Winter Meeting. 257 



"£> 



When slacked and perfectly dry sift it through the fine sieve (lOO 

 meshes). 



2. Completely dissolve four pounds of copper sulphate in two and 

 a half gallons of water. The easiest way is to suspend the sulphate in 

 a coarse bag just below the surface of the water until it is dissolved. 



3. Pour gradually two and a half gallons of water over four pounds 

 of good quick-lime in such a manner as to slack it to the finest powder 

 and give a good milk of lime solution ; let it cool. 



4. Put sixty pounds of the sifted, air-slacked lime_ into a shallow 

 box — one in which the material can be well worked with a hoe or shovel. 



5. Pour the well stirred milk of lime and the copper sulphate solu- 

 tion at tlicf same time into a third vessel and stir until the whole is thor- 

 oughly mixed. It will have a deep blue color and be thick. This is so 

 finely divided that it will remain in suspension for hours. 



6. Pour this immediately into the double flour bag filter and 

 squeeze out most of the water. 



7. Empty this wet, blue material at once (do not let it dry) into 

 the sixty pounds of air-slacked lime and work it up so that it will be 

 well distributed. If the resulting mixture is too moist add more air- 

 ;-'lacked lime. 



8. Rub this thiough the coarse sieve zchile still someivhat damp, 

 mix thoroughly and spread out to dry. 



9. When perfectly dry sift it through the fine-mesh sieve, crush- 

 ing all lumps. All of this can be readily made to go through the fine 

 sieve, except the small amount of sand which may be in the four pounds 

 of quick-lime. Mix so that the blue copper compound will be perfectly 

 evenly distributed throughout the whole mass. 



Store until needed ; it will keep indefinitely. 



This powder contains about three and a third times as much copper 

 per gallon as is contained in the liquid Bordeaux mixture. It may be 

 diluted to suit the need with, povrdered lime or flour, or may be used in 

 this condition. Where large quantities are needed use multiples of the 

 quantities given above.' 



If one hundred and thirty pounds of slacked lime, or an equal volume 

 of flour is -added to seventy pounds of the stock powder, the resulting 

 mixture will have practically the same copper strength as the "four- 

 four-fifty'' liquid Bordeaux mixture. It makes no difiference whether this 

 .idded Hnie be partially or completely slacked, as no subsequent reaction 

 takes place in the dry powder. Any other insecticide, as Paris green, 

 for canker worms, may be added in the form of powder in the proper 

 proportions. 



H— 17 



