No. 6. DEPARTMENT OF AGRICULTURE. 521 



fully done and the lime is of good quality, a smooth paste with very 

 little grit will be formed. The lime paste may be made in quantity 

 and kept during the entire season if care is used to keep it covered 

 with water or means used to prevent it from drying out. If it is 

 allowed to become dry, it will not work up smooth, and a lumpy, 

 gritty milk will result. 



The question has often been asked whether it makes any difference 

 whether the lime or the sulphate is first put into the tank; that is, if it 

 makes any difference whether the lime is poured into the copper 

 sulphate or vice versa. Investigations at the Vermont Station* have 

 shown that Bordeaux mixture prepared by pouring dilute copper 

 sulphate solution into dilute lime milk, stirring vigorously all the 

 while, or by pouring the solutions together into the tank, remains in 

 suspension better than that made by pouring the lime into the sul- 

 phate solution. The results of the work done at that station tend 

 to show also that the Bordeaux so prepared possessed better fun- 

 gicidal properties when used upon potatoes. 



Bordeaux mixture should be used only while fresh. If allowed to 

 stand for some time — say from one day to another — the precipitate 

 changes in such a way that it will not remain long in suspension. 

 This increases the difficulties of agitation. It is probable also that 

 the fungicidal value of old Bordeaux mixture is different from that 

 freshly prepared. But the rapid settling seems to be the most serious 

 objection. Lodemanf cites a case in his experience where Bordeaux 

 mixture several weeks old was successfully used on apple trees by 

 using extra precaution to keep the precipitate in suspension. All 

 other experience seems to indicate, however, that the freshly pre- 

 pared mixture is by far the most effective. 



Mixing Outfits. 



Where a large quantity of Bordeaux mixture is prepared a special 

 mixing outfit will greatly facilitate the work and will be found well 

 worth the expense of constructing it. 



The most successful of these outfits in operation consist of a system 

 of elevated tanks, so placed that the solutions may be run into a 

 third tank to form the mixture, and from the last into the spray tank. 

 For this purpose a series of tiers of three platforms, each higher than 

 the other, should be constructed. On the top one should be placed 

 the barrels holding the stock solution of copper sulphate and lime 

 ndlk. On the second platform should be placed two diluting tanks, 

 each with a capacity of a little more than one-half the total quan- 

 tity of Bordeaux to be prepared at one time. On the lowest plat- 

 form the mixing tank is to be placed. This tank should be large 

 enough to hold a full charge of mixture for the size of tanks used. 



•Vermont Agricultural Experiment Station, 9th Annual Report, 1S95, pp. 88-M. 

 tThe Spraying of Plants, p. 132. 



