22 The Progress of Physical Discovery. [JAN. 



croy, Vauquelin, Thenard, and other first-rate chemists, who paved the 

 way for the still more recent advances. 



Of those advances, to detail the particulars with any adequate degree 

 of fulness and precision, would be an undertaking which appears to be 

 demanded at the hands of some natural philosopher, who, with ample 

 space, should devote himself to the honourable* task of commemorating 

 the advancement of modern times in physical knowledge. It is not cer- 

 tainly within the capacity of this review, nor can so rapid a sketch as 

 that we are about to offer of the progress of physical discovery for the 

 last twenty years, possibly do justice to the importance of this branch 

 of science. Yet we feel the same kind of satisfaction in paying our 

 individual tribute, however trifling, to the genius of the age in which 

 we live, as each inhabitant of Mexico had in adding one stone, as he 

 passed along the road, to the great pyramid, that was thus raised up in 

 the midst of his country, 



We have already mentioned the celebrated discovery of Sir H. Davy, 

 of the agency of galvanism in the decomposition of salts, which was 

 sufficient to produce an alteration in all former ideas of chemical affinity, 

 by proving that the formation of all compounds may depend on the 

 electrical state of the materials of which they are composed. This was 

 of itself a revolution in physics ; but it was only a small part of the truths 

 which this clever man was destined to bring to light ; for, in 1809, he 

 announced to the Royal Society that he had succeeded in the decompo- 

 sition of the fixed alkalis. Sir H. Davy perceived that in this process 

 potash and soda experienced a disoxygenization, and that there resulted 

 a metallic substance, remarkable for its extreme affinity for oxygen. 

 This substance he named in the one case potassium, and the other 

 sodium ; and although the experiments of M. Gay-Lussac and Thenard 

 at first led them to believe that the changes of potash and soda were due 

 to a combination of those alkalis with hydrogen, and that they were 

 consequently hydrurets instead of metallic oxides, the French chemists 

 within a year altered their opinion, and were determined by the results 

 of further experiments, " a pencher," as they express it, " en faveur de 

 Thypothese qui consiste a regarder le potassium et le sodium comme des 

 corps simples." 



The years 1808 and 1809 were distinguished also by the separation 

 of the basis of three acids, whose composition had been formerly unknown, 

 viz. the boracic, fluoric, and muriatic, by the voltaic pile ; and of the 

 oxides of barytes, strontian, lime, and magnesia, by the same powerful 

 agency. The observations of M. Gay-Lussac on the combinations of 

 gaseous substances with each other, have been highly useful ; and M. 

 Guyton de Morveau, for the first time, decomposed water, by the dia- 

 mond, at an elevated temperature, and produced carbonic acid gas. 

 The diamond had been shewn, in 1797> by Mr. Tennant, to be neither 

 more nor less than crystallized carbon ; and we presume, that few of those 

 who now adorn themselves with its indestructible brightness are ignorant 

 that it is the same substance as the basis of common charcoal. Yet man- 

 kind have gone on digging out of the earth, and then worshipping, this 

 simple carbon, with as little knowledge of its nature, as the ancient 

 Romans had of the nature of the sun. 



The phenomena resulting from chemical observations upon organized 

 bodies, are far more complicated and obscure than those of inanimate 



