MANUAL OF FISH-CULTURE. 241 



piping, which runs from the pump to the pressure-tank, thence along 

 the sides of the refrigerator to the transportation-tanks, whence it flows 

 by gravity to a tank below the floor. From here it is pumped into the 

 supply tank for redistribution. 



In order to iirovide sufficient air circulation, the air is driven by a 

 pump to a 30-gallon reservoir in the top of the car over the boiler-room, 

 from which it is taken to the transportation-tanks or cans through two 

 lines of iron piping running along the sides and top of the car. One 

 pet- cock is placed in the pipe for each tank to be supplied with air, 

 which comes to it through a hole ;/-o inch in diameter. From the pet-cock 

 the air is carried into the tank with rubber hose and released in the 

 water through liberators made of American linden, placed in hard- 

 rubber holders. 



Before the present system of water circulation was adopted the water 

 was taken from four 40-gallon tanks located in the bottom of the refrig- 

 erator compartments, pumped into four 60-gallon supply-tanks, from 

 which it flowed through the transportation -boxes and was returned 

 thence to the lower tanks. The water supply was at first connected with 

 a rotary hand-pump, and afterwards an arrangement was adopted to fur- 

 nish power for the pump and an air-blower, by means of a friction wheel 

 placed on the truck at one end of the car. This wheel was attached 

 near one end to the top of the truck, so that it rested on the tread of 

 the car wheel and was held there by two spiral springs. When not in 

 use, it could be elevated above the car wheel by a lever operated from 

 inside the car. Power was transmitted from the friction wheel by means 

 of a countershaft and rubber belting. The friction wheel gave a great 

 deal of trouble, however, as it was impossible to make it strong enough 

 to stand the wear to which it was subjected. As the action of the truck 

 springs, while the car was in motion, moved the truck frame up and 

 down — sometimes 3 to 5 inches — the friction wheel would be jolted out 

 of position, and so uncertain was its operation that it could not be relied 

 upon and the pump and blower had to be worked by hand. 



This car is also fitted up with a hatching outfit, consisting of eight 

 lead-lined boxes about G inches high, which may be placed on top of 

 the refrigerators and made to fit in place of the lids, which can be 

 removed. These boxes each hold six McDonald jars. An aquarium, 

 specially made for the work, is placed in the center of each box, with 

 three jars on each side of it. The jars and aquarium are securely 

 wedged ill the box, so that they can not move. The supply of water for 

 the jars comes from the supply-pipes in the refrigerator compartments, 

 tlie pipe coming up through the top of the refrigerator near the center, 

 then branching out on each side with pet-cocks in it, to which is 

 attached the rubber tubing to supply the jars. The overflow is through 

 a pipe leading out of the bottom of the boxes into the tank under the 

 car. 



Fry are carried in cans, and yearlings and adults in the transporta- 

 tion tanks. Great care is taken not to make a sudden change in the 



r. C. K. 1897 16 



