822 KEPOET OF COMMISSIONER OF FISH AND FISHEEIES. 



4. — Incubation. 



The only apparatus in use at the liatching-liouse for the incubation of 

 eggs was that devised by myself in 1875. As adapted to use in a hatch- 

 ing-trough, it consists of movable frames, each a little more than a foot 

 square and about eight inches deep, and holding each 10 or 11 wire 

 trays so constructed that a horizontal aperture of one-eighth inch ex- 

 tends on all sides (except a small space at each corner) above each tray, 

 thus permitting the passage of a horizontal current of water. The 

 frames are made to fit the troughs pretty closely, and the water was 

 thus compelled to flow through between the trays. The picking was 

 done on a table, to which the frames were removed for the purpose. 

 This form of apparatus is very compact, simjile, and easily managed. 

 We had about 20,000 eggs in each frame, occupying a trifle more than a 

 square foot of space in the trough. There were six troughs, each 25 

 feet long. 



5. — Distribution of eggs. 



The total number of eggs obtained was, according to the estimates 

 made from day to day, 2,159,000. I think these figures too large by 5 

 per cent., but as the distribution of the eggs was made on that basis, 

 the estimate is retained. Early in January it was found necessary to 

 begin shii)ping eggs to other points for hatching, and the last case was 

 sent off February 19. The distribution may be summarized as follows : 

 Shipped to order of Commissioners of Fisheries of Massa- 

 chusetts _ 255, 000 



Shipped to order of Commissioners of Fisheries of Connec- 

 ticut 255, 000 



Shipped to order of United States Commissioner of Fish and 



Fisheries 890, 000 



Eetained to be hatched for Grand Lake Stream 470, 000 



Losses previous to distribution of eggs 289, 000 



2, 159, 000 

 The number of eggs obtained was far in excess of my expectations. 

 It was twice as great a number as I had expected the hatching-house 

 would ever have to receive. The volume of water flowing through the 

 troughs was, on the 16th November, twenty-two gallons per minute. 

 This would have sufficed, but in December it shrank to the very small 

 volume of five or six gallons per minute. This was due partly to a leak 

 under the dam that was not discovered until several months later, but 

 mainly to a long period of dry, cold weather. The result was a serious 

 injury to a portion of the eggs. There is now no doubt that they were 

 overcrowded. The water appears to have been of good quality, but too 

 warm, and the site of the spring, as already explained, did not admit of 

 the application of any practicable method of aeration. The water af- 

 forded an ample supply of air to the eggs that first received it, but be- 



