LIST OF TABLES. 



Page. 



TABLE I. Composition of commercial lead arsenates 9 



II. Composition of lead acetates 14 



III. Composition of lead nitrates 15 



IV. Composition of sodium arsenates 16 



V. Analysis of lead arsenates prepared in the laboratory 26 



VI. Monthly meteorological data, March to August, 1907, Washington, B.C. 29 

 VII. Comparison of monthly meteorological data for 1907 with the aver- 

 age for thirty-seven years 32 



VIII. Monthly meteorological data, March to August,1908, Washington, D.C. 



IX. Comparison of monthly meteorological data for 1908 with the aver- 38 



age for thirty-eight years 41 



X. Results of experiments with carbon dioxid 46 



XI. Results of experiments to determine solvent action of water con- 

 stituents on lead arsenate 47 



XII. Analysis of water used in spraying experiments 47 



50 



o 



