II. ELEMENTARY ILLUSTRATIONS. 143 



285. Conic crank gear, Davies. 



Steam engine. 



286. Parallel crank gear, Galloway. 



Steam engine. 



287. Chamber-wheel train, Pappenheim. 



Pump. 



288. Chamber-wheel train, Fabry. 



Ventilator for mines. 



289. Chamber-wheel train, Fabry. 



290. Chamber-wheel train, Root. 



Blower. 



291. Chamber-wheel train, Root. 



Blower. 



292. Chamber-wheel train, Payton. 



Water-meter. 



293. Chamber-wheel train, Evrard. 



Pump. 



294. Chamber-wheel train, Repsold, Lecocq. 



Pump. 



295. Chamber-wheel train, Dart, Behrens. 



Pump. 



296. Chamber-wheel train, Ganahl, Eve. 



297. Chamber-wheel train, with three wheels. 



298. Screw-wheel chamber train, Revillion. 



Ventilator. 



564b. Kinematic Compasses with Three Branches, 



designed by Reuleaux. 



Royal Academy of Industry, Berlin, Director, Prof. F. 

 Reuleaux. 



By means of this instrument it is easy when the orbs of two points of a 

 system are given, to find all the other curves of the same system. 



(See Reuleaux's " Kinematik," s. 24, and following.) 



The third branch of these compasses may be altered longitudinally, and is, 

 besides, provided with a joint, so that entirely obtuse angular triangles 

 (amblygons) as well as entirely acute-angled triangles (oxygons) can be 

 taken by the compasses, for which the three-branched compasses of older 

 construction were not adopted. 



These compasses were manufactured by J. Kern, mechanical instrument 

 maker, at Aarau, Switzerland, by order of the exhibitor. 



II. ELEMENTARY ILLUSTRATIONS. 



528a. Parallelogram of Forces. 



Dr. G. Krebs, Frankfort-on-the- Maine. 

 528b. Inclined Plane. 



Dr. G, Krebs, Frankfort-on-the- Maine. 



