of the Hastings Rotary Club. The subject was “Liquid Air,” and the members saw it, as well as heard of it. When placing a vacuum container on the demonstration stand, the lecturer explained that the vacuum flasks of commerce were the outcome of an invention of Sir James Dewar, which he used in research work, without anticipating their marketing possibilities. As the water like liquid was poured into the container, the fluid air began to boil. An engineer asked what would happen if a finger was put into the fluid. The reply was it would become hard and brittle and break into fragments like the finest porcelain. Three demon, strations were given. For a few seconds a daffodil flower was submerged. On taking it out of the liquid air, the colouring was unchanged, but at a touch it fell into yellow flakes of dust, A piece of rubber was similarly treated. Later, at the conclusion of the lecture, the remainder of the liquid air was thrown out on the lawn, and the leaves of grass fell into flakes of green. This wonderful fluid is obtained by compression and expansion till its volume is one-eight hundredth of normal atmosphere. The compression required is approximately 25001bs per inch. When freshly made its temperature is about minus 200 degrees Centigrade. A test glass of liquid oxygen was placed into the liquid air container, and because of the difference of volatility between pure oxygen and air, the power of expansion was shown by the inflation of a bladder placed over the toil of the test tube. Michael Faraday, when engrossed on his experiments, and be_ fore he secured the liquidation of air, was told by Humphrey Davy something of the possibilities of such a, discovery. The progress of our Dominion was in a great measure due to the success of scientists, for through the obtaining and retaining of low temperature we sent meat, butter, fruit and eggs to England. Another interesting experiment was the pouring of mercury so as to cover the shanks of two eye bolts. Mercury solidifies at minus 39 degrees centigrade. So when the vessel with the eye bolts and fluid mercury was dippied into the liquid air, the mercury was quickly a solid mass. Ropes were run through the two eyes, and a tug-of-war ensued between some strong men present but the bolts were unshiftable. Pure alcohol placed in a vessel and dipped into the liquid air became as stone. When the vessel was passed from hand to hand it was ‘touch not, taste not’; the frozen block could only be smelt. And alcohol requires minus 112 degrees Centigrade to produce solidification. An acetelyne light outfiit was shown burning brightly. The gas passed through a glass tube which, when brought in touch with the liquid air, immediately the gas was frozen to a solid, like snow in appearance. Later, as it recovered from its cold immersion, it could be seen in three states, liquid, solid and gaseous. Another experiment produced nitric acid, by red hot carbon coming nigh to liquid oxygen and burning the nitrogen in the atmosphere. Florists wire heated.. burnt with a small explosion when likewise brought near the liquid oxygen Mr Edmundson said liquid air was largely used in mining operations. A cartridge was made of cotton wool and charcoal packed into a hole and stamped in . The liquid air fired the cartridge and the explosion was effective without resultant . noxious gases. A kettle steamed . vigorous!v when its contents of liquid air felt the heat of a hand through an asbestos mat. The final demonstrating was the manufacture of a little liquid air. A worm shaped tube rested in the liquid air container and pres, sure was applied with a bicycle pump. Slowly the cold surrounding the tube and the pressure into it, former! drops of colourless moisture, and air had become fluid. It was a. demonstration far more interesting to see than it is possible to describe.