220 On the identity of Sanguinarine and Chelerithrine. 
A simple mode of obtaining the same effect in a yet more man- 
ifest degree is the following. Adjust two slender cylindrical rods 
six or seven inches long, so that, while they nearly touch at one 
end, they spread apart about an inch at the other. Hold them 
before the eyes R, L, at the distance of distinct vision in a verti- 
cal plane transverse to the line of view and with the angle down- 
ward (fig. 26). Then form the binocular resultant by directing 
the axes beyond them with varying convergence. ‘This result- 
ant stretching away from the angle obliquely towards the wall 
will be seen to increase in diameter regularly from its near to its 
remote end. 
From these facts it may be inferred that in order with the stere- 
oscope to obtain a perspective figure, all the lines of which shall 
corresponding parts of the component lines should be proportioned 
inversely to the distances at which they are to be united. 
(To be continued.) 
—— 
Art. X XI.—On the identity of Sanguinarine and Chelerithrine, 
and on the direct determination of Nitrogen; by Dr. James 
Scuuex of St. Louis, Mo. 
I wave used a small portion of hydrochlorate of Chelerithrine 
which I received in 1843 from my friend, Prof. H. Will of Gies- 
sen, and which the discoverer of that alcaloid had prepared him- 
self, to make a few analytical experiments as to its composition. 
As the salt was not found to be free from impurities, it was dis- 
solved in water, precipitated by ammonia, washed, dried, dissolved 
in ether, the filtered solution treated with animal charcoal, and the 
chelerithrine precipitated with a solution of pure sulphuric acid 
in ether; the sulphate of chelerithrine was washed with ether, 
dried and dissolved in water, when it yielded with ammonia 4 
precipitate of pure Chelerithrine, which absolutely showed the 
same properties and behavior as Sanguinarine. ; 
