362 On the Formation of IVuter by Compression . 



deniicians. This interesting young man, having accom- 

 panied M. Humboldt during the rest of his expedition to 

 Peru and the kingdom of Mexico, proceeded with him to 

 Europe. The efforts of these three travellers were so much 

 favoured bv circumstances, that they reached the greatest 

 heights to which man had ever attained in these mountains. 

 On the volcano of Antisana they carried instruments 2200, 

 and on Chiniborazo June 2^, 1802, 3300 feet higher than 

 Condamine and Bouguer did on Corazon. They ascended to 

 the height of 3036 loises above the level of the Pacific 

 Ocean, where the blood issued from their eyes, lips, and 

 gums, and where they experienced a cold not indicated by 

 the thermometer, but which arose from the little caloric 

 disengaged during the inspiration of air so much rarefied. 

 A fissure eighty toises in depth and of great breadth pre- 

 vented them from reaching the top of Chimborazo wheu 

 they were distant from it only about 224 toises. 



[To be continued,] 



LXT. On the Formation of Wafer Inj Compression; with 

 T\( flections on the Nature of the Electric Spark. Read 

 ieforc the National Institute hy M. Eiot. 



OOME time ago, conversing with M. Berthollct on the 

 nature and properties of heat, I told him I was convinced 

 that the combination of hvdrogen gas and oxygen gas might 

 be determined without the aid of electricity, merely by the 

 effect of very rapid compression. This result appeared to 

 me to bfe so immediate a consequence of the observations 

 already made on heat disengaged from air by compression, 

 that I thought it superfluous to assure myself of it. But, 

 having afterwards spoken of it to M. Laplace, he was so 

 much interested in this object as to induce me to verify it, 

 I therefore made the experiment, and it completely suc- 

 ceeded. 



I took the barrel of an air-gun the breech of which was 

 closed by a piece of very thick glass, in order that I might 

 observe the light disengaged, as usual, bv compression. The 

 barrel was of iron, and was furnished on the side with a 

 cock for imrodacing the gas, and its lower extrem.ity to- 

 wards the piston was surrounded by a cylinder of lead, suf- 

 ficiently heavy to accelerate the fall and render the com^ 

 prcssion more rapid. This apparatus was first tried by in- 

 troducing atmospheric air; but though we darkened the 

 apartment no sensible light was perceived, because, in all 



probability, 



