OF THE SALMON. 41 



diameter, and determine its length at least two inches 

 above the grate : the remaining water from the spring 

 can be led off sideways. 



"If you have an inclination for more breeding-troughs 

 than one, they should be fixed in the same direction as 

 the first, and a large pipe must be placed to the head of 

 the spring, which must empty itself into smaller pipes 

 laid across the water troughs, so that each trough may 

 have its proper quantity of water conveyed into it ; or 

 it may be managed by means of brass cocks; but this 

 is left to the choice of every one's own pleasure, as 

 the most convenient method will soon be found out. 



" 3d. After the box or trough is properly finished, 

 it must be placed horizontally upon two logs of wood, 

 stone, or brick, and within, upon its bottom, put some 

 clean washed gravel, about the size of peas and beans, 

 two inches high ; afterwards sprinkle some coarse 

 gravel or pebbles over it, the smallest of them the size 

 of beans, and some larger than hazel-nuts. This last 

 is done that, upon the surface of the gravel, many deep 

 holes may be formed, that the continual motion of 

 the water may not carry away the eggs, but that they 

 may remain where they were at first sprinkled in. 



" 4th. Then let the water run into the trough, as 

 directed in 2, and raise it higher or lower, according 

 to the instructions in Section 1st, so that the water 

 covers the gravel always one or two inches. This 

 done, you have accomplished all that is necessary to the 

 apparatus for breeding trout and salmon. 



Section III. 



" 1st. The time of spawning begins the latter end 

 of November, and commonly ends the latter end of 

 January, or beginning of February ; but the spawning 

 time of each separate trout continues only about eight 



