SCIENCE NOTES.

Digger (Invercargill RSA), Issue 26, 10 September 1920, Page 15

SCIENCE NOTES.

The concluding paragraph of this column in last week's issue, was as follows : — "What we have' said about the indestructibility of matter and the confeervation of energy is merely put in plain form and intended as a scientific definition." The latter portion should read "and not intended as a scientific definition." We are not possessed of a sufficient degree of recklesness to make an assertion which might provoke the displeasure of "A" and "John." Referenoe to our notes last week, will indicate that, within our experience, energy is never created or destroyed, arid that, when it appears, or disappears, it is always transformed into a quantity or quantities of energy in some other places or forms, but exactly eqnal in amount to the original energy. This great law, then, radium appears to disobey. In the first place radium is constantly throwing off heat, without itaelf getting any colder, although it has no apparent souree of supply from which it can replace the heat it has lost, thusleaving itself open to the same suspicions as those who are constantly spending money without any visible means of support. Now, we know that- a footwarmer will gradually cool down to the temperature of surrounding objects. The mere fact that we feel an ohject to be warm, implies that it is giving up warmth or heat to us, that is to say, it is getting cooler. Heat, like sound, is a form of .energy, that is of movement of matter, and, like other forms of energy, becomes exhausted in the material at its sonrce by dissipation through surrounding material. It may, however, be replaced as fast as it ft dissipated. This, one end of a poker, which is constantly giving heat energy to the surrounding ether, may be constantly receiving fresh heat energy through the other end from a hot fire; and while that is the case, the outer end need not grow cooler. With radium it is different. This wonderful substance can keep warm and give heat energy to the ether, and other things around, without itself getting any cooler, although the dissipated energy is not replaced from any visible external source, as a fire, etc. An other form in which radium is con- * stantly giving out energy is that of certain rays, which like the Rontgen rays, can pass Ihrough opaque i%.terials, and then act upon a photographic. plate. Rontgen rays are named after Professor Rontgen. Radium is constantly producing electricity with which it charges itself. Radium is constantly producing the ionisation of the surrounding air. Dry air is not a conductor of electricity, but if the molecules and atoms of nitrogen and oxygen, which compose the air, are hroken up into smaller parts, called ions, each of which is capable of carrying an electric charge, the air is in that way made into a conductor. Other phenomena of a chemical or physical kind, show that radium is constantly puttiug forth active forces capable of influencing other objects. A radium salt, if dissolved in water decomposes it. In the course of a day, hydrogen and oxygen gases are produced. in this way to the extent of more than 100 times the volume of radium itself.