116 



Frederick Guthrie on Salt -Solutions 



§ 253. Boiling-Points of Solutions of Nitre. — To determine 

 the boiling-points of solutions of nitre of various strengths, 

 40 grams, which were in the later experiments made up to 

 100 grams, were placed in a clean tin vessel having'a narrow 

 neck, together with a thermometer and an indefinite amount of 

 water. The whole was supported in a hot-air chamber so that 

 the neck only of the tin vessel projected. An arrangement 

 was also made for blowing hot air through the upper part of 

 the vessel. By this arrangement it was hoped that the 

 amount of water condensed in the vessel above the liquid 

 would be inconsiderable. The liquid was boiled until a 

 certain temperature was reached. The vessel was then re- 

 moved, partially cooled, and weighed. This was done at every 

 half- degree. Jn the table the temperatures are deduced at 

 which boiling occurs in strengths rising 5 per cent, from 20 

 per cent. In column II. the results are smoothed out under 

 the assumption that there is a rise of 1°'211 for every 5 per 

 cent. 





Table LYII. 





Per cent. 



I. 



II. 



20 



. . . 101-50 



101-50 



25 



. . . 102-83 



102-72 



30 



. . . 103 : 41 



103-93 



35 



. . . 10402 



105-14 



40 . 



. . . 104-50 



106-35 



45 



. . . 106-56 



107-56 



50 . 



. . . 107-22 



. 108*77 



55 



. . . 108-85 



109-98 



60 . 



, . . . 110-16 



111-19 



65 . 



. . . 110-81 



112-40 



70 



. . . 113-00 



113-51 



75 



. . . 114-92 



114-92 



The last of them is saturated at -758 millim. atmospheric 

 pressure, and the result is inserted in the table, § 252. 



§ 254. When a conception such as the above is once fairly 

 grasped, numerous exemplary phenomena which have hitherto 

 been vaguely entertained re-present themselves and claim kin- 

 dred with it. Thus it is well known that the temperatures of 

 fusion of many organic solids are notably lowered when in 

 contact with water, or even when imperfectly dried ; and 

 this is more marked with those whose temperatures of fusion 

 are not high, and which are nominally classed among insoluble 

 bodies. Such bodies will, especially when in a state of fine 

 division, condense water from the air ; and hold it with such 



