40 Silliman and Wuviaion Air and Gas. 
of the arms of the Crinoids, or in currents produced by the 
a of the arms of the latter? The excrementitious matter 
f the Crinoid could doubtless have passed out under the foot 
of the Platyceras, supposing the opening in the Crinoid some- 
times covered by these shells to have been the anus, but it is 
difficult to conceive how food could have passed in, if we s sup- 
pose this opening to be the mouth. 
Art. IV.—On the effect of Atmospheric Air when mixed with 
Gas in reducing its fear mcs power; by B. Sriumman, 
and HENRY 
E data given in n this article were obtained during an inves- 
hietaion of the Hydrocarbon Gas Process by the “ Gwynne-Har- 
ris” or ‘‘ American System,” some notice of the results of 
— we ip to publish in a future number of this Jour- 
rse of this investigation it became important 
to measure castle the effect of atmospheric air in reducing 
the illuminating power of gas. Owing toa mechanical defect 
in the apparatus connected with the exhauster, it was found 
that a variable quantity of air had for some time found its 
way into the gas holder, the influence of which in diminishing 
subject known to us when its study was undertaken by us were 
those of Messrs. Audouin and Bérard* (also quoted in the 
American Meter Cos. Pocket Almanac.) By these results 
the ratio of loss in illuminating power by the addition of each 
od given us Only his initils a the journal in 
they J aa being almost inaccessible to scientific 
In con ducting this research we soon found that the attempt to 
introduce by measure a given volume of air into the gas holders 
connected with the photometric apparatus, was attended wit 
sources of error, and that the requisite accuracy could be 
obtauat only by the eudiometrical analysis of each successive 
* Ann. de Ch. et Phys., 3d series, vol. Ixv, p. 423, 1862. 
+ Kinet Gaslight Journal, August 1, 1860, p. 41. 
pe ‘ 
as ss 
