60 KANSAS Academy of science. 



it coald escape, and thas give ns a ratio between this compound and genuine mus- 

 tard. I can at present give only the result of a few experiments, and will not at- 

 tempt to draw any definite conclusions. 



Not until I have been able to make a number of experiments with our new method 

 will I be able to say anything positive as to its merits as a guide in the estimation 

 of this substance. If, however, I find by repeated trials that I can establish a defi- 

 nite ratio, I have here a method that will serve the purposes of the pharmacist 

 admirably. 



The pharmacist needs ready methods for quickly arriving at qualitative determi- 

 nations; he needs easily-managed, practical methods to distinguish the genuine from 

 adulterated articles. This gives rise to the particular kind of manipulations known 

 to the pharmacist as pharmaceutical chemistry. While this process may not satisfy 

 the analyst, it may be superior to other processes for the use of the pharmacist. 



The apparatus I have decided upon after a long series of trials, consists of a con- 

 denser, graduated receiver, and a small Florence flask of two- or three-ounce capacity 

 to take the place of a retort. The graduated receiver is about two inches in diameter, 

 and contains 20 cc. of — solution of silver nitrate, introduced from a burette. To 

 the condenser is attached a tube which will just sit loosely in the receiver and extend 

 to the bottom of the silver solution. 



All joints are made air-tight by the use of perforated rubber corks and a moder- 

 ate heat applied to the solution containing the mustard. Continue distillation till 

 a vacuum is formed in the condenser, now remove the flame and the silver solution 

 will be drawn up into the tube at the mouth of the condenser. Repeat the applica- 

 tion and withdrawal of the heat till the volatile oil is all absorbed by the silver solu- 

 tion. A small tube closed by a stop-cock may be placed in the retort, and by 

 blowing through this any vapor still in the condenser may easily be forced out.* 

 ilow titrate the silver solution (after noting its exact volume) with ■^— sodium 

 chloride. Suppose after distillation our receiver contains 40 cc, or if not, it is 

 very convenient to make it up to that amount with distilled water. Now suppose it 

 required 10.7cc. of this solution to neutralize 5cc. of — sodium chloride, then 

 by proportion we find the amount of undecomposed silver nitrate. Subtracting 

 this from the 20 cc. with which we started, we find the amount precipitated by the 

 volatile oil : 



10.7 : 5 :: 40 : 18.691— Ag NO;, unprecipitated. 

 20 — 18.691 = 1.309 cc.—Ag NO 3 precipitated. 



.016966— Ag NO;; in 1 cc.Xl-a09=-0222 gm. silver nitrate precipitated by the 

 volatile oil from .5 gm. of pure mustard. 



CORRECTION. 



BY N. S. GOSS, TOPEKA. 



In my Revised Catalogue of the Birds of Kansas, I described what I then sup- 

 posed to be the nest and eggs of the Sycamore Warbler — Dendroica dominica albi 

 lora. I am now satisfied that the evidence is not reliable upon wliich the entry is 

 based. 



I have met with the birds upon several occasions in the State, during the summer 

 months, on the banks of the Neosho river, and always in or about the large sycamore 



*The apparatus and manner of using it were shown to the audience. 



