1006 SEC. 19. EDUCATIONAL APPLIANCES. 



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. 303. 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 M. Duhamel. 318. Apparatus showing the 

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

 vocals without movable reflector. 



EXAMPLES OF ELEMENTARY PHYSICAL APPA- 

 RATUS. 



The pieces of apparatus in this collection were made by the 

 pupils Messrs. Boughton and Owen in the Physical Laboratory 

 at the Science Schools, South Kensington. They are intended 

 to show what can be done by Science students in the matter 

 of making their own apparatus, and to indicate that neither 

 great expense nor great manipulative skill is required to put 

 such students in possession of instruments capable of illustrating 

 the ordinary laws and phenomena of physics. 



Frederick Guthrie. 



PROPERTIES OF AIR AND WATER. 

 4000a. Cardboard Mercury Tray. 

 4000b. Glass Millimetre Scale. 

 4000c. Boyle's Tube. 

 400Od. Siphon Barometer. 

 400Oe. Water Hammer. 

 4000f. Specific Gravity Bottle. 

 4OOOg. Apparatus for estimating density of Mercury. 



SOUND. 



400Oh. Monochord. 

 40001. Compound Motion Spring. 

 4OOOJ. Sensitive Flame. 

 4OOOk. Singing Flame Apparatus. 

 400O1. Singing Flame Apparatus [octave higher]. 



