MISCELLANEOUS! 1045 



4217. Expansion Apparatus. 



Royal Prussian Chief Mining Department, Breslau. 



4218. School Microscope, from the Optical Institute of 

 F. W. Schick, Berlin, with two eyepieces and three object-glasses. 



Royal Prussian Chief Mining Department, Breslau. 



4219. Collection of Forty Microscopical Preparations 



from the Institute of Rodig, Hamburg, with explanations by Prof. 

 Dr. Ferd. Cohn. 



Royal Prussian Chief Mining Department, Breslau. 



The collection serves, in connexion with other means of illustration, for 

 the purpose of teaching in the elementary public schools of the Silesiau 

 mining districts the rudiments of the physical and mechanical sciences, and 

 thus to prepare the children of miners for their probable future employment 

 as miners, engine attendants, &c. It is worthy of remark that the money 

 required for the acquisition of these collections, as indeed for the founding 

 of the appropriate schools, comes from a special fund, which owes its origin 

 and continued maintenance to some clauses in the older German mining laws, 

 according to which the revenues of certain mines are applied to school and 

 church purposes. Through the rapid growth and development of the Silesian 

 mining industry, this fund has risen to the value of 25,000/. per annum. 



The above-mentioned schools are not to be mistaken for the mining schools 

 proper, or the schools serving as preparatory institutions to these latter, both 

 of which are intended for grown-up pupils. 



4219a. Apparatus employed in teaching, for exhibiting the 

 action of Electric Currents on Currents of Magnetism. 



W. Gloukhoff, harden of Russian Standard Measures. 

 In this apparatus the mode of suspension of the movable conductors is 

 entirely new, and consists of a brass tube A, B, C, D, through which passes 

 an insulated brass wire E, F; the wire and the tube have on their tops the 

 metallic cups E and Z>, filled with mercury. Into the cup E the steel point of 

 suspension and one end of the movable conductor are plunged, and into the 

 cup D the other end. 



4220. Universal Rotation Apparatus with Twenty-six 

 Auxiliary Apparatus, viz.: 



1. Centrifugal pendulum. 



2. Spheres of different weight. 



3. Globe, 100 grammes in weight, movable horizontally, with 

 spring balance, on which the centrifugal force can be directly 

 measured. 



4. Two oblique glass-tubes for different kinds of liquids. 



5. Glass-balloon. 



6. Apparatus for demonstrating the flat spherical form of the 

 earth. 



7. Apparatus for flattening of an oil-globule (Ring of Saturn). 



8. Ring, chain, ball, cylinder, suspended on a cord. 



9. Bull, suspended on a long string, for Foucault's pendulum 

 experiment. 



10. Glass-balloon for demonstrating the rising of fluids. 



