348 Mr. Gervaise Le Bas on 



is approximately constant for the hydrocarbon and other 

 series, W representing an integer, which in this instance is 

 the fundamental valency number (loc. cit.). 



Conclusions. 



It may be useful to summarize the results so far obtained. 



(1) The law of additivity is exactly followed at the 

 melting-points of the complex liquid normal hydrocarbons 

 from undecane C n H 23 to pentatriacontane G 35 H 7!i , and at 

 equal intervals of temperature therefrom. The volumes of 

 the compounds in question under such conditions are propor- 

 tional to their respective valency numbers for the reason that 

 the atomic volumes of combined carbon and hydrogen are 

 as 4:1, a ratio which is the same as that between their 

 respective valencies. 



This is best represented by the following formula : 



M.V. of Cja 2 „ +2 = (6n+2)S=WS, 



W representing the valency number of the compound, and 

 S the volume of hydrogen under the conditions, that is to 

 say, the volume of the unit-stere. 



2. The specific gravities of the above hydrocarbons at 

 equal intervals of temperature from their respective melting- 

 points are equal fractions of their specific gravities at those 

 points. 



If the melting-points are considered to be corresponding 

 temperatures, the above results show that the law of corre- 

 sponding states is valid near the melting-point and possibly 

 below it. This is also true for the law of additivity. (An 

 experimental investigation of this point is in progress.) 



Thus there appears to be a remarkable mutual dependence 

 between the law of corresponding states and the law of 

 additivity. This indicates that those features of the pro- 

 perties of liquids and possibly also of solids which account 

 for the one, also account for the other. 



(3) The volumes of the simpler hydrocarbons under corre- 

 sponding conditions have also been studied. 



At Corresponding Pressures. — The valency law is approxi- 

 mately true at the critical points. Octane, however, is 

 somewhat divergent. 



Similar relations are found at equal fractions of the critical 

 pressures. 



The additive relation is much more closely followed at 

 considerable intervals of temperature from the critical points 



