pittier: origin o? chicle; 431 



A second lot of 5 crystals made from a corresponding mother 

 liquor by evaporation at room temperature gave the following 

 angles which are normal: 



The prisms of the rapidly-grown crystals represent thinner 

 wedges than normal, as if the tendency toward skeletal growth 

 parallel to the b axis had caused an actual lengthening of that 

 axis. 



The optical dispersion (a and |S), of one crystal from each lot 

 was determined from natural faces (m), and several less accurate 

 determinations of refractive index made on crystals having 

 good / faces. No differences of refractive index greater than 

 ±0.001 were found. Chemical tests do not indicate any solid 

 solution. 



TABLE 2 

 Dispersion of Potassixtm Trithionate. 



a y 



±0.0001 ±0.002 



1.5805 1. 62 1 



(1-5732) I. 612 



I 5673 



I • 5649 

 (1.5641) 1.602 



1.5607 



I -5591 1-596 



2VNa measured 72° =*= 3°, with no noticeable dispersion. 

 The above indices make 2V = 70° =*= 1°. 



BOTANY. — On the origin of chicle with descriptions of two new 

 species of Achras. H. Pittier, Bureau of Plant Industry.* 



Many statements in cyclopedias, handbooks, and even special 

 treatises, considered as facts, are really the expression of mere 

 rumors collected by travellers and reproduced without the 

 necessary discrimination. 



Thus we find in almost all the hterature of cacao, that this 

 product is the crop of a tree scientifically called Theobroma cacao 



* Published with the authorization of the Secretary of Agriculture. 



