﻿

40 



h 



45 



j 



58 



k 



74 



I 



92 



m 



112 



n 



121 



Frederick Guthrie on Magnetism and Diamagnetism. 15 



The lines become fainter, but read as far as 4195. 



rl36 Wave-length 4220 



137-5 „ 4210 



138-5 „ 4190 



6^140 „ 4174 



141 „ 4166 



I 142 X 4160 



L ' » 14158 



Each of the bands of which the groups 8, y, and a consist is 



made up of an immense number of fine bright lines separated by 



dark spaces. These lines are closer together on the side towards 



the red, till where they make up the bright edge of the band 



the dark lines can no longer be observed. 



Carbon-spectrum No. 2. 



Wave-length 6060 

 5803 

 5602 

 „ 5195 



4834 

 „ 4505 



4395 



Each of the bands of this spectrum also is brightest on the 

 least refracted side, and fades away towards the blue. Each 

 band is shaded with dark lines which are closer together at the 

 bright edge — so that the band presents the appearance of a cy- 

 lindrical pillar with equal flutings, seen at a little distance. The 

 dark lines are not so close together in the bandy as they are in 

 the band k. 



In conclusion, my best thanks are due to my friend Mr. S. 

 Okell for kindly placing his spectroscope at my disposal. 



III. A few Experiments illustrative of Magnetism and Diamag- 

 netism. By Frederick Guthrie*. 

 [With a Plate.] 



THE following few experiments do not exhibit any new facts ; 

 but they illustrate known facts in somewhat new forms, 

 and may in some cases be found useful as lecture-experiments. 

 § 1 . Magnetism of solid Sulphate of Iron. — The soft-iron poles 

 of a powerful electromagnet, of the form shown in Plate I. fig. 1, 

 are brought nearly into contact with one another, their upper sur- 

 faces being in a horizontal plane. A half sheet of thick cream- 

 laid note-paper is laid upon the poles, and powdered dry sulphate 

 of iron is strewn upon the paper. On tapping the paper, the 

 * Communicated by the Author. 



