Aboriginal Trade of the Northivest. 105 



with a complete cup from a mound situated at the Inter- 

 national Boundary Line. Though 500 miles apart, these 

 two localities are practically connected by a continuous line 

 of mounds, and it is not improbable that pottery made on 

 Eed River was passed from hand to hand until it reached a 

 distance of 500 miles from the workshop. 



No article of European manufacture has been taken from 

 the Manitoba mounds, not even from about the remains of 

 the intrusive burials, so that there is every likelihood that 

 the work of the builders in that country had ceased loug 

 before Kelsey, de La Verendrye, and later European adven- 

 turers made their appearance in the Northwest and revolu- 

 tionized trade. 



Variation of Water in Trees and Shrubs. 



By D. P. Penhallow. 



The amount of water which highly lignified plants con- 

 tain, particularly as influenced by season and condition of 

 growth, obviously bears a more or less important relation to 

 physiological processes incident to growth, and most conspic- 

 uously to those which embrace the movement of sap. 

 Studies relating to the mechanical movement of sap in early 

 spring, at once suggest the question as to how far this 

 is correlated to greater hydration of the tissues at the time 

 when this movement is strongest. It was with a view to 

 exhibiting this relation more clearly, that determinations of 

 moisture in a large number of woods, representing growth of 

 one and also of two years, collected at different seasons, were 

 made by me in 1874. 1 The range of seasons was not as com- 

 plete as could have been desired, and no attempt was made to 

 formulate a general law applicable to this question. With a 

 view to extension of data in this direction, I undertook 

 additional determinations in 1882. The final determinations 

 were made in most cases by Mr. W. E. Stone, then acting as 

 assistant. It is the object of the present paper to combine 

 all the results thus obtained, together with such other facts 



1 W. S. Clark : Agriculture of Massachusetts, p. 289. 



