212 ON ABSOEPTION-SPECTEA OP BEOMINE AND IODINE MON OCHLOEIDE. 
chloride spectrum exhibits a larger number of closely set or double lines than are seen 
in the corresponding portions of the spectrum of bromine. 
The curve and the map, on half the scale of Angstrom’s “ spectre normal,” have been 
very carefully drawn by Mr. William Dodgson, to whom we beg to tender our thanks. 
[Note. — Since the above paper was read, Professor Stokes has suggested to us that 
the wave-lengths might have been more easily determined by means of a curve in which 
the coordinates were the deviation, less a constant, and the squared reciprocals of the 
wave-length, less a constant, a curve which would come out almost a straight line. We 
communicated this suggestion to Mr. A. M. Worthington, who has worked it out, and 
who endorses Prof. Stokes’s recommendation,] 
