Nipher — Gravitational Repulsion. 189 



contact was made. A maximum reading was obtained at 

 11 :18 a. m. and the masses swayed in the opposite direc- 

 tion during the next 14 minutes. Forced vibrations were 

 again impressed upon the suspended masses, but they 

 were less violent in character than those at the close of 

 the observations represented in Plate XL VI. At 12 ob- 

 servations were discontinued until 12 :48 p. m., when the 

 reading showed only a slight decrease. At 1 :00 p. m. the 

 terminals were reversed and the direct contact was re- 

 moved. The conditions then were as represented in Fig. 

 3. At this time the apparent decrease in the initial at- 

 traction which existed at the beginning of the observa- 

 tions on June 2, was about 340 per cent. In other words 

 the apparent repulsion was then more than twice the 

 initial attraction. This conclusion seems to be fully jus- 

 tified by the amazing increase in the attraction which at 

 once resulted. At 1:53 p. m. direct contact between the 

 pin-point conductors and the shield and large masses was 

 made by dropping a wire into position. It was removed 

 at 2:02 p. m. Forced vibrations were again impressed 

 upon the suspended masses. The machine was stopped 

 at 2 :19 p. m. and I was called away for an hour. A few 

 readings taken between 3 :12 and 3 :22 p. m. shown at the 

 close of Plate XL VII indicate that the attraction had 

 then approached closely to the initial value on the morn- 

 ing of June 2. 



It will of course be understood that no attempt has 

 been made to secure results of precision in this work. 

 The only aim has been to determine whether or not it 

 would be justifiable to construct the much more expen- 

 sive apparatus which will be required for such results. 

 The suspended masses must be capable of being electri- 

 fied independently and the enclosing walls must surround 

 them in symmetrical form, so that their inductive action 

 will not produce deflection of the suspended masses. If 

 they are suspended in highly rarefied air, it may be neces- 

 sary to use a metal wire rather than a quartz fiber, which 

 must then be attached to an insulated torsion head. A 



