proceedings: botanical society 231 



described. The instrument has been found useful in the analysis of 

 aqueous solutions and is applicable to a large number of liquid binary- 

 systems. The sensitiveness in terms of refractive index is about 2 

 in the seventh decimal place, and therefore salt solutions, for example, 

 may be analysed with an accuracy of 0.0002 per cent. The possi- 

 bility of error resulting from the wandering of the achromatic fringe 

 was discussed together with methods for the avoidance of this difficulty. 

 Several possible fields of use for the instrument were mentioned. 



Discussio7i: It was brought out in the discussion that the temperature 

 effects, in the comparison of liquids of different concentrations at 

 different times as in the determination of the fixed points of a series 

 of solutions, were not important, since the temperature coefficients of 

 refractive index of the solutions of about the same concentration were 

 nearly identical. The applicability of the instrument to the analysis 

 of alcohol-water mixtures was mentioned, in answer to an inquiry, as 

 being somewhat limited by the solubility of the cement used in making 

 the glass cell container and the difficulties in making up and maintain- 

 ing known solutions. 



An informal communication was presented by E. G. Wherry of 

 the National Museum on The detection of certain elements by their' 

 absorption spectra. The spectra of the light reflected from minerals 

 and gems of certain kinds have been found of considerable importance 

 in the identification of these materials. Some 13 or 14 of the elements 

 in their compounds are capable of identification in this way. Most 

 of these belong to what are generally regarded as the rarer elements. 

 The methods developed, in which only the visible spectrum was used, 

 were described. The possible application to the detection of certain 

 elements in other materials was mentioned. 



Discussion: The use of the invisible part of the spectrum so as to 

 give the method a greater range of applicability was suggested. 



E. C, McKelvy, Secretary. 



THE BOTANICAL SOCIETY OF WASHINGTON 



The 102d regular meeting of the Botanical Society of Washington 

 was held in the Assembly Hall of the Cosmos Club at 8 p.m., Tuesday, 

 February 2, 1915. Fifty-two membeis and six guests were present. 

 Messrs. P. A. Yoder, Stephen Anthony, and James M. Shull were 

 elected to membership. The following scientific program was presented : 



S. C. Stuntz: Bamboo possibilities in America. After a brief intro- 

 ductory statement outlining the past history of bamboo introduction 

 into the United States, and sketching the present condition of bamboo 

 planting in this country, attention was directed to the possible future 

 uses for bamboo. Furniture, basketry, especially for parcel post ship- 

 ments, Venetian blinds, and barrel hoops were suggested as probable 

 industries in which bamboo would find use, while the development for 

 ornamental planting, and as a possible stock for paper was especially 

 emphasized. Lantern slides of bamboo plantations and uses abroad 



