EDUCATIONAL APPLIANCES. 



849 



of air ; one prismatical, one straight conical, one reversed conical. 307. Organ 

 pipe with glass furnace, according to Mr. Bourbouze, showing three different 

 vibrations with reflector. 308. Five different sounding boards in wood, and 

 one of wire. 309. Two flat wires for horizontal vibration. 310. Small sup- 

 port with movable bridges to fix the wire or sounding boards. 311. Sino- 

 meter, according Mr. Barberau. 312. Circular membrane in caoutchouc 

 with changeable tension. 313. Ditto of paper, 30 cent, diameter. 314. 

 Ditto, ditto, 30 cent, thick. 315. Two tuning forks in C, mounted upon wooden 

 box adjusted to give four vibrations in the second. 316. Two tuning forks in 

 C, mounted between magnetic poles, and intermitting tuning fork in C. 

 317. Vibration meter according Mr. Duamel. 318. Apparatus showing the 

 vibration through liquids. 319. Small apparatus, showing the vibration of 

 vocals without movable reflector. 



4001. Collection of Models and Apparatus for teaching 

 Physics, Sound, Light, Heat, Electricity, and Chemistry. 



Matthew Jackson. 



Tate's air pump. 



Magdeburg hemispheres. 



Glass globe for weighing air. 



Gay-Lussac's apparatus for vapour 

 densities. 



Dumas' apparatus for vapour den- 

 sities. 



Electrical alarum. 



Savart's toothed wheel apparatus. 



Sjren. 



Tuning forks. 



Hopkins' fork tube. 



Glass reflectors on stands. 



Set of lenses and half lenses, with 

 holder on card. 



Fergusson's pyrometer. 



Gravesand's ring and ball. 



Sir H. Davy's apparatus. 



Thermopile. 



Cylinder machine. 



Plate machine. 



Bertsch machine. 



Holtz machine. 



Winter's machine. 



Volta's condensing electroscope. 



Aurora apparatus. 



Bichromate battery. 



Zinc plates for Bunsen's battery. 



Tangent galvanometer. 



Set (11) of Hofmann's tubes with 



stands (1, with 2 stands) and 1 



span stand. 



Winkler's gas apparatus. 

 Imp. sulph. hydrogen apparatus. 



3 articles. 



Ammonia apparatus. 

 Collection of small instruments (18) 



on cardboard. 

 Organic analysis apparatus. 30 



pieces. 



Desiccators. Different patterns. 

 Distilling apparatus for carbon 



bisulph. (4 articles.) 

 Assortment of 12 test glasses. 

 Distilling apparatus. (4 pieces.) 

 Set of 7 1 graduated and other glass 



instruments. 

 Carbonic acid apparatus. 7 portions 



in card boxes. 



Arrangement of gas burners. 

 Bunsen's water bath and stand. 

 Sulph. hydrogen apparatus. 

 Cleaning brushes. 



4002. Calculating Disc, constructed on the system of Pro- 

 fessor Sonne. Specim3n for demonstration, size 50 centimeters, 

 with rough division ; for instruction in schools. 



Landsbcrg and Wolpers, Hanover. 

 4002a. Universal Lever, for lecturing purposes. 



C. Chzechovicz, Russia. 



Apparatus consisting of a set of levers and parallelograms, intended to 

 illustrate the principle of elementary statics, viz. : 

 The combination of forces applied to a body. 

 Combination of parallel forces. 



39503. H 



