I 



1914.] on the Cause of Chemical ProportioJts, 1'7«? 



and 74-8 oxide per cent. It is from the analysis of this compound 

 that he derives his knowledge of the elements of the acid. My 

 analysis of oxalate of lead, recently repeated, gives me 29 acid and 

 7) yellow oxide. Here then, in the offset, is a very material 

 difference betwixt us as to facts : any chemist, however, is compe- 

 tent to satisfy himself on this head without appealing to authorities. 

 Let a solution of acetate of lead be treated with oxalic acid, or any 

 soluble oxalate, and the oxalate of lead will be immediately tlirown 

 down. Let it be carefully washed, dried, pulverized, and again 

 dried in a temperature of 100°. If, then, 137 parts of this be put 

 into a platina or iron spoon, and be very gradually heated to a lo\V 

 red to prevent loss by decrepitation, there will remain 97 parts of 

 pure yellow oxide ; giving the constitution of the oxalate as under j 

 uaniely, 



Lead 90 



Oxygen 7 



Oxalic acid 40 



137 



The quantity 137 's here preferred because the numbers thence 

 resulting represent those for the respective atoms upon my system. 

 According to the analysis of Berzelius, an atom of oxalic acid 

 would weigh only 32'7j vvlilch is less tlian that of sulphuric acid; 

 in fact, he finds 26J- sulphuric acid in sulphate of lead, and only 

 25-2 of oxalic acid in the oxalate. Now it happens that all the 

 modern chemists who have analysed the oxalates (Berzelius ex- 

 cepted) agree with me in making the oxalic acid heavier than the 

 sulphuric, as may be seen from their analyses of the oxalate of lime 

 below : — 



Lime. Oxalic Acid. 



Dr. Thomson 24 40 



Gay-Lussac 24 38 



Berard 24 32 



NB. The atom for sulphuric acid is 34 on this scale. 

 About two years ago I made a series of expeiiments on oxalic acid 

 and tlie oxalates. I then determined (as I conceived) the constitu- 

 tion of the acid, assisted very materinlly by the masterly analysis of 

 Gay-Lussac, with which I found my results very nearly accord, as 

 well as by tliat of Dr. Thomson. Tlie atom of oxalic acid, I appre- 

 hend, is constituted of 1 hydrogen and 2 carbonic acid ; or of 1 

 hydrogen, 2 carbon, and 4 oxygen ; the total weiglit being 39*8, or 

 40. This being reduced to 100, and compared with the modern 

 analyses, the results will stand as under. Oxalic acid is composed of 



Per Theory. Gay-Lussiic. Tliorason. Berzelius. 



Hydrogen . . 25 275 4 7 



Carbon 27*1 2fi'5G 82 35-0 



Oxygen 70-4 7069 C4 (.•4'5 



100 100 100 100 



m2 



