The transmutation of the baser metals into gold was one of the chief aims of the alchemists. Although their labours proved fruitless as regards their immediate object, they laid the foundation of that scientific chemistry to which the modern industrial world owes a deep debt of obligation. In 1818 Faraday contemplated as a possibility the transmutation of the metals, for he said in a lecture delivered before the City Philosophical Society: " To decompose the metals, to re-form them, and to realize the once absurd notion of transmutation - these are the problems now given to the chemist for solution."
Interest in the subject was revived in 1907 by Ramsay's announcement of the development of spectroscopic quantities of lithium in solutions of cupric sulphate or nitrate exposed to the radium emanation. In control experiments made without the emanation no lithium was detected. Mme. Curie and Mile. Gleditsch repeated Ramsay's experiments, employing vessels of platinum instead of glass, but failed to detect the development of even a trace of lithium. They attribute Ramsay's results to solution of lithium present in the glass of his appatus. Mile. Gleditsch detected the presence of lithium in a sample of pitchblende from Joachimsthal, as well as in other radioactive minerals, but failed to find any simple relationship between the proportion of lithium and copper present in the minerals examined. The results are summarized in the table:
| Mineral. | Percentage of Copper. | Percentage of Lithium. | Ratio of Copper to Lithium. | | Joachimsthal pitchblende | 1.2 | 0.00017 | 7059 | | Colorado pitchblende. | 0.15 | 0.00034 | 441 | | Carnotite | 0.15 | 0.030 | 5 | | Chalcolite (Cornwall). | 0.54 | 0.00011 | 491 | | Autunite | Nil | 0.00083 | … | | Thorite | Trace | 0.0033 | ... |
Although Ramsay's theory is not disproved by Mile. Gleditsch's results, they afford it no support. Rutherford regards the ordinary chemical methods employed as inadequate for the detection of the transformation, assuming it to have occurred.
Perman exposed solid cupric nitrate and sulphate and auric chloride, contained in quartz vessels at a pressure of 0.1 mm., to the action of radium bromide for four months, but in no instance could the development of lithium be detected by the spectroscope. |