98 
air, even in the delta, was found to be extremely low. The con- 
sideration and presentation of this feature of the work of the ex- 
pedition will form the subject of a paper now in course of prep- 
tion. 
Incidentally our acquaintance with the Colorado River brought 
us face to face with a latent boundary question. The Gadsden 
Purchase treaty sets the line between Baja California and Ari- 
zona, from Andrade’s Ranch to Yuma, as ‘‘ thence up the middle 
of said river until it intersects,” etc. The river really consists of 
a network of channels in eee in which it is er to distin- 
guish the main channel, and the stream may shift the chief 
flowage to another ae within a single season, with the re- 
sult that large tracts of teriitory are within the United States one 
month and a few weeks later may form part of a district of Baja 
California. It needs but a slight appreciation of the value of the 
land involved to start a troublesome controversy. 
Respectfully submitted 
acDoucaL, 
Director of the Laboratories. 
THE PROTECTION OF OUR NATIVE PLANTS.* 
(A Prea To TEACHERS.) 
Again comes the cry, ‘Protect our native plants.” The 
strongest economic and aesthetic reasons have been often and con- 
vincingly presented, but the need for protection continues. The 
people who destroy have not been reached. Why, can best be 
shown, in ce briefly the classes most destructive to our 
native vegetatio 
Few ie are willing to make money slowly enough to 
respect the rights of others now, or those of the next generation. 
Plants of direct or indirect economic value will need protection 
as long as there is competition in business ; one might add they 
Se ee 
Caroline and Olivia Phelps Stokes Fund for the Preservation of Native Plants. 
