DISCUSSION OF THE VERTICAL FORCE. 



Notes to the above table: February 25th, G h 17 m , temperature interpolated, 28. March 2d, O b 17 m , 

 reading 32 minutes late, <=46.8. March lltb, 22" 17 m , reading 49 m late, <=41.7. March 27th, 

 20" 17 m , reading 40 m late, <=64.8. March 29th, 22 h 17 m , reading 43 m late, Z=50.5. April 9th, 

 16" 17 m , reading 25 m late, r=920, <=57.6. April 30th, 0" 17 m , reading 59 m late, r=805, <=49.3. 

 May 22d, 14 h 17 m , observations discontinued. Between this date and June 1st the instrument was 

 readjusted, the corrections required to make the readings of the first four months comparable with the 

 continuous series following will be investigated further on. June 29th, 22 h 17 m , reading 38 m late, 

 temperature 81. 8, interpolated. July 22d, 16 h 17 m , temperature 84. 5 interpolated. August 23d, 

 24th, seven observations were omitted between 20 h 17 m and 8 h 17 m on account of the magnet being 

 fixed by a spider's line which was found attached to the mirror. August 24th, 14 h 17 m , observation 

 rejected, the sun shining on the box. October 4th, 16 h 17 m , sun shining on the needle ; October 13th, 

 22 h 17 m , observation 7 m late ; October 28th, 22 h 17 m , observation 67 m late. In December the variations 

 of temperature are unusually large ; they seem to demand a greater value of the temperature coefficient. 

 December 8th, 16 h 17 m , observation 8 m late ; December 20th, 4 h 17 m , observation 9 m late ; December 

 30th, 18 h 17 m , temperature 69.0, interpolated. 



Notes to above table: February 3d, 14 h 17^ m , the temperature 73.5 is interpolated. May 9th, 

 10 1 ' 17i m , the temperature 59. 6 is interpolated. June 6th, O h 17i m , 2 h 17i m , and 18 h 17 m , the tem- 

 peratures 70. 4, 71 c .O, and 74. 4 respectively, were interpolated. August 3d, 12 h 17| m ; 5th, 

 22 h 17i m ; Gth, 10 h 17 m , and 31st, 14 h 17i m , the temperatures 69.0, 73.7, 76.0, and 67.G 

 respectively, were interpolated. September 1st, 22 k 17^ m , the temperature 77.0 is interpolated. 

 October 8th, 2 h 17| m ; 21st, 10" 17i m , and 28th, 6" 17^", the temperatures 66.l, 68. 1, and 70.8 

 respectively, were interpolated. November 3d, 14 h 173 m ; an ^ I 6tn > G h 17 m , the observations are 

 6 m and 7 m late. 



