- Keller and Boisbaudran
In 1863, François Antoine Edouard and Em. Keller presented a theory by using a Le Sage type mechanism in combination with longitudinal waves of the aether. They supposed that those waves are propagating in every direction and losing some of their momentum after the impact on bodies, so between two bodies the pressure exerted by the waves is weaker than the pressure around them. In 1869, Paul-Emile Lecoq de Boisbaudran presented the same model as Leray (including absorption and the production of heat etc.), but like Keller and Keller, he replaced the particles with longitudinal waves of the aether.
After these attempts other authors substituted electromagnetic radiation for Le Sage’s particles early 20th century. This was in connection with the Lorentz ether theory and the electron theory of that time, in which the electrical constitution of matter was assumed.
In 1900 Hendrik Lorentz wrote, that Le Sage's particle model is not consistent with the electron theory of his time. But the detection that trains of electromagnetic waves could produce some pressure in combination with the penetrating power of Röntgen rays (now called x-rays), led him to the conclusion, that nothing is speaking against the possible existence of an even more penetrating radiation then x-rays, which could replace Le Sage's particles. Lorentz showed that an attractive force between charged particles (which might be taken to model the elementary subunits of matter) would indeed arise, but only if the incident energy were entirely absorbed. This was the same fundamental problem which had afflicted the particle models. So Lorentz wrote:
|“||The circumstance however, that this attraction could only exist, if in some way or other electromagnetic energy were continually disappearing, is so serious a difficulty, that what has been said cannot be considered as furnishing an explanation of gravitation. Nor is this the only objection that can be raised. If the mechanism of gravitation consisted in vibrations which cross the aether with the velocity of light, the attraction ought to be modified by the motion of the celestial bodies to a much larger extend than astronomical observations make it possible to admit.||”|
In 1922 Lorentz first examined Martin Knudsen's investigation on rarefied gases and in connection with that he discussed Le Sage's particle model, followed by a summary of his own electromagnetic Le Sage model - but he repeated his conclusion from 1900: Without absorption no gravitational effect.
In 1913 David Hilbert referred to Lorentz's theory and criticised it by arguing that no force in the form 1/r2 can arise, if the mutual distance of the atoms is large enough when compared with their wavelength.
- J.J. Thomson
In 1904 J. J. Thomson considered a Le Sage-type model in which the primary ultramundane flux consisted of a hypothetical form of radiation much more penetrating even than x-rays. He argued that Maxwell's heat problem might be avoided by assuming that the absorbed energy is not be converted into heat, but re-radiated in a still more penetrating form. He noted that this process possibly can explain where the energy of radioactive substances is coming from - however, he stated that an internal cause of radioactivity is more probable. In 1911 Thomson went back to this subject in his article "Matter" in the Encyclopædia Britannica Eleventh Edition. There he stated, that this form of secondary radiation is somewhat analogous to how the passage of electrified particles through matter causes the radiation of the even more penetrating x-rays. He remarked:
|“||It is a very interesting result of recent discoveries that the machinery which Le Sage introduced for the purpose of his theory has a very close analogy with things for which we have now direct experimental evidence....Röntgen rays, however, when absorbed do not, as far as we know, give rise to more penetrating Rontgen rays as they should to explain attraction, but either to less penetrating rays or to rays of the same kind.||”|
- Tommasina and Brush
Unlike Lorentz and Thomson, Thomas Tommasina between 1903 and 1928 suggested long wavelength radiation to explain gravity, and short wavelength radiation for explaining the cohesive forces of matter. Charles F. Brush in 1911 also proposed long wavelength radiation. But he later revised his view and changed to extremely short wavelengths.
Read more about this topic: Le Sage's Theory Of Gravitation