1082 SEC. 20. MISCELLANEOUS. 



(22.) 1. FOUCAULT'S APPARATUS for transforming heat into 

 work by means of induced currents. Electricity. 



2. Electro-magnetic motor, applied to Geissler's tubes. 



3. Electro-magnetic motor, by Page. 



4. Apparatus of De la Rive for the rotation of the voltaic arch. 



5. Matteucci's induction coil. 



6. Magneto-electric machine, by Stohrer. 



7. Dynamo-magneto-electric machine, by Ladd. 



(23.) Large RUHMKORFF'S COIL, with Foucault's interrupter, 

 and accessories ; made at Paris. Gives sparks 40 centim. long. 

 (24.) 1. HYGROMETER, Regnault's. 



2. Hygrometer, Daniel's. 



3. Psychrometer. 



4. Condensation hygrometer, Belli's. (See Belli, Elementary 

 Course of Experimental Physics, Vol. II., Milan, 1838.) 



5. Psychrometer, Belli's. (See Belli, Elementary Course of 

 Experimental Physics, Vol. II., Milan, 1838.) 



6. Parchment hygrometer, Bellani's. 



7. Maximum and minimum thermometer, Bellani's. . 



8. Maximum and minimum thermometer, Walferdin's. 



9. Atmidometer of Landriani, perfected by Bellani. (See Belli, 

 Elementary Course of Experimental Physics, Vol. II., Milan, 

 1838.) 



(25.) ROSSETTI'S APPARATUS for the display of luminous electric 

 figures obtained by the discharge of positive or negative elec- 

 tricity upon the naked surface of a glass, the other surface of 

 which is furnished with an armature. (See Di una curiosa espe- 

 rienza elettrica : Atti delle Societa Veneto-Trentina di Scienze 

 Naturali, Vol. I., 1872. Nuovo Cimento, Vols. V., VI., 1872. 

 Carl's Repertorium der Physik, 1873. Journal de Physique, Paris, 

 1873, Novembre.) 



4564. Photographs of Scientific Instruments in the Phy- 

 sical Cabinet of Science, University of Pavia. 



Director, Prof. Giovanni Cantoni* 



1. Small apparatus for the study of reciprocal electrical influence, with two 

 electrometers. Volta. 



2. Two electrophori which recharge themselves and work as unfailing sources- 

 of electricity (first example of an electric machine by induction). Volta. 



3. Measurer of powerful electric tension, by Volta. 



4. Apparatus for the study of the electric spark. Volta. 



5. Apparatus for the dilatation of gaseous fluids. Volta. 



6. Electric duplicator by Giuseppe Belli. (Attempt at an electric multiplier 

 which served to introduce the next machine.) 



7. Electric machine by induction, G. Belli. (First example of an electro- 

 meter by induction, somewhat like the first machine of Holtz). 



8. Hygrometer, with durable indications (by the same). 



9. Psychrometer with bellows (by the same). 



