some new Objects in Chemical Philosophy. 4,3 
tube, so that no conclusion can with propriety be drawn from 
this failure. 
I stated in the last Bakerian lecture, that in attempting to 
produce ammonia from a mixture of charcoal and pearlash, 
that had been ignited by the action of water, in the manner 
stated by Dr. Woodhouse, I failed in the trial in which 
the mixture was cooled in contact with hydrogene. I have 
since made a number of similar experiments. In general when 
the mixture had not been exposed to air, there was little or 
no indication of the production of the volatile alkali ; but the 
result was not so constant as to be entirely satisfactory ; and 
the same circumstances could not be uniformly obtained in 
this simple form of the experiment. I had an apparatus made, 
in which the phenomena of the process could be more rigour- 
ously examined. Pure potash and charcoal, in the proportion 
of one to four in weight, were ignited in the middle of a tube 
of iron, furnished with a system of stopcocks, and connected 
with a pneumatic apparatus, in sucji a manner, that the mix- 
ture could be cooled in contact with the gas, produced during 
the operation ; and that water exhausted of air, could be made 
to act upon the cooled mixture, and afterwards, distilled from 
it ; figures of this apparatus, and an account of the manner in 
which it was used, are annexed to this paper. In this place I 
shall state merely the general results of the operations, which 
were carrried on for nearly two months, a variety of precau- 
tions being used to prevent the interference of nitrogene from 
the atmosphere. 
In all cases in which the water was brought in contact with 
the mixture of charcoal and potash, when it was perfectly 
cool, and afterwards distilled from it by a low heat, it was 
G 2 
