New Evidence, etc. 385 



of which are of red granite. The room containing the 

 apparatus is in the second story of this building, and 

 below this tower. 



Twelve copper wires about ten feet in length were sol- 

 dered to the lower part of the lightning rod, and spread 

 over the ground, their ends being injected a few inches 

 into the soil. The wire leading from the masses within 

 the building to the rod was also soldered to it. Connected 

 with this wire within the room containing the gravitating 

 masses were metal rods surrounding the apparatus on 

 which were hung sheets of metal to which were attached 

 about one thousand pins. Small holes were punched 

 through the metal, the pins were inserted, and the heads 

 were soldered to the metal. This was intended as a means 

 to put all of the air in the room in an electrical condition 

 as near uniform as possible. 



With such an apparatus a determination of the gravita- 

 tion constant would be utterly impossible. The position 

 of the suspended masses changes from day to day and 

 from night to day by greater amounts than was at any 

 time possible when the plate-glass machine was used for 

 electrification of the masses. Their position depends 

 upon the weather and upon the moisture in the surface 

 of the earth. The changes were often greater than was 

 ever caused by the removal or replacing of the large 

 masses. Results obtained on December 12th last are 

 alone sufficient to establish the fact that enormous local 

 changes in the earth's potential are constantly occurring, 

 and that these changes produce variations in gravita- 

 tional attraction between the large masses and the sus- 

 pended masses. 



On December 5th and 6th over an inch of rain and sleet 

 fell, and on December 8th and 9th there was a light fall of 

 sleet. The minimum temperature gradually fell from 

 28° on the 5th to 1° on the 10th. The ground was cov- 

 ered with a thin layer of ice and snow on the 12th. On 

 that day the morning temperature was 20° but rose to 56°. 

 The ground around the lightning rod between the build- 



