WENHAM'S REFLEX ILLUMINATOR. 159 



Dr. Carpenter. The interpolation within the brackets, 

 and the italics are our own. 



As is above set forth, this instrument was designed 

 by its maker for a dark ground illuminator, and for use 

 with high powers; was made and sold for this purpose, 

 ;and was generally so usad. Shortly after their intro- 

 duction into this country, Mr. Samuel Wells, of Boston, 

 Mass., made the discovery that the "reflex" when 

 worked with certain very high-angled objectives, could 

 be made to give a brilliantly-lighted field, accompanied 

 with beautiful resolutions of the severest tests, when the 

 latter were mounted in balsam, the effect being, as Dr. 

 Carpenter most justly observes, " that of very oblique 

 illumination" 



As is evident from an inspection of the cut, the instru- 

 ment can be variously modified in its working, simply 

 by changing- the angle of the facet. The fact, too, ap- 

 pealed almost simultaneously to all, that a serious objec- 

 tion to the instrument was that it could be only used 

 over balsam mounts, and of course with objectives of 

 the highest angles. The "reflex" was therefore modi- 

 fied by the London opticians to suit the angles of their 

 leading objectives, and, at the same time, or at least 

 shortly after, similar modifications of the instrument 

 were made here. There has been an effort here at home 

 to claim, on the part of our opticians, some originality 

 of design in the construction of these various modifica- 

 tions. The entire plan, however, belongs to Mr. Wen- 

 ham, and the simple changing of the angle of the facet 

 does not authorize any claim of invention The author 



