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foT the Advancement of Science. 277 



in triads, Prof. Dumas alluded to the ideas of the ancients of the trans- 

 mutation of metals and their desire to change lead into silver and mer- 

 cury into gold ; but these metals do not appear to have the requisite 

 similar relations to render these changes possible. He then passed to 

 the changes of other bodies, — such as the transmutation of diamonds 

 into black lead under the voltaic arc. 



After elaborate reasoning and offering many analogies from the 

 stores of chemical analysis, Prof. Dumas expressed the idea that the 

 law of the substitution of one body for another in groups of compounds 

 might lead to the transformation of one group into another at will ; and 

 we should endeavor to devise means to divide the molecules of one 

 body of one of these groups into two parts, and also of a third body, 

 and then unite them, and probably the intermediate body might be the 

 result. In this way, if bodies of similar properties and often associated 

 together were transmutable, one into the other, then by changes, por- 

 tions of one might often, if not always, be associated with the other. 

 Ihus, in nature when chlorine occurred, iodine and bromine might 

 also be found, and alwavs would be if thev were transmutable the one 

 into the other. Cobalt is thus mysteriously associated with nickel, iron 

 with manganese, sulphur with selenium, &c. In the arts during opera- 

 tions when certain radicles were produced, analogous ones were found 

 constantly to be associated. In the distillation of brandy, oil of wine 

 Js always an associated result. 



Dr. Faraday expressed his hope that Prof. Dumas was setting chem- 

 ists in the right path; and although conversationally acquainted with 

 the subject, yet he had been by no means prepared for the multitude of 

 analogies pointed out. 



Mr, Grove spoke of the importance of the view^ as, by knowing the 

 extreme compounds, it might serve as a guide in experiments and as a 

 check to the results. He adverted to the allotropic condition of sub- 

 stances when their principal characters were changed, but their chem- 

 ical qualities were unaltered; thus, carbon In the state of a diamond 

 had a change of property so complete that it had one of the properties 

 of metals given or transferred lo it by its conducting power for elec- 

 j Iriciiy under these conditions, and its other forms were states resistant 



to electric passage. He thought this fact of certain bodies having two 

 sets of physical properties with greatly differing character might, with 

 this law of the substitution of one set of chemical qualities for another 

 in a compound group, give the hope of the great realization of some of 

 the ideas embodied in the views of the possible transformation of one 

 body at the will so as to possess the properties of others. 



Prof. Williamson, Dr. Anderson, and Dr. Gladstone remarked en 

 these analogies, — and referred to the groups of bodies of similar char- 

 acters, but whose history was difficult or inexplicable. Thus, the met- 

 als of the platina group of bodies, the red states of phosphorus and of 

 sulphur, the carrying of certain of these properties into the sulphurets 

 of phosphorus, and The unsatisfactory history of bodies like the phos- 

 phates, might be rendered clear in future researches by the ideas re-^ 

 stilting from numerous examples of the triad groups alluded to by 

 "of. Dumas. 



