TRANSACTIONS. 



The Kansas Academy of Science met in its nineteenth annual session in the rooms 

 of the State Normal School, at Emporia, the meeting opening on the afternoon of 

 the 17th, and continuing through the 18th and 19th of November, 1886. Papers ac- 

 cepted by the committee on publication appear in the following pages. 



The election of officers for the following year resulted as follows: 



President — J. D. Parker. 



Vice Presidents — J. R. Mead, E. H. S. Bailey. 



Secretary — E. A. Popenoe. 



Treasurer — I. D. Graham. 



Curators — F. W. Cragin, L. L. Dyche, D. S. Kelly, N. S. Goss, A. H. Thompson. 



Librarian — F. W. Cragin. 



The address of the first evening session was given by Dr. John C. Branner, of the 

 University of Indiana, upon the subject, "Geologists, Professional and Unprofes- 

 sional;" of the second evening session by the retiring President of the Academy, Prof. 

 E. L. Nichols, of the University of Kansas, upon "The Sky." At the various sessions 

 the following papers, among others, were read: 



ON BLACK AND WHITE. 



BY EDWARD L. NICHOLS, PH.D. 



In the spectrophotometric study of pigments, the selection of a suitable stand- 

 ard of color is of considerable importance. The ideal standard would be a body 

 which reflects all wave-lengths of the visible spectrum equally well; but in practice 

 this normal white cannot be obtained, and it becomes necessary to adopt as a work- 

 ing standard some substance which gives a fair approximation to the normal white, 

 and having selected this, to determine as accurately as possible its variations from 

 that standard. 



It is my object in the present paper to describe some determinations of the char- 

 acter of certain pigments which had been selected as standard whites in the spectro- 

 photometric analysis of color. The mere inspection of white pigments with the 

 unaided eye brings to view marked differences of tint, the existence of which is for 

 the most part unknown except to those who have had occasion to make careful com- 

 parisons of such substances; and these differences are sufficiently pronounced to 

 lead to the rejection of all but a very few substances on the part of one seeking for 

 a standard white. Of these few, even the best are far from satisfactory, and I have 

 found none which, to the unaided eye, approaches more nearly the ideal standard 

 than the carbonate of magnesium. The oxide of the same metal, which when pre- 

 pared by burning magnesium ribbon or wire, gives a very brilliant white, loses splen- 

 dor when taken in bulk, and appears at a decided disadvantage when compared with 

 the carbonate. 



The carbonate of magnesium possesses the advantage of cheapness, and it may 



