3-52 SEC. 11. ASTRONOMY. 



1803. Spectrum Apparatus, for the observation of the spectra 

 of the fixed stars, planets, and nebulae ; arranged after the spectrum 

 apparatus of Boshkamper (belonging to the Observatory of Ham- 

 burg). Hugo Schroder", Hamburg. 



The spectrum apparatus is constructed on the simple principle which has 

 proved so successful at the Observatory of Botlicamp, with the difference, 

 however, that this apparatus is arranged for absolute measurement, and that 

 the one at the Observatory of Hamburg is attached at right angles to the prin- 

 cipal axis of the refractor. 



1804. Spectrum Apparatus, for observing the Solar Pro- 

 tuberances to be attached to the collimator of the spectroscope. 



Hugo Schroder, Hamburg. 



This spectrum apparatus, which is in reality a supplement of the first 

 one, can he fastened to the collimator of the other one with great readi- 

 ness. The object of this apparatus is the observation and measurement of 

 the solar spectrum as well as of the solar protuberances. The principle on 

 which it is constructed differs from that of the former one in that the rays 

 after once passing through the system of prisms do not issue from it in the 

 same direction as they entered, but are bent and scattered in favour of the 

 heavy prisms of flint glass. By means of a rectangular prism of crown glass 

 the raj-s are compelled to pass through the system a second time, and -leave it 

 in a direction parallel to that of their first entrance. By a second prism of 

 crown glass the rays are reflected into the observing tube which is attached to 

 the prism holder. The passage of the spectrum across the field of view, as 

 well as the absolute measurement, is effected by turning the first prism of 

 crown glass by means of the screw micrometer. This apparatus is, on account 

 of its convenient and highly stable construction, particularly to be recom- 

 mended for observers who have scanty room at their disposition, and yet wish 

 to undertake accurate measurements. 



. 1805. Star Spectroscope, after Dr. H. C. Vogel (described 

 in the Berichte der koniglichen sachsischen Gesellschaft der Wis- 

 senschaften, December 1873). H. Heustrcu, Kiel. 



This apparatus recommends itself for its simple construction, for its varied 

 application for all kinds of observations, and its reasonable price. 



18O6. Spectroscope made by Merz in Munich. 



Prof. Dr. Winneckc, Strassbtirg. 



18O6a. Farts of a Solar Spectroscope, made by Elliott 

 Brothers, in 1869. J. Norman Lockyer, F.R.S. 



In this instrument the prisms are brought to minimum deviation by means 

 of a spring, suggested by Mr. G. W. Hemming, and the light is brought back 

 through the prisms by a total reflection prism at the end of the train, on the 

 plan first employed, it is believed, in this instrument, and suggested by the 

 contributor. 



1806b. Solar Spectroscope, with diffraction grating or 

 speculum metal, presented to the contributor by Mr. Rutherfurd, 

 of New York. J. Norman Lockyer, F.R.S. 



