1893.] THE MICKOSCOPE. 25 



accompany the plates and other packages which I have purchased, 

 and with the best of results. 



Exposed to sunlight in a proper printing-frame, the film side of 

 the negative in juxtaposition to the sensitive side of the paper, 

 the latter soon becomes impressed by the negative, and when the 

 print is a little darker than desired it is removed to a tray, where 

 the Omega solution is poured over it. This both tones and fixes 

 it. The print is next washed in water from one to three or four 

 hours and the picture side is squeezed upon a polished sheet of 

 hard rubber or a sheet of ferrotype plate and allowed to dry thor- 

 oughly, when it will fall off, leaving a beautiful glaze surface. It 

 may now be trimmed and mounted upon cardboard if desired. 



NEW APPARATUS FOR THE MICROSCOPE WHICH 

 IS CHEAP, EFFICIENT, AND HOME-MADE. 



By Arthur M. Edwards, M. D., 



NEWARK, N. J. 



I am strongly in favor of cheap and efficient apparatus for the 

 microscope, and when it is made by the micioscopist himself it 

 is doubly to be commended. The beginners, and for that matter 

 some of the older microscopists, are not blessed with long pock- 

 ets ; and even if they were, economy is to be commended. I can 

 remember the time, not so long ago, when I looked in the illus- 

 trated catalogue of some maker of microscopes and envied the 

 possessor of some illuminator or lamp figured there. "Could 

 they be made at home?" I thought. Objectives and oculars must 

 of course be made in the shops, by expert opticians, but illumi- 

 nators and lamps could be made by any one of ordinary capacity 

 and some manual skill. I do not consider myself to be very 

 skilful, but I do think I can try. Illuminators were the first 

 things I made, and a half-inch plano-convex lens, costing not more 

 than twenty-five cents, was the first. I described that in the 

 Quarterly Journal of Microscopy for 1857, anc ^ ** 1S efficient 

 still with dry objectives, and even with immersion objectives. 



I wish to describe an attachment to the lamp now, or rather a 

 way of modifying the light of the lamp so as to use it with low 

 powers and to render it actinic for high powers. In the Micro- 

 scope, vol. xii, page 237, W. D. Grier mentions a cheap micro- 

 scope lamp which is very good as far as it goes, and costs $2.15, 

 but I think I can improve on it in the way of cost, and perhaps 

 have it quite as good in quality. The lamp I have used cost 1=; 

 cents. I surround it almost with a roll of drawing-paper, but 

 this can be done away with by using cheap white paper. If this 



