1130 EXPERIMENT STATION RECORD. 



grapes, ami Jerusalem artichoke, and flowers of sulpbur aistributed on the 

 artichoke leaves. In addition a tabulation is given of experiments with a 

 number of other species of plants. 



The results show that the api)lication of Bordeaux mixture to the leaves of a 

 plant diminishes the assimilation of carbon dioxid by these leaves for a time, 

 after which this effect passes off, as observed in the series where the leaves 

 were beginning to age, as well as in those where they still remained vigorous. 

 It seems probable that the stomata are partially blocked up by the presence of 

 the Bordeaux mixture, and that, as a consequence, less air diffuses into the 

 intercellular sjiaces of the leaf and less carbon dioxid comes in contact with 

 the absorption surface. 



Experiments on the effect of flue dust on soils and plants, E. IIasklhoff 

 (Lcnnlw. Vers. »s7tt^., 6*7 {J901), No. 3-.'j, ptt. 131-206, ph. 2; ahs. in Dent. Landir. 

 Presse, 34 (WOl), Xo. 95, p. 7^6, ftgs. 2; Chem. Zentm., 1907, II, No. 21, pp. 

 1755, 1756; Jour. Chem. Soc. [London'l, 92 (1907), No. 5Jtl, II, pp. 905, 906}.— X 

 study was made to determine the effect on soils and plants of the flue dust 

 from a considerable number of manufacturing establishments, including brick 

 kilns, blast furnaces, various chemical works, etc.. where both stone and lignite 

 coal were used as fuel. The effect of the flue dust on the soils and also on 

 plants grown in soils and where the dust was placed directly upon the plants 

 was investigated by means of pot cultures, using barley, rye, beans, and 

 mustard. 



The composition of the flue dust varied greatly, even when similar qualities 

 of fuel were used. The injurious constituents were found to be mainly 

 chlorids, sulphids, and probably sulphates. The presence of the flue dust in 

 the soil was found greatly to retard germination, and when placed on the 

 growing plants the foliage was seriously injured. The effect on the plants 

 seems to be indirect when the flue dust falls upon the soil and direct when it 

 falls upon the leaves. In the flrst case the greatest injury will follow sodiunj 

 sulphid falling on soils favorable to the production of hydrogen sulphid. When 

 applied directly to leaves the different materials interfere with the function 

 of the leaves, modify their structure, and check their development. The great- 

 est injury is done by sodium sulphid, followed by sodium suli)hate, and then 

 by calcium sulphid. 



A microscopical examination of the foliage will show striking injury, but 

 nothing that can l)e taken as tyincal of the kind of compound causing it. A 

 chemical analysis of the diseased plant, it is claimed, will give indications 

 regarding the nature of the substances which cause the injury. 



FIELD CROPS. 



Experimental work in field husbandry, C. A. Zavitz (Ann. Rpt. Ontario 

 Agr. Col. and E.rpt. Farm, 33 (1907), pp. 168-179, 181-226, figs. i7).— About 50 

 acres of laud divided into somewhat over 2.000 plats is devoted to this line of 

 w^ork, much of which is in continuation of that previously reported (E. S. It., 

 10, p. 25). In addition to reporting the results secured on these plats the 

 author discusses briefly the production of farm crops in Ontario and calls atten- 

 tion to the fact that barley surpasses oats in yield of grain per acre by nearly 

 100 lbs. per annum in the average of 25 years. 



In comi)aring the grain-yielding capacity of different crops it was found that 

 on an average for G years common emnier ranked first with 2,756 lbs., followed 

 by Mandscheuri barley with 2,715 lbs., and Joanette oats with 2,559 lbs. per 

 acre. In an 18-year test of 4 varieties each of barley, oats, and potatoes, and 

 an 11-year test of winter wheat, the highest yielding varieties were, respectively. 



