92 THE HISTORY AND HABITS OF THE SALMON. 



to ten days ; it would be more exact to say the mean 

 time lies betwixt. 



EXTRACT FROM THE LATE SIR FRANCIS A. MACKENZIE, 

 BART. 



(< In tbe autumn of 1 840, having chosen a brook run- 

 ning rapidly into the river Ewe, a hollow spot adjoining 

 to it was selected and cleared out, of the following di- 

 mensions : Length, twenty-three yards ; breadth, from 

 twelve to eighteen feet ; and all large stones having been 

 taken away, the bottom was covered one foot thick with 

 coarse sand and small gravel, the larger stones not exceeding 

 the size of a walnut. A stream from the brook was then 

 led into this hollow, so as to form a pool of about eighteen 

 inches in depth at the upper, and three feet at the lower 

 end, thus giving it one uniform gentle current over the 

 whole pool ; whilst the supply of water was so regulated 

 by a sluice, as to have the same depth at all times, and a 

 strong stone wall excluding all eels and trout, so destructive 

 both to spawn and fry. 



" On the 13th of November, four pairs of salmon, male 

 and female, were taken by a net from the Ewe, and care- 

 fully placed in the pool. On the 18th they showed a 

 disposition to spawn, but on the 20th, the whole was 

 carried away by some ill disposed persons, and on ex- 

 amining the pool, only a small quantity of ova appeared 

 to have been deposited. On the 23rd, four pairs of 

 salmon were again taken and placed in the pool, which 

 were observed to commence spawning on the following 

 day. Caught them carefully, squeezed gently about 1200 

 ova from a female into a basin of water, and then pressed 

 an equal quantity of milt from a male over them, stirred 

 the two about well, but gently, with the fingers ; after 

 allowing them rest for an hour, the whole was de- 

 posited and spread in one of the wicker baskets recom- 

 mended by Professor Agassiz, having about four inches of 

 gravel below them, and two or three inches of gravel 

 above. A similar quantity of ova, treated in the same 

 way, was also deposited in one of the copper wire bags, 



