ILLUSTRATING ITALIAN SCIENCE. 887 



Monaco, from a design given by Professor Respighi. The telescope is 

 mounted as in transit instruments, and may also be used as a meridian 

 telescope ; the object-glass, made by Signer Merz, of Monaco, has a free 

 aperture of 0- 108 TO , with a focal distance 1 582 m . The micrometer is composed 

 of 1 1 fixed equatorial threads and two movable threads, with a fixed meridian 

 thread. The eye-piece can be moved with the greatest ease, whether in the 

 meridian or vertically. The micrometer can be turned 90 to render the 

 threads parallel to the meridian, and then the instrument serves as a transit- 

 instrument. 



4555. Photographs representing the Daily Drawings 

 of the Solar Chromosphere, made by the spectroscope of 

 Professor Lorenzo Respighi. 



Prof. Lorenzo Respigki, Director of the Royal Observatory 

 of the Campidoglio^ Home. 



On the 26th October 1869, at the Observatory of the Campidoglio, the spec- 

 troscopic observation and the daily representation of the chromosphere on 

 the solar horizon were for the first time undertaken, and this work has been 

 regularly continued up to the present time. The instrument used in these 

 observations is an equatorial by Merz, with telescope of 4^- inches aperture, to 

 which is applied a spectroscope with direct vision, by Hoffmann, with five 

 prisms, with circle of position to fix the place of the various parts of the 

 chromosphere and of the protuberances. Notwithstanding the small dimen- 

 sions of the instrument and - the moderate dispersion of the spectroscope, the 

 chromosphere and the protuberances are clearly exhibited even in their 

 smallest details. 



The Photographs I., II., III., IV., and V. represent 140 drawings of the 

 chromosphere made with this apparatus by Professor L. Respighi. 



4556. Photographs of Scientific Instruments in the 



Institute of Physical Science, Royal University of Rome. 



Director ) Prof. Blaserna. 



1 . Balance of precision made by the mechanician Scateni, of Urbino ; the 

 suspension very simple and excellent. With a weight of kilogram 2 per 

 scale. Indicates to \ milligramme. 



2. Universal wheel, made in the workshop of Galileo, in Florence. It 

 allows rotary motion to be produced in cylinders and discs in horizontal and 

 vertical directions with the most different velocities. 



3. Scott's Phonautograph, made by the machinist De Palma, of Naples. 

 The writing lever has a special arrangement devised by Mr. Campbell, lecturer 

 at the Physical Science Institute, by which it rests only upon the centre of the 

 vibrating membrane, while the other support transforms the vibrations into 

 movements parallel to the axis of the rotating cylinder. 



4. Instruments of precision, made by Starke and Kaumerer, of Vienna : 

 (A.) Complete theodolite ; horizontal and vertical circle, which permits, by 

 the aid of microscopes with a movable ocular thread, to read up to I". 

 (B.) Apparatus for the measurement of the indices of refraction. For the 

 reading are added two microscopes with movable ocular threads, allowing a 

 direct reading of 1". Repeating movement, with excellent arrangement of the 

 plate bearing the prism. (C.) Cathetometer, with movable ocular thread, 

 allowing a reading of yi- millimetres. 



5. Magnetic instruments, according to Lament, made by Dr. Carl, of 

 Munich, Bavaria : (A.) Theodolite, for the absolute measurement of declina- 

 tion and of the horizontal component. The two microscopes allow the reading 



