492 



NATURE 



{Sept. 28, 1876 



metic, such as was seen in diagrams of thrust, pressure, speed, 

 and so forth. But this would take care of itself provided linear 

 drawing were taught sufficiently early. Passing on to discuss 

 certain points connected with the crowding of the population, 

 he remarked that the reil problem of civilization had been to 

 render life tolerable in large aggregations, and that this problem 

 was yet only partially solved. Among the difficulties of town 

 life he reckoned — (i) the insufficient supply of fresh air ; (2) the 

 mere proximity of persons facilitating the spread of contagious 

 or infectious disease ; (3) the getting rid of excreta or waste 

 products ; (4) a wholesome water supply to be provided and 

 kept pure. 



Mr. Baldwin Latham read a paper On Hydro-Geological 

 Surveys, in their bearing on health. He dwelt on the import- 

 ance of ascertaining the sub-water course, and making certain 

 that the well was on a higher level, so that it could not be con- 

 taminated by cesspools or other pollutions. These surveys 

 showed the absolute necessity of sewers being made water- 

 tight. 



Mr. W. J. Millar read a paper On the Strength and Fracture 

 of Cast-iron. The author described the results obtained in test- 

 ing cast-iron bars 36 inches span, 2 inches deep, and i inch 

 broad. The bars usually broke with straight fractures, but 

 occasionally curved fractures were observed. The average 

 breaking strength of 29 bars showing straight fractures was 

 3584lbs., the avera:je strength of 25 bars showing curved frac- 

 tures was 3551 lbs. Some results ot " set" and deflection were 

 given, showing that for successive applications of the same load, 

 2800 lbs., there was a decrease of set. The principal object 

 aimei at by the author of the paper was to show the relation 

 existing between form and position of fracture, straight fractures 

 taking place at or close to centre of span, and curved fractures 

 occurring at points more or less removed from centre of span. 



Sir William Thomson read a paper On Naval Signalling, in 

 whicti he advocated the use on board ship of the fog signalling 

 system instead of the flag system now in use. His method is 

 simply this — to signal according to the Morse telegraphic code 

 by means of two sounds of slightly different pitch. For the long 

 signals he would take a grave note, and for the short signal a less 

 grave note, or what he might call an acute and a grave note for 

 the dot and the dash. Sir William Thomson then gave several 

 signals to show the efficacy of the plan he proposed, and he 

 maintained that the shortness of the time required to make flag 

 signals was far less than could be attained by the phonetic 

 method. Long before the signal flags could be hoisted, the 

 order would be given and r«ad by every ship, and repeated by 

 the different ships in order, back to the admiral. Two sounds 

 of different pitch made in rapid succession was all that was 

 necessary, and to accomplish this all that was required was two 

 steam whistles, each with a different note. 



Many other papers of great value were read both in Sections 

 F and G, but as they were mainly technical, or very special, 

 our space prevents us referring to them in detail. 



THE CHALLENGER EXPEDITION'- 



HP HE task which I have undertaken this evening — to give a 

 -*■ general sketch, however slight, of the work and results of the 

 Challenger expedition in the space of a single lecture — is by no 

 means an easy one, for two reasons. The various lines of inquiry 

 bear on so many different subjects, and these dovetail into one 

 another in such a complicated manner, that it would take many 

 hours to explain them even in the most superficial way. The 

 other reason is that the observations which were made during the 

 Challenger expedition have only as yet been very imperfectly 

 examined, and only half digested, owing to want of time, and 

 the great collections in natural history which were brought home 

 in the ship have been only glanced at, and it is therefore scarcely 

 safe for me to use either the observations or the collections as the 

 bases of generalisation. I must therefore this evening, in this 

 address, only be regarded as giving a most elementary idea of 

 the objects of the expedition and its results, and what I say must 

 be regarded as preliminary, and subject to further reconsideratioa. 

 Still, some new and remarkable facts and phenomena which have 

 hitherto been unknown, or only vaguely guessed at, are suftciently 

 definite, and I will devote the short time at my disposal to the con- 

 sideration of one or two of these. The superficial area of this world 

 of ours IS about 197,000,000 of square miles, and of these about 



'Report of Address given at tlie Glasgow Meeting of the British Asso- 

 ciation, September 11, by Sir ClWyville Thomson. Revised by the Author. 



140,000,000 are covered by the blue sea at an average depth of 

 2,500 fathoms — about 15,000 feet. This vast region under the 

 sea has not until comparatively recently excited much curiosity. 

