INVEETEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 1061 



difficult objects. In 1862 I adapted a semicircular arc carrying a 

 condenser, and afterwards I constructed gimbals to carry an achro- 

 matic condenser at any angle of obliquity, attached to a double- 

 motion stage placed exactly beneath the upper stage movements : by 

 this contrivance particular angles of illumination could be readily 

 attained \vithout the excessive aberration of the usual wide-angled 

 achromatic condenser. The instrument is exhibited in the South 

 Kensington Museum Collection, No. 3551 — described as follows : — 

 ' 3551. Microscope with complex adjustments, searcher, and oblique 

 condenser apparatus. This Microscope is fitted with a peculiar 

 hypocycloidal movement and traversing screws for very delicate 

 observations. The condenser possesses wide rectangular movements 

 combined with a unique oscillatory oblique action for directing the 

 minute image of a flame or of the sun either directly or obliquely 

 upon any desired point in the field of view, giving fine views of 

 many difficult objects ' " 



ToUes' "Radial Arm" and "Circular Track" Microscopes. — 

 Our information in regard to these Microscopes is derived from 

 certain sworn depositions which have been forwarded to us, and 

 which we print verbatim. 



" Invention of Sicinging Suhstage. 

 Washington City, District of Columbia, ss. 



I, J. J. Wood WARD, a Surgeon in the United States Army, and a 

 resident of the city and district aforesaid, do hereby solemnly swear 

 that Mr. R. B. Tolles, of Boston, visited me at the Army Medical 

 Museum, Washington, District of Columbia, June 30, 1871 ; that he 

 had with him several objectives and a small Microscope-stand fitted 

 with a radial arm beneath the stage, carrying a condensing lens of 

 about one inch focal length, and so arranged that by deflecting the 

 arm, any degree of obliquity in the illumination could be obtained ; 

 and that I was so pleased with the contrivance that, November 8, 

 1872, having occasion to inquire of Mr. Tolles the price at which 

 he would make a large stand for the Museum, I made it a condi- 

 tion in a letter written on that day, that the stand should have a 

 ' radial arm to carry an inch condensing lens for oblique light.' 



J. J. Woodward, 



Surgeon U.S. Army. 



Sworn to and subscribed before mo this cightoonth day of Septem- 

 ber, A.D. 1880. 



LODIS SCHADE, 



Notary Public. 



I, Edward W. Mori.ey, of Hudson, in the State of Ohio, Professor 

 of Clutmistry and Toxicology in Cleveland CoUogo, and Professor of 

 Chemistry in Western Keservo Collogo, on oath depose and say that 

 on the Hcveuth or eighth day of August, 1872,1 was in Boston, in the 



