336 Dr. T. Andrews on the Heat disengaged during the 



i<^nition, only O'OOl grm. phosphorus was required. Th( 

 heat evolved by the combustion of this weight of phosphorus 

 is nearly six units ; but as a part entered into combination 

 with the tin and thus escaped combustion, I have taken onl,, 

 four units from the final results as a correction. The saPj^,^ 

 small quantity of phosphorus was found to be sufficient in ai: 

 the subsequent experiments with oxygen. In some instances, 

 indeed, its presence might have been wholly dispensed with ; 

 but as it rendered the success of the experiment in all cases 

 verv certain, and at the same time introduced a very trifling 

 correction, 1 always employed it. In the tables which follow, 

 M designates the weight of oxygen absorbed by the metals or 

 oxides. 



Protoxide of Tin and Oxygen . 



The protoxide of tin was prepared, according to the direc- 

 tions of Fremy, by boiling the hydrated oxide in a dilute so- 

 lution of hydrate of potash. It was afterwards dried at a low 

 red heat in a current of dry carbonic acid gas. The experi- 

 ment was performed in the same manner as the last. The 

 whole of the heat was given out in sixteen minutes. 



2. 3. 



1-213 grm. 1-085 grm. 

 Q^-S 1 1°-3 



l°-5 l°-6 



3°-013 2°-723 



3°-029 2°-74.4 



1618 grms. 1610 grms. 

 117 grms. 117 grms. 



2. 3. 



4328 4364 



