12 PAEIS GEEEN SPRAYING EXPERIMENTS. 



sets of 6 samples each of Paris Greens were obtained and sent to all 

 the collaborators. Each sample weighed 1 ounce and contained the 

 following amounts of soluble arsenious oxid: 



Per cent. 



No. 1 2.84 



No. 2 4.00 



No. 3 5.00 



No. 4 6.00 



No. 5 7.00 



No. 6 8. 00 



DIRECTIONS FOB SPRAYING. 



(1) Treat each of the 6 samples with 9.5 gallons of water (approxi- 

 mately 1 pound to 150 gallons) and spray hardy trees such as apples 

 and pears. 



(2) Treat each of the 6 samples with 9.5 gallons of water and 2 

 ounces of previously slaked lime, and again spray hardy trees such as 

 apples and pears. 



(3) Treat each of the 6 samples with 15.5 gallons of water (approxi- 

 mately 1 pound to 250 gallons) and spraj 7 delicate trees such as peaches 

 and plums. 



(4) Treat each of the 6 samples with 15.5 gallons of water and 2 

 ounces of previously slaked lime, and again spray delicate trees such 

 as peaches and plums. 



Make duplicate and triplicate experiments in each case if enough 

 trees are available. When possible tell what varieties of trees were 

 sprayed. 



Carefully note the date of spraying and observe the trees for at 

 least three weeks. Also note whether the leaves fall from these trees 

 earlier in the fall than from similar trees that were not sprayed. 

 Keep a record of the weather conditions during the experiment. 



Always use the whole of the 1 -ounce sample forwarded to you with 

 the required amount of water. This precaution is of the greatest 

 importance, because of the fact that these 1 -ounce samples are prepared 

 from Paris Green to which is added definite amounts of pure arsenious 

 oxid in order to obtain the various percentages of this substance. 

 These are mixed as thoroughly as possible, but such mixing can never 

 be perfect. Therefore, if only a part of the sample were used a 

 higher or lower percentage of arsenious oxid might be present in that 

 part than in the whole sample. 



REPORT FROM THE MARYLAND STATION, COLLEGE PARK. 



By B. H. SMITH, T. B. SYMONS, and J. K. HAYWOOD. 



Forty-eight trees were utilized for this experiment, two for each of 

 the solutions tested, one with and one without the addition of lime. 

 The apple trees were York Imperials; the pears, Keiffers; the plums, 



