Molecular Attraction, IX. Molecular Attraction and the Law of Cravitation
The Journal of Physical Chemistry
General Outline of the Paper I . The usual idea of molecular attraction. 2. Statement of the recently discovered law governing J . E. Mills 17. Direct measurement of the attraction of two masses. 18. Comparison of all of the attractive forces. 19. The nature of mass. 20. Proposed modification of the statement of the law of 21. Facts in accord with the suggested changes. 2 2 , Sunimary. I. The usual idea of molecular attraction.-Newton thought that the force of gravity was exerted by each
... rted by each individual particle of a mass and made the statement: "Gravitatem in corpora universa fieri.'" It is said that he attempted to apply the law of gravitation to explain chemical affinity and the molecular cohesion to be observed in all liquid and solid bodies, but I have not been able to verify this stakment. Certain it is that the subject was investigated later by Helmholtz and Clerk Maxwell and has been discussed by numerous investigators. The conclusion that the two following facts existed proving that gravitation could not be the cause of molecular cohesion seems to have been almost universally accepted. First: The molecular cohesion was a far greater force than the gravitational force. Second: The sphere of molecular action was small. If the molecular force obeyed the law of gravitation the sphere of molecular action could not remain small but must include the entire mass taken. This is true because the number of the molecules increases as the cube of the distance from a centrally chosen molecule and the gravitational attraction diminishes only as the inverse square of that distance. The fact that the molecular sphere of action is small seemed to demand that the molecular force decrease with the distance a t least as rapidly as the inverse fourth power. The writer desires to point out some recently discovered facts which seem to indicate that the grounds for this conclusion should be very carefully reconsidered. 2 . Statemelzt of the recently discovered law concerning gravitation. Principia, Book 111, Prop VII, Coral, 2 . J . E. Mills The law expresses the relation between the energy added and the distance apart of the molecules. For a mass of liquid of M grams, containing n molecules each of molecular weight m, if v is the volume of the liquid and V the volume of the saturated vapor, and s, the distance apart of the molecules of the liquid and s, the distance apart of the molecules of the saturated vapor, we have, Therefore The above relations assume (see page 423). A. That the molecules are evenly distributed throughout B. That the number of molecules does not change. Substituting the above values of d and D in equation I the space occupied by them. we have 3. I J is, as before, an intensity factor, and where m is a factor identical with, or proportional to, ordinary mass.