i 9 io.] 



Bordeaux Mixture. 



80 i 



found that the suspended matter (containing all the copper) 

 had almost completely disappeared, through subsidence, from 

 the upper half of the liquid in so short a time as five minutes — 

 the percentage of copper in the upper half of the cylinder 

 being only i'6. Another similar cylinder was rilled with 

 home-made Bordeaux mixture, and exactly the same treatment 

 given to it, but here the tendency of the suspended matter 

 (i.e., all the copper) to subside was very different, — the per- 

 centage of copper in the upper half of the cylinder, after 

 five minutes, being 48*4. In the second experiment, the 

 adhesive property of home-made Bordeaux mixture was 

 compared with that of the mixture made from the proprietary 

 powder mentioned above. Investigations showed that in the 

 case of leaves sprayed with home-made Bordeaux mixture, 

 the first shower of rain removed only 2*92 per cent, of the 

 copper, and the second shower 3*65 per cent, of the copper — 

 making a total washed off of 6*57 per cent, of the copper. In 

 the case of leaves sprayed with Bordeaux mixture made from 

 the proprietary powder the first shower removed 46*60 per 

 cent, of the copper, the second shower 5*97 per cent, of the 

 copper — making a total washed off of 52*57 per cent, of the 

 copper. 



The Irish Department of Agriculture have carried on 

 investigations for several years past in the spraying of 

 potatoes with Bordeaux mixture, both home-made and made 

 from spraying powders, and now strongly urge the farmer 

 to prepare his own mixture. 



It is clear that on account of the marked tendency of the 

 suspended matter to settle, and of the very low adhesive 

 powers, all Bordeaux mixtures put up in powder form should 

 be avoided. 



Ready-prepared Bordeaux mixture in paste form stands in 

 quite a different category to the above-mentioned Bordeaux 

 powders. Through the recent chemical discoveries of Mr. 

 Pickering, Bordeaux mixture can now be prepared by 

 a new process and put on the market as a concentrated 

 paste. From the chemical standpoint, certain advantages 

 (which cannot be discussed here) are claimed for the Bordeaux 

 mixture made from this paste over that made by mixing equaJ 

 quantities of copper sulphate and lime, as described above. 



