SiO ANNUAL REPOIVr OF THB < tff. Do«. 



tioDS together, and then diluting. That is, the diluting was done 

 before mixing in one case; in the other, after mixing. The vast dif- 

 fcitnces in the rates of settling are well shown by the pictures. In 

 the properly prepared mixture there was practically no settling at 

 the end of twenty minutes, while the improper preparation gave a 

 mixture which settled approximately one third of the total column in 

 the same time, as shown by the clear liquid above the sediment. At 

 the end of one hour the properly prepared Bordeaux showed less 

 thaL an inch of clear liquid on top, indicating only a slight settling; 

 the improperly prepared showed nearly two-thirds of the column 

 clear. The importance of these differences in practice are at once 

 appiirent. A mixture such as that in the left-hand cylinder does not 

 need continuous agitation; simply stirring thoroughly every five or 

 ten minutes, or a few turns of a separate agitator while moving from 

 one tree to another, will be amply sufificient. For the mixture pre- 

 I)aved in the other way, continuous agitation would be necessary to 

 insure a uniform distribution of the remedy. 



Moreover, the compound formed when the concentrated solutions 

 are mixed is without doubt different in its chemical make-up, and in 

 all probability has not the same fungicidal value as has that made 

 with the diluted solutions. Just how this is, however, has not been 

 fully worked out. From the standpoint of its physical properties 

 alone, the heavy flaky — "curdled" — precipitate is less effective as a 

 fungicide. In the first place it cannot be so easily applied; in the 

 se- ond, the flakes do not adhere so well, and in the third the coating 

 of the mixture will not be as complete as when the precipitate is 

 finer grained. 



Bordeaux mixture should never be made with hot solutions. This 

 applies especially where the copper sulphate is dissolved in hot water, 

 or when freshly slaked lime is used. The writer has found that the 

 mixture made with cold solutions is even very much better than 

 when only moderately warm. Thus, for instance, quite a marked 

 difference was observed when the solutions were mixed at GO degrees 

 (F.; and at 80 degrees (F.). The 60-degree solutions gave a mixture 

 with very much better "staying-up" qualities than the 80-degree. 

 When the hot solutions are mixed a different precipitate is formed, 

 the dehydrated or anhydrous black copper oxid. This precipitate 

 settles very rapidly, and upon that score alone, is to be avoided. 



Nothing but fresh or quick lime should be used. Air-slaked lime 

 is very unsatisfactory and should never be used. It yields a mixture 

 which settles rapidly, and which is, moreover, mixed with heavier 

 particles of carbonate of lime. The compound is, therefore, quite 

 difl'erent from the properly prepared Bordeaux mixture. The lime 

 should be carefully slaked by adding to it just enough water to keep 

 it moistened and prevent it from "burning." If the slaking is care- 



