22 A Bulletin on Orchard Practice 



knife or whatever pruning instrument is used should be 

 dipped in a rather strong solution of carbolic acid after each 

 cut is made to avoid spreading the germs by contact. 



Growers should use extraordinary care to prevent the in- 

 troduction of pear blight to their localities, for sooner or 

 later they are sure to experience considerable loss if it is allowed 

 to spread. F. A. H. 



BORDEAUX MIXTURE AND ITS PREPARATION. 

 BY W. H. LAWRENCE. 



Bordeaux mixture is composed of a number of compounds 

 formed by pouring together solutions of bluestone and the 

 milk of lime. The chemical changes taking place are very 

 delicate, and in order that these may take place correctly great 

 care must be exercised in mixing. The method of mixing has 

 not only an important bearing on the chemical, but also on the 

 physical, nature of the mixture. The most valuable of the 

 compounds, and one which is easily modified in the mixing, is 

 a bluish, gelatinous r>recipitate having about the same specific 

 gravity as the fluid in which it is suspended. In mixing the 

 Bordeaux by the different methods used by the orchardists the 

 following gave the best results, and is the only one recom- 

 mended : 



Sulphate of copper (blustone) 6 pounds 



Quick-lime 4 pounds 



Water 50 gallons 



To prepare 50 gallons of Bordeaux mixture, weigh out 6 

 Ibs. of bluestone and place it in a sack; suspend the sack 

 from a stick laid across the top of a barrel, so that the bot- 

 tom of the sack hangs clear of the bottom of the barrel. Pour 

 in enough water to cover the bluestone. As soon as all the 

 bluestone has dissolved take out the sack and add enough 

 more water to make 25 gallons. Bluestone is readily dissolved 

 in hot water and the use of this will facilitate rapid prepara- 

 tion when work is rushing. Slake 4 Ibs. of good quick-lime in 

 a barrel, taking care to do it in such manner that when the 

 lime is all slaked the mass will be a smooth paste, free from 

 small particles of unslaked or burned lime. In order to get 



