On Stocking. 17 



tion, and the other, very variable. The cost of in- 

 bation is fixed for all trout and salmon Ova per 

 gallon, and for each class of Ova per thousand ; but 

 as the same space is required in practice for every 

 gallon (at Howietoun this space is two boxes), 

 while in different classes of Ova the number to the 

 gallon varies from 23,000 to 50,000, it is evident 

 that the space required per thousand, and the 

 consequent cost of incubation per thousand is 

 nearly double per thousand for eggs running 23,000 

 to the gallon to that for eggs running 50,000 to 

 the gallon, in practice the limits are first-class 

 salmon, 23,000; first-class trout, 28,000; eggs 

 from young salmon and grilse, 30,000 ; ordinary 

 trout, 40,000 ; well-bred trout, 32,000 ; ordinary 

 wild lake trout, 40,000 ; wild hill-burn trout, 

 50,000. Hill-burn trout can be improved to 

 produce eggs running 40,000 to the gallon. 



The principal hatching house at Howietoun 

 cost a little over 3000, and as at present fitted 

 incubates 80 gallons of Ova. The cost of renewals 

 of hatching houses is about 14s. per annum, and 

 the proportion of wages is about 2 per week for 

 say 15 weeks, as in practice the house cannot be 

 all filled under five weeks, and the eggs require 

 about ten weeks for incubation. Moreover the 

 house and boxes are used for fry for a further 

 period of fifteen weeks. The calculation will 

 stand thus : 



