110 



Frederick Guthrie on Salt Solutions 



may raise the temperature from 19° to 38°. The solution is 

 perfectly limpid and neutral. 



§ 18l>. In order to make a more systematic attack on the 

 (3 molecule, a fresh quantity was taken of the salt which had 

 been dried in vacuo over sulphuric acid, and had then stood in 

 air over sulphuric acid for three weeks. 



Table XLII. 

 Substance = 5'6462. 



Volume of air 









drawn through 

 at uniform rate 

 of 3300 cubic 



Temperature. 



Loss. 



Loss by 3300 

 cubic ceutims. 



centims. in 15'. 









9900 



o 

 26 



0-0005 



•0002 



t) 



29 



0-0012 



•0004 





32 



0-0025 



•0008 



n 



34 



00053 



•0018 



»> 



36 



0-0068 



•0023 



>> 



38 



0089 



•0030 





40 



0-0129 



•0043 



?> 



50 



00236 



•0079 



16500 



58 



01450 



•0290 



9900 



53 



00146 



•0149 



)) 



50 



00222 



•0074 





45 



0-0209 



•0070 (in 30') 



19800 



55-5 



00821 



•0137 



, 



>> 



0-0192 



0032 



9900 



>> 



0022 



•0007 



6600 



»» 



00014 



•0007 



19800 



56 



00074 



•0012 



9900 



57 



0-0029 



•0010 



>> 



57 



00022 



•0007 



19800 



57 



0000 



•0000 



It seems that the almost inappreciable loss at 26° is really 

 continuous with the greater losses at higher temperatures. 

 The loss at 25° having been shown in Table XLI. to be inap- 

 preciable, w r e may consider the loss to begin between 25° and 

 26°. It is observed that the rate in Table XLII. is four times 

 as great as in Table XLI. ; and a consequence of this is that, 

 for given volumes at the same temperature (40°), the losses are 

 absolutely and relatively to the quantity less in Table XLII. 

 than in Table XLI., but not four times as small. |Hence, 

 as we might anticipate, at a given temperature and for a given 

 volume more water is withdrawn by a slow current than by a 

 quick one ; while in a given time more water is withdrawn by 

 a quick current than by a slow one. With regard to the first 

 of these facts, it need only be remembered that the slow current 

 becomes more saturated than the quick one. Although the 



