236 EXPERIMENT STATION RECOED. 



pteris, and begonia. One compartment was treated with 150 liters (39.6 gals.) 

 of pure carbon dioxid twice a day at 7 a. m. and at 12 m. The other com- 

 partment was used as a check. Observations taken at the end of a 4- and a 

 7-week period showed an increased growth from carbon dioxid assimilation 

 ranging from 24 to 152 per cent. The leaves were a much fresher green and the 

 colorings of the begonia leaves were more intense. From a commercial stand- 

 point the increased production from two kinds of plants paid for the cost of the 

 carbon dioxid. 



A test was made relative to the rapidity of assimilation. The amount of 

 carbon dioxid in the greenhouse was re<luced from 5.2 per cent to about 2 per cent 

 in 30 minutes time, and to about 0.26 per cent in SO minutes. The plants were 

 removed from the house and the test repeated, but in this case the carbon dioxid 

 content was reduced only from 2.33 to 1.43 per cent in 55 minutes. Shading the 

 greenhouse appears to have no material effect on the rapidity of assimilation. 



The authors are of the opinion that these experiments indicate that the carbon 

 dioxid content of organic manures is of considerable imix)rtance as a fertilizer 

 ingredient. 



The home vegetable garden, A. Kruhm (New York and London, 1914, PP- 

 I]'-{-105, /}/•<. 23). — In part 1 of this popular treatise the author discusses the 

 general jirinciples of gardening. In part two specific directions are given for 

 growing various vegetables, together with suggestions relative to improved 

 varieties. 



A radish-cabbage hybrid, F. Gravatt (Jour. Heredity, 5 (1914), No. 6, pp. 

 269-272, figs. 2). — The author here describes a cross between two genera which 

 shows extraordinary vigor but absolute sterility. 



Strain tests of tomatoes, C E. Myers {Pennsylvania Sta. Bui. 129 (1914), 

 pp. 139-150). — In the present bulletin the author gives a brief summary of a 

 test of a large number of strains of six varieties of tomatoes, conducted from 

 1908-1911 inclusive. Data secured for the various strains are reported in tab- 

 ular form and discussed. 



The principal fact brought out by these tests is that variations in yield 

 of more than 13 tons per acre of marketable fruit occurred between different 

 strains of the same variety. In some cases considerable variations in earliness 

 of the strains were also observed. The author concludes that these variations 

 may be attributed to hereditary rather than environmental conditions. It is 

 suggested that, whenever practicable, seed should be given a preliminary cul- 

 tural test a year in advance of the time when it will be needed for general 

 planting. 



Garden notes on new trees and shrubs, W. J. Bean (Roy. Bot. Gard. Kew, 

 Bui. Misc. Inform., No. 2 (1914), PP- 49-54, pls. 3). — A descriptive account is 

 given of a number of new trees and shrubs that have been under observation in 

 the Kew Gardens. Among these plants are a gooseberry-black currant hybrid, 

 two horse chestnuts, a Japanese cherry, and several Chinese shrubs. 



The improvement of tree fruits, E. B. Babcock (Univ. Cal. Jour. Agr., 1 

 (1913), No. 5, pp. 11-14; 1 (1914), ^os. 6, pp. 14-19, figs. 2; 7, pp. 17-24, figs. 

 5 ; 9, pp. 3-8, figs. 2). — The author discusses the various applications of selection 

 in plant production and reviews recent investigations in the improvement of 

 different tree fruits by selection and breeding. Special attention is given to the 

 question of improvement through bud selection. 



Apple growing in Delaware (Bui. Bd. Agr. Del, 3 (1913), No. 2, pp. 15).— 

 A popular bulletin containing the 1910 census statistics of apple production for 

 the United States, information relative to varieties adapted for Delaware, and 

 brief cultural directions. 



