S52 SEC. 19. EDUCATIONAL APPLIANCES. 



4026. Th. Miiller's Di-Electric Machine, with accessary 

 apparatus, viz. : 



Electric tuft. 



Electric turbine. 



Electric puppet-dance. 



Electric peal of bells, with three bells. 



Lightning tube. 



Lightning conductor. 



2 electric excitors. 



Electric pistol. 



2 condenser jars. 



Kgl. Preuss. Oberbergamt, Breslau. 



This machine has of late been much used in elementary schools in 

 mining districts of Germany for instruction of the children in some parts of 

 their future calling. With 12f inches diameter of disc, it gives sparks over 4 

 inches long. The machine can be depended on even in unfavourable weather. 

 It is simple in construction, and the peculiarity of it consists in the collection 

 of the positive and negative electric currents in two separate Leyden jars of 

 special form, which again are so connected together that the opposite electric 

 currents compensate each other. Thus the loss of electricity is reduced to a 

 minimum, and strong actions are obtained with the excited glass surface. 



GEOMETIUCAL APPARATUS. 



4027. Board, exhibiting square foot divided into square inches. 

 Made by Fenoult. 



4028. Cubic Quarter Arshin, divided into cubic vershoks. 

 Made by Fenoult. 



4029. Collection of Geometrical Forms, with sections. 

 17 models. Made by Stroukoff. 



4030. Collection of 37 geometrical forms intersecting each 

 uther. Made by StroukofF. 



4031. The Cube of two, the cube of three, the cube of a 

 binomial and a trinomial quantity. Made at the St. Petersburg 

 Workshop of School Apparatus. 



4032. Large Cone, with sections and hemispheres for deter- 

 mining the focus of curves. Made by StroukofF. 



4033. Sphere with sections. Made by StroukofF. 



4034. Model of a Kiosk, composed of geometrical forms. 

 Made by General Tsitovitch. 



4035. Apparatus for demonstrating the theory of projections, 

 by Scliildknecht. 



