42 



A. Kruss. Hamburg. 



No. 2770. 

 A. KrilSS (Principal Dr. Hugo Kriiss). Hamburg. 



7 Adolphsbrucke. 

 Optical Works. 



Large Automatic Spectroscope with 6 Prisms ; with dispersion 

 of 32 degrees; with fixed telescope. Original Construction. (Fig. 1.) 



In spite of the movement of the prisms, which is necessary to obtain 

 the minimum of deviation for the various rays of the spectrum, the dispersion 

 between the red and violet rays being 82 degrees, the telescope remains fixed 

 and, therefore, also the eye of the observer. This is attained by an ingenious 

 mechanism, and the use of a central mirror. The spectrum may be made to 

 traverse the field, either quickly by hand or slowly by means of a micrometer- 

 screw, which also serves for measuring the distances between the spectrum lines. 



Automatic Spectroscope with 6 Prisms, with dispersion of 

 32 degrees. Original Construction. (Fig. 2.) 



The automatic adjustment of the prisms is effected by a new ingenious 

 mechanism, which acts with greater ease and precision than those hitherto used. 

 The vertical axis a, which is fixed in the center of the prism stage, bears six 

 sliding and rotating rings, each of which is connected to one of the six prisms. 

 The collimator 8 and the telescope B have reflecting prisms placed before 



