56 
Marks 
We supply the following 
Accessories and auxiliary apparatus for petrologlcal 
researches. 
Huyghenian eye-pieces 1 to 5 with crossed lines . . each 
10.— 
BertranD'S eye-piece (with quadruple quartz plate) . . 
35 — 
Stauroscopic plate 
7.— 
Micrometer eye-piece No. 28 
15.— 
60.— 
Groniometer eye-piece No. 40 
30.— 
Eye-piece for tlie oTbserration of axial images No. 50 
(for the medium and small stand) 
30.— 
Spectroscopic eye-piece No. 53 
165.— 
Micro-spectro-pliotometer after Engelmann No. 54 . . 
480 — 
Abbe camerae No. 43 and 44 M. 30.— and 
43 — 
Set of 8 selenite and mica films after Mohl 
10 — 
Respecting the appliances for i)lioto-micrography and for the 
projection of objects in general and of axial images in particular 
we refer to pag. 92. 
Analyser for projection (made to screw to the projection 
eye-pieces). 
30.— 
