And perhaps it is just as well, at first, not to have too much radium, for besides being wonderful it is also dangerous. If a pound or two could be gathered in a mass it would kill every one who came within its influence. People might go up and even handle the white powder without at the moment feeling any ill-effects, but in a week or two the mysterious and dreadful radium influence would begin to take effect. Slowly the victim's skin would peel off, his body would become one great sore, he would fall blind, and finally die of paralysis and congestion of the spinal cord. Even the small quantities now in hand have severely burned the experimenters. Professor Curie himself has a number of bad scars on his hands and arms due to ulcers caused by handling radium. And Professor Becquerel, in journeying to London, carried in his waistcoat pocket a small tube of radium to be used in a lecture there. Nothing happened at the time, but about two weeks later Professor Becquerel observed that the skin under his pocket was beginning to redden and fall away, and finally a deep and painful sore formed there and remained for weeks before healing. It is just as well, therefore, that scientists learn more about radium and how to handle and control it before too much is manufactured. But the cost and danger of radium are only two of its least extraordinary features. Seen in the daylight radium is a commonplace white powder, but in the dark it glows like live fire, and the purer it is the more it glows. I held for a moment one of Mr. Hammer's radium tubes, and, the lights being turned off, it seemed like a live coal burning there in my hand, and yet I felt no sensation of heat. But radium really does give off heat as well as light--and gives it off continually _without losing appreciable weight_. And that is what seems to scientists a miracle. Imagine a coal which should burn day in and day out for hundreds of years, always bright, always giving off heat and light, and yet not growing any smaller, not turning to ashes. That is the almost unbelievable property of radium. Professor Curie has specimens which have thus been radiating light and heat for several years, with practically no loss of weight; and no small amount of light and heat either. Professor Curie has found that a given quantity of radium will melt its own weight of ice every hour, and continue doing so practically for ever. One of his associates has calculated that a fixed quantity of radium, after throwing out heat for 1,000,000,000 years, would have lost only one-millionth part of its bulk.