104 PROCEEDINGS OF THE SOCIETY. 



with or without the Microscope. The first of these was an ordinary 

 projection lantern made with a small body, but so constructed as to 

 exclude all light from the room except what passed through the lenses. 

 The manner of using this in connection with a Microscope was also shown. 

 The other lantern was a larger and more complete article, which could be 

 used for all purposes, including enlargements. The fine definition given 

 by this lantern was then demonstrated by the exhibition on the screen 

 of some photomicrographs of mounted preparations of insects, and by a 

 further series of whole insects mounted in balsam, all of which were 

 defined with remarkable sharpness and brilliancy. 



In addition to the foregoing, Mr. Barton also exhibited and de- 

 scribed several new forms of Microscope, with detachable circular 

 stage, &c. ; a new form of electric arc lamp for lantern use, with 

 vulcanite milled head for ensuring perfect insulation to the operator - y 

 also an arc lamp of ordinary construction. A new form of lime-light 

 was also exhibited, which attracted much attention, from its extreme 

 brilliancy and the perfect steadiness and silence with which it burned,, 

 with a consumption of from 5 to 1\ ft. of gas per hour. 



Mr. E. M. Nelson thought Mr. Barton was to be highly congratulated 

 upon the successful demonstration which he had given them. He was 

 very much struck with the perfection to which the lamp had been 

 brought, and inquired how so intense a light had been obtained, and 

 if the gas had been enriched in any way by ether or by the admixture 

 of some hydrocarbon, and how it was produced with such complete 

 absence of noise. 



Mr. Barton said that nothing whatever was used but the two gases 

 themselves, the effect being produced by the particular way in which 

 the gases were caused to impinge upon one another previous to their 

 entrance to the mixing chamber, and by the construction of the chamber 

 itself through which they were passed. 



In reply to other questions, Mr. Barton said that this form of lamp 

 required the gases to be used under pressure, although this could, at 

 the expense of light, be reduced to a consumption of 1\ ft. per hour. 

 The heat was intercepted by a water-trough in the usual way, and the 

 projection with the Microscope could be successfully carried out with 

 objectives as high as \ in. or even T \r in., but for all-round purposes 

 a ^ was about the best, provided that the lenses were properly 

 corrected for the purpose ; everything depended upon the quality of 

 the lens and the nature of the object to be shown. 



The President was sure that the Fellows of the Society present 

 would feel grateful to Messrs. Boss, and to their representative, 

 Mr. Barton, for the Microscopes and lanterns which had been sub- 

 mitted to their inspection, and especially for the extremely inter- 

 esting exhibition on the screen, which was a remarkable illustration 

 of perfect definition. The photographs did not appeal to him so 

 strongly as the natural objects. He had great pleasure in proposing 

 that the hearty thanks of the Society be given to Mr. Barton for what 

 he had shown them, and to Messrs. Boss for the instruments and 

 apparatus exhibited. 



The vote of thanks, having been put to the Meeting, was carried by 

 acclamation. 



