658 



REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



[54] 



occurred during the summer, except the development of a case of Melan- 

 cholia in oue of the seamen, who was in consequence transferred to the 

 naval hospital at Chelsea, Mass., and subsequently to the Government 

 Insane Asylum in the District of Columbia. No satisfactory cause for 

 the disease could be assigned. 



The determinations and record of the densities of sea- water have been 

 continued by this department during the yeaL'. The observations have 

 been chieily confined to surface densities, and the collection of water 

 for the purpose has usually been made at 12 o'clock each day that the 

 ship was at sea. The specimen is kept until it has taken about the 

 temperature of the room and of the instruments employed, and the same 

 care as heretofore exercised in the reading and reduction. The record 

 in itself presents no remarkable features calling for extended remarks. 

 The high gravities of the Southern waters, where evaporation is rapid, 

 is observable, and especially in those inclosed basins like Exuma Sound 

 and Tongue of the Ocean, where there are no active currents to restore 

 the equilibrium with the ocean water in general. In contrast are the 

 low gravities of the Northern waters, where evaporation is slight and 

 the water is freshened by the Arctic currents. 



The record of temperatures and densities observed during the year is 

 appended : 



Record of temperatures and specific gravities. 



