1884. 105 Trans. N. Y. Ac. Sci. 



played other specimens and machinery, in illustration of his paper 

 on 



A NEW PROCESS OF CUTTING INTAGLIOS AND CAMEOS, SO AS TO 

 PRODUCE THE FINER EFFECTS OF THE ANCIENT GLYPTIC WORK. 



DISCUSSION. 



A MEMBER called attention to the interesting fact, recorded by Pliny 

 the Younger, of the emerald of the Emperor Nero, which had been 

 cut in the form of a double convex lens. 



The President remarked on the great interest of historical records 

 connected with engraved gems, as illustrated by the ancients. Schlie- 

 mann's discoveries of engraved gems had accumulated largely with the 

 progress of his excavations. 



The work of the engraver was carried on in the most early times of 

 history. The number of ancient gems, represented in the work of 

 King on this subject, indicates that this was then a very common form 

 of art. The great hardness of their material has resulted in their fre- 

 quent and often perfect preservation for long periods. Gems were cut 

 long before the discovery of the diamond, corundum being commonly 

 used for the purpose, in powder. There was even reason to believe 

 that the first architectural excavation and piercing of granyte had been 

 effected by this means. The ancient Pelasgic monuments show 

 evidence of having been fashioned by means of bronze tools and this 

 mineral in powder. In piercing holes, a tempered solid rod had evi- 

 dently been often employed ; the principle of the diamond-drill was 

 therefore very ancient. 



A paper was then read by Mr. Edward W. Martin, illustrated 

 by lantern views, on the subject of 



PHOTOMICROGRAPHY — PROCESSES AND RESULTS. 



DISCUSSION, 



Dr. JULIEN called attention to certain present limitations of the 

 process, and to new methods and apparatus recently proposed to 

 obviate these difficulties. ' 



The President remarked that hereafter lantern slides will be 

 brought into use to display and illustrate the infinitely little as well as 

 the infinitely large. The problem of a satisfactory microscopic attach- 

 ment to the lantern still remained unsolved at present ; only one or but 

 a few persons can well see the same microscopic object at one time. 

 The electric light was full of promise in this direction, whether by means 

 of storage batteries or of some method for the generation of electricity 



