1881.] 



MICROSCOPICAL JOURNAL. 



29 



Supplementary Note to the 

 Notice of " Riddeirs Bin- 

 ocular Microscopes." * 



BY SURGEON J. J. WOODWARD, 

 Bvt. Lt. Colonel, U. S. Army. 



I have just received from my 

 friend, Mr. John Mayall, Jr., a note 

 calling my attention to a partial ac- 

 knowledgment of the priority of Rid- 

 dell made by Mr. J. W. Stephenson 

 in a communication to the Royal 

 Microscopical Society, June 4th, 1873. 



I regret very much that this ac- 

 knowledgment should have entirely 

 escaped my notice, and hasten to 

 give it equal publicity with my pa- 

 per. (This Journal, Dec, 1880, p. 

 228.) It will be found in the Report 

 of the Proceedings of the Royal Mi- 

 croscopical Society for June 4th, 1873 

 ( The Monthly Microscopical Journal 

 Vol. X, 1873, p. 41) in the following 

 words : " Mr. J. W. Stephenson said 

 he took the present opportunity of 

 stating that, to his surprise, he found 

 that the mode of dividing the cone 

 of light in his erecting binocular 

 microscope by means of two prisms 

 was used by Professor Riddell, of 

 New Orleans, in the year 1853, in 

 his form of binocular. The arrange- 

 ment of that instrument differed 

 from his own in the following res- 

 pect, e/Zz. .• that his (Mr. Stephenson's) 

 prisms were so placed that, com- 

 bined with the reflecting plate above 

 they acted as an erecting instrument, 

 and by entering into the cell of the 

 object-glass could be used for high 

 powers whenever required ; whilst 

 those of Professor Riddell were 

 placed above the object-glass simply 

 to produce binocular effect. He 

 had only just heard of this through 

 the kindness of Mr. Frank Crisp, 

 and he took the earliest opportunity 

 of notifying it to the Fellows of the 

 Society." 



But while hastening to give due 

 credit to Mr. Stephenson for this ac- 

 knowledgment, I cannot but express 



* See this Journal, December, 1880, Vol. 

 I, p. 221. 



my surprise that, so late as 1875, Dr. 

 Carpenter, in the work cited in my 

 paper, should have continued to give 

 the credit of Riddell's invention to 

 Mr. Stephenson ; nor am I less sur- 

 prised that the latter gentleman, after 

 his attention had been called to Rid- 

 dell's invention by Mr. Crisp, should 

 have studied it so imperfectly as to 

 have overlooked the upper prisms, by 

 which Riddell's microscope also 

 " acted as an erecting instrument " so 

 many years before. The arrange- 

 ment of Mr. Stephenson by which his 

 prism " entering into the cell of the 

 object-glass could be used for high 

 powers whenever required," is, as I 

 pointed out in my paper, a real im- 

 provement on Riddell's instrument, 

 for which I have already given Mr. 

 Stephenson full credit. 

 Army Medical Museum. 

 January i8th, 1881. 



Riddell's Binoculars. 



A LETTER FROM MR. J. W. STEPHENSON. 



I have read with much interest 

 Colonel Woodward's historical notice 

 of Riddell's Binocular Microscope, 

 which appears in the December num- 

 ber of your Journal, but at the same 

 time I am not a little surprised that 

 he has supposed it to be necessary 

 now to make an appeal to me, to 

 " hasten to accord full credit to Pro- 

 fessor Riddell " inasmuch as the Pro- 

 ceedings of the Society of which he 

 is an Honorary Fellow (The Royal 

 Microscopical Society), record that I 

 did so nearly eight years ago. The 

 matter is thus reported in the Monthly 

 Microscopical Journal, Vol. X (1873), 

 p. 41 : " Mr. J. W. Stephenson said 

 he took the present opportunity of 

 stating that, to his surprise, he found 

 that the mode of dividing the cone 

 of light in his erecting binocular 

 microscope by means of two prisms 

 was used by Professor Riddell, of 

 New Orleans, in the year 1853, in 

 his form of binocular. 



The arrangement of that instru- 

 ment differed from his own in the 