 It seemed to be practically inaccessible, and certain hasty and 

 incorrect assumptions in regard to some of its conditions had 

 reduced it to a barren uniformity and divested it of any interest. 

 The laying of deep-sea cables for the purposes of ocean telegra- 

 phy, by bringing to light certain phenomena which threw a doubt 

 upon previous conclusions, stimulated inquiry, and gave rise to 

 new speculation ; and the systematic scientific exploration of the 

 depths of the sea by several special exploring expeditions put 

 our knowledge upon a totally different footing. We now know 

 that the sea covers a vast region which is to a certain degree 

 comparable with the land — a region which has its hills, valleys, 

 and great undulating plains ; that it has its various soils — widely 

 different materials laid down and accumulated in different places ; 

 that it has its climates, whatever the very exceptional conditions of 

 those climates may be ; and that it has its special races of inha- 

 bitants which depend, like the inhabitants of the rest of the 

 world, upon the conditions of climate and on the nature of the 

 soil lor their distribution. 



The Challenger expedition was despatched on a very special 

 errand — to investigate the physical and biological conditions of 

 the great ocean basins. And, under this general heading, certain 

 more minute instructions indicated the particular questions, phy- 

 sical and biological, which were specially to engage our atten- 

 tion. We were instructed throughout our long course, which 

 extended round the world and traversed the Atlantic and Pacific 

 Oceans and the Southern Sea so far south as it was possible to 

 go without running the risk of being entangled for a winter in 

 the ice — a contingency for which we were not prepared — to select 

 certain stations at convenient distances, and at each of these to 

 determine certain points. We were to determine, in the first 

 place, the exact position of the station ; then, with the best ap- 

 pliances at our disposal, we were to determine the precise depth ; 

 we were to bring up by means of the sounding apparatus a cer- 

 tain amount of the material of the bottom for microscopical 

 examination and for chemical analysis ; we were to bring up a 

 specimen of the|water from the bottom for analysis and physical 

 examination ; we were to determine the bottom temperature with 

 accuracy ; and we were to determine the temperature of the sea at 

 different levels from the surfacetothe bottom ; we were togetspeci- 

 mens, if possible, of the sea water from various depths. Lastly, we 

 were to endeavour, by the use of the trawl or dredge, or any other 

 instrument which might be suitable, at each station to procure a 

 fair sample of the creatures which inhabit the bottom, and in 

 this way to get, if possible, a general idea of the fauna inhabiting 

 the depths of the sea. The instructions of those in charge of the 

 scientific departments in the Challenger, bothnavaland civilian, did 

 not, however, by any means end here. The officershad been selected 

 in order that they might study by the light of their own previous 

 experience the bearings of those various data upon one another, 

 and this was a very serious addition to the work of the expe- 

 dition. It was found necessary, in order that this might be 

 carried out to its fullest extent, that the instructions given by the 

 Admiralty should be comparatively flexible, and that the details of 

 the working of the ship should be left to a certain extent to the 

 captain of the ship and to the cirector of the scientific staff, so as 

 to enable them to deviate from any definite line or course when 

 it became desirable for any purpose that they should do so. I 

 have only to add that the equipment of the vessel was such as to 

 leave very little to be wished for, and that the liberal arrange- 

 ments of the Admiralty, which were admirably carried out by 

 the Hydrographic Department, worked in the most satisfactory 

 way. The Challenger left Sheerness on December 17, 1872. 

 She crossed the Atlantic four times during the year 1873, and 

 along a course of nearly 20,000 miles she established 150 

 observing stations, at each of which, with few exceptions, all 

 the required observations were made. In 1874 she went south- 

 wards from the Cape of Good Hope, spending nearly a month 

 among the southern ice, and dipping within the Antarctic Circle, as 

 far as she could with safety, considering the lateness of the season 

 and her unprotected condition. She then traversed the seas of 

 Australia and New Zealand, and made some most interesting 

 observations among the islands of the Malay Archipelago. She 

 arrived at Hong Kong on November 10, having run a course in 

 the year 1874 of upwards of 17,000 miles, along which sixty-six 

 observing stations had been established. In 1875 she traversed 

 the Pacific, with a course of about 20,000 miles and 100 stations ; 

 and in the early part of the present year she crossed the Atlantic 

 I for the fifth time, filling up here and there blanks in her former 



