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are then used to produce nascent hydrogen, with the excess of nitric acid in 

 the benzole. When distilled, aniline results ; to this arsenic acid is added to 

 give an atom of oxygen which produces rose aniline, and qnick-lime is added 

 to absorb the arsenic. The residuum which is obtained by filtration is the 

 London purple of commerce. The compound is therefore made up of lime 

 and arsenious acid, with some carbonaceous matter about each atom. Exper- 

 iments which I made with it in 1878, as an insecticide, and its use on the 

 Colorado potato-beetle by Professors Budd and Bessey of the Iowa Agricultural 

 College proved highly satisfactory." 



Mr. A. K. Whitney, of Franklin Grove, Illinois, found it to be a perfect 

 antidote to the canker-worms which had not been prevented from ascending 

 the apple trees, and experiments upon the cotton-worm conducted under his 

 direction all showed that its effects are fully equal to those of Paris green. 

 Like the latter it kills the worms quickly, and does not injure the plants, 

 if not applied in too great quantity. 



Its cheap price removes all temptation to adulterate it, as every adulteration 

 would prove more expensive than the genuine article. It is superior to Paris 

 green, because of its finely powdered condition, which allows it to be more 

 thoroughly mixed with other ingredients and thus used in smaller proportion. 



Very careful experiments made with the view of ascertaining the proper 

 amount of dilution to give the powder resulted as follows : Half pound of 

 the poison to eighteen of dry dilutents proves satisfactory, and any greater 

 amount is simply a waste of the material. If applied in water, half pound 

 of the powder to from fifty to fifty-five gallons of water is the proportion 

 which will give most general satisfaction, by killing the worms and not injur- 

 ing the plants. 



London purple can be sold in New York at the low rate of six cents per 

 pound, and at corresponding rate in internal towns, thus bringing the cost of 

 the insecticide very much below anything else in the market. It has the fur- 

 ther advantage over other arsenical compounds, in its penetrating power ; it 

 seems to be more effectually absorbed into the substance of the leaf and is 

 therefore more persistent. 



Pyrethrum Powder. From the same authority we cull the following regard- 

 ing the Pyrethrum insecticide. It is used against various household pests 

 under the names, "Persian Insect Powder," or "Dalmatian Insect Powder," 

 and sold at prices that forbid its use in the field. The former is the powdered 

 flower of Pyrethrum carnevin and P. roseum; the latter is made from P. 

 ceneraricefolium a native of Dalrnatia. Experiment by Wm. Saunders of 

 Ontario, and Prof. Riley, prove that the powder produces most satisfactory 

 results when applied to field insects. A single puff of the powder upon plants 

 covered with the cotton-worm sent the insects wriggling to the ground. In 

 this substance we have an excellent insecticide, which is not dangerous either 

 to plants or man, and the only thing apparently to be considered in connection 

 with it is how to reduce the cost so as to bring it within reach of the means of 

 those who need to use it. 



A Mr. Milco, of Stockton, California, is trying to solve this problem, and 

 has begun raising the plants used in making the Dalmatian powder. The 

 powder which he has made is selling now in California at $1.25 per pound, 

 but he expects to reduce the cost of production to less than a twelfth of this 

 amount when the business is fairly established. 



Pure Pyrethrum powder was mixed with a small quantity of powdered rosin 

 and applied to plants infested with cotton worms of various ages ; the smaller 



