Chemistry and Physics. 115 
On the amount of Ammonia contained in the Atmosphere; by M. 
Fresenius.—The quantitative determination of the ammonia in the at- 
mosphere, by M. Grager, gave 0°323 grms. ammonia or 0:938 carb. 
amm. in 1,000, grm. of air. In this determination, the quantity of 
ammonia already existing in the chlorid of platinum, (used to precipi- 
‘ate the ammonia collected from the air,) was not determined. In an 
experiment made by Dr. Kemp, 3°68 grms. of ammonia, or 10°37 car- 
bonate of ammonia were obtained. In this case the ammonia was ab- 
tres (610 cub. in. or about 11 qts.) each, were arranged so as to fill 
one in the day, the other at night. To each of these there was at- 
tached a collecting apparatus of two small flasks connected together 
and containing dilute hydrochloric acid (1 pt. acid sp. gr. 1°12, and 20 
pts. water). For forty days the air was passed through the apparatus. 
The quantity passed by day was 345,250 cub. cent., (about 12-2 cub. 
ft.) by night 344,250 cub. cent. (about 12°1 cub. ft.) 
The usual precautions in estimating ammonia by chlorid of platinum 
Were observed. ‘The ammonia already existing in the chlorid of plati- 
num was estimated, making use of the same quantity as that employed 
in the two experiments. ‘I'he ash of the filters was also very carefully 
determined. 
The air which passed during the day and night gave respectively 
0027 and -0029 of platinum and ash, from which ‘00064 and ° 7 
Were to be deducted for the ash, and ‘00182 for platinum, from deter- 
mination of ammonia previously existing in the chlorid. The remain- 
ders were d ‘00041 platinum. From this it would result that 
The author presents these results as an approximation, the quantity 
of ammonia obtained being too small for accurate results, as any error 
in weighing or determining the ash, would produce an enormous differ- 
€nce in the results. G.C.S. 
- On the varieties of Chloroform; by MM. Sovserran and Mt- 
ALHé.—(Journ. de Pharm., July, 1849.)—Chloroform is obtained, as is 
known, both from common and methylic alcohol (pyroxylic spirits)— 
the produets although generally considered as identical in composition, 
ie such different properties as to render an investigation very de- 
Sirab] 
Pyreumatic odor. Chlorine is a constituent. Sul] hurie acid was found 
t the most suitable substance for destroying this impurity of the 
