370 EXPEDITION TO JAPAN. 



coast of America and west coast of Melville island, in a great measure unaffected by its dissolving 

 influence ; for it is in that direction that our enterprising whalemen who resort to those seas 

 find their most open cruising ground, and I have heard of no instance in which that open water 

 has been explored to its limits in a northeast direction from Behring's Straits. The same 

 physical laws operating upon the G-ulf Stream produce similar results upon it after passing 

 Spitzbergen, and the mass of water from these two streams thus accumulated about the pole 

 (after parting with their warmth) find no outlets except those to the southward, between Spitz- 

 bergen and the east coast of Greenland, and through the passages among the islands leading 

 into Baffin's Bay, and thus form the streams known as the Greenland and Labrador currents ; 

 these uniting in the north Atlantic, become the counter-current to the Gulf Stream after passing 

 Newfoundland. 



The same atmospheric meteors of revolving storms, or cyclones, prevail on the coasts of China 

 and Japan as those that have been rendered so painfully familiar to us by their devastations 

 among the West India islands, and along our Atlantic coast. This subject, however, is being 

 fully and ably discussed by Mr. Redfield, and I mention it here merely as an additional illus- 

 tration of the resemblance in the physical phenomena which characterize the western shores of 

 the two great oceans. 



In the passage of the United States steam frigate Mississippi from Simoda, Japan, to the 

 Sandwich Islands, in October, 1854. the thermometer manifested a cold aqueous space between 

 the meridians of 155 degrees east and 170 degrees west, and the parallels of 30 and 35 degrees 

 north, which bears a general correspondence in the Pacific ocean to the position of the Sargassa 

 sea in the Atlantic. — (See Thermometric Diagrams, Plate XIV.) Plates VIII and X show the 

 prevailing winds, the oscillations of the barometer, and the temperature of the air and water for 

 each day during our last visit to the bay of Yedo and first visit to Simoda. They are interesting 

 as an indication of the fluctuating atmospheric pressure, and the equable temperature of the air. 

 The great changes in the temperature of the water at Simoda coincide with the changes in the 

 pirection of the wind, (see Diagrams, Plate X,) yet is not attributable entirely to the thermal 

 influence of the wind upon the water, as would seem to be the case from a simple inspection of 

 the Diagram, but is owing chiefly, no doubt, to the peculiar position of the harbor in regard to 

 the Kuro-Siwo, which sweeps directly past its mouth, and from which a superficial layer of 

 warm water is driven into the harbor by every southerly wind of any force. The specific gravity 

 of this layer being less than that of the torpid water of the harbor, it remains on the surface 

 until expelled by a northerly wind, or until the thermal equilibrium is restored between it and 

 the sub-surface water, when the normal temperature of the harbor again manifests itself. The 

 bay of Yedo being more remote from the Kuro-Siwo, the water thermometer shows no such 

 extreme fluctuations as at Simoda. — (See Diagram, Plate VIII.) 

 Very respectfully, your obedient servant, 



SILAS BENT, Lieutenant. 

 Commodore M. C. Perry. 



United States Navy. 



