of Superheated Vapours. 



409 



tain quantity of aqueous vapour, which at low temperatures par- 

 tially adheres and in various proportions at various temperatures. 

 It is seen what great changes this adhesion, consequently the 

 variable going out of play of a certain quantity of vapour, occa- 

 sions in the values of cj> belonging to low temperatures. 



The method has accordingly been proved by a twofold test to 

 be perfectly applicable ; and this is the direct confirmation of an 

 antecedently justified expectation. 



§4. 



The vapours which I investigated by this method were sul- 

 phide of carbon, chloroform, and ethylic alcohol. The chloro- 

 form was a small, carefully preserved remainder of the prepara- 

 tion made use of in my earlier experiments ; the two others were 

 newly prepared. In the following the Tables on the vapour of 

 sulphide of carbon shall first be given. In the last column the 

 vapour-pressures p are still shown ; they are calculated from $ by 

 the formula _ <ft(273-f-^ 



v 



It may further be remarked that the absolute values of <f> and 

 p are affected by at any rate small errors in the above-mentioned 

 weighings of the individual volumes of the tubes, which cannot 

 be excluded ; and therefore in this point the possibility of small 

 errors must be borne in mind. The course of the values of 

 (f>, however, which is alone of importance, depends essentially 

 upon very exactly observed values of H. Where several series 

 of observations gave somewhat differing numbers for the latter 

 values, I have noted down, in the column " H corrected," the 

 numbers made use of for the calculation ; I have also inserted 

 in this column notices of the cessation of saturation. Here, 

 however, according to the Tables, the difference is never more 

 than 0*1 millim. 



Sulphide of Carbon, 



Table V. 



W 2 = 378-4. W 



= 408 



. R = < 



57-425. 



c= 0-824. 



/. 



H. 



H cor- 

 rected. 



w r 



Vapour- 

 volume. 

 v. 



Air- 

 volume. 

 V. 



<p. 



Vapour- 

 pressure. 

 P- 



27-2 



41-2 



55-8 



62 



71-5 



72 



74-5 



88-2 



millims. 

 +5-75 



5-85 



5-95 



6 



61 



61 



6 



62 



"6 : i* 



202-9 



202-82 



20274 



202-69 



202-61 



202-61 



202-61 



202-53 



174-75 

 174-45 

 1741 

 174 



173-8 



173 4 



172 5 

 1721 

 1716 

 171-4 



171 



170-4 



71-65 

 71-59 

 71-56 

 71-56 



7160 



71-59 



millims. 

 123 

 129 

 135 

 138 



142 



149 



