Chemistry and Physics. 481 
H.SO, sol. SnCl, sol. © Calculated. 
3 ec, req. 1°87 ce. 1°85 ce. 
5 3°10 - 
10 6°16 615 
25 15°38 15:37 
Twenty-five ce. fe the sulphuric acid oo gave 0°4633 
rams barium sulpha 
Perhaps the slater in drinking water can be determined by 
means of the chromic acid method, but my experiments are as 
yet incomplete. — 
laving worked for Some time with the method of ee 
iron by means of stannous chloride, I am convinced that 
importance is not yet recognized generally. |The ohana 
modification seems to simplify the process as given in the last 
edition of Fresenius’ analysis. To the iron solution which has 
just been decolorized by stannous chloride, add a small pipette 
full of iodine solution, equivalent to about one-fourth cubic 
centimeter of stannous ‘chloride, cool, then add a little starch 
paste and stannous chloride until the color disappears. The 
equivalent in stannous chloride of the pipette of iodine solu- 
tion substracted from the whole amount used leaves the quan- 
tity required by the iron. By this means the use of a second 
burette is avoided and less calculation is required. 
Office of State Gas Inspection, 32 Hawley street, Boston. 
SCIENTIFIC INTELLIGENCE, 
I. CHEMISTRY AND PHysics. 
On the Gases enclosed in Lignite.—Tuomas, in continuation 
of tis erica upon the gases enclosed in coals, has examined 
with this view the lignites of Bovey Heathfield, Devonshire, = 
also a specimen of mineral resin, a . retinasphaltam” of Hate 
ett. A leafy lignite weighing 1 0 grams, on being kept in a 
Sprengel vacuum at 50° for fous days, scckon’ 56°1 cc, of gas, 
canara: of CO, 87°25, O 0°24, CO 3°59 and N . 92== 100. It 
100 grams of resin, comsting of CO, 882 ‘24 an 0°23, a : ies 
0-47, CO 7-0, N 3°16=100. On further bestia hk sonic began 
to melt, and ‘decom saat set in at 110° to 112°, the gases col- 
lected below 150° consisting of H,S 0°41, CO, 78°88, C,H,, gases 
Am. Jour. Sct. ae Series, Vou. XIV, No. 84,—Dec. , 1877. 
