1895.] On the new Gas obtained from Uraninite. 61) 



observations I made while photograph No. 4 was being taken, to 

 show that the yellow line was visible during the whole exposure. 



Thursday, April 4th, 1895. 

 Plate F. Exposure 4. 



r4'42. P'xposnre started. 



4-43. Yellow line brightening ap considerably. 



4*44. Suddenly as bright as hydrogen. 



4.45. Yellow line double. 



4'46. Comparison with D gives yellow line in position of D 3 . 



4.47. Pump much less full ; 7 c.c. of gas collected. Yellow 



a, line much brighter. 



Q> 

 EH 



4.48. Air-break introduced. Line still visible, but very faint. 



Hydrogen lines getting brighter and some double lines 



appearing in green. 

 4.48'5. Air-break and jar removed. Yellow line the only one 



seen, being as bright as C. . Line in green the only 



other line visible. 



4.50. Replaced jar. Yellow brightening and the other lines 



more refrangible, brightening with it. 



4.51. Very bright. Steeple nearly full of gas. 

 -4.52. End of exposure. 



The lines which appear both in the photographs of the capillary 

 tube and of the gas collected over mercury, are as follows. The lines 

 indicated by an asterisk are near lines recorded in the chromosphere 

 by Young or myself, or photographed during the eclipse of 1893. 



Micrometer Wave-length 



reading. (Rowland). 



- 3-2495 4581* 



2917 4523* 



2981 4513* 



3234 4479 



3316 4469-5* 



4146 4368 



5740 4196* 



5884 4181 



5933 4177* 



6139 4156* 



6176 4152-5* 



6262 4144* 



6290 4141 



With regard to the observations in the visual spectrum, I have not 

 found the uraninite gas, as obtained and observed by my method, to 



