yune I, 1876] 



NA TURE 



115 



the Section of Chemistry. There is, however, so close 

 and intimate a relation between all the various branches 

 of physical research, that it is not only difficult to draw 

 exact boundaries between their provinces, but also to 

 determine to which group any given province shall belong 

 when it becomes necessary to map out the whole field of 

 science into some four or live divisions. 



Our province may be regarded in the main as com- 

 prising the physical history of the earth — the constitution 

 of its mineral parts and the forms and characters they 

 present when crystallized, the geological succession and 

 nature of its component rocks ; the past and present 

 distribution of land and water, and the causes which have 

 led to its modifications ; and lastly those meteoric in- 

 fluences which not only affect climate, but are active 

 causes in the carving out of the earth's surface and in the 

 redistribution of the materials of which it is composed. 

 Nor do we only take the purely scientific and theoretical 

 portions of our subjects, but also the application of scien- 

 tific principles to produce economic results, and to lessen 

 the dangers of those who in the exercise of their calling 

 meet the forces of nature under some of their most de- 

 structive aspects. 



It is of course only with the apparatus which has been 

 devised for the purpose of carrymg on the investigations 

 into the physical history of the earth, and the applica- 

 tions of scientific principles which 1 have just mentioned, 

 that we are mainly concerned, and not with abstract 

 questions relating to any branches of science. It may, 

 however, be found necessary to enter more or less into 

 such abstract questions if only to show the character of 

 the investigations which have to be pursued, and to 

 elucidate more fully the difficulties with which inquirers 

 have had to contend, or which still have to be conquered. 

 Such questions may also have to be discussed should the 

 history of the gradual development of some of our modern 

 appliances be gone into. Some of the earlier forms of 

 instruments which are now exhibited are indeed of great 

 interest, whether they are regarded in the light of what 

 may be termed milestones on the road of scientific pro- 

 gress, or as memorials of the eminent men by whom they 

 were devised or used. The goniometers of Hauy and 

 WoUaston, the nascent safety-lamp of Davy, the blowpipe 

 of Plattner, the barometer of De Luc and H. B. de 

 Saussure, the thermometer of Gay Lussac, the geological 

 maps of William Smith, the logbooks of Cook, Franklin, 

 and Parry, the instruments and maps of Livingstone, are 

 replete not only with scientific but historical mterest. 



It is, indeed, as constituting an epoch in the history 

 of scientific discovery, that such a collection as that 

 among which we are now assembled has its highest value 

 and interest. The third quarter of the nineteenth century 

 has just come to its end, and we may venture to compare 

 the advances which have been made during the last 

 twenty-five years not only in our own particular walks of 

 science, but in every branch of it, with the advances 

 which had been made during the previous quarter of a 

 century, the close of which was marked by the first Great 

 Exhibition held in London. Great as had been the pro- 

 gress in scientific knowledge and in the application of 

 scientific principles during that second quarter of the 

 century, and favourably as it contrasted with the by no 

 means despicable attainments of the previous quarter, the 

 advances made during the last twenty-five years both in 

 our knowledge of the principles of the great forces of 

 nature and in the accuracy and delicacy of our instru- 

 ments for their investigation are such that the present 

 generation has at least no cause to be ashamed of them. 

 Possibly when another quarter of a century has elapsed, 

 those who come after us and those among us who survive 

 as labourers in the field of science, may look back upon 

 some of the processes now in vogue as antiquated, and 

 may even feel surprise at our having been upon the verge 

 of some great discoveries and yet having failed to make 



them ; but I venture to hope that the names of many of 

 those living investigators which we find recorded in the 

 Catalogue of this Exhibition may not only then, but even 

 in after ages, be looked upon with reverence and esteem. 

 We must, however, turn to the consideration of the 

 branches of science comprised under this Section, and in 

 directing your attention to some of the objects which ap- 

 pear to me of more than common interest, I shall ven- 

 ture an occasional observation on some matters which 

 appear to be well fitted for discussion at an international 

 conference such as the present. 



In regard to meteorological instruments we have not 

 only isolated specimens but sets of instruments as supplied 

 to meteorological stations, and to the royal and merchant 

 ships of this country. With the exception of Russia, 

 however, the means of comparison with other countries 

 are, I believe, wanting. It will be for the representatives 

 of other countries to see whether some useful hints may 

 not be derived from the experience of British meteorolo- 

 gists as embodied in these selections of instruments. 



Mr. R. H. Scott in the " Handbook to the Collection" 

 has given so excellent an account of the nature of the 

 meteorological instruments here exhibited that I need 

 add but little to it, especially as he will be good enough 

 to make a communication upon them. 



Takmg the principal forms it will be seen that among 

 the barometers there are more than one exhibited which 

 are of historical interest, while numerous exa-nples of 

 modern improvements in mercurial barometers are 

 shown, of which perhaps those intended to facilitate their 

 use and increase their accuracy when employed by tra- 

 vellers by land and by sea, are the most noteworthy. For 

 ordinary use, however, that comparatively recent form of 

 barometer, the Aneroid, seems likely to compete with the 

 older form, and the precision of mechanism which some 

 of them exhibit is marvellous. That extreme delicacy, 

 however, has its disadvantages, and for trustworthy ob- 

 servations the actual weighing of the atmosphere by the 

 column of mercury will long be preferred. 



The principal features of the thermometers are their 

 accuracy and sensitiveness. It might be worth while to 

 consider whether any means could be devised for facili- 

 tating the adoption of a uniform scale of notation. It 

 will, however, be a difficult matter to supersede the scale 

 of Fahrenheit in this country, where it seems to have 

 taken so deep a hold. The more general introduction of 

 instruments marked with both Fahrenheit's and the cen- 

 tigrade scale might assist the adoption of the latter, but 

 the smaller unit of heat on the former scale gives it prac- 

 tically some advantage. 



Of anemometers, both for meteorological and mining 

 purposes, a large number will have been seen, some of 

 them furnished with means of recording both the direc- 

 tion and strength of the currents. Of several of these, 

 details will be given at this Conference. 



With respect to rain-gauges but little need be said, 

 unless it be to call attention to the system, which, thanks 

 to Mr. G. J. Symons, is now so universal in this country, 

 viz., for observers who make only one daily entry of the 

 rainfall, to take their observation at 9 A.M. and to enter 

 the amount of rain to the preceding day. The late 

 Meteorological Congress has no doubt discussed this and 

 other points of international interest. 



Of hygrometers, both ancient and modern forms are 

 exhibited, the hair hygrometer still holding its own among 

 those of the indirect class, notwithstanding the influences 

 of modern civilisation. One cannot but be touched by 

 the pathetic note of the Geneva Association for construct- 

 ing scientific instruments. " The most isolated hamlets 

 have now to be searched in order to obtain hair un- 

 combed," and therefore fit for these instruments. 



It is perhaps in the self-recording instruments that the 

 greatest advance made during the last quarter of a century 

 will be observed. The extended use of electricity and 



