608 Reply to criticism of the Unit-Steve Theory. 



in the real physical sense, v, the specific volume or the volume 

 of 1 gramme, is different for combined carbon, hydrogen, 

 or iodine; so that v is only an average volume of the unit 

 mass o£ a particular molecule. In a molecule CH 3 I, the 

 volume of unit mass would depend upon the part of the 

 molecule from which the unit mass is derived. A redistri- 

 bution of the matter of the molecule in such a way as to 

 secure uniform density throughout, would yield a value of 

 v independent of its position, and thus be of physical 

 significance, v being only an average value, has no definite 

 physical significance. By enlarging the value of v, M times, 

 we obtain the whole molecular volume. M is thus a mere 



M 



multiple, and ^ a number only. Mv is a volume simply, so 



M 



that ^r- and v cannot be said to be two factors in a similar 

 W 



way to those of momentum 



momentum = mass x velocity. 



The volume Y m is not divisible in the way indicated, but 

 bv the help of the law of additivity, may be divided up into 

 anumber of individual atomic volumes. By assuming the 

 relation between these atomic volumes and the volume of 

 combined hydrogen — obtained approximately by a direct 

 method — we are able to find the number of hydrogen 

 equivalents in the molecule W. 



The relation S=^f? thus gives the exact value of: the 



hydrogen equivalent in each molecule. Since Y m is affected 



by a number of constitutive influences, the value of ~ must 

 be also, and consequently the unit-stere S. 



(c) In referring to the direct method of calculation, 

 Vanstone states that the stere- values for C and H will 

 depend upon which compounds we take for comparison. 

 Probably, but these slight differences from the normal or 

 mean value which are noticed are generally considered to 

 be due to irregular disturbances affecting the measurements, 

 and thus are of no particular significance. This is seen to 

 be the case in the instances taken note of. 



