160 END-ON VIEWS OF GAS SPECTRA UNDER HIGH DISPERSION. 
exact determinations being hereafter attempted of them, guides and possible explanations of 
some of their major variations. The tracts of dimness and brightness noted in the Table, which 
the range of groups present when they are most perfectly developed, are borrowed from 
Ancstroém’s and THALéy’s Table in the above quoted Memoir, those observers, as well as 
Picker and Hrrrorrr, in the admirable pictures which they have respectively published of it, 
having apparently mapped and noted the banded, or low-temperature spectrum of nitrogen, 
although not with all the structural details which it possesses, yet in its whole extent under 
the finest and most favourable conditions of completeness and perfection. 
ERRATA. 
Page 103, line 18, erase “ and double.” 
Page 104, line 2, delete the second word. 
Page 143, top of 3rd column, for 37,707 read 38,707. 
On Plate XII., lowest spectrum strip, the single black line at 45 200 nearly, 
should be closer up to 4& 000, or over the first line of the Citron band of the carbo- 
hydrogen group below, 
BS: 
