ILLUSTRATING ITALIAN SCIENCE. 897 



(Atti dell' Istituto Veneto, Vol. III., Ser. IV., 1874 ; Nuovo Cimento, 

 Vol. XII., 1874. Ann. cle Chim. et cle Phys. T. IV. 1875., Journal de 

 Physique, 1875). 



(21) 1. RHEOTONU of Breguet and Masson. 



2. Sine compass. 



3. Tangent compass. 



4. Thermometer, Riess's. 



5. Reometric Balance, Bernardi's. 



A magnetic needle, working upon horizontal pivots, is surrounded by a 

 frame, on which is wound a wire, and is united in action with the yoke of a 

 sensitive balance. The-intensity of the current traversing the wire is measured 

 by the weight that must be placed in one of. the scales of the balance, in 

 order that the beam, and consequently the needle, may rest horizontally. 



6. Galvanometer (vertical) for instruction. 



7. Galvanometer of Du Bois Reymond, made by Sauerwald. 

 8. Torsion galvanometer. 



(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. Atmidoineter 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. L, 1872. Nuovo Cimento, Vols. V., VI., 1872. 

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

 1873, Novembre.) 



30508. 3 L 



