[11] A FOREIGN REVIEW OF AMERICAN FISH CULTURE. 487 
In each trough the eggs are arranged on wire frames fixed in an in- 
genious manner (the Williamson apparatus) which we shall describe 
below. This method economizes much space (which is particularly 
useful when large quantities of eggs are to be operated on), and thor- 
oughly aérates the water by keeping it constantly in motion. 
Long boards, forming covers, should be placed over the troughs; for 
the light which, by daytime, penetrates the canvas of the tent would 
be sufficient to destroy the eggs. 
The water which feeds these hatching troughs comes from the river. 
It is raised to a height of 3 meters and led into the apparatus by means 
of a hydraulic wheel, supported by two boats in the middle of the river, 
and furnished at its circumference with large buckets which at each 
revolution pour their contents into a wooden aqueduct raised on poles. 
This wheel, placed in the midst of the rapids, is thus driven by a very 
strong current, and is sufficient to raise and supply the apparatus with 
about 300,000 liters of water per hour. 
The water of the river McCloud, which is almost always limpid dur- 
ing the fine season of the year, becomes generally turbid during the 
spawning season of the salmon, as these fish root in the sand to make 
their nests. In order to serve for the incubating process, this water 
must be considerably filtered. The filter used consists of three wooden 
boxes, the one of which, larger than the others, forms a first receptacle. 
The water flows through it, first through a vertical wall of coarse cloth 
or canvas, doubled, and firmly extended on a trame, and afterwards 
through four similar walls of flannel or some woolen fabric; each wall 
presenting a filtering surface of 1 square meter. In the two other boxés 
it flows through a triple canvas and seven flannel filters. 
As the temperature of the water in the hatching troughs averages 
12 to 14 degrees C., the eggs are generally embryonated at the end of 
sixteen days; when they have reached that degree of development de- 
sired for their transportation, they are packed in damp moss and placed 
in boxes measuring 60 by 15 centimeters. This packing in itself in- 
volves considerable work, considering that 10,000,000 eggs represent a 
volume of about a hundred decaliters. More than 200 decaliters of 
moss are required for packing these eggs in an almost equal number of 
boxes, which are packed two by two in hay in open cases, having an 
upper compartment destined for the ice which is supplied during the 
journey. The whole thus packed makes a hundred packages, weighing 
in all more than 20 tons. On account of the heat the packing must be 
done very rapidly, and requires a great degree of activity. 
At last everything is ready, and nothing remains to be done but to 
forward the packages to their destination. They are (care being taken 
to shake them as little as possible) by a rather rough road of 35 kilo- 
meters, taken to Redding, Cal., the nearest station on one of the branch 
lines of that gigantic railroad (the Central Pacific Railroad) which unites 
the coasts of the Pacific and Atlantic, climbing the solitary heights of 
the Rocky Mountains and crossing the immense prairies of the ‘Far 
