1826.] Scientific Notices — Chemistry. 69 



also noted ; whilst the presence of gyrogonites and Carpolithes 

 thalictroides is quoted as completing the resemblance of the 

 Hordwell strata to those of the Paris basin. 



The author further observes, that the freshwater strata do not 

 crop out in Beacon Cliff, as had been supposed, but are con- 

 tinued for about a quarter of a mile or more in Barton Cliff, 

 interposed between the diluvium and white sand that cover the 

 London clay : and, scarcely hesitating to refer the white sili- 

 cious sand (which rises in Beacon Cliff, and is continued 

 through Barton as far as the High Cliff, near Muddiford), and, 

 consequently, the analogous bed resting on the London clay in 

 Alum Bay, to the freshwater series, he concludes, from the incli- 

 nation of the strata in the latter place, that the freshwater 

 formations suffered, though in a less degree, the disturbance to 

 which the vertical strata of the Isle of Wight were subjected. 



June 16. — A paper was read, entitled. Notes on the Geolo- 

 gical Structure of Cader Idris ; by Arthur Aikin, Esq. FGS. ; 

 an abstract of which will appear in our next number. E. W. B 



Article XIII. 



SCIENTIFIC NOTICES, 



Chemistry. 



1. On the Absorption of Gases by Liquids, By T. Graham, MA. 

 (Communicated by the Author.) 



1. Liquids are in general miscible with one another, in all 

 proportions as water and alcohol, or in a limited degree as ether 

 and water ; ether agitated with water taking up one-tenth of its 

 weight of that liquid. 



2. Frequently the mixing of liquids exhibits the closeness of 

 chemical union, among other points, in the manner in which 

 the volatility of the compound liquid is affected. Thus the 

 vapour from pure alcohol at 170° Fahr. supports a column of 

 mercury of 30 inches, but by mixing the alcohol with a quantity 

 of water, we impair the volatility of the alcohol ; and we may 

 form mixtures which require a temperature of upwards of 200°, 

 to produce vapour capable of supporting such a column. In the 

 same way portions of water are retained with so great force by 

 sulphuric acid, as to require, in order to drive them off, a degree 

 of heat greatly higher than the boiling point of water. From 

 these, and other instances of this affinity, we learn, that in a 

 mixture of a volatile and more fixed liquid, the tendency of the 



