150 MOSQUITO ERADICATION 



eye-bolts welded together, one bolted to the box, the other to the 

 shutter. (4) Screw hooks in the shutter, working on eye-bolts on the 

 box. This works fairly well. (5) Screw eyes in the shutter, working 

 on a bolt supported by a strap attached to the box. By knocking out 

 the cotter pin, the bolt can be pulled out and the shutter removed." 



Sluice-boxes, according to Fuchs, 1 are the cheapest and most 

 satisfactory type of tide-gate, where the stream is not too large. 

 With labor at 35 cents an hour, he gives costs of various boxes as 

 follows: A 3 by 4 by 16 foot box, placed several feet, under 

 water, $202; a 2 by 3 by 16 foot box, placed just below low water, 

 $33; a 2 by 3 by 20 foot box, placed just below low water, $105. 

 These costs include both labor and materials. 



SPECIFICATIONS FOR LARGE SLUICES 



Headlee 2 gives the following specifications for sluices and gates 

 employed as an outlet for a large creek in New Jersey, measuring 

 from 75 to 80 feet wide: 



1. "All sluices shall have an inside measurement of 6 by 3 feet, and 

 shall be built of 3-inch tongued and grooved long-leaf pine, free from 

 knots or serious blemish; they shall not be shorter than 15>^ feet and 

 shall extend from the outside of the dike, facing back under the dike. 

 These boxes shall be stiffened with 4 by 5-inch ribs, bolted at each 

 corner with a 3^-inch bolt, properly washered and drawn up with a 

 satisfactory nut. These ribs shall be placed around the outside of the 

 box, fitting it closely, at distances of 18 inches apart. The first and 

 last shall be made flush with the ends of the box. The planking shall be 

 firmly spiked to these ribs with 6-inch galvanized spikes. The top of 

 the box shall be covered with 2-inch long-leaf pine spiked on the top of 

 the ribs. 



2. "The dike shall be faced on the river side with plank piling for 

 120 feet . . . This facing shall consist of 3-inch long-leaf pine 

 planking, free from knots and serious blemish, not less than 14 feet long, 

 driven in until the top shall be 1 foot below the level given for the top of 

 the dike. If the tops of the piles are splintered, split or broomed by 

 driving, they shall be cut off below the lowest point of injury. In any 

 case, the cut of ends shall not be such as to make length of pile less than 

 provided. The top of the piling shall be even and bound together 



1 Transactions of the First Annual Conference of Sanitary Engineers, 

 U. S. Public Health Service, 1919. 



2 "Some Recent Advances in Knowledge of the Natural History and the 

 Control of Mosquitoes," New Jersey Agricultural Experiment Stations 

 Bulletin 306, 1916. 



