[5] OPERATIONS AT CENTRAL STATION. 883 



tofore have been only crude guesses. That the percentage of loss was 

 not unusual is shown by the fact that the number of fish produced, if 

 counted by the standards previously employed b^^ the Commission, 

 would have been largely in excess of the entire number of eggs brought 

 to the station. 



The number of eggs furnished by Chapman's shore was 1,981,000. 

 The yield of this shore the previous year was upwards of 20,000,000. 

 The White House, which the previous season had furnished nearly 

 7,000,000 eggs, yielded in 1882 but 2,503,000. 



The same proportional diminution of the crop occurred at all the 

 shores occu])ied by our force of spawn takers. The season was a dis- 

 astrous one to the fishermen, the catch having fallen off materially from 

 1881. The falling off both in the number of fish and in the crop of 

 eggs is probably to be attributed to the abnormal low conditions of 

 temperature prevailing in the river during the season. The discussion 

 of the observations of temperature and the relations of this to the run 

 of fish will be found in another part of the Annual Report. 



It is a matter of interest to record that nearly two-thirds of the entire 

 number of eggs for the season were taken between the 25th of April 

 and the 10th of May. 



Cod. — Early in February, 1882, experiments were instituted with a 

 view of determining the possibility of transferring impregnated eggs of 

 the codfish from New York to Washington, and hatching the same in 

 artificially prepared sea- water at Central Station. Experts of the Com- 

 mission were sent to 'Sew York to report to Mr. Eugene G. Blackford, 

 at Fulton Market, who had made all preliminary arrangements for the 

 conduct of the experiments. 



In anticipation of the receipt of eggs arrangements were made at Cen- 

 tral Station for circulation of salt water. These were briefly as follows : 



A supply tank, into which the salt water was pumped by hand, and 

 from which it flowed continuously through hatching apparatus similar 

 to that employed at Wood's Holl in the season of 1881 and specially 

 devised with a view to handling floating eggs. From the hatching ap- 

 paratus the water passed into a receiving tank below, from which it was 

 pumped again by hand into the supply tank ; the limited amount of 

 water used being kept in continuous circulation and as far as possible 

 aerated in its circuit. To maintain the purity of the water a false bot- 

 tom was placed in the supply tank, and over this a layer of animal 

 charcoal, through which all the water was required to filter. 



The salt water employed in the experiment was made from crystallized 

 sea-salt, the amount used being 5 ounces to the gallon, giving a brine 

 of about the density of the water at Wood's Holl. 



The first eggs were received on February 16th, being forwarded on 

 wire-bottomed trays covered with damp cloth. These eggs were a total 

 loss. It was evident that the delicate membrane of the cod egg would 

 not stand the shock of this method. 



