cxxii GENERAL SUMMARY OF SCIENTIFIC AND 



The English have as usual performed by far the largest portion 

 of the hydrographic work of the past year. Under the direction of 

 the British Hydrographic Office, surveys of a permanent character 

 are being carried forward on the shores of England, Ireland, the 

 Gulf of St. Lawrence, Newfoundland, Labrador, Jamaica, Mauritius, 

 the east coast of Africa, Japan, Australia, and the Fiji Islands, while 

 detached surveys have been made in the Mediterranean, on the 

 coasts of China, and among the Pacific islands. Interesting results 

 have been derived from the examination by British surveyors of the 

 Mediterranean entrance of the Suez Canal, the approaches to which 

 do not seem to have shoaled as much as was anticipated. 



Since the publication of the Record for 1875, the admirable work 

 done by the English surveying- ship Challenger has been brought 

 to a close by her arrival at SiDithead on the 24th of May, 1875. Re- 

 suming the sketch of her cruise where it was left in the Record for 

 1875, the ship, after refitting, left Yokohama on the 11th of May, 

 1875, for a short cruise of about three weeks to Kobe and the In- 

 land Sea, where some dredging was done, but witliout much success. 

 The expedition finally left Japan on the 16th of June, and, constant- 

 ly dredging and sounding in dejDths of from 1875 to 3950 fathoms, 

 arrived at Honolulu, Sandwich Islands, on the 27th of July. The 

 soundings between Japan and the Sandwich Islands were quite uni- 

 form in depth, the average of twenty-two being 2858 fathoms. The 

 bottom was generally red clay, frequently filled with concretions of 

 peroxide of manganese from the size of a grain of mustard seed to 

 that of a large potato. These concretions were formed by concen- 

 tric layers, starting from a nucleus consisting of some foreign body 

 like a shark's tooth or a bit of pumice. 



On the 11th of August the Challenger proceeded to the island of 

 Hawaii, where the volcano of Kilauea, then in eruption, was visited, 

 and good photographs were obtained of it. On the 19th of August 

 the ship sailed for Tahiti, arriving there early in September. Many 

 soundings and dredgings were made on the way, with an average 

 dei3th of 2800 fathoms ; the bottom being generally of red clay, and 

 many things of great interest to the biologist being discovered. 



Leaving Tahiti on the 2d of October, Juan Fernandez, at a dis- 

 tance of 4000 miles, was reached on November 13th, the section be- 

 tween the two places having an average depth of 2160 fathoms. 



From Juan Fernandez the Challenger sailed for Valparaiso, sound- 

 ing, trawling, and taking serial temperatures constantly. From Val- 

 paraiso the homeward voyage was commenced on the 11th of De- 

 cember, ma the Strait of Magellan, where some valuable additions 

 were made to the naturalists' collections, the ship reaching Port 

 Stanley, Falkland Islands, January 23d. While here, magnetic ob- 

 servations were made at the exact spot where Sir James Ross's 

 magnetic observatory was established in 1842, when it was discov- 



