ARTIFICIAL HATCHING OF SPAWN. 37 



unhatched, to have more, so that there shall be more 

 stream and movement in the water, and, consequently, 

 less time for deposit to settle, so that we had on 

 perhaps as much as a stream of three-quarters or an 

 inch in diameter. When the fish are hatched, half 

 that quantity would he preferable, as they are not 

 well able to struggle against a stream, and would be 

 carried down perhaps to the end box, and so against 

 the perforated zinc face, where they would stop up 

 the holes, and finally be smothered. The boxes 

 were then properly steeped in water and seasoned, 

 and being of elm the joints drew closely together 

 after a while, and the boxes held the water without 

 material leakage. 



I may here describe how the ova was subse- 

 quently deposited in these boxes. The gravel was 

 first placed at about one and a half or two 

 inches below the cuts above described. The ova was 

 scattered thickly over it, among the interstices of the 

 gravel, to the extent of some 4,000 or 5,000 or more 

 in each box. With a fine brush, such ova as might 

 be too prominent was cautiously swept into some 

 crevice, and the whole was then very carefully 

 covered over with good sized gravel stones, tolerably 

 flat and sizeable ones of say one inch, or one and a 

 half inch square, being selected, the object being to 



