THE STREAMERS IN THE ELECTRIC SPARK. 



87 



Antimony. 



Fig. 34. Capacity 0-0223 microfarad, inductance 40 microhenries, period 5-9 micro-seconds, velocity 

 1300 metres per second. 



The antimony lines, like those of bismuth, fall into three well-marked classes. The arc lines 4033, 3637 

 show as drawn-out bands filling the whole spark gap. 4352, 4265, and unidentified lines with approximate 

 wave-lengths 3600, 3400, and 3320, belong to the condensed-spark class, the first streamer being very 

 marked and the rest rapidly fading away. The remainder appear to be ordinary spark lines, but are 

 difficult to identify. 



Copper, NicM, Platinum, Figs. 35, 36, 37. 



These metals show no well marked lines, and the faint lines are so numerous and close together that they 

 are not resolved in the photographs. The oscillations are represented by long lines throughout the 

 spectrum, which only show at the top of the spark. The reason of this is probably that the streamers of 

 the individual lines are too weak to affect the plate, and that the direction of the drawing out of the spark 

 by the mirror is such that at the top of the image the streamers of neighbouring lines fall with their 

 lengths over each other, and being thus superposed give a luminosity sufficient to register itself. At the 

 bottom of the image the streamers are broadside on and are not superposed. The effect is observable more 

 or less in all the photographs. 



