STORMONTFIELD EXPERIMENT. 31 



discharged from the feeding pipe is too small. 

 A larger run of water and a greater fall would 

 scour the gravel better, and keep it freer of 

 algae and impurities of all kinds. The boxes are 

 filled to within an inch or two of the top, first 

 with a layer of fine gravel, next with one of coarser 

 gravel, and lastly with stones as large as road 

 metal. These deposits, previous to being put 

 into the boxes, should be washed clean, and 

 allowed to lie exposed to the action of the sun 

 and air, in order to rid them of the larvae of 

 insects, which destroy more ova than all other 

 enemies put together. 



When the young fry seek change of quarters, 

 they drop down to the lower canal, where they 

 are regularly fed. At this time the canal is 

 swarming with them there are more fish there, 

 were they allowed to reach to the full-grown state, 

 than would pay the rental of the Tay for one 

 year. All the fry do not leave the boxes at the 

 same time ; many of them linger on through the 

 summer. As will be seen by looking at the plan, 

 there is a connecting stream with the pond, which 

 the keeper shuts off with a sluice; this he keeps 

 shut until all the smoults are out of the pond, 

 which is emptied and cleaned ere this sluice is 



