35G Kxpt'rimcnls on tJie Torpedo. 



ties. Hence, if \vc take the azotic atmosphere as a standard, 

 the oxygenous and the carbonic acid will observe a decreas- 

 ing ratio to it in ascending, and the aqueous vapour an 

 increasing one. The specitic gravity ot oxygenous and 

 azotic gases bcino; as 7 to 6 nearly, tlieir dmiinution hi 

 density will be the same at heights reciprocally as their spe- 

 cilic gravities. Hence it would be found, that at the height 

 of Mount Blanc (nearly three English miles), the ratio of 

 oxygenous gas to azotic, in a given volume of air, would 

 be -nearly as 20 to 80: — eonseOjUently it follows that at any 

 ordinary heights the difference in the proportions will be 

 scarcely if at all perceptible*^. 



LXVH. Experiment :> on the Torpedo, h/ Messrs. Hum- 

 boldt and Gay-Lussac. Extracted from a Letter 

 from M. Humboldt to HI. Berthollet, dated Roriie, 

 15 Fructid. Year 13 f- 



JL HE pha?nomenaof electric fish ought to be the subject of 

 our renewed researches, with a view^ to the opinion of many 

 philosophers, who conceive that they are capable of being- 

 explained upon the principles of that beautiful theory with 

 which \'olta has enriched science. You well know, my 

 respected friend, what must have been our anxiety to pro- 

 cure the torpedo; and you will perhaps be astonished that 

 I should be so long in writing to you respecting it. At 

 Genoa we found some of them, but we were then without 

 instruments. At Civifa Vecchia we searched for them in 

 vain. At last, during our stay at Naples, we procured 

 them verv frequently, of great size, and very vigorous. I 

 shall relate to you, in this letter, the series of experiments 

 u hich M. Gay-Lussac and I have instituted upon the action 

 of the torpedo (Rsja Torpedo of Linnsus). M. de Buch, 

 a German mineralogist, was present at our experiments. I 

 present to vou the results which they afforded, and relate 

 tiic facts without introducing any theoretical notions. 



Our experiments were principally intended to discover 

 ihose condition? in which the torpedo is unable to comniu- 



■ Air brought trom the summit of Helvelyn, in Cumberland (1 100 yards 

 above the sea — barometer bein^ I^CjO), in Julv 1804, gave no perceptible 

 Jill'ereuce from the air taken in M:inch.ester. J\T Oay-Lussac determines 

 the con«tit\!tlon of air brought from an elevation of four miles to be the same 

 ir ;li."t at the earili'- surface. 



■^ riotn ./.ivsiV '/[■ (7(./Ji;V, no. IC'j. 



nicate 



