ABSORPTION SPECTRA OF THE ALKALOIDS. 
479 
The measurements and descriptions of spectra. 
Aconitine. From Dr. C. K. A. Wright. Plate 53, fig. 1. 
(P2 grm. in 40 cub. centims. of alcohol of 0*8 sp. gr. 
Thickness of 
layer of liquid. 
Description of spectrum. 
Wave-lengths. 
millims. 
5 
Continuous to. 
2860 
4 
Continuous to. 
2860 
3 
Continuous to.. 
2770 
Absorption band. 
2799 to 2714 
Rays transmitted. 
2614 
Spectrum ends at. 
2573 
2 
Continuous to. 
2747 
Absorption band. 
2747 to 2614 
Rays transmitted very faintly till . 
2614 
Spectrum ends at. 
2573 
1 
Continuous. 
2747 
Very weak. 
2746 to 2614 
Weak to. 
2547 
This solution, which had been prepared with dilute alcohol (proof spirit), was kept 
two years to ascertain whether it would undergo any change likely to make an 
alteration in its spectrum. About 20 cub. centims. were contained in a bottle 
holding 50 cub. centims., it was freely exposed to air in this manner, by occasional 
removals of the stopper, in order to subject it to the conditions which might affect an 
ordinary pharmaceutical preparation. It yielded the same spectrum before and after 
this period of keeping. In order to test whether violent chemical treatment might 
affect the spectrum, it was boiled with concentrated sulphuric acid for fifteen minutes, 
till all the alcohol was expelled; it was then diluted with a known volume of water 
and again examined, but it was found quite unaltered. It was not subjected to 
treatment with alkalies, though it is known that it may be thus converted into 
benzoic acid and a new base. If the treatment with sulphuric acid is sufficiently 
prolonged it equally effects this transformation, and there is less liability to darken¬ 
ing of the solution by the formation of resinous products than by saponification with 
alkaline solutions. The liquid should then show the absorption band characteristic of 
benzoic acid. (See Phil. Trans., Vol. 170, p. 257, 1879.) 
Aconitine. From Dr. Stevenson. 
0’2 gr. in 40 cub. centims. of alcohol of 0‘8 sp. gr., or approximately 1 in 200. 
Unfortunately, no exact measurements of this spectrum can be given, but the 
diagram which was made at the time when that of the previous sample of aconitine was 
drawn, was precisely the same, hence it may be inferred that the measurements were 
3 Q 2 
