Ui' STEAM AKlÖlNO) FROM BOILIXU SALT SOLUTIONS. 'i 



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latter, in lioklino* it in tlie sterim over the solution. This method of 

 ascertaining the temperature of tsteam is, as ^lagnus liimself allows, 

 by no means convincing ; fur, as already observed by Faraday and 

 others, when such a. thermometer is held in the steam arisini»- from 

 boihng pure water, temperatures higher than 100° are always in- 

 dicated. 



The other method consists in previously heating the bulb of a 

 thermometer to a temperature higher than that of the boiling solu- 

 tion, and then introducting it into the steam. It is said that, in this 

 wav, temperatures a])proaching the boiling point of the solution are 

 indicated. I have, however, repeatedly tried this method, and liave 

 fully convinced myself that if sufficient care is taken to protect the 

 bulb of the thermometer against the splashing up of the hot solution, 

 the temperature rapidly falls to 100°. 



After referring to these two methods proposed by liudortf, and 

 after giving a good liistorical summary of the subject, to which I am 

 greatl}'^ indebted for this part of my paper, Magnus goes on to describe 

 his own method and the results obtained by its means. His apparatus 

 consists of a double-walled metallic vessel, filled to a convenient lieight, 

 both within and without the inner walls, with the experimental 

 solution. Steam, generated by heating the solution from bel<jw, rises 

 in the inner as well as in the outer chamber, and escapes by means of 

 a lateral tube, also metallic and provided with two holes, one of 

 whicli opens into the inner clinmbcr and the otlier into the outer 

 chamber. The object <jf li:n iug iloublc chambers is to kec]) the inrier 

 one surrounded by hot steam, so as to prevent loss oi heat by radia- 

 tion. The temperature of the steam is indicated by means of a 

 thermometer held horizontally and inserted in the lateral tulje, its bullj 

 Ijcing placed in the centre of the inner chamber. The following are 

 the results oljtained Ijv jMau'nus with a solution of calcium chloride. 



