614 report — 1878. 



vation, and have been in many cases accompanied by observers trained in one 

 department or another of physical research. 



I will simply name among many such equipped and instructed expeditions of 

 these later days, the splendid circumnavigating voyage of the Austrian frigate 

 Novara, under the command of Admiral von Wiillerstorf-Urbair (the report of 

 the scientific results of this expedition has been published by the Austrian Govern- 

 ment in eighteen beautifully illustrated volumes, and the completion of this work, 

 after seventeen years of heavy labour, was one of the scientific events of the year 

 1877) ; the voyage of the Italian corvette Magenta round the world, so well 

 chronicled by Professor Enrico Hillyer Giglioli; the very important sounding 

 voyages of Captain Belknap, in the American surveying ship Titscarora ; the Sassier 

 expedition, the last crowning effort with which the elder Agassiz closed a long and 

 brilliant career devoted to the study and illustration of nature, and the many 

 scientific explorations undertaken from year to year by the officers of the American 

 Coast Survey, with the co-operation of the younger Agassiz and Count Pourtales ; 

 the tentative cruises of the Britishgunboats Lightning and Porevjrine, culminating 

 in the Challenge!- expedition ; the scientific voyage round the world of the German 

 frigate Gazelle ; the several expeditions sent out by different Powers to observe the 

 transit of Venus ; the German Arctic expedition, under Captain Koldewey ; the 

 several Swedish expeditions, so rich in zoological results, to the Spitzbergen Sea, 

 under the guidance of Otto Torell, Nordenskjbld, and others; the exhaustive 

 researches into the conditions, physical and biological, of the North Sea by the North 

 Sea Commission, under the direction of Dr. H. A. Meyer ; the voyage of the 

 Tegethoff, which Lieutenant Payer has rendered ever memorable by his thrilling 

 story of disaster, success, and heroism ; the Arctic voyage of the Alert and the 

 Discovery, of which Sir George Nares has just published the semi-official narrative, 

 a simple and charming account of almost superhuman effort and insuperable ob- 

 struction, which it is impossible to read without a feeling of regret that the devoted 

 little band had attempted what was so hopeless, and at the same time a conviction 

 that if their task had been practicable by human skill and bravery, it must certainly 

 have been accomplished. But although this expedition of necessity failed in its 

 main object, that of reaching the Pole, the additional information which we gain 

 from Captain Nares's volume and from the more popular sketch of the voyage by 

 Captain Markham on the physical condition of the Arctic Sea, is in the highest 

 degree valuable. I must also mention the very important cruises in connection 

 with the Norwegian Department of Fisheries, which, through the skilled labours 

 of Professor Mohn and Professor G. 0. Sars, annually contribute largely to our 

 knowledge of the distribution of temperature, of the course of the ocean currents, 

 and of the range of animal life in the North Atlantic. I observe in a letter from 

 Professor Mohn, dated from Hammerfest on the 10th of last month, that the 

 expedition of the past year has had a successful cruise to Bear Island, where it 

 has left letters for the Dutch Arctic schooner, the Willem Barentz, and has made 

 many important temperature observations. Professor Mohn speaks highly of the 

 service rendered by Negretti and Zambra's new reversing thermometer. This is a 

 most ingenious instrument, so constructed that by a simple mechanical arrangement 

 the temperature may be registered at any given depth, irrespective of any number 

 of zones of temperature, higher or lower, through which the instrument may have 

 passed in descending. In the Challenger we felt greatly the want of such a ther- 

 mometer, for although generally throughout the ocean the temperature of the water 

 falls steadily from a surface maximum to a minimum at the bottom, in the Arctic 

 and Antartic seas — where a special interest attaches to the vertical distribution 

 of temperatures— the coldest layer is frequently, as in Professor Mohu's observa- 

 tions, on the surface ; and a warmer belt intervenes between it and a bottom- 

 stratum, probably, in many cases, of intermediate temperature. With the ordinary 

 deep-sea registering thermometer, the temperature of the lowest layer cannot be 

 ascertained with certainty. We had Negretti and Zambra's earlier instrument on 

 the reversing principle on board during the latter part of our cruise, but through 

 some defect in construction we did not find its indications trustworthy for great 

 depths. I always believed the plan of construction of this instrument to be good,. 



