221 
Mr. Porrett’s experiments , &c. 
in which the elements of these new acids are combined in 
them, and also into the proportions in which they unite with 
different saline bases. 
My object in this paper, is to add to the analyses contained 
in the former, two analyses which I have since made ; and 
then to apply to the whole, the admirable theory of Dalton, 
by which the proportions in which bodies can combine, are 
conceived to be governed by the relative weights of their 
chemical atoms, and also Berzelius’s addition to this theory, 
by which the combinations of oxides with one another, are 
conceived to take place in such a manner, that the oxygen 
contained in one of these bodies, is either equal to, or is a mul- 
tiple by a whole number, of the oxygen contained in the 
others. 
I begin with describing the two analyses to which I have 
just alluded. 
Analysis of prussiate of mercury. 
A. Fifty grains of this salt finely pulverised, were kept at 
the temperature of 21 2° for six hours, at the end of which 
time, they weighed exactly the same as before. 
B. Forty grains of this salt were dissolved in water and 
decomposed by hydro-sulphuret of potash : the products of 
this decomposition were prussiate of potash and black sul- 
phuret of mercury ; the quantity of the former could not be 
ascertained with accuracy, owing to the escape of much of 
the prussic acid, but that of the sulphuret amounted to 37.2 
grains. 
C. Disappointed in my attempt to estimate the quantity of 
prussic acid by the last experiment, owing to its very volatile 
nature, I availed myself of the property I had discovered 
