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PACIFIC SALMON FISHERIES. 211 
The principle of the salt bath is simply that the specific gravity of the good eggs is 
greater than that of the bad eggs, hence upon being placed in the salt solution the 
good eggs sink and the bad remain afloat and are easily removed. It is vitally essen- 
tial to the success of the undertaking that the solution be of the proper strength, and 
it is for this reason that the beginner is apt to become discouraged. If the solution is 
too weak all the eggs, both good and bad, will sink, while if it is too strong all will 
remain afloat. The margin of the proper density is so narrow that in the operation it is 
necessary every few minutes to strengthen the solution by adding more salt or brine, 
otherwise the small amount of fresh water which adheres to a basket of eggs as it is 
lifted from the hatching trough into the solution will affect unfavorably the results 
when treating succeeding baskets. Experience and careful observation, however, 
will soon make it possible for the operator accurately to judge when to add a bit of the 
stock solution. It is a convenience, of course, to have a salinometer at hand when 
preparing the solution. Itis commonly the practice as an aid in preparing the solution 
to test it occasionally with a few eggs. r 
Highly successful results in using the solution with red salmon eggs have been 
attained at the Yes Bay station, and a detailed description is accordingly given of the 
methods pursued at that place. 
The chief item of equipment consists of a water-tight wooden tank 4 feet long, 24 
feet wide, and 10 inches deep for holding the solution in which the eggs are immersed. 
Before each basket is immersed it is necessary that the surface of the solution be 
perfectly quiet, for any ripple or current will tend to disturb the buoyant effect of the 
solution upon the eggs. Therefore it was found of great convenience last winter to 
use a floating frame made of half-inch material 6 inches wide fastened together verti- 
cally and at right angles, thus forming open squares about 6 inches either way. After 
each basket of eggs is lifted from the salt bath this frame is placed in the solution to 
stop all motion of the water, being pushed down until it is almost submerged and held 
firmly against the side of the tank fora few seconds. Upon being carefully withdrawn 
the solution is quiet and the next basket of eggs may be immersed without further 
delay. 
Another piece of equipment is a feather fan with which gently to push the floating 
dead eggs away from over the submerged basket into which the good eggs have settled. 
Unless the dead eggs are quickly moved they too will sink. A feather fan made by 
fastening eagle feathers to a thin strip 8 inches long by 14 inches wide works much 
more satisfactorily for this purpose than a wing. An ordinary hand scaff net about 
12 by 14 inches in size for removing dead eggs from the tank, a dipper, and a bucket 
complete the outfit. Wood and metal surfaces in all equipment should be well 
coated with asphaltum or some similar preparation. 
At Yes Bay as soon as five or ten million eggs are far enough advanced to stand light 
concussion the baskets are lifted out of the troughs and the eggs are stirred thoroughly 
with the hand, which causes practically all of the unfertile or empty eggs to turn white. 
As soon as the line of the fish shows plainly when held up to the light and there is a 
distinct curvature to the tail, the eggs are sufficiently well advanced in development 
to stand stirring. After this process the baskets are returned to the troughs and allowed 
to remain three days, for when first turned the unfertile eggs are about as heavy as the 
good eggs and consequently would sink if the salt solution were applied at once. 
On the fourth day after stirring, everything being in readiness, five or six baskets are 
removed from a trough and set ontop todrain. After afew moments a basket is grasped 
at each end and is lowered into the tank containing the solution until the liquid comes 
through the eggs. A light shake is then given to level up the eggsin the basket. Next, 
slowly and very gently, the basket is lowered until the brine comes almost to its rim 
and is held perfectly still fora moment. All the eggsin the basket will rise, but soon 
the good eggs will begiu to sink, and presently, if itis a basket of poor eggs, the surface 
