PRESERVATION OP PISIIERY PRODUCTS FOR FOOD. 
349 
the sides of the car between the office and boiler room. They are 30 feet long, 3 feet wiih), and 25 
inches deep. Under the car, l)etween the trucks, is a reservoir tank holding (100 gallons of water, 
and from which water is pumped into the pressure tank near the office; it then passes from this tank 
to the fish cans and tanks, and then back to the reservoir. In the middle of the car, over the com- 
partments referred to, are four berths and several lockers for the use of the crew. The office also 
contains two berths, a writing desk, and a typewriter. These cars are fully equipped with all modern 
improvements in the way of brakes, couplers, signal whistles, etc., and have Pullman trucks and 
33-inch Allen paper wheels. With the large water capacity provided, they are capable of carrying 
much greater loads of fish than ever before. 
Ill transporting- fresh-water sjiecies both water and air circulation are used, bnt 
witli salt-water species the salt water is nsnally kept aerated by circulation only as it 
is not generally practicable to provide for a change of water. When the temperature 
is high, ice is sometimes iiacked about the transportation tanks to keep them cool, 
and in extreme cases a can tilled with ice is jilaced in the water. In this manner 
marine species have been carried successfully for six days or more. 
In the above-described cars the carrying capacity is to some extent sacrificed for 
the comfort of the crew, since they live on the cars throughout the year. Also the 
fish must not only reach their destination alive, but in a vigorous, healthy condition, so 
that they may live and be used in reproducing. Neither of these conditions is essen- 
tial in transporting live fish to market, consequently a greater carrying capacity could 
be secured in cars designed especially for that trade. 
A method of operating the air-pump by means of the rotary motion of the car axles 
was attempted on the 41. S. Fish Commission transportation cars. The experiment 
is thus described on page 241 of the report for 1897 : 
An arrangement was adopted to furnish power for the pump and an air-l)lower 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 hy 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 
Avheel 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 he worked by hand. 
As a general rule fish will carry best in Avater of a low temperature. Cold Avater 
absorbs more air than Avarm; it also lessens the activity of the fish, causing them to 
consume less oxygen, and it retards decomposition in the organic substances con- 
tained in the water and the consequent generation of noxious gases. The lowering 
of the temperature therefore offers a threefold advantage. Whenever practicable the 
fish should be kept in confinement Avithout food for a day or tAvo before being trans- 
imrted, so that there may be no danger of the Avater being made impure by excrements 
of the fish. 
In Europe considerable attention has been given to transporting fish alive. 
Well-smacks are used in the North Sea fisheries prosecuted by Germany, Holland, 
and England. Live cars are employed by many of the shore fishermen, and in many 
of the fish-markets both fresh-Avater and marine sj)ecies are kept alive in tanks. The 
difficidty of keeping sea fish alive Avhen natural salt water can not be obtained is met 
by the use of artificial salt Avater. But the most interesting feature of the European 
fish marketing is the overland transportation of live fish. 
