C 369 ] 



LI. Experiments on Ammonia, and an Account of a new 

 Method of analysing it, hj Cgmhustion tcith Oxygen and 

 other Gases; in a Letter to Humphry Davy, Esq., 

 Sec. R.S. oic, fom Williaim Henry, M.D., F.R.S. 

 V. P. of the Lit. and Phil. Society, and Physician tp 

 the Lifirmary at Manchester *. 



MY DEAR SIR fj 



J- SHOULD sooner have communicated the account, which 

 you are so good as to request, ot my turther experiments 

 on the dec<)n)|)Ostion of ammonia, if 1 had not been anxious 

 to obtain, by frequent and careful repetition of them, re- 

 sults not dffecteci by any of those numerous causes of error, 

 which easily insinuate themselves inio procet^sesof somuch 

 dehcacv. You have already been informed that the fact, 

 which I lately mentioned to you, (tending to prove the ex- 

 istence of oxygen as an element of the volatile alkali, by 

 the discovery of oxytjen gas in the products of its analysis,) 

 is not emitted to contidcnce, owing to the admission of a 

 small quantity of atmospherical air in a way which \vas not 

 at all suspected. Frequent repetitions of the same process, 

 under circumstances whoilv unobjectionable, have fully sa- 

 tisfied me that no portion whatsoever of oxygen gas is 

 evolved by electricity from ammonia even when, by ir.eans 

 of an apparatus C'.nstructed for the purpose, the only me- 

 tallic surface exp(.sed to the gas consists of the sections of 

 two platina wires, each l-5nih of an inch in diameter, the 

 wires themselves being inclosed in glass tubes which are 

 sealed hermetically round them, and then ground away, 

 so as to expose only the points. Nor does any difl'erence 

 in the nature of the products arise from electrifying the gas 

 either under increased or diminished pressure, the laticr of 

 which, it appeared to me probable, from the known in- 

 fluence of elasticity in impeding the combination of gaseous 

 bases, might prevent the oxygen of the alkali from uniting 

 with hydrogen to form water, and occasion the expansion 

 of both into the slate of gas. 



Having failed, therefore, to acquire, in this way, proof 

 of the existence of oxygen in the volatile alkali, I was next 

 led to seek for some unequivocal mode of evincing the pro- 



• From Philotaphical Transactic«:s for 1809. 



\ 'thin lerter, ia \u original form, was read to the Society May !8, J 809, 

 tome new (ibicrvaiioiis were added, and some correctioiii I'uriiisiied by the 

 author, Id con-.cqucnce of snh^eijuciit experiments made in Jui>e: it was 

 transmitted to the secretary for publication July 10. 



Vol. 3-1. No. 139. Nov. I8O9. A a duclion 



