. ARSENATE OF LEAD PASTE 



41 



small glass of ammonia; the Paris green should completely dis- 

 solve. If it does not it is evidently adulterated. 



If a microscope is available and a little pure Paris green is 

 examined it will appear made up largely of regular, more or less 

 spherical, bodies with smooth edges (Fig. 65); if adulterated 

 many irregular-shaped particles will be observed mixed with the 

 more spherical bodies (Fig. 66). 



The fact that there is some free water-soluble arsenic in Paris 

 green, which amount may be illegally excessive, makes it more 

 or less dangerous to use in the hands of a careless grower, for, as 

 intimated above, it is very likely to burn tender foliage. At the 

 same time some crops can stand a large amount of this insecticide 



*< 



* rfi .c va & i^ml&7v&fvE& 



i *** ?** c te^iteN^ss 



:g$ H 



f *ft 4 



FIG. (55. Good Paris green, as it appears 

 under the microscope. 



FIG. 66. Poor Paris green as seen with the 

 microscope. 



without injury. Cabbage plants, for example, when good-sized, 

 show no serious effect when sprayed with soap and Paris green at 

 the rate of five pounds of the latter in fifty gallons of water. Less 

 than one-half of those proportions would burn the leaves of apple 

 trees. 



Use Lime with Paris Green. This burning quality of Paris 

 green can be restrained by the use of two pounds of quicklime for 

 every pound of Paris green used. Since the larger part is not 

 soluble in water, but is held in suspension simply, there should be 

 constant agitation of the liquid while spraying. 



3. Arsenate of Lead Paste. This contains less than 1 per 

 cent of free or soluble arsenic and about 15 per cent of arsenic 

 oxide. It is a much safer and more satisfactory poison than the 



