It can be calculated from the formnla {f = .t I X — - that 



592 



The distance between the mirror, wiucii was attached to the 

 beam, and by whicii the ra}- of liglit was reflected, and the film, 

 on whicli tlie movements of the ra^' of light were photographed, 

 was : 410 cm. ± OS. 



V A:(57-3°) 



1 mm. permanent deviation of the distinctly observable image on 

 the film corresponded to a horizontal force normal to the beam ot 

 345 xlO'' dynes on one of the balls or, of 2-96 >; 10—" dynes 

 per gram of mass of one ball. 



The film was moved vertically about 3-4 mm. per hour, by means 

 of a registering time|,iece, for 86 honns at a stretch, behind a narrow 

 horizontal slit in a light-proof case. 



Every hour an illuminating apparatus, set in motion electrically 

 by means of a clock-work, flashed a ray of light on the slit in such 

 a way that a time-line, divided into mm. was registered. 



After many difficulties, caused by a sensitiveness to various dis- 

 turbances, which jiroved relatively great, and which prevented the 

 balance from acquiring a position of steady equilibrium, we succeeded 

 in registering nearly straight lines on several films, the deviation 

 from straight lines being less than 1 mm. 



If we consider that an effect of the "ether wind" would be 

 perceptible to the left in the morning, to the right in the evening, 

 or the reverse, a force exerted on one of the balls, or more exact: 

 a difference of force, exerted on the two balls of 1 '48 ■ 10— " dynes 

 per gram, may be considered excluded. It was shown that not even 

 so small a force was released, though the ether rushed through a 

 field of trillions of dynes of intermolecular attrtiction : for the field 

 of gravitation in one gram of platinum possesses trillions of dynes ! 



The order of magnitude (of the number of dynes) of total inter- 

 molecular attraction cannot be directly calculated for paraffin and 

 platinum, but it can lie indirectly approximated from the total 

 amount of intermolecular attraction in 1 cm', of water ; the physical 

 constants of paraffin and platinum i-equired for a direct calculation, 

 are unknown. We base our indirect calculation on the supposition, 

 that the attraction between the molecules of liquids and of solids 

 is equal, if the specific density is equal. The comparatively small 

 amount of heat, necessary to melt ice, and the slight linear con- 

 traction of melting ice. permit of this supposition. An error in 

 this calculation for water and ice of double or half the amount is 

 improbable. 



For water the force with which the outer layer of molecules is 



