7 9 8 



Bordeaux Mixture. 



LJAN., 



given as the Bordeaux mixture flows into the spraying 

 machine. Here the best type of strainer is one with copper 

 gauze with very fine meshes — 35 to 40 holes to the linear inch. 

 Such a strainer, made with a wooden bottom and sides of 

 copper gauze, is fitted to spraying machines of the type shown 

 in Fig, 15, A simple and very useful type of strainer (suitable 

 for "barrel " spraying machines and for general straining), as 

 recommended by the United States Department of Agricul- 

 ture,* is made as follows. It is in the form of a wooden box 

 about a foot square (Figs. 3 and 4), the bottom of which is 

 formed of hard wood, with a hole bored through it, into which 

 a piece of gas-pipe, ij- in, or 2 in. in diameter and from 6 in. 

 to 9 in. long, is fitted. The box is, of course, open at the 

 top. Fitting just inside this box is a second and lighter box, 

 also open at the top, and having an overhanging strip nailed 

 round the top which supports it. The bottom of this inner 

 box should be made so as to slope at an angle of about 30 0 , 

 and should be made of fine copper gauze. The slanting 

 bottom makes it harder to clog, and the inner box, being 

 removable, can be inverted and washed in a tub of water 

 (Fig. 4). Bordeaux mixture if properly strained will pass 

 easily through nozzles which throw the finest "misty " spray, 

 while if not properly strained, frequent clogging of the nozzle 

 will result. I have on several occasions sprayed for a whole 

 day using the nozzle shown in Fig. 10 — where all the fluid has 

 to pass through the minute hole in the circular disc (to right, 

 below, in the illustration) — and owing to the Bordeaux mix- 

 ture used having been properly strained, have not had to stop 

 once for any blocking of the nozzle. 



If the lime used is freshly burnt (and it must never be 

 forgotten that air-slaked lime is useless for making Bordeaux 

 mixture) and carefully weighed out there is no need to test 

 the mixture before using it. When using "stock solutions" 

 it is a good plan to apply a test at the first mixing. A rough 

 test consists in immersing a clean iron wire or French nail in 

 the Bordeaux mixture for one minute ; if safe to use, the mix- 

 ture does not affect the nail ; while if unsafe, a copper-plated 

 appearance is given to it. A more delicate and quite simple 

 test is as follows : — Procure from a chemist a 10 per cent. 



* Farmers' Bulletin, No. 243. 



