58 
Ordinary Meeting, January IStli, 1874. 
E, W. Binney, F.B.S., F.G.S., Vice-President, in the Chair. 
Mr. Rooke Pennington, of Bolton, was elected an ordinary 
Member of the Society. 
A drawing was shown representing some further improve- 
ments of Dr. Joule’s mercurial air exhauster described in 
the Proceedings of February 18, 1873. 
In the section represented by Fig 1, W W is a wooden 
frame ; P a pulley for raising or lowering a flask of mercury 
held in a wooden box, M, working in a slide ; s s s s are 
india rubber stoppers ; E is the exhauster ; t, e the entrance 
and exit tubes ; g the gauge ; / a funnel to admit sulphuric 
acid ; B, B moveable brackets to support any apparatus. 
In Fig 2 the exhauster is drawn to a larger scale- 
t, e are the entrance and exit tubes, fitting tightly in an 
india rubber disc a, which disc is kept tightly pressed 
against the exhauster by means of the ring, 6, h. The 
mercury is represented sunk below the entrance tube, as is 
the case when the moveable flask is in its lower position. 
On raising the flask by means of the pulley, the mercury 
rises in the exhauster and forces any air it may contain 
into the upper part of the exhauster by raising the india 
rubber plug. The air then makes its exit through the pipe e. 
This latter is also used for withdrawing the acid which 
gradually accumulates. 
Fig 3, also drawn to a large scale, represents a convenient 
means of introducing sulphuric acid for removing aqueous 
vapour, or to let air into the apparatus. The orifice at the 
bottom of the funnel is about tw of an inch diameter to 
prevent violent action. 
It may be useful to mention that the junctions are made 
with black india rubber tube fastened by softened iron wire. 
