298 A. W. Wright—Spectroscopie Examination 
The tube containing the iron being strongly heated, gas was 
given off, which brought the gauge to 29 mm. in about 15 
minutes. The heat was such as to redden and soften the glass. 
The vacuum tube, when the discharge was passed through it, 
appeared like an ordinary tube containing carbon compounds, 
and the spectrum gave the hydrogen lines very brilliantly, 
with the four chief carbon bands in great strength. e coc 
was again closed and the pump set in operation, the spectrum 
being observed from time to time throughout the process of 
exhaustion. As the tension of the gas decreased, the hydrogen 
lines became relatively stronger, and the carbon bands grew 
narrower ; the one in the red beginning to be resolved into 
lines when the pressure was much reduced. At 1 mm., the 
carbon bands were still prominent, and some narrow bands 
belonging to nitrogen were observed. 
In the first of the specimens of iron thus far examined, the 
proportion of carbon found by chemical analysis was very 
small, and in the second none at all was detected. The thirc 
series of experiments was made with an iron containing a larger 
amount of carbon. This was a fragment of the well-known 
meteorite from Arva, in Hungary, which has the following 
composition: Fe, 90°471; Ni, 7321; residuum containing car- 
bon, silica, and cobalt, 1:404.* On attempting to bore into 
this iron, as had been done with the others, great difficulty was 
experienced, as the metal has nearly the hardness of steel. 
fter the expenditure of much labor, a sufficient quantity of 
the iron was obtained for the examination, representing (*°224 
cubic centimeter of the solid metal. It was in a state of minute 
subdivision, being almost entirely reduced to fine powder. 
After it was placed in the tube connected with the _ the 
ange was 
that the joints of the pump were perfectly tight. The gauge 
rose, on opening the stop-cock, to 98 mm. As the gases were 
rarefied by the pump, the hydrogen lines shone out very bril- 
liantly when the pressure was reduced to a few millimeters, 
at 2 mm., the vacuum tube had to the eye the ne 
of an ordinary hydrogen tube while the electric disc 
passing through it. At this pressure, the second and third 
carbon bands, counting from the red end, were = bright. 
The pump was stopped when the tension was re it 
mm., but the gauge rose very slowly, gaining about a milli- 
meter in three ioe The spectrum was as before except that 
* Analysis of A. Léwe. Notice in this Journal, II, viii, 439. 
