618 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



natural and synthetic gem that we are enabled to discriminate between 

 them. AVhen examined by a loup or by a Microscope the flaws in the 

 natural gem are crystalline or more or less angular in formation. In 

 the synthetic these specks or flaws are globular or semi-curved, and this 

 is the one and only difference between the natural and the synthetic 

 gem. Fig. 81 shows a Microscope, designed by the author and manu- 

 factured by Messrs. Eaphaels, Ltd., of Hatton Grarden, arranged for 

 the convenient examination of mounted or unmounted srems. The 



Fig. 81. 



instrument has two object-glasses of 1 in. and 2 in. respectively, and 

 these are amply sufficient for the purpose. The structure of the Micro- 

 scope will be readily understood from the figure. A dichroiscope can 

 be connected, if desired, with the stand. 



Beck's Latest '' London " Microscope.*— The stand (fig. 82) is made 

 on the Handle Model, which has the limb of the Microscope so shaped 

 that it forms a handle by which the Microscope can be lifted without 

 in any way endangering the fine-adjustment. The base and pillar 



* R. and J. Beck's Catalogue, 1913, p. 115, fig. 1334. 



