51 
placed in double rows in the breeding pond, with a 
foot-path 18 inches wide between each double row. 
In each box is put first a layer of fine gravel, then 
a coarser layer above—the whole being covered with 
water to the depth of 2 inches. In these boxes the 
spawn is deposited. The water passes by gravitation 
through each row of boxes from the canal stretching 
along the upper end of the pond. This canal is 
copiously fed with water from the filtering pond. 
The boxes are laid with a fall of 2 inches on each, 
or 2 feet in the row of 12 boxes, and the water passes 
from box to box by openings or notches 4 inches wide 
in the middle of the divisions between the boxes. 
In these boxes the spawn lies from 90 to 130 days, 
according to temperature. The ova may be hatched 
in a much shorter time by raising the temperature. 
About a month before hatching two black specks 
appear in the egg, which are the eyes of the future 
fish ; andafaint line runs around nearly three-quarters 
of the egg, showing the body of the future salmon. 
When this is seen the egg is alive and will probably 
hatch out all right. There is a curious question 
about which much unceidainty prevailed, but which 
Frank Buckland has satisfactorily settled, and that is, 
that the eggs do not grow—otherwise, do not increase 
in circumference or diameter ; but the fishes inside 
them most certainly increase in bulk, till at last they 
become so large that the egg-shells suddenly burst. 
The head of the young fish comes out first, then the 
tail, while -the egg remains attached to its body; but, 
instead of the egg or bag being round, it is now ob¬ 
long in shape ; and in this bag, which is called the 
umbilical vesicle, it carries all the food which is to 
last until it begins to eat. 
The average weight of a young salmon just hatched 
is nearly 2 grains, bag and all ; at a year old he is 
nearly 2 oz. in weight; at 16 months old, after the 
smolt has been a few months in the sea, he becomes 
a grilse of say 7 lbs. ; at two and a-half years old he 
becomes a salmon of 12 lbs. to 16 lbs. weight—a very 
great increase certainly in so short a time. 
There is no animal, I presume, that increases so 
rapidly and at so little cost, and that becomes such 
