2 go Mr. Porrett’s experiments , & c . 
or understood, and the analyses of which were very difficult : 
but I would not allow this consideration to have any influ- 
ence in deterring me from making such a contrast, for as I 
had not the vanity to give these analyses as perfect, so I feel 
no mortification in now proving, that they were not so ; and 
being confident that I had not spared either time or trouble 
in making them, I expose their imperfections without hesita- 
tion, confiding in the candid judgment of those, who, having 
undertaken similar investigations, are aware of the numerous 
difficulties, and sources of error attendant upon them. 
I have arranged and collected these comparisons into the 
form of a Table, which I beg leave now to introduce. 
I infer from the Table, that the acids and salts included 
in it, are so composed as to harmonize perfectly with the 
doctrines of Dalton and Berzelius, and to be very com- 
patible with the opinion respecting the compound nature of 
azote. 
I shall be happy if this attempt to elucidate the nature and 
composition of these bodies, adds in any degree to the daily 
and rapid progress now making in chemical science. 
ROBERT PORRETT, Jun. 
Tower , Feb. 22, 1815 . 
