Ordinary Meeting, January 21st, 1873. 
E. W. Binney, F.R.S., F.G.S., Vice-Presi- 
dent, in the Chair. 
The Pkesident explained a simple ap- 
paratus by means of which a very high 
decree of rarefaction of air could be 
O 
produced with much facility, and which 
might in some circumstances be found 
preferable to the common air-pump or 
even the Sprengel. It consists of a glass 
funnel a surmounting a globe 6, from 
the lower part of which a tube c descends 
to a jar of mercury d. The tube e, in 
connexion with the receiver to be ex- 
hausted, is furnished with a vulcanised 
indiarubber plug which fits into the neck 
of the funnel. In using the apparatus 
the stopcock / is shut and the funnel 
filled with mercury. Then by lifting 
the tube e with its plug, the mercury 
fills the globe b and the pipe c. The 
tube e is then replaced, and the stopcock 
being opened, the mercury descends in c 
emptying the globe. By returning the 
mercury into the funnel by means of a 
pump, or more simply, by lifting the jar 
d, the process is repeated until the requi- 
site degree of rarefaction is produced. 
Scale 
(Z 
