ABSORPTION SPECTRA OF THE ALKALOIDS. 
513 
Nicotine. From T. and H. Smith and Co. 
(P367 in 36 - 7 cub. centims. of alcohol of sp. gr. (F8. 
This substance exhibits no absorption band. 
Thickness of 
layer of liquid. 
Description of spectrum. 
Wave-lengths. 
millims. 
20 
Continuous, strong to. 
5 
Continuous, strong to. 
3132 
Weak to . . 
3008 
4 
Continuous, strong to. 
3033 
Continuous, weak to. 
2980 
3 
Continuous, strong to. 
3033 
Continuous, weak to. 
2977 
2 
Continuous, strong to. 
2977 
Continuous, weak to. 
2947 
Continuous, very faint to. 
Continuous, strong to . . 
2834 
1 
2875 
Continuous, weak to. 
2801 
Caffeine. From T. and H. Smith and Co. 
OT in 40 cub. centims. of alcohol of sp. gr. 0'8. 
Thickness of 
layer of liquid. 
Description of spectrum. 
Wave-lengths. 
millims. 
5 
1 
Transmits all rays to. 
All to. 
No absorption band visible. 
2965 
2942 
Having recently examined the spectra transmitted by pyridine, piperidine, quino¬ 
line, tetrahydroquinoline, and the hydrochlorides of these bases, it has been found that 
the absorption band of pyridine does not appear in the spectrum transmitted by 
piperidine, and that quinoline and tetra-hydroquinoline exhibit selective absorption 
very strongly, the curves differing from each other and from those of them hydro¬ 
chlorides. Observations made on simple bases differ from those made on substitution 
products in this way that the bases are the more diactinic, while addition products 
are more diactinic than the bases. 
Summary. 
Many alkaloids are capable of saponification, the products of the reaction are a new 
base and an organic acid which is frequently of the aromatic series. 
The acid is not invariably of the aromatic series, otherwise its presence would 
