THE ARTIFICIAL PROPAOATION OF MARINE FISH
9
the other, producing a rise and fall in level analogous to tidal aotion.
With the plug removed to admit air, the water level similarly rose and
fell in the Chester jar, effecting frequent gross water renewal.
The McDonald tidal box (Fig. 1) was designed to increase eggcarrying capacity and to facilitate the cleaning of incu.bators. It
usually took the form of a large timber trough 4 m long, 79 cm wide
Cnomber C
containing removob
incubator
A
5'
Supply chomber
Outlet chomber D
Fobrlc bottom
to incubotor
1
Cleats
Y
L ongitudlnol sect ion
Section k - - Y
FIQ. 1. The McDonald tidal egg-hatching box. (After Brice, 1898.)
and 31 cm deep, divided by cross pa,rtitions into twelve compartmente.
Each compartment was further sub-divided into upper (supply),
middle and lower (outlet) chambers. The upper chamber contained
three pookete: a cgntral pooket (A) into which hatchery sea water
flowed at a fast rate, with a small hole piercing the inner face permitting the passage of water into the middle chamber of the oomPartment. Since the rate of inflow w u much fader than the outflow
9
the other, producing a rise and fall in level analogous to tidal aotion.
With the plug removed to admit air, the water level similarly rose and
fell in the Chester jar, effecting frequent gross water renewal.
The McDonald tidal box (Fig. 1) was designed to increase eggcarrying capacity and to facilitate the cleaning of incu.bators. It
usually took the form of a large timber trough 4 m long, 79 cm wide
Cnomber C
containing removob
incubator
A
5'
Supply chomber
Outlet chomber D
Fobrlc bottom
to incubotor
1
Cleats
Y
L ongitudlnol sect ion
Section k - - Y
FIQ. 1. The McDonald tidal egg-hatching box. (After Brice, 1898.)
and 31 cm deep, divided by cross pa,rtitions into twelve compartmente.
Each compartment was further sub-divided into upper (supply),
middle and lower (outlet) chambers. The upper chamber contained
three pookete: a cgntral pooket (A) into which hatchery sea water
flowed at a fast rate, with a small hole piercing the inner face permitting the passage of water into the middle chamber of the oomPartment. Since the rate of inflow w u much fader than the outflow