252 Observations on the Absorption of [Ocr. 
ral.*—A volume of this mineral dried in the air absorbed the fol- 
lowing proportions of gases :— 
Carbonic acid 2aS\) . i...-0.0-0.0:0-s:erarersiots Coy 
AZGUC oo ccs ccd ace wake ek y= 9 otal eee nnaaeem 
PAO Omen Fo Soir swine sor yore ive sates Si 
OREN. aha Son eee mis.» » ofp © = nro ,n 60s opm > woh 
Exper. 7, with different Kinds of Woods.—The wood was dried 
in the open air, and then small pieces of it were kept for several 
weeks in large flasks containing muriate of lime. Yet some hygro- 
metrical water remained in it, which became evident when the wood 
freed from air was iotroduced into ammoniacal gas, a watery vapour 
spreading itself during the absorption, which the heat disengaged 
during the process forced out. The same appearances took place 
when adhesive slate, linen, wool, and silk, were exposed to the 
same treatment. All these bodies again absorbed the vapour, The 
linen threads were firmly pressed together in bundles of the specific 
gravity 0°78. One volume of the following substances absorbed the 
following proportions of the different gases :— 
Hazel. | Mulberry. Fir. Linen Thread, 
Ammoniacal gas ...........-! 100 88 =: 68 
Carbonic acid .......s00 Res 1 | 0°46 1: 0-62 
Olefiant’. co.cc csc etecevess 0-71 _ — 0-48 
Oxy-carbureted hydrogen.... 0°58 — — 0°35 
Hydrogen .....-.-.0+-se00e- 0°58 0-46 0-75 0°35 
Carbonic oxide...........-.. 0°58 — — 0°35 
Oxygen .....-s eee eee eceeee 0:47 0-34 0°50 0°35 
Roe eas cece tee cae 0-21 0-18 021 0°33 
Exper. 8, with raw Silk and with Wool_—The specific gravity of 
the skein of silk was 0°731, of the wool 0°G. Before the experi- 
ments both were dried over muriate of lime. The temperature was 
as in the preceding experiments. One volume of each absorbed the 
following proportions of the different gases :— 
Wool, Silk, 
Volumes, Volumes. 
Airmeniacal vas 2. o:.-. soos 6» dcah Bales a ele 
Carbonic acidigas si. 'at0.c\0t URS) oS lise 5 eee a 
VCH AIRE Neree, ci2 cc’ ere 5.0 cle io sts O'DY oc the ee mama 
Oxygen ...-.csecccececoes O43 ..ceeeee O44 
CaO DIGS 630 o's o's 00 sins OS, eet dae ee 
FAVATOGEN 2. oie eet ve con OB RN ep ee Oe 
OC es oN cee tice ie Uae eras cae oy OaneD 
* This yery light variety of chalk is found en Jura, and has only the specific 
gtayity 0°465. 100 parts of it dissolve completely in nitric acid, and give out 35 
parts of carbonic acid gas, which amounts to 83 parts of carbonate of lime. The 
remaining 17 parts are chiefiy water; which always exist in a greater or smaller 
proportion in all stones possessed of a certain degree of porosity. 
