70 ELECTRICAL EXPERIMENTS ON GLASS. 



phosphorus*. Examine the gasses, which the same acids 

 evolve from different metals, or the different colours of ar- 

 tificial fireworks; do not all these modifications demonstrate, 

 that the caloric of the air, added to the ingredients latent 

 in combustibles, carries off various particles, the number 

 of which will ever remain unknown to us ? Of the nature 

 of carbon, nitrogen, hidrogen, oxigen, abundant as they 

 are, we are still ignorant. Are they simples? or are they 

 compounds ? How many varieties do these four bases af- 

 ford merely by the proportions in which they are combined? 

 Why does the new inflammable mixture that alarmed 

 Proust, and prevented him from pursuing his experiments, 

 Action of wa- appear still more terrible than fulminating silver? Before 

 the electric 11 m y experiments, if I na d spoken of the combined action of 

 flffid, will burst water, lead, and the electric fluid on the most tenacious 

 any metals. me tals, as solders and iron, should I have ventured to say, 

 that the igneous expansion in them might at length become 

 sufficiently powerful to burst a cylinder of the best iron of 

 ten lines in diameter, and two lines aperture, consequently 

 four lines thick ; •as well as a large cartridge of an alloy of 

 nine parts copper and one tin similar to the former, which 

 so long resisted a force of about forty feet, and was burst 

 by one of a hundred and forty in ten explosions ? That of 

 iron exhibited undulations at the ninth explosion, but was 

 not actually cracked till the fortieth. I could wish, that 

 some one would try two cylinders of similar materials, to 

 find the proportion of the resistance, which is not in the 

 ratio of the square of the thickness, as I had imagined. 

 The progress of the resistance is greater on doubling the 

 , thickness of the iron ; for a cylinder of iron of half the 

 thickness was cracked at the fourth explosion, and at the 

 seventh the cracks were wider than at the fortieth in the 

 thicker cylinder. I cannot but be persuaded, that the ig- 

 neous action tends to decompose the metals subjected 

 to it. 



* Journal de Physique, February 1807 \ or our Journal, vol. XVII, 

 p. 246. 



X, 



