1092 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [2] 



will always be under surveillance. The surface of the gi'ouud presents 

 a steep incline, of which advantage has been taken to arrange the 

 floors of the hatchery in a descending series, with a total diiierence in 

 elevation of about 11 feet. The water is introduced upon the highest 

 of the six floors devoted to the development of the embryos, with ample 

 room for aeration and reaeration at each plunge. The latter circum- 

 stance atones for the small minimum volume (9 gallons per minute was 

 the lowest observed this season), and in part for the fact that it is 

 wholly spring water. The volume is least from August to early March, 

 after which the spring rains and the melting of the snows produce so 

 great an augmentation that there is a great suri^lus during all the 

 season of hatching the reserved spawn and growing the alevins. The 

 minimum volume can be augmented by the introduction of water from 

 other, not very distant, si)rings. 



This house was founded in haste, in December, 1880, and was at first 

 only 30 feet long and 20 wide, but this season we have added wings 

 that increase the floor area to about 1,500 square feet. The floors 

 have all been cemented, and the foundation walls, of massive masonry 

 carried up to a height of from 1 to 8 feet above the ground. Cement 

 pipes were laid to introduce the water from the principal spring, and 

 an aqueduct, partly of bored logs and partly of assorted gravel, brings 

 in the water from another spring GOO feet distant. This will henceforth 

 be the headquarters of the establishment. Here the eggs will be packed 

 for shipment, and the reserve hatched. Here will be the storerooms 

 and workshops. 



^ The fixtures for the development of the eggs are similar to those in 

 use at the other houses and also at the Penobscot establishment. Plain 

 wooden troughs are furnished with movable frames in which the egg- 

 trays are arranged in tiers ten deej), with provision for change of water 

 by a horizontal current. A single new feature has been introduced in 

 the method of aeration. Two troughs are placed side by side and the 

 water allowed to pour from one to the other nearly the whole length, 

 exposing a very broad and thin current to the action of the air, and in- 

 creasing the opportunity of aeration probably twenty-fold over that 

 afforded by a connecting open spout 6 inches wide. In a rough way 

 it may be estimated that by the repeated use of this arrangement in the 

 new house a gallon of water there is fully equal in efficiency to five gal- 

 lons in hatchery No. 1. 



No change has been made in the location of the fishing ground or the 

 fixtures and appliances pertaining to the work of spawning, except 

 trifling alterations in the form and proportions of the inclosures. 



2. — Fishing and spawning. 



The spring fishing of 1881 was much better than usual, both as regards 

 the numbers and size of the fish taken. Through the summer there 

 was more rain than usual, and in August and September the lake and 



