Mr. Davy’s Researches on the 
246 
In considering the dry muriates, as compounds of oxy- 
muriatic acid and inflammable bodies ; the argument that I 
have used in the last Bakerian lecture, to shew that potassium 
does not form hydrate of potash by combustion, is considera- 
bly strengthened ; for from the quantity of oxymuriatic acid 
the metal requires to produce a muriate, it seems to be shewn 
that it is the simplest known form of the alkaline matter. 
This I think approaches to an experimentum crucis. Potash 
made by alcohol, and that has been heated to redness, appears 
to be an hydrat of potash, whilst the potash formed by the 
combustion of potassium must be considered as a pure me- 
tallic oxide, which requires about 19 per cent, of water to 
convert into a hydrat. 
Amongst all the known combustible bodies, charcoal is the 
only one which does not combine directly with oxymuriatic 
acid gas ; and yet there is reason for believing that this COin- 
must be assumed to exist in ammonia, will be exactly sufficient to neutralize the hy- 
drogene, in an equal volume of muriatic acid ; or if it be said that ammonium is a 
compound of 2 of ammonia and 1 of hydrogene in volume, then equal volumes of 
muriatic acid gas and ammonia will produce the same compound as oxymuriatic 
acid and ammonium, supposing they could be immediately combined. I once thought 
that the phenomena of metallization might be explained according to a modified 
phlogistic theory, by supposing three different classes of metallic bodies : First, The 
metal of ammonia, in which hydrogene was so loosely combined as to be separable with 
great ease, and which, in consequence of the small affinity of the basis for water, it had 
little tendency to combine with oxygene. The second, the metals of the alkalies and 
alkaline earths, in which the hydrogene was more firmly combined, but in combustion, 
forming water capable of being separated from the basis. And, thirdly, the metals 
of the earths and common metals, in which the hydrogene was more intimately com- 
bined ; producing by union with oxygene, water not separable by any new attractions. 
The phasnomena of the action of potassium and sodium upon muriatic acid, referred 
to in the text, seem however to overturn these speculations so far as they concern the 
metals from the fixed alkalies, 
