vegetable and animal substances. 481 
14, and to nitrate of the same metal 20.75; that is, 13.125 
of the former salt neutralize 20.75 of the latter. In the se- 
cond place, 14 parts of oxide of lead yield 21 parts of dry 
ferroprussiate of lead ; or the atomic weight of dry ferro- 
prussic acid is 7: 
The mean of my analyses of ferroprussiate of lead, gives 
the relation of the constituents of the acid, as marked in 
the table. These proportions, reduced to the atomic weight 7, 
afford 
Carbon . . 2.5774 
Azote . . . 2.4703 
Ferreous matter 1.9523 
7.0000 
Were we to suppose the prime equivalent of the ferro- 
prussic acid 7.5 instead of 7 ; and were we farther to suppose 
that the carbon in the above result should be 2.25 = 3 atoms, 
and the azote == 3.5, or two atoms, then we might conceive 
an atom of dry ferroprussic acid to be made up of 
Carbon 3 atoms 2.25 
Azote 2 3.50 
Iron 1 1.75 
1 7-5° 
But experiment does not permit me to adopt this theoretical 
representation. 
The best mode that has occurred to me for analyzing 
ferroprussiate of potash, is to convert it, by the equivalent 
quantity of nitrate of lead, into the ferroprussiate of this 
metal ; then to separate the nitrate of potash by filtration ; 
and, after evaporation, to determine its weight. In this way, 
mdcccxxii. 3 Q 
