§ =100.= In his presidential address to the Chemical Society, March 25, 1909, after having brought forward some exceedingly interesting arguments for the possibility of transmutation, Sir William Ramsay described some experiments which he had carried out on thorium and allied elements.[125] It was found, as we have already stated (§ 98), that, apparently, carbon-dioxide was continually evolved from an acid solution of thorium nitrate, precautions being taken that the gas was not produced from the grease on the stop-cock employed, and it also appeared that carbon-dioxide was produced by the action of radium emanation on thorium nitrate. The action of radium emanation on compounds (not containing carbon) of other members of the carbon group, namely, silicon, zirconium and lead, was then investigated; in the cases of zirconium nitrate and hydro-fluosilicic acid, carbon-dioxide was obtained; but in the case of lead chlorate the amount of carbon dioxide was quite insignificant. Curiously enough, the perchlorate of bismuth, a metal which belongs to the nitrogen group of elements, also yielded carbon-dioxide when acted on by emanation. Sir William Ramsay concludes his discussion of these experiments as follows: “Such are the facts. No one is better aware than I how insufficient the proof is. Many other experiments must be made before it can confidently be asserted that certain elements, when exposed to ‘concentrated energy,’ undergo degradation into carbon.” Some such confirmatory experiments were carried out by Sir William Ramsay and Mr. Francis L. Usher, and they also described an experiment with a compound of titanium. Their results confirm Sir William Ramsay’s former experiments. Carbon-dioxide was obtained in appreciable quantities by the action of emanation on compounds of silicon, titanium, zirconium and thorium. In the case of lead, the amount of carbon dioxide obtained was inappreciable.[126] [125] Sir WILLIAM RAMSAY: “Elements and Electrons,” _Journal of the Chemical Society_, vol. xcv. (1909), pp. 624 _et seq._ [126] For a brief account in English of these later experiments see _The Chemical News_, vol. c. p. 209 (October 29, 1909). The Possibility of Making Gold.