316 Scientific Intelligence. [APRIL, 
to fall. The precipitate weighed 175-2 gr. This he considers 
equivalent to 28 gr. of carbonic acid. It is in reality equiva- 
lent to 28°7 gr. Thus these two analyses corroborate each 
other,—(See Gilbert’s Annalen, vol. xlix. 412.) 
Il. Iodine. 
Lampadius has observed that iodine dissolves with great 
facility in sulphuret of carbon, and gives it a dark reddish brown 
colour. One grain of iodine gives a deep colour to 1000 gr. of 
this liquid. Hence he recommends the sulphuret of carbon as 
an excellent reagent for detecting the presence of iodine. 
Ill... Analysis of the Tourmalin. 
I mentioned in the number of the Annals of Philosophy for 
last July, that boracic acid had been detected as a constituent 
of the tourmalin. This discovery was announced by Lampadius 
in March, 1818. It was made, he says, in his laboratory, by 
Mr. Breithaupt and himself. Since that time, the tourmalin has 
been examined by Dr. Gmelin, of Tubingen, with the express 
object of verifying the discovery of Lampadius. But hitherto 
his efforts to detect the presence of boracic acid have been 
unsuccessful. He had repeatedly analyzed the tourmalin in 
Berzelius’s laboratory, and had always met with the same loss 
as had occurred to Bucholz, 
IV. Phosphate of Iron. 
M. Vogel, of the Academy of Sciences at Munich, has made 
a set of experiments to determine the composition of the different 
hosphates of iron. Native prussian blue (as it is called) he 
ound composed of 
Water. CYST AR OT AOSEO 
Protoxide of iron...... 5 li ae IE 5 4:5 
Phosphoric acid. ...... Set Ly. ae 
984 
Artificial protophosphate of iron he found composed of 
Water oy. oO) are 27°0 
Protoxide of iron ...... 43°6 .......- 4:5 
Phosphoric acid. ...... 27°4 w..eeee . 26 
98:0 
The perphosphate of iron he found a compound of 
(ORE ie lin chan hota hac si ee 
Peroxide of iron. ...... 37 weveeeee 5°00 
Phosphoric acid... ..2... 38 sveseee. Old 
99 
It is obvious from the equivalent numbers which Ihave added 
