110 
Mr. Chenevix on the Action of 
rod the crucible was about half filled with borax. Upon this 
was placed the metal to be fused ; and if it had been before 
melted into a cylindrical form, the axis of the metallic cylinder 
was placed horizontally, and was of course perpendicular to 
the axis of the cylindrical excavation at the bottom of the 
crucible. More borax was then added to cover the piece of 
metal, and another quantity of lamp-black was pressed hard 
over the whole in order to keep it tight together. An earthen 
cover was finally luted to the crucible, and in this state it was 
exposed to heat in a forge, in which upon another occasion, I 
had, in the presence of Mess. Hatchett, Howard, Davy, and 
others, completely melted a Hessian crucible lined and pre- 
pared in the same manner. The fuel which I used was the 
patent coak of Mess. Davey and Sawyer. In the present ex- 
periments I moderated the heat so as not materially to injure 
the crucible, and upon taking it out of the fire, the lining was 
generally found so compact and so firm that it remained in a 
solid mass after the crucible was broken. When the metallic 
cylinder occupied the space at the bottom, it was natural to 
suppose that it had been fused ; because in no other state but 
that of liquidity could it have run into the mould. In order 
however to prevent all objections I had the precaution to make 
the hole of a different diameter from the metallic cylinder, 
and to observe whether the necessary change in the shape of 
the latter ensued. If, after such a test, repeated as often as 
required, I perceived that the metal did not vary in its specific 
gravity, I thought myself authorised to conclude that it was 
exempt from air. 
M. Richter says that he had hoped to have put himself in 
possession of a considerable piece of palladium by repeating 
