34 



REPORT — 1867. 



Table to shotu the Speed of Currents of Air as indicated hy the Ether Manometer. 



v.= Vp.X 25-31. 

 Temp. 60° Falir. Bar. 30 inclies. 



On tlie Refraction Equivalents of Salts in Solution. By Dr. Glad.stone, F.R.S. 

 The object of this paper was to describe some preliminai-y obseiTations on the 

 effect -which various salts dissolved in water exert on a ray of light transmitted 

 throiiofh them. The author in this way expected to anive at the refractiou-equi- 

 valents of all the metals, and of the substances capable of combining -with them to 

 form soluble compounds. As yet, however, he rather indicated the method than 

 the results, as he was unprepared to give precise numbers. 



Experiments for tlie Verijication of the Laws of Dr. Henry and Dalton on the 

 Absorption of Gases by Liquids. By Dr. N. de KHANrKOi". 



The fact of absoi-ption of gases by liquids was known by natm-al philosophers 

 at the end of the seventeenth centm-\-, but the first serious observations on this 

 subject were made by Cavendish and IMestley. 



At the beginning of this centui-y, in the Philosophical Transactions (1803, part 1, 

 pp. 29-42), Dr. Henry published a. vei-y important memoir, " Experiments on the 

 Quantity of Gases Absorbed by Water," in which he formulates the law of absorption 

 in the follo-sving manner : " The results of at least fifty experiments on carbonic 

 acid, sulphm-etted hydrogen gas, nitrous oxide, oxygenous and azotic gases, esta- 

 blish the folio-wing general law — that under equal circumstances of temperature, water 

 takes up, in all cases, the same rohime of condensed gas as of gas under ordinary 2^res- 

 sure. But as the spaces occupied by every gas are inversely as the compressing 

 forces, it follows thatu-afcr takes up, of gas condensed by one, tiro, or more additional 

 atmospheres, a quaidity which, ordinarily compressed, would be equal to ticicc, thrice, 

 Si-c. the volume absorbed under the common pressure of the atmosphere.'' This law 

 was accepted -svithout change until now. 



Nevertheless it was e^ident that so simple a relation between the power of 

 absorption of gases by liquids and the pressure, could only be considered as a rough 

 approximation, and that in reality a phenomenon so intimately connected with the 

 molecular structure of the liquids could not be exjiressed in such a simple form, 

 because the unlimited admission of this law compelled one to admit also an un- 

 limited absorption of gases already known to be impossible for all gases, especially 

 for the condensible ones. Ur. Ilenry, from the nature of the apparatus he con- 

 structed for his researches, could not come to any other conclusion. His apparatus 

 consisted simply of a glass bell, in which he introduced the absorbing liquid and 

 the absorbable gas. This bell was connected with a manometer by a tube of india- 

 rubber, and after the establishment of the required pressure, could be separated 

 from the manometer and shaken bj- the observer a long time, for producing the 

 total absorption. This construction had two great imperfections : — 1st, it did not 

 admit of a pressure of more than three atmospheres without forcing the joint; and 

 2udly, the long contact of the hands of the observer -with the bell made very un- 

 certain the evaluation of the temperature of the gaseous vohmie before and after the 

 absoii^tion. Saussure repeated the experiments of Dr. Henry without changing 

 considerably his apparatus, and came natm-ally to the same result. Nearly forty 

 vears after, Prof. Bunsen, of Heidelberg, made a valuable series of experiments on 

 the absorption of gases at different temperatures, but the ingenious apparatus he 



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