MANUAL OF FISH-CULTURE. 203 



feet; width, 3 feet 8 inches; depth, 11 inches. The table or trough is 

 constructed of 2-inch lumber and raised to a convenient height by 

 short, stout legs. The table is divided into 9 water tight compart- 

 ments by means of crosswise partitions of 1^-inch plank. 



At Woods Hole the dimensions of the troughs containing 12 boxes 

 are as follows: Length over all, 13 feet; width, 2 feet 7 inches; depth, 

 12 inches. The plank is li inches thick. The bottom of the trough is 

 2i feet above the floor. The compartments are separated by 1^-inch 

 partitions and are 22 inches long, 12 inches wide, and 10| or 11 

 inches deep. 



Two inches from each end of each compartment there is a 1-inch 

 wood partition. The partition d at the supply or upper end of the 

 compartment extends with its middle portion to the bottom of the 

 trough, while the two sides extend only to within IJ inches of the bot- 

 tom. The partition e, at the discharge or lower end of the compart- 

 ment, extends its full length to within li inches of the bottom of the 

 trough. Between the two partitions d and e in each compartment there 

 is snugly fitted a movable box in which the eggs are placed. This 

 box, which is constructed of J-iuch plank, is 9 to 9i inches deep in the 

 center, but only 8 inches deep at the corners, the bottom sloping 

 ui>ward toward the sides and ends of the box and being covered with 

 linen scrim. A wooden strip at the bottom, ^ inch thick and conform- 

 ing to the shape of the bottom of the box, extends the length of the box. 

 The box rests on cleats in the corners of the compartments which keep 

 the center of the box IJ inches above the bottom of the trough. 



The space at the supply end of each compartment is divided into 

 three pockets by 1-inch wood partitions. The middle pocket connects 

 with the main compartment by means of a small hole {^^ to -^ inch) 

 through the center of the partition and end of the box immediately 

 above the lengthwise strip, and the two lateral pockets connect by a 

 space at the bottom with the main compartment. 



At Woods Hole the water used in hatching is pumped from the 

 harbor to two tanks of about 18,000 gallons joint capacity. The water 

 is led to the hatching-room through a 4 inch wooden pipe and is sup- 

 l)lied to the hatching apparatus through a 2^-inch hard-rubber pipe 

 which branches from the main pipe and runs directly over each row of 

 tables. At Gloucester the main supply-pipe is of hard rubber, 3 inches 

 in diameter; this leads from a tank of 15,000 gallons ca^pacity, the 

 bottom of which is about 6 feet above the level of the troughs. A small 

 soft-rubber tube, provided with a rubber pet-cock, carries the water to 

 the middle pocket at the back of each box. As the pocket is always 

 full of water when the boxes are in operation, a considerable amount 

 of water goes through the small hole with much force, creating a strong 

 current in the box and keeping the eggs in constant rotary motion. 

 This current is one of the principal features of the apparatus. 



^luch more water enters the middle i)f)cket than can pass through 

 the smal'l hole into the box, and the sui[)lus flows over the sides and 



