electro-magnetic fields on the spark spectra of gold, etc. 89 



Wave-length 



A 4168*2. This line shows distinct widening — but it is too weak to 



affect the sensitive plate when the calcite is intro- 

 duced. 

 4061 "5. This becomes a triplet, and the two outside components 



seem to vibrate perpendicular, and the inner one parallel, 



to the lines of force. 

 4057 '5. This becomes a triplet. The two outside components 



vibrate perpendicular, and the inner one parallel, to 



the lines of force. 

 4020 "5. The line shows marked widening, but it is too weak to 



affect the plate when the calcite is introduced. 

 3853*2. A broad line which seems to be widened. 

 3738-9. This line becomes a triplet, the two outside members 



vibrating perpendicular, and the inner one parallel, to 



the lines of force. 

 3682-9. This becomes a triplet, and the components vibrating like 



those of 3738-9. 

 367 TO. It shows distinct widening — but the line is too weak to 



affect the plate when the calcite is interposed, even after 



more than 60 minutes' exposure. 

 3639-2. This line becomes a triplet, the two outside components 



vibrating perpendicular, and the inner one parallel, to 



the lines of force. 

 35726. A weak line, which seems to be a triplet, the members of 



which vibrate like those of 3639 '2. 

 2872-2. The line becomes a widened reversal or doublet. 

 2832-2. The line is distinctly widened ; and, on analysing it with 



the calcite, seems to be a triplet, with the two outer 



members vibrating perpendicular, and the inner one 



parallel, to the lines of force. 

 2822 - l. The line is distinctly widened, but it is too weak to 



analyse. 

 280T4. This line is widened, and the calcite separates it into 



a triplet, with the two outer components vibrating per- 

 pendicular, and the inner one parallel, to the lines of 



force. 

 2662-5. The line is widened. On analysing with the calcite the 



components are weak, but it seems to be divided into 



a triplet, with the two outside members vibrating 



parallel, and the inner one perpendicular, to the lines 



of force. 

 2613-4. There is a distinct widening. With the calcite it is 



divided into three, and the two outer members vibrate 



parallel, and the inner one perpendicular, to the lines 



of force. 



t'.-r- -' i These lines are widened, but are too weak to analyse. 

 24/5-/. J J 



2204-3, A weak nebulous line, which seems to show signs of being 



widened. 



7—2 



