322 



DIEECT PROPERTIES OF MOLECULES 



116 



The values we have found of the magnitude s, which 

 may, perhaps, be looked upon as the diameter of a gaseous 

 molecule, are almost all approximately equal, and most of 

 them do not differ by so much as one-millionth of a milli- 

 metre. Hence it would seem that all gaseous molecules and 

 their spheres of action have nearly equal sizes. 



But if we recall the manifold uncertainties in the 

 assumptions upon which our conclusions rest, we must 

 hesitate to consider this result of the calculations as a 

 certainly proved truth. And some of the numbers that 

 differ from 1 must certainly give rise to doubt. 



For hydrogen that is, for the gas with just the least 

 density and the least molecular weight the calculation has 

 given the greatest value for the diameter. It is possible 

 that the reason for this striking circumstance lies only in 

 this, that at 238 the liquefied hydrogen has not yet 

 attained its highest density. But there still remains the 

 suspicious circumstance that the greatest values of the dia- 

 meter are found just for the simplest chemical compounds, and 

 especially for those of them whose molecular weight is small. 



We easily see that such relations between the weight 

 and diameter of molecules cannot in general correspond to 

 actuality if we try to employ the numbers we have here 

 obtained to calculate that magnitude which Loschmidt 

 terms the volume of the molecular path. He under- 

 stands by this, as we have already mentioned in 69, the 

 volume of the space which a molecule occupies while it 

 traverses its straight free path, and thus the volume of the 

 cylinder, whose section is that of the molecule, viz. ^TTS*, 

 and whose height is the free path L. According to the 

 assumptions of our theory, the product of these two magni- 

 tudes ought to have a constant value. But we do not at all 



