40 Improvements in Physical Science [Jan. 
Phosphorus. Oxygen. 
; 15 + 1 
Hypophosphorous acid.... 100 + 66°66 
- 15 + yy 
Phosphorous acid.....- +++ jo 4. 13333 
- . 15 + 3 
Phosphoric acid ........ { 100 + 200 
If this opinion be true, we are far, indeed, from a true know- 
ledge of the composition of phosphoric acid. At all events it will, 
I think, be acknowledged, even by Berzelius himself, that my 
mode of analysis or synthisis by the combustion of phosphureted 
hydrogen is susceptible of much greater precision than the very sus- 
picious method had recourse to by Berzelius; and that the compo- 
sition of phosphoric and phosphorous acids as determined by him is 
radically wrong. When he peruses what I have here stated, I dare 
say he will feel ashamed of the terms in which he has spoken of my 
determinations, and allow that a man may fall into mistakes, when 
treating of so difficult a subject, without any culpable carelessness 
or want of precision. 
4. Action of. Phosphoric Acid on Indigo.—Dobereiner tried the 
effect of phosphoric acid. upon indigo, both when anhydrous, and 
when in the state of a hydrate. But in neither case was there any 
action whatever. Sulphuric acid, then, is the only known acid that 
has the property of dissolving indigo without destroying the colour. 
When the sulphate of indigo is boiled, a portion of the indigo pre- 
cipitates, and the rest loses its blue colour, and is of course decom- 
osed. (Schweigger’s Journal, xiv. 372.) 
5. Uric Acid.—Gay-Lussac has ascertained, by heating a mix- 
ture of uric acid and oxide of copper, and receiving the gaseous 
products over mercury, that this acid, when decomposed, yields 
two volumes of carbonic acid and one volume of azote. (Ann. de 
Chim. xevi. 53.) It contains, therefore, two atoms of carbon and 
one atom of azote. In this respect it agrees with cyanogen. Pro- 
bably it will be found to differ from hydro-cyanic acid by containing 
an atom of oxygen instead of hydrogen. It is likely that uric acid 
will be found to be composed of one atom oxygen, one atom azote, 
and two atoms carbon. 
6. Rosacic Acid.—Vogel has made some experiments on rosacic 
acid, which is known to appear in urine in certain cases of disease, 
It is soluble in boiling alcohol, and by this means may be separated 
from uric acid. Sulphuric acid dissolves it, and converts it into 
uric acid. It gives a permanent red colour to sulphurous acid. 
Nitric acid converts it equally into uric acid. (Ann. de Chim. 
xcvi. 306.) From these experiments it would seem that rosacic 
acid approaches very near the uric acid in its nature. 
7. Acid of Stick Lac.—Dr. John has discovered a new acid in 
stick lac by the following process. The lac is pulverized, and washed 
in water till it gives no further colour to that liquid. ‘The watery 
