174 MR. R. ROUTLEDGE ON THE 



ratio 2 : i sufficiently close to justify his conclusion that 

 they " completely confirm the results formerly obtained by 

 Davy." Indeed Landolt points out a serious defect in his 

 process — namely, that however rapidly the amalgam may, 

 after washing, be transferred into the acid, the adhering 

 water will nevertheless take up some more ammonia from 

 the continuously decomposing substance, while the hydro- 

 gen escapes. 



It must be observed that Davy himself appears to have 

 found a difficulty in obtaining consistent results ; for he 

 does not seem to have ever entirely satisfied himself as to 

 the proportions of the two gases. These are the words in 

 which he sums up his observations : — " As it does not 

 seem possible to obtain an amalgam in an uniform state, 

 as to adhering moisture, it is not easy to say what would 

 be the exact ratio between the hydrogen and ammonia 

 produced, if no more water was present, than would be 

 decomposed in oxidating the basis. But in the most 

 refined experiments which I have been able to make, this 

 ratio is that of one to two ; and in no instance in which 

 proper precautions are taken, is it less ; but under common 

 circumstances often more. If this result is taken as accu- 

 rate ..... .", &c.* 



This statement of Davy's being apparently the only 

 authority for the assertion that the decomposing amalgam 

 gives off the gases in atomic proportions, and yet being in 

 conflict with G-ay-Lussac and Thenar d's results, it ap- 

 peared to me desirable to attempt to obtain more exact 

 determinations. 



I used amalgam prepared by electricity in the manner 

 described by Landolt. 



A simple mode of eliminating the disturbing effect pro- 

 duced by the attraction of ammonia for moisture suggested 

 itself. A U-shaped glass tube was provided, open at both 



* Bakerian Lecture, 1809. 



