GEOGRAPHY. 265 



and dredging expeditions from •^vliose labors tlie necessary material has 

 been accumulated for making a complete relief model of the Caribbean 

 Sea. During the cruise of the Challenger it was shown that in a sub- 

 marine lake the temperature is constant to the greatest depth, and is 

 the same as that of the ocean at the depch of the rim of the lake at the 

 deepest point. The labors of Commander Sigsbee, U. S. N., from 1874 

 to 1878, while commanding the Coast Survey steamer Blake, showed 

 that the temperature of tbe Gulf of Mexico below a depth of 800 fath- 

 oms is constant at 39^^^, the normal temperature of the ocean at that 

 depth in the region of the equatorial current. It was consequently in- 

 ferred that the Caribbean Sea, from which the Gulf of Mexico receives 

 its waters, is inclosed by a rim which was 800 fathoms below the sur- 

 face at its deepest part. This inference has been completely borne out 

 by the researches of Commander Bartlett and Lieutenant Commanders 

 Browuson and Tanner, of the United States Navy, and the results of their 

 labors are admirably shown by a contour model of the Caribbean Sea ex- 

 hibited at the New Orleans Exposition. This model is on a horizontal 

 scale of 33 miles to an inch and a vertical scale of G,000 feet to the inch. 



Baron Nordenskiold has communicated to the Journal of the Royal 

 Geographical Society a synopsis, by Herr Axel Hamberg, of the obser- 

 vations for temperature, specific gravity, and saltuess of the expedition 

 of 1883 to East Greenland and the adjacent waters, but no attempt is 

 made to form any general deductions from the data presented. 



The Danish gunboat Fylla, of 500 tons, Capt. C. Normann, was en- 

 gaged during the summer of 1884 in surveying, sounding, and dredging 

 on the west coast of Greenland and in Davis Strait. The greatest 

 depth found was about 900 fathoms, while in the narrowest part of Davis 

 Strait depths of only 400 fathoms were found. The ship was fitted with 

 the very best appliances, a Sigsbee machine being used for sounding. 

 In Disco Bay, where no soundings had been before made, depths of from 

 200 to 270 fathoms were found, while a ridge on which there are but 

 180 to 190 fathoms constitutes a sort of threshold between the bay and 

 Davis Strait, preventing icebergs with a greater height above the water 

 than 150 feet from passing from the great fiord of Jacobshavn to 

 the ocean, the average proportion between the exposed and submerged 

 surfaces being as 1 to 8.8. As was the case with the Nordenskiold ex- 

 pedition to East Greenland, it was found, in taking serial temperatures 

 of sea- water, that the coldest water is not found nearest the bottom, 

 but that the temperature increases with the depth in the polar current 

 and underlying water layers. 



