3i8 



INFRA-RED EMISSION SPECTRA. 



149. 



rent and variable pressure and vice versa. In figure 149, is given the 

 curve of the 1.06 /* band for variable pressure (current const. 0.02 

 ampere), which is the ordinary gas conduction curve of the visible 



spectrum. Ordinates are de- 

 flections in centimeters, ab- 

 scissae are pressures in milli- 

 meters. The maximum lies 

 at about 2 mm., which agrees 

 well with observations in 

 the visible spectrum. 



In figure 150 are given the 

 emission curves of the bands 

 at 0.546, 0.667, 0-75. 0-90. 

 1.06, and 4.75 /x, keeping the 

 pressure constant at 1.4 

 mm. and varying the current. 

 The curve c contains the green mercury line. 



All the curves agree in showing that the intensity (plotted as ordi- 

 nates) increases with in- ^,^ 

 crease in current in the 

 secondary, which agrees 

 with Langenbach and 

 with Ferry (loc. cit.), 

 for the visible spectrum. 

 Several large Leyden 

 jars were used in paral- 

 lel with the vacuum- 

 tube when the intensity 

 of the radiation increas- 

 ed, due to an increase in 

 the current through the 

 tube. 



Ammonia (NH3). 

 The ammonia used 

 was made by heating 

 ■NH,Cl-f KOH (solid) 

 and passing the gas 

 through tubes of CaO 

 which had been heated for several hours. These tubes were heated 

 while starting, to expel the air. The first sample was examined just 

 after the CoH^OH vapor, and from the appearance of the curve a 



3 

 -.013 



=.02/ 



".030 



Fig. 150. 



6 Amp. in primary 

 =.033 Amp. in secondary 



