194 Forestry Quarterly. 



We take from the Experiment Station 



Migration Record for September, 1908, the following: 



of Deleano finds that there is a double move- 



Mineral Salts. ment of mineral matter during the life of a 



plant, one from the soil to the plant, the 

 other from the plant to the soil. He found that under certain 

 conditions plants could return to the soil mineral matter equal to 

 50 per cent, of the plant's weight. While the nitrogen content of 

 the plant remains fairly constant after once attaining a maxi- 

 mum, and the carbohydrates increase and are stored up, the 

 mineral matter gradually diminishes until the death of the plant. 

 The explanation of this is that this mineral matter is not actually 

 assimilated by the plant but is held by the plasma of the cells 

 through its semi-permeability. When the vitality of the cell be- 

 comes reduced or the cells are dead, the plasma becomes per- 

 meable and the mineral matter escapes by simple diffusion. 



A study of the Role and Functions of Mineral Salts in the Life of a 

 Plant. Inst. Bot. University of Geneva, 7 ser., 1907, No. 9, pp. 48. Ab- 

 stract in Bot. Centralblatt, 107, (1908), No. 1, p. 4. 



The Plant World for March contains an 



Vegetation article by Charles H. Shaw on vegetation 



and in relation to altitude, particularly with 



Altitude. reference to light intensity and evaporation. 



He calls attention to the fact that in making 

 calculations of light intensity from the sun's altitude there is not 

 one varying factor but several, namely, variation according to 

 sine of angle of incidence ; disproportion as to variation of dif- 

 fuse light ; diminution with decreasing elevation of the sun due 

 to increasing length of path of light through the atmosphere; 

 disproportionate absorption in the lower layers of atmosphere ; 

 local conditions quite beyond calculation. In reference to the 

 latter error, he points out that from measurements in Buitenzorg, 

 Java and in Cairo, Egypt, light diminished rapidly between 11 

 and 12 o'clock on a clear day. The greatest intensity found 

 anywhere in the world is not in the tropics but in the Yellowstone 

 Park. 



In regard to evaporation at high altitudes the writer refers to 

 his results from a series of porous cup atmometer records in the 

 Selkirks. The results as a whole seem impossible to harmonize 



