IJ 88 



As regards the reimls'we tbi'ces oti contact of the molecules, for 

 them I assume the same thing' as before {cï. among others loc. cit. 

 I § 7 p. 856), namely that as soon as the molecule is compressed 

 (the atoms or the electron rings pressed inwarii from their state of 

 eqnilihrinm). there is excited a qnasi-elaslic rej)ulsive force, which 

 (for not too great compressions! likewise increases linearly with the 

 deviation from the state of equilibrinm. 



§ 3. Construction of the Fundamental Equations. 



Hence in the first of the three above indicated cases (/ ^ (>), the 

 attraction of M through .1/, (when MQ=^.>' is put in tig. 1) may 

 be represented by F — fXA,Q, i.e. by f :K{MQ~MA,), or by 



F = /(.c-(/-9)). 



In the integrations ,v is tlien to be taken from /— o to /— .?. 



In the second case (/<<>> è Co +^*)) '" ^^ ^H- '^) ^^'^ attraction 

 of M by J/, \^ fX A,P=:f>{MP-{-A,M), whereas that which 

 M experiences from J/, \s = f y, l'A,= f K [MA^—M P). Hence, 

 putting MP again = .r, we get: 



h\ = / {x + (^ - /) ) ; F, = /' ( (o - /) .r). 



In this X must be taken between and / — s for F^\ for F^ oidy 

 between and q — /. H" .t;. becomes >o — /, F^ would become 

 negative, i.e. P gets outside the sphere of attraction of ;T/,. 



In the third case of course tiie same expressions hold as in the 

 second case, but now ,/; can also be taken between and /— .v for 

 Ft, 1—s now being <^q — /. ('2/ <^ o+.v). 



Throughout the entire path between MPz=^0 and Ml*^l—s we 

 may thus write in this third case for the joint action 7'=/'\ — F^,'\.e. 



F = fX^ ^- 



It seems, therefore, as if the attractive action starts from the 

 point M, and is propoi'lional to double the distance from J^ to that 

 neutral initial point, where in all the three cases mentioned the 

 total action will, of course, be = 0. 



We shall treat this last (third) case tirst, as it' is by far the most 

 important. We shall then be able to treat the two tirst cases in a 

 simple way. The now following considerations, therefore, all refer to 

 small volumes (/< 1,35 to l,5.v, i.e. r< 2,5 to 3,4/;,), both for 

 liquids and for solid bodies. 



For the square of velocity ?/' in the point /^(.l//^ = .r) tl^e follow- 

 ing equation then holds: 



