22 



NATURE 



[May II, 1876 



Conference Room ; P, Chemistry ; Q, Light, Heat, 

 Sound, and Molecular Physics. 



The number of exhibitors — governments, societies, de- 

 partments, and individuals— amounts to about 1,000, and 

 the collection contains altogether somewhere about 

 15,000 objects, arranged in this first edition of the 

 catalogue, under 4,576 heads. The countries repre- 

 sented are the United Kingdom, Austro-Hungarian 

 Empire, Belgium, France, Germany, Holland, Italy, 

 Norway, Russia, and Switzerland. The list from Spain 

 is not yet received, and the fact that America is occupied 

 with her own Centennial Exhibition sufficiently accounts 

 for her absence, though the American Government 

 heartily sympathises with the object of the collection. 

 In the catalogue the objects are arranged under twenty- 

 one sections ; the numbers enable the visitor at once to 

 identify each object or group of objects, and in most 

 cases the appended descriptions are sufficiently detailed 

 to enable anyone to understand the purpose and construc- 

 tion of the apparatus. In many cases the descriptions 

 are as minute as in a special text-book. 



Under Section i,Arithmetic, are described various Slide- 

 rules, 19 in all, 26 Calculating Machines, including Bab- 

 bage's famous "Difference Engine," which is described in 

 considerable detail, besides some interesting and ingenious 

 miscellaneous apparatus. Under Section 2 are classed in- 

 struments used in Geometrical Drawing, Instruments for 

 tracing Special Curves, Models of Figures in Space, and a 

 collection of Pliicker's models of certain quartic surfaces, 

 contributed by the Mathematical Society. 



As might be expected in a collection of scientific appa- 

 ratus, those connected with Measurement, Section 3, occupy 

 a large space : there are upwards of 350 entries under this 

 head, comprising, besides a variety of extremely interesting 

 and curious special collections, apparatus for Measurement 

 of Length (nearly 100 entries) of Area, of Volume, of Mass, 

 of Velocity, of Momentum, of Force, of Work, of Angles, 

 and of Time (80 entries) ; many of the objects in this 

 section are of a remote antiquity, and not a few are con- 

 nected with scientific discoveries of the highest import- 

 ance. 



Section 4, Kinematics, Statics, and Dynamics, is a 

 very full and instructive one ; it is impossible to give 

 ■ here anything like an idea of the nature and variety of 

 the apparatus exhibited under this head. It contains 

 22 sub-sections and sub-sub-sections, including several of 

 'sGravesande's apparatus, apparatus illustrating the Me- 

 chanical Powers, Pendulums and Gyroscopes, Vibrations 

 and Waves, Falling Bodies and Projectiles, and other 

 departments of the very comprehensive section, includ- 

 ing 54 Crank Trains, 50 Toothed-wheel Trains, and 67 

 Ratchet Trains. 



To many. Section 5, Molecular Physics, will be intensely 

 interesting ; its six sections contain no entries ; the Air- 

 pumps and Pneumatic Apparatus alone numbering 44. 

 Osmose Dialysis and Diffusion, Condensation of Liquids 

 and Solids, and Hydrometers, are some of the other 

 subjects illustrated here. 



Sections 6, 7, and 8, Sound, Light, and Heat, are of 

 course among the most important, the catalogue containing 

 410 entries under these heads. There are apparatus illus- 

 trating the Sources, Measurement, and Interference of 

 Sound, and a variety of other phenomena, including Musical 



Sounds ; in Section Light, under the head Selectors, there 

 are 36 groups of apparatus connected with the Spectro- 

 scope, and 30 to illustrate Polarisers, besides Photometers, 

 Radiometers, apparatus bearing on Reflection, Refrac- 

 tion, and Diffraction, Photography is a varied and in- 

 teresting sub- section. The multitude of apparatus con- 

 nected with Heat is classified under Sources of Heat, 

 Thermometry (56 entries), Calorimeters, Pyrometers, 

 Freezing Machines, Conductors, &c. 



Sections 9 and 10, Magnetism and Electricity, are 

 likely to prove two of the most attractive, as they are cer- 

 tainly among the most important. All departments of 

 these subjects — and how varied they are even scientific 

 men may be astonished to learn — are illustrated with great 

 fulness ; the number of entries in the Catalogue is 650, 

 commencing with the greatest natural magnet yet known, 

 weighing, with armature, 152 kilograms, sent by the 

 Teyler Foundation, Haarlem, and concluding with a 

 minute description of the Polar Light Apparatus, by 

 Prof, Lemstrom, Of apparatus connected with Elec- 

 tricity the variety is astounding. Friction and Induction 

 Machines, Galvanic Batteries (there are 32), Thermo- 

 Electric Batteries, Induction Coils, Magnetic-Electric 

 Machines, and other modes of producing Electricity or 

 Electric Currents, are abundantly represented. So, also, 

 apparatus for producing, collecting, observing, regulating, 

 and measuring electricity ; of Galvanometers alone there 

 are 43, In the Electrical Section, no doubt the most 

 attractive department to the general public will be that 

 devoted to apparatus for the application of Electrical 

 principles to practical purposes, illustrating, as it does, 

 every stage in the progress of the Electric Telegraph. 

 The Catalogue in this department contains 204 entries of 

 Telegraphic apparatus alone, not to mention the various 

 other applications of electricity to military and other 

 purposes. 



Astronomy, Section 11, is at the same time one of the 

 oldest and one of the most popular of the sciences, and 

 therefore the apparatus in the section will probably have 

 more than an average number of visitors. The historical 

 interest of this section is probably greater than that of any 

 other, and it is significant of the importance attached by 

 Italy to this Collection that she has parted with, even for 

 a short time, those precious relics of Galileo that cannot 

 fail to excite the veneration of all beholders. But besides 

 these there are many other instruments of great historical 

 interest, from the Suspension Astrolabrum, made in 1525, 

 sent by Prof. Buys Ballot of Utrecht, down to the latest 

 form of spe.troscope, and a relief landscape of the moon. 

 Celestial photography is largely represented, both by its 

 instruments and results, and teachers will be much 

 interested in the varied and ingenious apparatus that 

 have been devised for the practical teaching of astro- 

 nomy. 



Of the multitude of objects in Section 12, Applied 

 Mechanics, it would be impossible with our space to give 

 any satisfactory idea. The catalogue contains under this 

 head 470 entries in all, many of which, as indeed is the 

 case in all the other sections, include a considerable 

 number of separate pieces of apparatus. Of Prime 

 Movers alone there are 66 groups, ranging through many 

 forms from a collection of the Original Models of Steam 

 Engines and other machines of James Watt, downwards. 



