1863.] "'^l [Oliver. 



improved plan of setting the binocular prism ; the introduction of a cir- 

 cular rotating and concentric stage ; the plan by whicli exact amplification 

 of the image in the binocular instrument is obtained ; the invention of a 

 direct vision-erecting prism ; the improved and perfect (mark the word 

 "Perfect ") mechanical finger ; the optical superiority of the lenses ("the 

 lenses have no superiors"); and lastly, " for the erection and conduct of 

 an optical establishment in our own city wherein work equaling the best 

 done abroad is done on principles of honesty and thorough meclianical 

 skill ; and all this as the result of oue unaided individual." Tlie Franklin 

 Institute of the State of Pennsylvania also deemed it wise to give a silver 

 medal for the same reasons. These all-sufficient reasons — which were the 

 embodiment of the combined opinion of the Committee on Sciences and 

 the Arts of the Franklin Institute, a committee composed of sucb repre- 

 sentative men as B. Howard Rand, M. D., J. G. Hunt, M.D., George R. 

 Morehouse, M.D., J. Soils Cohen, M.D., E. Otis Kendall, Charles M. 

 Cresson, M.D., E. Thomson and H. C. Wood, Jr., most of whom as mem- 

 bers of this Society are now with us in higher and more exalted positions 

 — must bring vividly before us, in this later generation, the admiration and 

 respect with which he was held at that time — a proof of scientific gratitude 

 for individualized success, made still greater when it is known that its 

 award was the second since its founding in the year 184B. 



Listen to what the United States Centennial Commission for Awards at 

 the International Exhibition held at Philadelphia in 1876 found sufficient 

 reasons to offer a bronze medal for the microscope stands of Mr. Zent- 

 mayer : "For superiority of workmanship, rigidity and freedom from 

 tremor, and the convenient arrangement of their moving parts as unsur- 

 passed by any in use." "Besides the forms already familiar to microscop- 

 ists, he has presented one which is substantially new, and which embodies 

 a number of important improvements .... this exceedingly ingenious 

 stand is in every imporjant respect original with the exhibitor, and is pre- 

 sented as a characteristically American stand." .... "Tlie objectives 

 of 3-inch focus, 1^-inch, y^g-inch, ^ inch, ^incb and ^-inch are not sur- 

 passed in defining power by those of any other maker." "The resolving 

 power of the ^ and i-inch is also remarkable." .... "For a pocket 

 microscope which folds up witliout separation of parts into a case, which 

 when in use forms its stand, and is small enough to be carried without 

 inconvenience in the coat pocket." "For an admirable dissecting 

 microscope, furnished at a low price." " Further, of tbe numerous forms 

 of apparatus accessory to microscopic observations, exhibited by Mr. 

 Zentmayer, may be mentioned as especially worthy of commendation, 

 a very ingenious erecting prism, a mechanical finger for picking up and 

 arranging diatoms and other minute objects," etc. 



To tliis stand he added a most important arrangement, without which no 

 microscope can be considered complete. This consisted in a swinging sub- 

 stage, which, while carrying an achromatic condenser or illuminating 

 apparatus, held a mirror which swung around a pivot placed beliind the 



PKOC. AMER. PHILOS. SOC. XXXI. 142. 2 T. PRINTED JAN. 15, 1894. 



