878 REPORT OF COMMISSIONER OF FISH AND FISHER. 
60 to 120 pounds. The effect on the filters was like sledg • •; 
blows, and resulted in breaking the diaphragms on three occasions, 
which allowed free alum to be circulated through the whole series 
of aquaria thus supplied. Nearly all of the fish were killed. Many 
attempts were made to control the pressure, but all eiforts proved 
ineffectual until it occurred to Mr. Barry to apply a steam safety-valve 
to the supply pipe, and this solved the problem most satisfactorily. 
On July 25 a large consignment of various species of trout was re- 
ceived from the Wytheville station and transferred to the aquaria. 
Fish and numerous aquatic plants were received from Washington at 
the same time. Later, additional supplies of trout were brought from 
Northville, Mich., while other species were received from the rivers in the 
vicinity of Quincy, 111. The installation was completed July 25, when 
the first shipment of fish and plants was received, and considering all 
the disadvantages under which the work was accomplished, it may be 
considered creditable that such results were accomplished in less than 
three weeks from the time the first of our material reached Cincinnati. 
The exhibit of the Commission was broadly grouped under three 
general heads : scientific inquiry, fish-culture, and fisheries ; though the 
aquaria! display, which was intimately associated with and related to 
each of the above-mentioned divisions, might be appropriately consid- 
ered a separate section. 
Under the head of scientific inquiry were exhibited models, photo- 
graphs, and illustrations of the coast laboratories and the vessels used 
by the Commission for scientific research, including a special series of 
views of the station at Wood’s Holl, Mass., and the scenery in the im- 
mediate vicinity. There were also full-sized specimens of apparatus 
employed in marine investigation, together with charts and models of 
the ocean showing results of exploration. Next came alcoholic and 
dried specimens of various forms of fishes, crustaceans, etc., and speci- 
mens of many small forms of life mounted on slides for the microscope; 
these, together with sections of fish eggs, sponges, etc., constituted a 
very interesting microscopical display. The publications of the Com- 
mission were also placed under this section. The fishes and other 
animals, mentioned elsewhere as “objects of fisheries,” may appropri- 
ately be referred to here, since they have also been objects of scientific 
inquiry. 
Under fish-culture was included an historical collection of apparatus 
used for the artificial propagation and distribution of fish ; also photo- 
graphs, transparencies, etc., showing the same in action. This collec- 
tion embraced the most approved forms— full-sized specimens and mod- 
els of apparatus now used for artificial hatching and for distributing 
fish and ova. Associated with these were models and illustrations of 
hatching houses, etc., including floating barges and steamers ; a lay 
figure and numerous photographs, transparencies, and other devices, 
illustrating the methods of fish-culture; statistical charts showing the 
