CHAPTER III
RADIUM IN WAR
When we remember how all forms of scientific knowledge were called upon to help in the great struggle, it is not surprising to hear that, although in a comparatively humble way, Radium has had to do its share.
Now radium is one of the most, if not actually the most, remarkable substance known. About a generation ago scientific men, or some of them at all events, were getting rather cocksure. Of course they were quite right when they realized how much was known about things and what great strides had been made during the years through which they had lived. They were proud of the achievements of their scientific friends, for I am not imputing personal vanity to anyone, and they had reason to be proud. They made the mistake, however, of thinking that in one direction at least they had learnt all that there was to be known. The present generation of scientific men seem to be almost too prone to go to the other extreme and to dwell rather much on how little we know now and the wonderful things which are going to be discovered in time.
But that is by the way. A generation ago men seem to have pretty well made up their minds that
they knew all about atoms. They said that everything was made up of atoms, that the atoms could not be subdivided nor changed into anything else except temporarily by combination with other atoms, and that when these combinations were broken up the atoms remained just as before, quite unchanged. They believed that the atoms were unchangeable and everlasting. Professor Tyndall, in a famous address, referred to this in somewhat flowery language, telling his hearers that the atoms would be still the same when they and he had "melted into the infinite azure of the past," which a wag translated into the slang expression of the time, "till all is blue."
Now not very long after Professor Tyndall made this historic speech Professor Henri Becquerel, of Paris, was trying some experiments with phosphorescent materials, that is, materials which glow in the darkness. In the course of these experiments he used some photographic plates upon which, to his surprise, he found marks which he thought ought not to have been there. Thinking at first that he had accidentally "fogged" his plates, as every photographer has done at some time or other, he tried his experiments again with special care but still he got the mysterious marks.
Those marks were caused by some of those "unchangeable and everlasting" atoms deliberately and of their own accord blowing themselves to bits.
For the celebrated Frenchman was not content to let the matter of those mysterious marks rest: he wanted to know what caused them and he did not desist until he was on the track of the secret. It
appeared after careful investigation that they were made by the action of something in some of the ore of the metal "uranium" which he had been using. Moreover, this something evidently had the power of penetrating through the walls of the dark-slide to the plate within. Finally, it was tracked down to the uranium itself which was unquestionably proved to be giving off something in the nature of invisible light, or at all events invisible rays, of strange penetrative power. A little later it was observed that certain ores of uranium seemed to give off these rays more freely than would be accounted for by the amount of uranium present, from which fact it was inferred that there must be something else present in the ore capable of giving off the rays much more powerfully than uranium can. Madame Curie ultimately found out two such substances, one of which she called, after her native land, Polonium (for she is a Pole), and the other Radium. It is the latter which is responsible for by far the greater part of the rays formed.