14 H. N, MOSELEY. 



the alcoholic solution shows three absorption bands (PI. II, 

 fig. 15 a), fine, an extremely intense band with well-defined 

 edges, extends from a little beyond the less refrangible side 

 of D to about one third of the distance between D and E. 

 The next band is faint, not so broad as the preceding, and 

 situate a little to the less refrangible side of E. The third 

 band is also faint, but rather darker than the last described ; 

 it extends from F towards the red, and shades gradually off 

 towards its red edge. The position of the bands is given in 

 the figure. The least refrangible band is so well marked 

 that it is easily seen with a weak solution; but the two 

 others, being fainter, require strong solution used in consider- 

 able thickness, and with not too high a dispersion, to come out 

 well. The red end of the spectrum is cut off as far as 

 almost up to B ; the blue end is visible just into the violet. 



If a drop of hydrochloric acid be added to the spirit solu- 

 tion the colour changes at once to a clear pale blue, and the 

 spectrum changes to a single band (PI. II, fig. lob), dark in 

 the centre, and shading off at the edges, which band is 

 placed nearer the red than the dark band of the alkaline 

 solution, and overlaps the D line towards the green by 

 about one third of its breadth. The original colour and 

 spectrum are restored on the fluid being again rendered 

 alkaline with ammonia. 



If an ianthina be pricked and made to discharge its purple 

 into a test-tube containing glycerine the colouring matter is 

 dissolved, and a solution obtained which has a deep violet 

 colour, and gives the three bands like the spirit solution. 



If the purple be treated in the same manner with ether 

 a coloured solution is obtained, resembling exactly the spirit 

 one in appearance, fluorescence, and spectrum. The ether 

 does not become very highly tinged, but leaves a coloured 

 residue, which, after the ether is poured off, may be dis- 

 solved in absolute alcohol. A blueish solution showing one 

 absorption band is the result. 



If the fresh purple fluid be treated with acidified ether a 

 most brilliant dark blue solution is obtained, which is not 

 fluorescent, and which gives the spectrum shown (PL II, 

 fig. Id[c). 



No method by which the colouring matter, which may be 

 called lanthinin, could be preserved was discovered. All 

 the various solutions mentioned above faded in the course 

 of a week or two, and the ethereal solutions even more 

 rapidly. 



Phosphorescence. — The phosphorescent light emitted by 

 three genera of deep-sea Alcyonarians was examined spec- 



