214 FISHERIES OF THE UNITED STATES 



MOVIXG FLOAT FISH-WAYS. 

 With coimter-cuiTeuts from below. 



o2G51. Workiug model of the McDonald llsli-way. By M. McUouald, Lex- 

 iugtou, Va. Patented. This lish-way is constructed npou the 

 priucixile of having three sets of transverse partitions sloping up- 

 ward. The water jiassing through the sluice from the dam tends 

 to sink iu the middle line of huckets, and emerges at the sides at 

 a lower level, being checked by abutting against other partitions 

 placed below them at right angles which deflect the water ui> 

 stream, and these currents from below operate as retarders to the 

 fall of the water from above. One has just been constructed on 

 the Savannah River, Ga., which has an inclination of one foot in 

 three. 



III. PROPAGATION. 



DEVICES USED IN OBTAINING AND IMPREGNATING OVA. 



42936. Model of uatiu'al spawning race, invented by Stephen H. Ainsworth, 



West Bloomtield, N. Y. Not patented. This device consists of 

 two sets of frames covered with wire-cloth, placed in two layers ; 

 the upper one has meshes coarse enough to allow the eggs to pass 

 through, and is covered with coarse gravel in which the fish make 

 nests and sjjawn. The upper screens are then lifted and the ova 

 taken from the lower ones. S. H. Ainsworth. 



42937. Pans used in catching the eggs of fish when taken by hand. They 



remain in these until impregnation has taken place. 



42938. Dipper used for supjilying water to the impregnating pans and iu 



the transfer of fry. 



HATCHING-HOUSES. 



26940. Model of hatching-house at United States salmon-breeding station 

 at Bucksport, Me. Scale, | inch to the foot (-^V)- C. G. Atkins. 

 The hatching-troughs are arranged iu sets of foirr across the 

 building, and fitted with Brackett trays. The water enters 

 them from a feed-trough along the side of the room and escaiies 

 by pipes through the floor. 

 42811. Model of the Druid Hill hatching-house Druid Hill Park, Baltimore. 

 Built in 1875, by the city of Baltimore, under the direction of 

 Major T. B. Ferguson, State commissioner of fisheries, at a cost 

 of .$7,000. The building is of blue stone, with white granite 

 trimmings ; the center 18| by 33 feet, is two stories high, and on 

 either side are octagonal wings 14i by 20 feet, whose sides are 

 almost entirely of glass. The greatest amount of light and air 

 is admitted through these and two large windows in the gnlde 

 end of the main buildings ; the inner door of the A'estibule is 

 also of glass. The windows are all furnished with dark green 

 water-proof ciu-tains, to exclude the sun and light when desir- 

 able. The water is supplied from a strong spring on the side 

 of the hill near by, and is piped into the filtering tank which 

 is just below the ceiling of the hatching room, which occni)ies 

 the first floor of the building. The supi^ly pipe is so arranged 



