96 



OFFICIAL REPORT OF THE PROCEEDINGS OF THE 



seems to be the danger of an incomplete union between the lime and the 

 arsenic, so that the full forty minutes' boiling, possibly even with more 

 lime and the addition of lime when diluting, would probably render 

 the mixture entirely safe." 



Arsenic, Soda, and Lime. — This is often known as the Kedzie formula, 

 as it seems first to have been recommended by Professor Kedzie, of 

 Michigan. The method of its production is fully described in the fol- 

 lowing letter from Professor Kedzie: 



Ageicultubal College, Michigan, September 5, 1899. 



The formula I recommended for an arsenical spraying mixture to take the place of 

 Paris green was the following : Boil two pounds of white arsenic with eight pounds of 

 sal-soda in two gallons of rain water. Boil these materials together in any iron pot not 

 used for other purposes ; boil them fifteen minutes, or until the arsenic dissolves, leav- 

 ing only a small muddy sediment. Put the solution in a two-gallon jug and label 

 Poison, Stock Material for spraying mixture. The spraying mixture can be prepared 

 whenever required in the quantity needed at the time, by slacking two pounds of lime, 

 and adding this to forty gallons of water ; pour into this a pint of the stock arsenic 

 solution ; mix up, stirring thoroughly, and the spraying mixture is ready for use. The 

 arsenic in this mixture is equivalent to four ounces of Paris green. 



Advantages of this Method: First— It is very cheap and the materials can be 

 found in every village in the State ; 



Second— The stock material (arsenite of soda) is easily prepared and can be kept in 

 that form for any length of time, ready for making a spraying mixture of lime and 

 water ; 



Third— The arsenite of lime in the quantity required for spraying will not burn the 

 leaves, or injure the trees or plants ; 



Fourth — It will be uniform in quality and not vary in stre'ngth, as Paris green often 

 does ; 



Fifth — It makes a milky colored spray and the color on the trees will show how 

 evenly it is distributed. 



Every one using such deadly poison should bear in mind the possible danger from 

 its use; the pot, the jug, and every apparatus for making the arsenite of soda should 

 be used for no other purpose of any kind. 



Very faithfully, 



(Signed:) P. C. KEDZIE. 



Mr. Smith, of Hood River, Oregon, varies this formula, recommend- 

 ing: " Instead of two pounds of lime I used not less than six pounds; 

 and I found that the additional lime prevented burning foliage and 

 also retained the poison longer on the trees. I also used one quart 

 instead of one and a half pints of the arsenic to fifty gallons of water. " 

 And again, " I would recommend using freely of the lime up to say ten 

 pounds to fifty gallons of water.'" 



