ie 4 
Chemistry and Physics. 109 
sc the est of the above-mentioned investigations and give the 
tes 
When f rrocyani id of potassium is added to a salt of quinia in the 
— a rallowish white cloudy precipitate falls, provided the es ved 
ot added in excess; otherwise nothing characteristic results. This 
ipitate is soluble by heat and readily so in ae of ferrocyanid ‘of 
potassium without any subsequent change occurrin the solution. If + 
ferrocyanid of potassium be added to a soluble salt of cinchotia whether 
ded in excess or not, whether added to a strong or a weak solution, a 
yellow white curdy precipitate falls. If a very gentle heat be now ap- 
lied this precipitate dissolves, but as the liquid cools again a crop of 
splendid pide (gold-yellow) cryuala § falls so abundantly as sometimes to 
give tinous appearance to their mass. These crystals are flat plates, 
PON ae 
upon the other in the same way as are crystals of nitrate of urea. e 
erystals are best observed pe a low magnifying power, fifty diameters, 
and will then be found such as we have described them. _ The precipitate 
is not soluble in excess of ferrocyanid of age rae but like this latter is 
decomposed by boiling with mineral acids. This test for cinchonia is a 
very delicate one, not less so than that 1 by the biniodid of potassium, and 
is far more characteristic, since none of the alkaloids manifest the reac- 
tion except cinchonia. In practice it will be well, for obvious reasons, to 
use a slight excess of ferrocyanid of potassium, as little excess of acid as 
possible, and to heat the liquid very gently a the first precipitate has 
fallen. 
5. Note on the use of the Molybdate o Ammonia test for Phosphoric 
_ Acid ;s by J. W. Brit, Acting c—— U.S. A., (communicated for this 
Jou ed on that i 
e observ: on conducting the process for 2 
tedecetion of shneapneté acid i in a liquid we were nearly sure contained 
a eesistgie nh ag chrome-green, instead of the char- 
jy, acteristic yellow preci ipitate. was observed in the laboratory of Mr. 
ae Hen ry Wurtz, who examined i "igi and corroborated an examination 
= Wehad made proving that a soluble iodid was present as well as 
shierio acid. For a while we were puzzled to account for this phenome- 
non, it appears to us that it may be explained thus. 
ree nitric acid liberated some iodine and this reduced t the — 
date to the state of the molybdo-molybdate, Mb20s, eos this in sol 
is a cobalt-blue. This blue liquid abi | mixed with th e yellow pre 
three weeks large erystals of iodine will be found lining the sides of the 
tube, the liquid will h have become brown- red in color . a gas will have 
been eliminated sufficient sometimes to have burst The reac- 
tion may be SS thus: the — ow sesiin pitate, si kEe 
acid, the iodid of eee give =. sgtnaoNtajeobbet 
1858). -In a recent paper on on the earthy carbonates (Ann. de 
de Pi , third series, vol. li, p. 302), Bineau concludes that the car- 2 
