a man of science, has a curious appearance now, but was all in place in Rey's time. Rey, who had answered the other objections by argument, had recourse this time to experiment. "If a furnace is built in a wall separating two rooms, in such a way that the vessel shall be on one side and the ventilating registers and doors for feeding in coal on the other, I maintain that the increase in weight will still take place, although no vapors can enter the chamber containing the vessel. I have confirmed this by an experiment which I made at the forges of Jean Rey, Lord of Perrotasse, my elder brother, where I found the increase in tin, which I calcined on a pig, as they call it, or an ingot of sixteen or twenty quintals of iron, at the instant when, coming out of the furnace, it was cast into its mold; for it can not be said that vapors of coal contributed anything to it. Therefore, the volatile salt can not be accepted in this case,"
Finally, with a single experiment Rey swept away all the objections in a lump. "I have just read in Homerus Poppius," he said, "in the third chapter of his book entitled Basilica Antimonii, of the new way that he practices in calcining antimony. He takes a certain quantity of antimony, weighs it, and having pulverized it, puts it in the shape of a cone on a marble; then takes a burning mirror, holds it in the sun so as to bring the pyramidal point of the reflected rays upon a point of the cone of antimony, which fumes abundantly, and in a little while the antimony, touched by the rays, is turned into a pure white earth, which he separates with a knife and turns the rays upon the rest till all has been turned white, and then the calcination is done. It is a wonderful thing that, although in this calcination the antimony loses much of its substance in the vapors and fumes that exhale from it copiously, its weight increases instead of diminishing. Now, if we ask the cause of this increase, will Cardan say that it is the disappearance of the celestial heat? That has been infused more largely by means of the solar rays. Will Scaliger say that it is by consumption of the airy parts? Thinning into earth and increasing in volume, it forces more in. Will Cæesalpin allege his soot? There is no fire to produce any soot. Does the vessel give up any of its own substance? Indeed, the rays are conducted so directly upon the matter that they do not touch the marble. Do you speak of the vapors of charcoal? No charcoal is used in this transaction. The volatile salts which have been so ingeniously brought forward lose here all their savor and grace. Perhaps moisture will be suggested, as has been recently done by some one. But where can it come from? From the marble? No, no, that is not conceivable. From the air? Still less; for the operation is best practiced in the warm days of summer, in the most violent heats. of the dog star."
