= 87 



The bisection of the pencils for producing stereoscopic effect is made by 

 adjustable semi-circular stops placed over the oculars, without these, i. e., with 

 full}' exposed oculars, the instrument gives binocular vision without specific 

 stereoscopic effect. 



The distance between the oculars is adjustable - by altering the position 



<>f one of the ocular tubes -- to suit the inter-pupillary distance of any individual 



.observer's eyes. The instrument is available (but in conjunction with achromatic 



objectives only) for use on any of our large stands in which the tubes admit of 



shortening to at least 140 mm (5'/2 in.). 



Xo. UK). *ABBE'S Spectroscopic Ocular (Micro-Spectroscope). Fig. 42. 



This ocular is specially designed for the examination of the absorption spectra 

 of microscopic objects, but is also adapted for spectroscopic analysis of larger 

 objects, liquid strata, etc. 



The achromatic eye-lens is accurately adjustable with respect to the slit 

 situated in the plane of the diaphragm. By a lever arrangement a comparison 

 prism can be applied to the slit to facilitate spectroscopic comparison of the object 

 with other absorption media, which are attached in suitable holders at the side of 

 the ocular. An assortment of small glass tubes is supplied for this purpose. 



93. 94. 



Longitudinal section of the whole instrument. Slit mechanism separately. 



'('/ Full Size.) (Plan view; Full Size.) 



Vig. 42. ABBE'S Micro-Spectroscope, Xo. 190. 



A direct-vision AMICI prism, which may be turned aside about a pivot, 

 is placed above the ocular. A scale of wave-lengths is projected upon the 



ABBE'S Spectroscopic Ocular (Micro-spectroscope), in case 



Marks 

 200. 



Codeiuord 

 Peorus 



c t:>^ ore-net. 



