188 M. C. Lea on Picramic Acid. 
Art. XIV.—On the Formation of Picramic Acid; by 
M. Car ; 
Ir is to Mr. Aimé Girard that we owe the first isolation of 
ficromis acid, and correct determination of its constitution. His 
views however of the circumstances under which it is formed do 
not altogether agree with the results of my observations, and I ad- 
vert to them now, because his second paper contains a criticism 
on the results obtained by another chemist, which criticism I 
think depends upon an inexact view of the reactions 
In a paper published by Dr. Evan Pugh in Jickig’s Annalen, 
he endeavored to establish the identity of picramic acid wit th 
Wohler’s nitrohzematic acid, Mr. Girard, while he agrees with 
Mr. Pugh in his —o rejects his experiments and reason- 
ings as ‘insuffici 
“This rhs in fact” he says “proceeded exactly as Mr. 
Wohler had done before I demonstrated the formation of picra- 
mic acid by means of sulphydric acid. His process consists in 
mixing picric acid with protosulphate of iron, boiling with excess 
of baryta, precipitating the soluble baryta salt with ammoniacal 
acetate of lead and finally in decomposing the lead salt by sulphy- 
dric aci ow it is evident that under these circumstances, 
even supposing that the protoxyd of iron had not converted the 
picrie acid to picramic, the sulphydric acid alone would have 
produced this reduction 
. At first sight this het seems perfectly legitimate, so 
much so, that it is probable that no test by experiment was 
thought necessary. Had such been made it would have been 
ascertained that alblydeic tid is wholly without power to reduce 
ge eg whether free or in combination with lead, to picra- 
_ The fact appears to have been overlooked that sul phydric acid 
vl ie ape of producing this reaction either upon picric 
<3 or as far as ef experiments go, agaee any ean It is 
sulphydric acid is passed aoa such a solution, sauiphydt 
of ammonia is form xe and acts on ‘ic aci 
Puiladeiphia, Wor. $0, 1860. 
* Comptes Rendus, xiii, 59. 
