Mr. Grove on some Electro-Nitrogurets. 99 



rubbing between the folds of filtering paper; when thus dried 

 and reduced to powder its colour was unaltered ; it had no 

 metallic lustre: the specific gravity of a portion of it which 

 I tried, proved tobe4'6;it conducted electricity, and was 

 acted on by acids precisely as metallic zinc, but the hy- 

 drogen evolved from it by dilute sulphuric acid was mixed 

 with a little nitrogen ; when this solution was supersaturated 

 with caustic potass it evolved no ammoniacal odour. 



Five grains of the substance well dried, were placed in a 

 narrow tube bent so as to form a retort, and heated to red- 

 ness by a spirit-lamp ; they gave out a permanent gas, which 

 was at first collected over recently boiled mercury, but as no 

 ammonia was detected, the gas in subsequent experiments 

 was collected over water : the following is the result of four 

 experiments, the air in the tube having been first rarefied 

 and a portion expelled by heating it at parts distant from the 

 substance : — 



Experiment. Cubic inches. 



1st 5 grains gave 0*7 



2nd 0-75 



3rd 0*76 



4th 0-72 



4 )2'93( 0*73 

 This gas was examined by detonation in an eudiometer, 

 which differed from those of Volta and Henry in being fur- 

 nished with a loop of platina wire, which could be ignited at 

 pleasure by a feeble voltaic current ; this eudiometer I have 

 found to possess many advantages, but it would be out ot 

 place here to dilate upon them. The gas expelled from the 

 zinc compound, when mixed with one-eighth of oxygen, de- 

 tonated, and contracted to five-eighths of the whole volume ; 

 the residue suffered no further contraction by oxygen or hy- 

 drogen, and exhibited all the negative characters of pure ni- 

 trogen : upon several subsequent examinations portions of the 

 original gas were found to contain from one-third to one- 

 fourth hydrogen, and on examining the very last portion, 

 or that which remained in the retort, I found it to leave a very 

 small residuum when detonated with oxygen ; the last por- 

 tions of gas given out contained a greater proportion of hy- 

 drogen than the first, it thus appearing that the nitrogen was 

 evolved at a lower temperature than the hydrogen ; the re- 

 siduum in the tube was unaltered as to colour, but contracted 

 in bulk, and a little dew had collected in the bend of the 

 tube. 

 Cadmium was subjected to the same process as zinc; its 

 H2 



