C. Wolf on the equivalent of Cerium. 53 
by a jointed rod with a stopcock in the pipe by which the gas 
enters. When the bell rises from the pressure of the gas, it 
Songer closes this cock, and thus cuts off the farther supply. 
he gas is then under a constant pressure depending upon the 
weight of the bell ; as gas is consumed the bell sinks and open- 
ing the cock allows more to flow in. The difference of weight 
of the bell from its greater or less immersion in the water is 
inappreciable ; a very slight diminution of pressure, hardly 
perceptible without a microscope, is observed when one of the 
outlets is suddenly thrown open to its full extent, and is due 
probably, to the friction of the gas in the tubes, which should 
therefore be of considerable size. 
The apparatus should not be painted, as oil is acted upon by 
water which has been long in contact with gas. Asphaltum 
varnish seems-to answer better. 
Art, VIIIL—On the Equivalent of Cerium; by the late Dr. 
HARLES Wor, of Cincinnati, Ohio. 
Ar the suggestion of Professor Bunsen in Heidelberg, the 
father “ the late Dr. Charles Wolf of sacar Ohio, p ste 
in my hands and preparations relating to an invest 
tion, which ison hed feeds while in the laboratory of Prof. 
Bunsen, and requested me to collate the same and prepare 
them for publication. This task I cheerfully accepted, the 
more, that I deemed the death of this young and promising 
chemist a real loss to the cause of science. : : 
I here give a translation of Dr. Wolf’s investigation on the 
regan of cerium, which Bunsen pronounces very valuable. 
ve examined all the data with the test care and gone 
culations. The — 
my hands, all buta iew 
notes, but these 
it, with the aid 
