4(J MAGNETICAL OBSERVATIONS. 



The value of lo&amp;lt;j. n*K was computed for the following temperatures : 

 At temp. 76 log. **K= 1.41047. 

 &quot; 50 log. **K=* 1.41032. 

 Change of log. n&quot; K for 1 F., 0.6 units of the 5th decimal. 



The observations of deflection at distances of 1 foot and 1.3 feet, and at five different stations, give the 

 value of the induction-coefficient P: 



Station I. 1856, August 7 . . P = + 0.0004 



&quot; II. 1856, August 17 . . . -0.0007 



&quot; V. 1856, October 10 . . . 0.0085 



&quot; VI. 1856, December 10 . . . -0.0037 



&quot; VIII. 1857, January 26 . . . +0.0118 



Mean . . . P= 0.0001 



This value of Pis so small that it was neglected in the computation of the intensity. 

 The experiments of vibrations and deflections at the same five stations give for the magnetic moment 

 m of magnet D 3. 



Station I. 1856, August 7 . . m = 0.4952, temp. 83 



II. 1856, August 17 

 &quot; V. 1856, October 9 

 &quot; VI. 1856, December 10 

 &quot; VIII. 1857, January 25 



0.4945, 

 0.4915, 

 0.4899, 

 0.4895, 



78 

 74 

 69 

 50 



The means of the 1st and 2d, and of the 3d and 4th values give : 



1856, August 12 . . TO = 0.4948, temperature 80 



1856, November 9 . . . m = 0.4907, &quot; 72 



Loss of magnetism for ten days 0. 00046. * 



From these the values of m were interpolated for the two stations, at which no experiments of deflec 

 tions have been made, viz : 



Station III. August 26 . . . . m = 4942 



&quot; IV. September 17 . 0.4931 



m and A are expressed in feet and grains. 



Mean 2.6258 



Corr. for rate + 2 



T = 2.6260 



STATION No. II. POTBERO. 



Time of 1 vibration. 



August 16. 2 s . 6203 



&quot; 16. .6217 



&quot; 17. .6197 



&quot; 17. .6192 



83.0 



Temp. 

 77.0 



78.0 

 78.0 

 78.0 



T = 2.6202 



Horizontal intensity, August 7 and 8. 

 X= 7.533. 



Angles of deflection. 

 Distance. u. Temp. 



August 17. 1 foot 7 30 8&quot; 81. 



&quot; 17. 1.3 feet 3 24 29 80.7 



Horizontal intensity, August 16 and 17. 

 X = 7.574. 



1 Mr. Chas. A. Schott found 185, r ), September 13, m = 0.5104, which gives the loss in 334 days = 0.0156, or the 

 loss in 10 days 0.00047, showing a very regular decrease of the magnetism of D 3. 



