DISEASES OF PLANTS. 1137 



tool station, at an cstiiiiatnl cosl I'nr the first year of .$t;4,1 per township, or 

 abont .'5 cts. p(M- acre. In licKii'i'in;,' tlu' work about l."),UO() acres were set apart 

 for protection, bnl (iwinj: to the contour of the country about 70,000 acres were 

 actually iiatrolliMl. The i)atrol of the 70,000 acres cost less than one-half cent 

 per acre. 'I lie Iota! (-(tst for the ir),000 acres, includin.u; construction of fire lines, 

 was 2 cents ]h'v acre. Based on the year's work the estimated total cost of the 

 protection for a period of 40 years is given as .'fl.lvS-l.O'J initial expense and 

 .*.")42.SS animal expense thereafter. The i)r()l):U)Ie net returns from the ex- 

 perimental .iica at the end of 40 years are i)resented in tabular fonn, in which 

 the i)rice per acre is estimated at .f.'5, !$4. $5, and $(5. respectively, and the in- 

 terest on the investment compounded at ."'), 4, and .'> per cent, respectively. At 

 lh(» interest rate of '> per cent and the valuation of only .$.". per acre for stumpage 

 it is figured that the net receipts will be over $45,000. 



In conclusion the authors state that fire protection as practiced at McCloud has 

 met with success, but that each tract offers local conditions of its own which 

 nuist largely determine the character of the plan. 



DISEASES OF PLANTS. 



Results of experiments to test the adhesiveness of some copper fungicides, 

 W. Keliiofkr {Zt.scin: I'fldiizciihniiih:, 11 [ItlOl), Xo. I, i)i). 1-12, i)l. 1). — A 

 series of experiments was carried on to test the adhesiveness of a number of 

 <'opper fungicides. Grape leaves were sprayed with fungicides containing calcu- 

 lated amounts of copper, after which they were allowed to dry for 24 hours. The 

 leaves were then split along the midrib and one-half subjected to artificial rain 

 for an hour or more. Roth halves were analyzed, and the differences in the 

 ;i mount of copper expressed in percentages were taken to represent the amount 

 or proportion of adhesiveness. 



In the first series, after subjecting the leaves for one hour to a rainfall 

 amotmting to 20.4 mm., the proportions of the fungicides still remaining were as 

 follows : Cojiper sulphate solution 0.7 per cent, azurin 44.7 per cent, 2 per cent 

 Bordeaux mixture 60.7 per cent, Bordeau.x mixture in which 1 part of lime to 2 

 parts of copper sulphate was used 67.8 per cent, Bordeaux mixture in which 3 

 parts of lime to 2 of copper sulphate was used 38.1 per cent. Burgundy mixture 

 slightly alkaline 68 per cent and strongly alkaline 40.7 per cent. 



The addition of sugar at the rate of 100 gm. to each hectoliter of solution was 

 tested with Bordeaux mixture. Burgundy mixture, and neutral and basic verdi- 

 gris solutions. The Bordeaux mixture was less adhesive when sugar was 

 added, but little diftVrence was noted due to its addition to Btirgundy mixture 

 or to neutral verdigris, while its addition to the basic verdigris solution greatly 

 increased the adhesiveness of the fungicide. 



When subjected to a light rainfall amounting to 16.9 mm. in 24 hours the 

 adhesiveness of the Burgundy mixture seemed greatly reduced, while the pre- 

 cipitate formed by Bordeaux mixture was less affected. This was attributed 

 to changes induced by atmospheric phenomena, especially the presence of ammo- 

 nium nitrate and carbonic acid in the air. A number of glass plates were 

 sprayed with Bordeau.x mixture and Burgundy mixture, and after drying were 

 washed with water containing .'immoniimi nitrate and carbonic acid, with the 

 result that less of the Bordeaux mixture was removed than of the Burgundy 

 mixture. The carbonic acid in this experiment removed more of the fungicide 

 than the ammonium nitrate. lu both cases the adhesiveness was in proportion 

 to the alkalinity of the fungicide. 



In concluding his investigations the author recoumiends for practical pur- 

 poses spraying with Bordeaux mixture which is made slightly alkaline by an 

 excess of lime. 



