1872.] Chemical Science. 541 
M. J. Boussingault has made some experiments to investigate the condition 
in which carbon exists in meteoric iron. In the meteoric iron of Caille, o-12 
per cent of combined carbon was detected, while the celebrated Lenarto 
meteorite was found to contain neither graphite nor combined carbon. 
New forms and new modifications of apparatus are constantly being 
proposed and described for the convenient generation of H2S, CO, and H 
in laboratory work. Many of these are somewhat complicated and expen- 
sive, more or less difficult to fill, and liable to breakage. Mr. William 
Hutchings advocates a trial of the following application of an old principle :— 
A large wide-necked jar is provided with a well-fitting stopper of cork or 
caoutchouc. Owing to the difficulty of boring a large 
hole in caoutchouc, cork will generally be preferred. 
In this a hole is bored wide enough to take a piece of 
large-bore glass tube, A B. This tube is of such a 
length that it reaches almost to the bottom of the jar, 
and projects 2 or 3 inches above the stopper. One end 
of it, B, is held in the gas-blast, and turned round and 
round till it softens and partially runs together, leaving 
only a small opening. The other end is fitted with a 
caoutchouc stopper, through which passes a glass tube 
of suitable bore with a glass stop-cock, all fitting per- 
feGtly tight. The tube reaches a little way below the 
stopper, and 3 or 4 inches above it,and is connected by 
india-rubber tube with wash-bottle, &c. The opening 
at B is covered with lead-shavings, a plug of lead wire, 
or pieces of glass, to allow the acid to rise into the 
tube, at the same time preventing any of the bits of 
marble, zinc, or sulphide of iron falling out. The tube, 
A B, being filled, is closed by its stopper and stop-cock 
tube, and inserted through the cork into the jar, which 
is a little over two-thirds full of the dilute acid. Ac- 
cording as the stop-cock is opened, a stream of gas of 
any required amount is given off, and on closing the 
cock the acid is all driven into the jar. It is evident 
that the tube A B must not fit air-tight into the stopper 
of the jar. The best way of arranging is, after boring 
the hole in the cork for the tube AB, to cut a little 
channel with the triangular file, just sufficient to 
allow of the rise and fall of the liquid in the jar. 
A jar about ro inches high, and appropriately wide, 
with a tube of 1 to 14 inches bore, gives a very suitable 
apparatus for ordinary use. By using a very large jar, 
or a large cylinder, and larger and much longer tube, a constant stream may 
be had for many days. 
Professor Dewar recently exhibited, before the Royal Society of Edinburgh, 
two modifications of Sprengel’s pump adapted to lecture illustration. In both 
instruments the mercury receptacle is made of iron, and, instead of the india- 
rubber joint of the original, a well-ground stop-cock, terminating in a Y-shaped 
piece bored out of the solid. In the one form the drop-tube is of glass, at- 
tached by means of marine glue; in the other, of carefully made india-rubber 
tube, 4 or 5 m.m. in thickness, of a very small uniform bore, made expressly 
for the purpose by the Edinburgh Rubber Company. The iron funnel-shaped 
receptacles are ground at the inner apex, so as to fit perfedly finely-ground 
iron tubes. By means of these tubes the preliminary exhaustions are made 
by a hand-pump, and then they are withdrawn. This device saves a separate 
joint. The barometer tubes are attached to solid T-shaped pieces of iron 
tube, and between these pieces and the main tubes each has a small glass 
bulb. Both forms work, for all practical purposes, as well as glass, and suit 
admirably for Frankland’s water analyses, Graham's experiments, &c. 
It would seem that the amount of ammoniacal gas absorbed by charcoal 
continually decreases as the temperature rises from 0° to 55°, but at that point 
