120 



DE. B. D. STEELE, DR. D. McINTOSH AND DK. E. H. ARCHIBALD 



PAET II. 



Tli e Conductivity and Molecular Weights of Dissolved Substances. 



and E. H. AKCHIBALD. 



By D. MCINTOSH 



THE second part of this investigation deals with the solubilities of substances in the 

 liquefied halogen hydrides and sulphuretted hydrogen, and with the conductivities of 

 the resulting solutions ; the molecular weights of a few substances, when dissolved in 

 each of these solvents, have also been determined. 



The Temperature Bath. 



As liquid air was not available in sufficient quantities to make use of the bath 

 described in Part I., a mixture of carbon dioxide and ether, which under atmospheric 

 pressure gives a very constant temperature of 81, was used for the measurements of 

 solutions in hydrogen bromide and sulphide. 



The same mixture, under reduced pressure, was used for the measurement of 

 solutions in hydrogen chloride. By carefully regulating the pressure over the 

 mixture the temperature was maintained at 100. 



For the hydrogen iodide solutions a temperature of 50 was 

 obtained by slowly running cold ether into the vacuum vessel 

 and syphoning off the warmer upper layer. 



The Determination of Solubilities. 



The solubilities were measured by means of an apparatus 

 (fig. 1) which consisted of a test-tube A, to the bottom of which 

 a delivery tube B was sealed. The bottom of A was covered 

 with a thick layer of asbestos which acted as a filter, and the 

 whole was immersed in the constant-temperature bath. 



The liquefied gas and the substance of which the solubility was 

 under investigation were introduced into A, where they were 

 vigorously stirred with a platinum rod. A portion of the liquid 

 was then blown through the delivery tube into a weighed and 



The volume of liquid in the test-tube was observed, the liquid 



Fig. 1. 



graduated test-tube. 



allowed to evaporate, and the residue weighed. The solubility was calculated from 



the data thus obtained. 



