374 Magnetic Influence of Solar Light. 



1. Experiments on the magnetic influence of light, trans- 

 mitted through coloured glass media. 



The pieces of steel employed in these experiments were 

 all of the same length, namely, two inches, and of diameters 

 between 0.05 and 0.04 inches. They were placed upon a 

 table, one half being under the glass which was slightly 

 inclined so that the sun might strike directly upon it, and 

 the other half freely exposed to the white light of the sun 

 without any paper covering. It having been previously 

 shewn that undecomposed light could produce no magnetic 

 effects, the free exposure of one-half of each cylinder to it, 

 could not in any way vitiate the results due to the action of the 

 light passing through the coloured medium, and every precau- 

 tion was observed to guard against other interfering causes. 



I now proceed to give details of the experiments under 

 the present section. 



CatJles of IZxptvimtnu. 



TABLE I. 



Shewing Duration Oscillations of Testing Needle, with Cylinder A in front, 

 uefore and after exposure. 

 Medium Green Glass A. 



ft 

 x 



o 

 o 



Hours of 

 Expos. 



From 



Feb. 

 28th 



10 



To 



o 



In. 



2 



Temp. 



In. 



0.05 



Before 

 Expos. 



60° 



After | ° 

 Expos.: 6 



Duration of 

 Oscillations. 



Before After 

 Expos. Expos. 



96° 10 

 ... 10 

 ... 1 1 01 

 10 

 10 



Sums, ... 

 Means, ... 



95 

 95 

 95 

 94 

 95 



95 

 96 

 95 

 95 

 95 



50i 474 



476 



10 94.8 '95.2 



Remarks. 



Whence it appears that there was an increase in the 

 duration of ten oscillations of 0.4 of a second, a result so 



