1825.] of Claude-Louis BeHhollet. 87 



and the second detailing his striking discovery of fulminating 

 silver. 



It was one of the doctrines commanding the most universal 

 assent at the time, that acids and alkalies are bodies, in each of 

 which there is indefeasibly inherent a peculiar and distinct nature 

 and principle. This BerthoUet denied. He asserted that the 

 terms acidity and alkalinity convey no positive and independent 

 meaning, but imply mere relation, and that alone. He said that 

 these words were adopted solely for the purpose of facilitating 

 the explanation of the affinities of certain classes of bodies for each 

 other, and that the same substance which acts as an alkali when 

 united with one body, may act as an acid when it forms an union 

 with some other. And he referred for the truth of this opinion 

 to the strong fact that the same body, oxide of lead, not only, in 

 combination with all the substances usually termed acids, acts 

 as an alkali, but also in union with potash, soda, ammonia, and 

 lime, forms in some cases crystallizable compounds, possessing 

 all the properties of salts, and consequently acts as an acid. 

 This doctrine, however, notwithstanding its own merit, and the 

 fame, now universal, of its author, met with no favour from men 

 of science, although, of late years, the labours of Davy and 

 Berzelius have forced its correctness upon the understandings of 

 nearly all the chemical world. 



In the remarkable discovery which BerthoUet at this time 

 made of a new compound which has been named fulminating 

 silver, although we have no particular account of the circum- 

 stances attending its first formation, yet we are sure from its 

 nature he must have incurred imminent danger. Had he then 

 met the fate which so many have since encountered from hand- 

 ling this substance, and perished on the threshold of discovery, 

 the loss to science must have been nearly irreparable. 



Fulminating silver, by the application of a low heat, by the 

 slightest agitation, by a brush from a feather, or the pressure of 

 a fallen drop of water, instantly explodes with tremendous 

 violence. By detonation in a strong metaUic tube, BerthoUet 

 found the products to be, the silver reduced to its metallic state, 

 azote, and water. Before its discovery, no analogous compound 

 was known, except that of fulminating gold ; and the numerous 

 experiments made on that subject by various chemists during35 

 years, proved successful in adding only two others to the list. 



In the year 1791, BerthoUet conferred one of his most signal 

 benefits upon his country by the publication of his work, 

 entitled " Elements of the Art of Dyeing." France in general, 

 and the neighbourhood of Lyons and Uouen in particular, had 

 long been celebrated for the assiduity and success with which 

 the art of dyeing had been there cultivated. Ever since the 

 days of Colbert, whose zeal for the prosperity of his country is 



