Waterbury evening Democrat., 1893-12-19
MAKING LIQUID AIR.
A SCIENTIST EXPLAINS HIS CHEM.
 IcAL DISCOVERIES.

f(AL DISCOVERIES.
 Professor DewAr's Experiments May Prove
 to He the Greatest Investigations of the
 Century-PowerfuI Gases Reduced to a
 Fluid state.
 Tho Pail Mall Budget of London pub hshed an interview with Professor James Dewar on what is represented as being "a great scientific discovery" that of making liquid mir. Introductory to the interview the article says that this hq- uefactions of permanent gases and the use of wanna to preserve great cold mark one of the most important chemical dis coveries of the century" It is held by scientists that any gas may be hque6ed If the pressure and cold may be obtained and a vessel of sufficient strength to withstand the great pressures
 Of the gases that may be liquefied car. oonic acid gas has been found to be tho cheapest and readiest made, and while it has been known for many years that it could be iquified it has generally been so prepared only in small quantities for scientific uses The uso of compressed air as a motive power has presented many difficulties. the principal one being its bulkiness; hence large vessels must be used in order to get a sufficient amount of motive power, and it is hard to make these strong enough and at the snme time liLynt in weight
 As a motive power 1t is used at pres sure of from GOO to 900 pounds. But if Professor Dewar has discovered an eco nomical and ready way of hquefying it. it will tend to solve a problem in carry ing n motive power in storage bulk that will be of great benefit to the students in this line. In tho talk with the represent ative of The Pall Mall Budget, he says: Well, don't think there's very much to say, because I've told all have to tell about the matter in my two lectures, | but do believe there's a great deal more to be learned about the subject You see, at present we've got these gases down to BIO degrees below zero, and the lowest possible temperature is 27i degrees be- low If wo could get some 30 degrees lower down. we might liquefy hydrogen Hydrogen has never been liquefied in a free state yet.
 Now. it's n strange thing that air can be made into a homogeneous fluid. You would think as oxygen can be liquefied | dL - 4C@ uCslCGS hIlu HllIOSSu DOl -l99 degrees, that us you made the air colder and colder the oxygen would be- | come liquid first and then the nitrogen 1 saw that prediction made in a stand ard work only the other day. Now, dare say, you will ask why the oxygen don't come down first
 Stepping quickly back to the desk Pro- lessor Dewar took up pencil and began to draw with rapid strokes on tho back of letter The diagram when it was finished looked more like the law of di- minishing returns turned up on ono side than anything else that am acquainted with While he drew he rapidly ex- plained how the influence of atmospheric pressure on the different volumes of nj trogen and oxygen in air makes them boil almost exactly at the same tempera- ture. As he made each point he drowned a little. drawing mp the wrinkles between his eyes Now. that. in the old theo- logical days. would have been taken as providential dispensation The strange thing is that when liquid air evaporates again they are under the same pressure, and the nitrogen goes of first, as you , would expect.
 Ozone can be liqueied by acting on the vapor given of from liquid oxygen by electricity 1t is splendid dark blue color, almost us dark as indigo. Ozone has not the same molecule as oxygen, and the electricity breaks up three twos into two threes That is the secret of it The queer thing about liquid ozone is that when it goes back into gas again it explodes You wouldn't think it, but it is stronger than dynamite us an explo- sive, It's simply because the ozone goes back into the molecular form of oxygen 80 fast. The force that comes from the electricity makes it explode without meeting with any outside body. It's a tremendous explosive.
 We have discovered that liquid oxy- gen acts as lens It is so transparent to heat, so to speak that even at 1S1 degrees below zero you can focus heat on it from one side and light piece of paper by it on the other You know that's just what happens in the earth. The suns heat gets focused on to the earth through the lens formed by the vacuum of space, which is so cold that ii hasn't any temperature at all-absolute- ly zero"
 Professor Dewar gave lecture or Liquid Air" at the Royal institution ir the presence of the Prince of Wales, tho Duke of York. Lord Salisbury and other notable persons. He showed that by tht withdrawal of heat the air is converted into liquid with total loss of chemical properties, incapable of supporting com bustion, or of entering into combination even with phosphorus and sodium, while certain physical properties remain. Tht conversion of oxygen into ozone was alsC described, and the retention by oxyger of its peculiar optical properties at tho lowest temperature was demonstrated by the very dense and well defined band of It's spectrum In ordinary conditions oxygen shows no unreasonable therna absorption. but at low temperature it thermal absorptive power becomes mani fest