[ io6 ] 
yill. An Account of a new Eudiometer , 
By itfr.Cavendifh, .F. F. & 
Read January 16, 1783. 
PRIESTLEY’s difcovery of the method of deter-* 
mining the degree of phlogiftication of air by means, 
of nitrous air, has occafioned many inftruments to be contrived: 
for the more certain and commodious performance of this ex- 
periment ; but that invented by the Abbe fontana is by much 
the mod: accurate of any hitherto published. There are many 
ingenious contrivances in his . apparatus for obviating the fmaller 
errors which this experiment is liable to ; but the great im- 
provement confifts in this, that as the tube is long and narrow,, 
and the orifice of the funnel not much lefs than the bore of 
the tube, and the. meafure is made fo as to deliver its contents 
very quick, the air rifes flowly up the tube in- one continued 
column ; fo that there is, time to take the tube off the funnel,, 
and to fhake it before the airs come quite in contact, by which 
means the diminution is much greater and much more certain 
than it would otherwife be. For indance, if equal meafures. 
of nitrous and common air are mixed in this manner, the bulk 
of the mixture will, in general, be about one meafure ; 
whereas, if the airs are buffered to remain in contact about 
one- fourth of a minute before they are fhaken, the bulk of 
the mixture will be hardly lefs than one meafure and two- 
tenths, and will be very different according as it is .futfered to 
i- 
remain 
