800 Intelligence and Miscellaneous Articles. 



five bright lines *. I determined their positions by means of a 

 Steinheil's apparatus with a prism, according to a scale, in which 



C D E b F G 

 are situated at ... . 35 | 50 | 69-5 | 74 | 87 | 117 

 If the five lines from the red onwards be designated by O a , 0^, O y , 

 {> 



O e , we have 















0„ 



0, 



o y 



o s 



o e 





at 45 



57-5 



72 



88-5 



158 



"With the aid of the spectral apparatus with four prisms lent me 

 by M. Kirchhoff, I determined the lines according to Kirchhoffs 

 plate, according to which 



a P y S e 



are situated at 935 1231 1625 2164 2489 



o 



From comparison of these KirchhofPs lines with Angstrom's plates 

 the wave-lengths of 



°a /3 °y S e 



are 602 558-2 519 481 453 

 The intensity of O is the greatest ; then follow 0„ and O s , and 

 last O e and O The lines are sharp towards the red end of the 

 spectrum, fading towards the violet. Their wave-lengths agree 

 best with those given by M. Vogel ; only he did not observe O a , 

 perhaps because the pressure of the gas was not sufficient. Pliicker's 

 lines O a and O5 are probably mercury-lines. 



Contrary to Mr. Schuster's latest statement, I find the spectrum 

 of pure oxygen equally at both poles. I find this identity in the 

 hydrogen also, and in the nitrogen only an intensifying of two of 

 its lines (95 and 125 of the first scale). If the gases are not pure, 

 other lines may come in at the negative pole, because the ponder- 

 able mass is thrown off at that pole. 



I have intentionally employed only simple induction-currents, 

 because with the rapid and violent discharge of a Leyden jar por- 

 tions of the electrodes and glass sides may be carried along in the 

 discharge-current, which with the quiet discharge of the simple 

 induction-current remain undisturbed in their places. At all events 

 I hold that the question whether there is a plurality of spectra of 

 a pure gas is still an open one, and am inclined rather to ascribe to 

 each simple gas one spectrum only. With oxygen, which I have 

 pursued within variations of pressure from 200 millims. to the 

 most extreme rarefaction, I have never seen any other lines than 

 the five named ; and these, brightest at 2 millims. pressure, dimi- 

 nish in brightness in both directions from that point, so that at 

 very inconsiderable and at high pressures only a glimmer of light is 

 visible, which I would not call a continuous, but much rather an 

 indistinct spectrum. — Monatsbericht cler koniglich jpreussichen Aka- 

 demie der Wissenschaften zu Berlin, Sept. & Oct. 1878, pp. 705-709. 



* Between Op and O y three, before O a four, and behind O e one broad streak 

 of light are to be seen, but so faint that they can never be confounded with the 

 five lines ; besides, they are quite destitute of a sharp margin, and cannot be 

 analyzed with the four-prism apparatus. 



