RELATIVE VALUE OF POISONS. 221 



Where larger quantities were used, a 40-gallon barrel was placed in a 

 four-wheeled wagon with wheels 5 feet apart, and the lowest axle 23 

 inches from the ground. This was drawn by two mules, b.eing made to 

 straddle one row of cotton, the mules walking in the furrows that the 

 wheels ran in. One man drove the wagon, and two others, provided 

 with fountain-pumps, distributed the poison contained in the barrel, 

 wetting nine rows for each trip across the field. Meantime, one or two 

 other men, with a two-horse wagon, containing several smaller barrels, 

 were engaged in carrying water from a pond to the ends of the rows of 

 cotton, where it was transferred to the distributing wagon. With these 

 two pumps worked slowly, the mules walking very slowly, we found that 

 a barrel of water went over about three acres of cotton, wetting it 

 fairly, but not so well as was to be desired. The men were therefore 

 made to work the pumps faster, so that a barrel lasted for two acres. 

 Not satisfied with this, we enlarged the holes in the rose-nozzle a little, 

 so that without materially diminishing the force of the pump we were 

 able to apply a barrel of fluid to the acre.* In this way about 30 acres 

 a day may be poisoned by four hands and four mules. 



My dry poisons were applied by a sieve made of a 2-quart tin bucket, 

 the bottom of which was replaced by perforated tin, and which was 

 provided with a socket at the side for the insertion of a wooden handle 

 about three feet long. 



My experiments with dry poisons were not extensive enough for me 

 to determine accurately the amount of labor required to poison an acre; 

 but Mr. Lide, the manager of George O. Baker's plantation at Selma, 

 Ala., tells me that a hand can poison from one to two acres of cotton per 

 day. He tells me, further, that one barrel of Eoyall's mixture goes over 

 about three acres. 



Before giving details of the experiments, I may briefly state the con- 

 clusions to which they led me, as follows : As an insecticide I prefer 

 Paris green to any other substance used, and find it less likely to injure 

 the cotton than any other. Next to this, I should place commercial 

 arsenic (arsenious oxide, As 2 O 3 ), though this is more likely to scorch 

 the cotton than the preceding. I should place London purple next in 

 the list, as being less valuable as a poison and more liable to injure the 

 cotton. Fowler's solution of arsenic (arsenious oxide dissolved in a solu- 

 tion of sodium or potassium carbonate in water) serves fairly a an in- 

 secticide, but my experience is that it is very liable to injure the cotton, 

 probably owing to the alkaline nature of the solution. A considerable 

 quantity of the mixture known as the Texas Cotton- Worm Destroyer 

 was used, the directions accompanying the package being followed ; but 

 I failed to obtain satisfactory results from its use in any trial. Oil of 

 turpentine, kerosene, and carbolic acid in water were applied but when 

 applied so as to kill the caterpillars I found that they always injured the 

 plant. 



* It is far better to employ the larger size of pump, which, from its greater capacity, 

 distributes more water than the one used by me, and with less labor. 



