SOME NEW BASES OF THE LEUCOLINE SERIES. 271 
Fractions of higher boiling-points were not examined, one other within the 
series, viz., 380°-885°, was obtained (which would probably contain the base 
C,,H,;N) but only in very small quantity and containing paraffin; but from 
those fractions examined, viz., 290°-295°, 305°-310°, and 310-315°, 325°-330°, 
345-350°, and 360°-365°, we have been able, by the analysis of the platmum 
salts, to separate and identify five new members of the series of Leucoline bases, 
viz., the base C,,.H,,N' from fraction 290°-295°, C,,H,.N from fractions 305°— 
310° and 310°-815°, C,,H,,N from fraction 325°-330°, C,,H,,N from fraction 
345°-350°, and C,,H,,N from fraction 360°-365°. Taking Leucoline, Iridoline, 
and Cryptidine with boiling-points 238°, 256°, and 274° respectively, it will be 
seen that the boiling-points of the five higher members of the series would be 
292°, 310°, 328°, 346°, and 364°; we have not been able to ascertain the actual 
boiling-points of these higher members of the series, but have shown that the 
fractions, within a range of 5° C., consist practically of such bases; and, as is 
seen from analyses of chloroplatinate from fractions 305°-310° and 310°-3135", 
also from other analyses not noted, the same base extends over a considerable 
range of temperature. ; 
In a former paper on these bases,” wherein the identification of C,,H,,N, 
C,,H,,N, and C,,C,,N was recorded, an apparent anomaly in their boiling- 
points was observed; the base C,,H,,N being found in fraction 270°-275° 
instead of in fraction 290°-295°, C,,H,,N in fraction 290°-295°, instead of 
fraction 310°-315°, &c., and the explanation was offered that fractional dis- 
tillation had not been pushed far enough, that were it continued at least 
twenty-five or thirty times, these three bases would be found in fractions 
 290°-295°, &c. The present investigation has shown this to be the case, 
fractional distillation being continued to twenty-five times before the bases 
were submitted to examination, with the result already stated. 
It is necessary to mention that fractional distillation at these very high 
temperatures was effected by means of the high-range thermometers made by 
the late Dr GetssLtER of Bonn; these thermometers are so constructed as to 
indicate temperatures up to 460° C. All distillations above 300° C. were made 
in the above manner, distillation being pushed as long as any distillate was 
produced, the limit to this bemg found to lie about 390° C., when a thick tarry 
| residue was left in the flask. 
When recently distilled these bases are of a pale brown colour; they rapidly 
darken when exposed to the atmosphere, and even when enclosed in hermeti- 
cally sealed tubes the same darkening in colour goes on, but more slowly. 
They thicken and appear to become resinous when kept for some time in an 
imperfectly closed vessel, and, as the series is ascended, the more rapidly do 
they become resinous. 
* Trans. Royal Society, Edinburgh, vol. xxviii. part 11. p. 569. 
