868 S Kr. 19. EDUCATIONAL APPLIANCES. 



The chief advantages of this apparatus (already used in several institutions 

 in Holland and Germany) are 



1. It allows, with very little expenditure of time and heat, the illustration 

 of the fundamental principles of heat on the lecture table. 



2. It produces steam of high pressure, the properties of which may be 

 shown with very little danger. 



3. The relatively small expense (10/.) renders possible the introduction of 

 this apparatus into schools where physics and mechanics form an important 

 part of the system of education. 



MISCELLANEOUS. 



4192a. Cosmo graphic Apparatus for teaching purposes. 



Letettier, France. 



4193. Stativ (stand), with a fixed and a movable pulley, besides 

 string and counter-weight. 



4194. Polyspast, to be appended to the same stand, with 

 four pulleys, string, and counter-weight. 



4195. lever Apparatus, with attached needle (for the 

 balance) and stand. 



4196. Twenty-one Weights belonging to the foregoing objects. 



Royal Prussian Chief Mining Department, Breslau. 



4197. Oscillating Machine (centrifugal apparatus), with the 

 following auxiliary apparatus : 



a. A two-fold brass ring with iron axle. 

 I). A glass globe with axle. 



c. A glass cylinder with inserted Sieboglinder (centrifuge). 



d. A double pendulum regulator with throttle-valve. 



e. Two balls, joined to each other by a chain. 

 /'. A balancing ruler with sliding weights. 



Royal Prussian Chief Mining Department, Breslau. 



4198. Model of a Suction Pump. 



Royal Prussian Chief Mining Department, Breslau. 



4199. Model of a Fire Engine (force pump). 



Royal Prussian Chief Mining Department, Breslau. 



4200. Pour Optical Lenses, with stands, and a round 

 Paper-Screen, with stand. 



Royal Prussian Chief Mining Department. Breslau. 



4201. Optical Prism. 



Royal Prussian Chief Mining Department, Breslau. 



4202. Steel Magnet. 



Royal Prussian Chief Mining Department, Breslau. 



4203. Two Magnetic Needles, with stands. 



Royal Prussian Chief Mining Department, Breslau. 



