426 The Philosophical Instruments in the Paris Exhibition. 



he is enabled to produce tools of an accuracy hitherto unknown, 

 while these in their turn create machinery which has contributed 

 largely to make our country famous and wealthy. 



But philosophical instruments embrace a wide range of 

 utility. By their aid we are enabled to explore with safety 

 deep mines pregnant with the fierce fire blast, the astronomer 

 guages the heavens, and guides the mariner over the pathless 

 ocean, and the wonderful phenomena of light, heat, and 

 sound, are examined and made to minister to the wants and 

 comforts of mankind. 



The Official Catalogue of the Paris Exhibition enumerates 

 490 exhibitors of philosophical instruments. At the Exhibition 

 of 1862, the number was 351. Looking at the countries of 

 the former exhibitors, we cannot help being struck by the 

 spread of philosophical science over the globe. For, while 

 the exhibitors of scientific instruments at the international 

 Exhibition of 180 2 came, with few exceptions, from well-known 

 countries, several at the Paris Exhibition represented nations 

 which we have hitherto regarded as but semi-civilized. 



As astronomical instruments show mechanical progress and 

 invention in their most refined development, we shall commence 

 with them. The instruments of this description by no means 

 represented the high perfection to which their makers have 

 attained. This, however, is not surprising. Astronomical 

 instruments are, as a rule, far too valuable to be sent to an 

 Exhibition. There were, nevertheless, some fine equatorials 

 exhibited. 



The largest of these instruments was constructed by 

 Brunner, of Paris, for the Boulik Observatory in Egypt. The 

 object-glass is 8'4 inches in diameter, and it is provided with a 

 very perfect clock movement. 



Mr. Dallmeyer also exhibited an excellent six foot equa- 

 torial with a 5 inch object-glass. A notable feature of this fine 

 instrument is that the same clock sets two circles in motion, 

 one of which shows sidereal time, while the other moves the 

 telescope. M. Evrard, of Paris, exhibited a large astrono- 

 mical telescope with a 9*2 inch object-glass, but the perform- 

 ance of this instrument was not equal to that of Mr. Dallmeyer, 

 which on competitive trial was found to be the best refracting 

 telescope in the Exhibition. The superiority of this, and 

 other English astronomical instruments, is partly due to the 

 excellence of the optical glass made by Messrs. Chance, of 

 Birmingham. These gentlemen, and M. C. Eeil, of Paris, 

 manufacture the best optical glass. 



Reflecting telescopes, which have been highly instrumental 

 in enlarging our acquaintance with the heavenly bodies, and 

 especially with the nebulae, were very poorly represented. One, 



