133 
apparent than real. They were described, however, and also 
the methods of guarding against them. In closing, Prof. 
Egleston discussed the general importance of this subject. 
There is no chemical or metallurgical industry wherein the 
constant analysis of the gas, rendered possible by this appa- 
ratus, will not very soon furnish the key to effecting an im- 
portant saving, and where the theory and working of the 
process may not be studied in minute detail. Moreover, in 
order to adapt the apparatus to the study of any gases given 
off in any operation, it suffices simply to vary a little the 
character of the absorbent liquids used. Experiments and 
modifications are now in process, to adjust and perfect this 
apparatus for the analysis of hydrocarbons and complex 
gases, or for any operation which can be performed by the 
Regnault or Doyere methods. 
Mr. W. Gooutp LeEvison read the following paper :— 
On a Simple Connective for Battery Carbons. 
To follow the interesting papers we have heard, with so 
simple a thing as a means of attaching a connecting wire to a 
battery-carbon, would seem to me too great a transition for 
your attention, were I not aware that just such simple mat- 
ters often give great aid in difficult and laborious work. The 
connecting wire is usually fastened to battery-carbons b 
means of a clamp, costing from 25 cents to $1.00, which 
needs, especially when nitric acid is used, to be often re- 
newed (except in case of the more expensive forms), and 
always requires a large portion of the carbon plate or rod to 
praject above the liquid. Not only is the projecting carbon 
a considerable item of expense, as well as of weight, in bat- 
teries of the Bunsen form, when true gas-carbon is used, but 
the liquid, creeping over it, evaporates rapidly, and it soon 
becomes covered with an efflorescent crystallization of salts, 
In such batteries, all these inconveniences may be obviated 
by the simple means which a glance at the carbon I hold in 
my hand, will explain to you. It is drilled to a depth of two 
centimeters, with a seven millimeter drill, and to a greater 
depth by a three millimeter drill. In the inner hole is then 
driven a brass pin, to which the connecting wire is soldered ; 
and a glass tube slipped over the wire is then cemented in 
the larger tube by means of melted shellac or other suitable 
cement. The carbon may be so short as to be wholly im- 
mersed in the acid; and although the acid certainly does 
penetrate to the wire, and ultimately corrode it, yet it lasts a 
