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CLASS X.
PHILOSOPHICAL INSTRUMENTS AND PROCESSES DEPENDING UPON
TIIEIR USE.
[The figures after the Names (between parentheses) refer to the Exhibitors’ Numbers and to the pages in theOfficial Descriptive and Illustrated Catalogue.]
Jury.
Sir David Brewster, F.R.S., Chairman , St. Andrews, Fifeshire , N.B.; Principal of the University,St. Andrews .
Professor Colladon, Switzerland .
E. B. Denison, 42 Queen Ann Street.
J. Glaisher, F.It.S., Reporter , 13 Dartmouth Terrace, Lewisham; Observer in Greenwich Observatory,Sir John Hersciiel, Bart., F.It.S., 32 Harley Street; Master of the Mint.
E. It. Leslie, It.A., United States ; Artist.
L. Matiiieu, France ; Member of Bureau of Longitude, of Institute , and of Central Jury.
W. H. Miller, F.It.S., Scroope Terrace, Cambridge ; Professor of Mineralogy.
Richard Potter, A.M., University College, London ; Professor of Natural Philosophy.
Professor Sciilbarth, Zollverein ; Professor of Chemistry and Natural Philosophy.
Associates.
J. S. Bowekbank, 3 Highbury Grove.
ltev. W. S. Kingsley, Sidney College, Cambridge ; Fellow of Sidney College.
L. A. J. Quetelet, Belgium ; Secretary to the Royal Academy at Brussels (Juror in Class XXX.)Lord Wrottesley, 34 St. James’s Place.
The duties of the Jury upon Philosophical Instrumentshave been found to be very heavy, as indeed might beexpected in a field so vast,—including instruments re-lating to Astronomy, Optics, Light, Heat , Electricity, Mag-netism, Acoustics, Meteorology, &c.; in fact, all relating toPhysical Science , collected by a large number of exhibitors.
Astronomical instruments claim our first attention, theexhibitors of these, though few in number, have effecteda most beneficial advance by the use of as few parts intheir construction as possible; this is mainly observablein the British portion. The workmanship of those exhi-bited by Germany deserves the highest praise; the instru-ments are, however, few in number, and do not fullyrepresent German art.
America claims particular notice by the application ofelectro-magnetism to the registration of astronomicalobservations, thus enabling the hand to do the work ofthe mind. This method has the further advantage ofenabling us to record the observations taken at widelyseparated Observatories , the length of the wire used beingimmaterial; thus is established a means the best possiblefor the determination of the difference of longitude. Ob-servatories so connected afford the means of performingthe most delicate experiments dependent upon the appre-ciation of minute portions of time. This method has beenrecently used in America , for the determination of thewave-time of electrical currents; from which experimentsit would seem that its velocity of propagation is muchsmaller than that determined by Wheatstone.*
Of nautical instruments, there are several exhibitors;but with the exception of those of America by Ericssonand St. John, there is hut little novelty of construction.In surveying and levelling instruments, beyond some im-provements observable in those exhibited by Austria , thereis no novelty. In optics there are many exhibitors, aud we
* See Gould’s Astronomical Journal, vol. i., Nos. 2, 7,and 14,
remark the improvement of optical glasses in England,France, and Switzerland , and that the construction oflarge discs of glass for telescopes, in England, promisesto add considerable optical power, and thereby tend tothe advancement of Astronomy , &c. Of microscopes theBritish are by far the best. In physical optics generally,Frauce is pre-eminent, having exhibited a number ofdelicately-constructed instruments, none of the same kindbeing contributed by any other nation: she also excels inlenses and in prisms. There are many other classes ofoptical instruments to be specified hereafter.
There are many photographic cameras, to the improve-ment of which much attention is at present being paid inboth England and France . This leads us to the mostremarkable discovery of modern times,—the art of Photo-graphy >—and never before was so rich a collection ofphotographic pictures brought together, the products ofEngland, France, Austria, and America .
Before going further, it would be well to inquire intothe utility of the photographic process as regards its ap-plication to art and science,—and, indirectly, to literature,—by affording a faithful transcript of authentic papersand original documents, upon which subsequent literaryand historical research must necessarily be greatly de-pendent. That photography is yet in its infancy, therecan he little doubt; and it is more than probable that itspresent application, (which we believe to be well repre-sented in the Exhibition,) is no more its ultimatum thanwere the first applications of the telescope, shortly afterthe chance placing of two pieces of glass by Jansen’schildren had led to its invention. Who, at that time,could have predicted the important part that the instru-ment, based upon that discover}', was destined to play inthe world of science? or have foreseen the excellencewhich it has since attained by successive improvements—even now making,—and of which the Exhibition affordsample proof.
Viewing Photography in connection with Art, it may
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