Moreover, if a speck of radium be placed against a screen covered with suitable materials each particle
which strikes it will make a little splash of light. At least that is what it looks like when seen through a magnifying glass, but to the naked eye there only appears a beautiful steady glow.
Suppose, then, that instead of putting the speck of radiant matter in front of a screen we mix it up intimately with a fluorescent substance such as sulphide of zinc, we then get the same conditions in a slightly different form. Each particle of the substance serves as a tiny screen which glows every time a particle hits it. Thus is produced a luminous paint which glows by night, suitable for painting the dials of instruments which have to be used in the dark.
No doubt some of my readers will have experienced the strangely mingled delight and horror of seeing a Zeppelin in the night sky intent on dropping murder and death on the sleeping civilians of a peaceful town or city. Some too may have witnessed the later acts in that wonderful drama, when, beside the silvery monster illuminated by the beams of the searchlight there must have been, though quite invisible, a little aeroplane manned by one man or at most two. That aeroplane was, no doubt, fitted with instruments at which the pilot glanced now and then and which he was able to see and read because of the tiny speck of radium mixed into the paint. The little alpha particles gave him the light by which to see, but they gave no help to the Germans on the Zeppelin. Hence, in due time he did his work and the gigantic balloon, the pride of the Kaiser and his hordes, fell to the ground, a blazing wreck. How he did it I cannot
tell, but of this I am sure, that most probably radium helped him by making luminous and visible the instruments which guided him.
But probably it has rendered and will still render us even greater services in the way of helping to repair the damages to our injured manhood. How many men came back from the war crippled with rheumatism because of the hardships through which they went. That disease is believed to be due to a substance which mingles with the blood and which, although usually liquid and harmless sometimes changes into a solid and settles in the joints. Now it is believed that radium properly administered will act upon that solid and cause it to change back into its liquid form again, thereby curing the disease. Certainly many of the mineral springs at such places as Bath and Buxton give forth a water which shows a certain amount of radio-activity and it may be that which gives those waters their healing properties. If so, we may look forward with confidence to the time when radio-activity will be induced to play a still more successful part in meeting this painful and widespread illness.
Then, of the other ills which will inevitably arise in our men through the hardships which they have endured are sure to be some of the cancerous type, many of which appear to succumb to treatment by radium. If a very small quantity indeed be carried for a few days in a pocket it will imprint itself upon the skin beneath as if it burnt the tissues. It is never advisable, therefore, to carry radium in the pocket without special precautions. One cannot help
feeling, however, that in that little fact is a hint of usefulness when the best modes of application have been discovered, for as a means of safely and painlessly burning away some undesirable growth it would seem to be without a rival. It is said, too, that it has the strange power of discriminating between the normal and the abnormal, attacking the latter but leaving the former, so that when applied, say, to some abnormal growth like cancer it may be able to remove it without harmful effect upon the surrounding tissues.
Of this, however, it is too soon to write with confidence. It has not been known long enough for our doctors to find out the best modes of use, but that will come with time: meanwhile there are indications that in all probability it will render good service to mankind.