MISCELLANEOUS. 1077 



GROUP V. PLANIMETERS, COMPASSES, AND INSTRUMENTS OF 

 PRECISION. 



1. Octagonal Planimeter, of the Florentine Tito Gonella, by Carl Starke, of 



Vienna (1852) ; an exquisite instrument. 



2. Three polar planimeters (1) from the Tecnomanasio of Milan ; (2) by 



Amsler-Laffon, of Schafhausen ; (3) by Ertel, of Monaco (1869). 



3. Planimeter, by Amsler-Laffon, of Schafhausen ; a very delicate instru- 



ment of recent invention (1873). 



4. Tychonic scale, designed by Giuseppe Pavan, of Padua (1874). 



5. Box compasses, by Montan, of Padua (1827). 

 G. Crystal grating, by Merlo, of Milan (1870). 



7. Compass fitted by Montan, of Padua (1827). 



8. Calculating circle, constructed by Professor Legnazzi (1856). 



9. Calculating rule, Gravet-Lenoir (1860). 



10. Crystal grating, at the workshop of the Observatory of Padua (1849). 



1 1 . Apparatus to graduate the small levels designed by Professor Legnazzi 



(1866). 



12. Box compass complete, by Toni, of Milan (1853). 



13. Box compass, by Bordogna, of Milan, a celebrated maker (1780). 



14. Ellipsograph, designed by Prof. Legnazzi, and constructed at the Royal 



Observatory of Padua in 1870. 



15. Compass of precision to take thicknesses. 



1 6. Compass of Bauernfeind, constructed by Mayer, of Dunkelsbuhl, which 

 serves for the praetorian tablet (1871). 



17. Rule to draw a parallel at a given distance, by Rodella, of Padua (1819). 



18. Wide compass for drawings of precision (1872). 



19. Steel callipers with vernier (1870). 



20. Models of spikes with measuring wedges for the measurement of a base ; 



invented by Bessel, constructed by Ertel (1874). 



21. Models of rectilinear verniers for public instruction (1848). 



22. Ebony pantograph from the workshop of the Royal Observatory of 



Padua (1830). 



23. Rod Compass, by the distinguished mechanician Montan, of Padua 



(1824). 



GROUP VI. HYDRAULICS. 



1. Model of a careening basin, constructed 70 years ago. 



2. Model of a shell fitted in the Canale di Navigazione of Pavia ; designed 



by Leonardo da Vinci (1485). 



3. Hydrometrical pendulum of Venturoli, constructed by the engineer 



Albanesi, of Venice, in 1790. 



4. Model of the Cremona regulator for dispensing water. 



5. Model of the Piedmontese regulator for dispensing water. 



6. Model of the regulator of the Milanese Bocca Magistrale for dispensing 



water. 



7. Ball plummet, 30 metres long, with small brass chain for centimetres 



and millimetres (1860). 



8. Pilot tube, modified by Mallet, length 14 metres, with float, constructed 



by the Royal Observatory of Padua (1852). 



9. Tachymeter, of Brunnings, constructed in the workshop of the Royal 



Observatory of Padua, in 1483. 



10 Portable hydrometer, in several pieces, length 8 metres, of recent con- 

 struction, to take the surface of the water of rivers with perfect 

 accuracy, whence to deduce the declivity of the superficies, and to 



