THE NATIONAL SCIENTIFIC INSTITUTIONS AT BERLIN. 133 



luachinerj^, etc., while the second division has to test on the principle 

 of Wohler-Spaugenberg dnratiou experiments, and the third is confined 

 to the official testing of paper. A mechanical workshop has been 

 placed under the charge of the second superintendent. 



The Institute owns two excellent machines for the testing of finished 

 articles, having a power of 100,000 and 50,000 kilograms (system Wer- 

 der and Marten's), six smaller machines for the same purpose, eleven 

 machines for duration tests, photographic, microscopic, etc., apparatus. 



The Royal Testing Station of Building Materials. — This was founded on 

 March 1, 1871, in connection with the Technical High School; it decides 

 as to the quality of cements and other building material furnished to 

 the Government. The station owns apparatus for the testing of dura- 

 bility and other physical properties of burnt and unburut artificial 

 stone, natural stone, cement, plaster, lime, clay pipes, and all other 

 building material. 



The hydraulic press of the station, of 140,000 kilograms (308,646 

 pounds) pressure, permits the test of bodies (including pillars of brick 

 or natural stone) of 1 meter height and of 55 by 55*^'" diameter. Tests 

 can be made both as to the stone and to the binding material. 



A 20fold lever is employed in testing the resistance of cylindrical 

 bodies, and a 30 fold lever is used in the testing of elasticity of roofing 

 paper and of the adhesiveness of mortar. 



Tests of clay pipes are made by horizontal pressure of from 1*0 to 30 

 atmospheres to 1 to 3 meters internal diameter. 



The tests of cement are made in accordance with the rulings of No- 

 vember 12, 1878, of the Ministry of commerce, industry, and public 

 works. 



With regard to adhesiveness of cement and cement mortar, a 50-fold 

 normal lever apparatus is used with sample piece of 59 centimeters at 

 the point of rupture ; in pressure tests and break tests the hydraulic 

 press, a 500-fold lever and a 20-fold lever are employed. 



With regard to fineness of grain, sieves of from COO, 900, and 5,000 

 meshes to the square centimeter are employed. In all cement tests the 

 officially introduced normal sand alone finds employment. 



A horizontal disk of emery, operated by a gas motor, which also oper- 

 ates a diamond plane machine used in finishing the bodies for pressure 

 tests, is employed in the experiments as to the wear of the building ma- 

 terials. 



VII.— THE VETERINARY COLLEGE AND THE MILITARY SCHOOL OF FAR- 

 RIERY. 



[Omitted here."] 



VIII. -OTHER SCIENTIFIC AND MEDICAL INSTITUTES. 



The Astro physical Observatory. — Until the iirst quarter of tlu^ present 

 century astronomy employed itself almost exclusively witli the discovery 



