302 OISAPFEARANCE OF OXIGEN AND HIDROGEN. 



Slow abforption 2. On reading the account above alluded to, it occurred to 

 of oxigen and ^^ ^j^^^ -^ ^,^^ poffible, that the diminution in bulk, mirrht have 

 bidrogen over . . , » o 



water. arifen from a partial abforption of one or of both gafes, by the 



water of the trough. In order to afcertain this, I introduced 

 like proportions of both gafes, into a jar, placed in a mercu- 

 rial trough, which was in the fame room with the other; and 

 after fuffering this experiment to continue as long as the other, 

 I found that of 12 cubic inches of both gafes introduced into 

 the jar, 3| had difappeared; but I could fcarcely perceive 

 any moifture on the fides of the jar, owing to the fmall quan- 

 tity of water which had been formed. 



The decreafe in volume, in thefe experiments, could not be 

 owing to any condenfation of the gafes, by the coolnefs of 

 the furrounding air ; for I found that it took, place gradually; 

 and the mixtures were made in the beginning of January, and 

 ilood till the end of May; confequently there fiiould have 

 been rather an increafe than a decreafe in bulk, if the tern* 

 peratiire of the air vi^as the caufe. 



The refiduary air contained in the jars, ftill confifted of ox« 

 ygen and hydrogen gafes; for when received into a phial, on 

 the application of a lighted taper, a fmart explofion took place, 

 and the fides of the phial grew dim. On adding fulphuret of 

 lime to another portion of the refidue, a rapid abforption of 

 the oxygen gas took place, and hydrogenous gas was left be- 

 hind. 



From thefe fads we may fairly conclude, that the decreafe 

 in volume was owing to the fpontaneous combination of the 

 two gafes to form water.* 



T. s. r. 



Orkney, June 20th, 1 SO*. 



V 



* It deferves to be confidered whether the abforption of the 

 purer gafes v/ithin, and the cfcape at the furface of the water ex* 

 pofed to the atmofphere, according to thedoftrine explained in Mr. 

 Henry's paper (page 297 ) may not have occafioned the deficiency. 



W.N. 



Letter 



