THE USE OF COAL-TAR. 387 



a wire screen, set in sucb a shape, that if the 'hoppers jump against it, they must 

 fall into the trough. It runs so close to the ground that few, if any, of the pests 

 escape below it. 



Mr. C. L. Watrous, of Des Moines, Iowa, suggests a contrivaDce of 

 this sort, with the addition of a wing on either side of the trough, ex- 

 tending forw^ard and outward, so as to catch more locusts, that may be 

 npon the ground. He further states that this is about the only means 

 that was employed there for killing them. 



Mr. G. Y. Swearingen, of Sidney, Iowa, under date of June 14, 1877, 

 states : 



The cheapest, and to my mind the most successful, device or machine is muslin or 

 ducking, 10 feet long, about 2^ feet wide, fastened to strips at each edge, stretched at 

 ends and in center or more places with other strips; a piece, 18 inches wide at rear, 

 supported by upright strips. Saturate with coal-oil, and have a boy at each end carry- 

 ing it slowly over the ground. 



The locusts, in hopping, light on the saturated surface, and are killed by the coal-oil, 

 which appears to me to be the most destructive to them of anything yet tried. 



Coal-tar. — This may be used with most of the contrivances just de- 

 scribed for the use of kerosene, and while not equal to the simple kero- 

 sene pan for speed in trapping and destroying, is yet very useful, espe- 

 cially in the neighborhood of gas-works where the coal-tar can be obtained 

 at nominal cost. It also permits the use of the simi)lest kind of pan. 

 Enough tar is spread over whatever receptacle may be used to cover well 

 the bottom, and when this becomes sufficiently matted with the young 

 locusts so as no longer to destroy the new comers, another coating is 

 added, and so on until it becomes necessary to remove the whole mass, 

 when it is shoveled from the pan and burned ; or, what is far preferable, 

 wherever there are wet ditches, it may be thrown into these, when the 

 oil contained in it, spreading over the surface of the water, destroys such 

 locusts as may jump into or be driven into such ditches. Where the 

 tar is scarce, as a matter of economy it will pay to melt the accumulated' 

 mass in iron vessels. By skimming off the dead locusts that rise to the 

 surface, and thinning the residuum with a little coal-oil, it may be used 

 again. 



The Hon. A. B. Bobbins, State senator from Willmar, Minn., deserves 

 credit for having, by an opportune letter in the Saint Paul Pioneer Press 

 and Tribune of May 17, successfully drawn the attention of the people 

 of his State to the advantageous use of coal-tar. It had been applied in 

 one way or another in previous years, not only in Kansas and Colorado, 

 but even Minnesota. 



The New Ulm (Minn.) Herald of May 28, 1875, had urged its use 

 spread upon sheets of building-paper, and the same recommendation 

 was referred to in full in a report to the geological and natural history 

 survey of Minnesota for 1876. The Farmers^ Union^ of Minneapolis, 

 under date of August 8, 1876, in a letter from Greeley, Colo., had de- 

 scribed the use of the same material spread over stout canvas fastened 



