~ 
214 O. W. Huntington—Spectrum of Arsenie. 
Arr, XXXIV.—On the Spectrum of Arsenic; by OLIVER W. 
Honrineton. With Plate IV. (Contribution from the 
Physical Laboratory of Harvard College.)* 
Tv has been noticed, in the case of the spectrum of nitrogen 
gas, that the spectrum obtained from an electric discharge of 
low intensity through a rarefied atmosphere differs from that 
obtained when the intensity of the discharge has been in- 
creased by a Leyden jar. In the case of the low tension dis- 
. charge, the bands of the spectrum appear fluted on the more 
refrangible side; but upon the introduction of a Leyden jar 
into the circuit the fluted appearance at once vanishes, and the 
spectrum breaks up into isolated bands. This difference has 
been ascribed to a difference of condensation of the molecule. 
, upon passing the spark 
through them, we could obtain no definite or satisfactory 
result. The arsenic spectrum was feeble, the hydrogen 
brilliant, and the fluted indefinite bands which accompany the 
them in order to bring out the arsenic spectrum. We, e 
fore, prepared several tubes with pure hydrogen We arranged 
i Pp 
which was connected with one of the openings. The hydrogen 
was prepared from pure zine and sulphuric acid, and most care 
fully dried. We would allow the gas to slowly pass throug 
the apparatus for twenty-four hours, then exhaust, and after 
exhaustion heat the tube as hot as practicable under the 
* From the Proceedings of the American Academy of Arts and Sciences, Bos- 
ton, 1881, p. 35. 
