that the mercury column is vertical, but it is unnecessary to 
dwell on such obvious precautions, which are essentially the 
same with this apparatus as those so fully detailed by Bunsen 1m 
his work on “Gasometry.” It is obvious moreover that the 
number of these corrections is considerably diminished in using 
this apparatus as compared with the ordinary mercury pueu- 
matic trough, and besides the convenience and comfort of work- 
ing in a warm room, it has the additional recomendation thats 
requires a very small amount of mercury. 
The above apparatus as represented in fig. 9 may also be 
used with great advantage in Gay Lussac’s process of ‘determin: 
ing the density of vapors. The method of using it is obvious 
to any one who is familiar with the process. After a welg 
amount of the liquid under examination enclosed in a thin g! 
bulb has been passed up into the eudiometer tube it is readily 
converted into vapor by passing steam or the vapor of some 
a of astill higher boiling 
L the i ed 
ced in the annular space between the two tubes and the differ 
ence of level of the mercury in the two limbs of the instrument 
may be most accurately determined by means of a cathetometer 
aided by the simple contrivance just described. 
* Hydrocarbons of hi iling points, obtained by the method 
of Mr. . M. Warren, pe reer pros. A gowmceabessoceyt Sidh determi 
