«6 



PERSPIRATION OF FRAXlNELlA- 



Potassium ab- 

 sorbs phoNph. 

 hid. gas vrith> 

 out flame. 



suTph. hid. 

 with. 



Arsenicatcd 

 hidrogen con- 

 taiiis oxigen. 



Nooxigen in 

 sulphur or 

 phosphorus. 



Collection of 

 ^Experiments, 



since we can at pleasure cause the hiHrogen of these gasse* 

 to be absorbed or not by the potassium. 



" INIr. Davy observes, that we have said potassium ab- 

 sorbs phosphuretted hidrogen gas with flartie ; while on the 

 contrary, as he has found, it absorbs it without flame. This 

 is true, and the mis,take has even occasioned us to make 

 another, which Mr. Davy does not mention : it has led ur 

 to say, that potassium absorbs siilphurettfd hidrogen ga» 

 without the emission of light. The fact is, these two ex- 

 periments were made at the same time, and one was written 

 down for the other. This may easily be conceived, for th«5 

 phenomena are too visible not to be perceived. If we give 

 this explanation however, it is not to exculpate ourselve* 

 from the mistake.*' 



** Mr. Davy coftn plains of our having said, that, if he 

 were acquainted "with the action of arsenicated hidros^en gas 

 on potassium, he would have inferred from it the existence 

 of oxigen in this gas. We think thfe same still, because we 

 do not obtain, on treating arsenic with water, a quantity, of 

 hidrogen gas representing that which potassium is Capable 

 of giving with water. 



'* Mr. Davy could have wished, that we had spoken of 

 his experiments to demonstrate the existence of hidrogen 

 in feulphur and phosphorus ; and complains, that we have 

 only endeavoured to point out errours. ***** But our 

 only object was to inquire, whether these experiments de- 

 monstrated tlie existence of oxigen in these two substances: 

 and, as no one of them proves this, and as the result of all 

 •re contrary to ours, we conld not but draw inferences frona 

 them opposite to those of Mr. Davy." 



** in a Collection of our Experiments, now in the press, 

 we shall answer all Mr. Davy's objections, and endeavour to 

 render him the com pletet>t justice." 



Assertion that 

 ?,he bastard dit 



X. 



Obxermtions respecting the Sensible Perspiration of the Die-' 

 tnmnus Albus, or Fraxinella, By Mr. Robert Lyall, 

 Surgeon, ]SL R, P. S. E, Sfe, Communicatedhythe Author. 



jl.T has been said, that in calm summer evenings the 

 dictaninui albuf evolves hidrogen gas, or a highly odorous 



inflammable 



