248 On Sir H. Davy’s Safe-lamp. 
water was partly if not wholly carbonic acid gas. _ The fixed air 
being displaced from the barytes, the water will unite with the 
earth and form a hydrate. In introducing the experiment of 
Sir H. Davy, your correspondent seems not aware of that of 
Dobereiner of Jena. The former distinguished chemist in elec- 
trifying too great a portion of mercury did not succed in amal- 
gamating it: but it is of a piece with that of Dobereiner. The 
latter, by using a minute portion of mercury in contact with 
water, and submitting it to the action of Voltaic electricity, found 
oxygen developed at the positive wire, while 0 hydrogen ‘evolved 
at the negative extremity: but the fluidity of the mercury was 
arrested, and a solid amalgam,formed; aud this amalgam when 
submitted to heat gave off hydr ogen, while the mercury resumed 
its fluid form. This would look as if hydrogen was a metal 
dissolved in caloric, and illustrates the electrization of ammonia 
associated with mereury—which phenomenon admits of an easy 
solution, if we admit nitrogen to be a compound of oxygen and 
hydrogen, of which I see no cause to doubt. Iam not pre- 
pared to say that amalgamation with mercury is conclusive on 
the question of metallization—the experiments of Crosse would 
lead us to doubt it. 
Sir Wumpury Davy’s Safe-lamp. 
Tam happy in adding my complete conviction of the perfect 
safety of this invaluable discovery. It cannot be over-rated. 
The triumphs of humanity in this instance are complete, and 
will laud in grateful reminiscence the name of Davy. 
On Thursday (28th ultimo) I descended the * William” Pit 
here, in company with that enlightened practical miner Mr. 
Peele, when Sir H. Davy’s safe-lamp was put to the severest 
proof, in a recess of the most dangerous workings of the mine, 
and where a candle would have proyed certain destruction, We 
only wanted the presence of Sir Humphry to have shared in our 
admiration of the imposing spectacle. The flame of the lamp 
was first capt with a blueish flame, a lambent light was then 
seen playing in the cylinder, and the flame of the fire- damp af- 
terwards enlarging filled the whole wire-gauze. For some time 
the flame of the wick could be discerned within the lucid at- 
mosphere of fire-damp, and then the whole was calmly extin- 
guished. More brilliant results the friends of humanity could 
scarcely have dared to hope for. Sophistry is put to the’ blush. 
Independent of experiments which ] had myself made with the 
safe-lamp, I placed implicit reliance on the manipulations of 
this illustrious chemist;—my confidence has not been shaken, 
nor have my expectations been deceived; and my conyietion is 
now absolute. 
As 
