MATHEMATICAL INSTRUMENTS. 275 



APPROVED SET OF 



PHILOSOPHICAL APPARATUS 

 FOR $600. 



Fig. 144, inertia apparatus, $1.50 ; 145, pair of plates 

 for attraction of cohesion, $1.50 ; 148, set of tubes for 

 capillary attraction, $1 ; 150, set of five ivory balls for col- 

 lision, $1.25 ; 153, 154, 155, 156, 157, set of mechanical 

 powers, $35 ; 123, planetarium, $1.50 ; tellurium, $6.50 ; 

 95, quadrant, $15: 92, surveyors' compass, 820; two 

 pole surveyors' chain, $1.25. $90.50. 



Optics. Fig. 698, large prism, $1.50 ; 699, apparatus 

 for the recomposition of light, $1 ; set of four lenses, two 

 and a half inches diameter, $6 ; multiplying glass, 50c. ; 

 694, 695, 696, 697, set of four eye models, $13 ; 702, 

 camera obscura, $3.50 ; 701, cosmorama and twelve views, 

 $4.25 ; pair of six inch mirrors concave and convex, $3.50 ; 

 752, large compound microscope, $19 ; 733, magic lantern, 

 $15 ; 740, set of astronomical sliders for the magic lantern, 

 $20 ; six comic sliders for magic lantern, $7.50 ; sliders re- 

 presenting blooming carnation, $1.25 ; death on the pale 

 horse, $1.25. $94.75. 



Electricity. Fig. 270, twenty inch plate electrical ma- 

 shine with mahogany frame, $38 ; 276, Ley den jar, $1.25 ; 

 277, discharger, $1.25; 291, battery of four quart jars, 

 $6.50 ; 281, quadrant electrometer, $"l.25 ; 275, insulating 

 stool, $3 ; 296, bells, $2 ; 300, plates and dancing images, 

 $1.25; 294, magic picture, $1.75; 305, long hair man, 

 75c. ; 302, one dozen pith balls, 25c. ; 316, orrery, $2.50 ; 

 314, horsemen, $2.50 ; 332, aurora tube, used also as 

 guinea and feather tube in pneumatics, $6 ; 335, spiral 

 tube, $2.50; 337, luminous word, $3; 322, bucket and 

 syphon, $1 ; 345, pistol, $3 ; 341, fire house, $4. 



$81.75. 



Pneumatics. Fig. 177, best lever air pump with maho- 

 gany frame, $70 ; 188, bell receiver, $2 ; 217, open top 



