INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 1063 



Microscope.* This arm was hinged to have its axis of rotation as 

 nearly in a line passing through the object place on the stage as was 

 conveniently practicable. The stage having mechanical movements 

 was of considerable thickness and the axis of the arm was therefore 

 fixed at a point about three-fourths of an inch below the place of the 

 object. The arm swung over an arc of a circle graduated to read 

 angles of obliquity of the arm, and the condenser had an independent 

 motion of its own so that its axis could always be brought to coincide 

 with a line passing through the object on the stage. That at this time 

 and for an indefinite period before, I had known of such an arrange- 

 ment of swinging arm on a Microscope used by Mr. Tolles particu- 

 larly for trial and testing of objectives. In this case the whole 

 arrangement could be attached to the main arm of the Microscope 

 and detached readily. The axis of motion of the arm was under the 

 stage, but the whole apparatus had adjustment laterally (or sidewise) 

 so that the swinging arm could bo brought into line with any radius 

 of the object as a centre through a considerable range of obliquities. 

 That in the summer of 1875, I, by Mr. Tolles' direction constructed 

 and adapted to a Microscope-stand of his class B, numbered [ ] 



and now belonging to Dr. J. Bacon of this city a cirrular track as a 

 substitute for a radial arm. That this circular track having its centre 

 coincident with the object place on the stage involved no change in the 

 model or construction of the B stand, whereas the incorporation of a 

 radial arm required considerable change ; and I desire to distinctly 

 state that the circular track was adopted for that instrument instead of 

 the swinging radial arm to avoid such change and reconstruction. 



I have also to state that during the period named, from 1871 to 

 1875, the plan as an invention of Mr. Tolles of a swinging radial 

 arm for condenser, and other accessories of a Microscope having its 

 axis of motion in the object or object-place on the stage was 

 familiarly known and talked of in the shop where his Microscopes 

 were made. Orlando Ames. 



Witness, F. L. Hates. 



Suffolk, ss. Boston, March 19, 1878. 



There personally appeared the above named Orlando Ames and 

 made oath that the foregoing statement, by him subscribed, is true. 

 Before me, Francis L. Hates, 



Justice of the Peace." 



In July 1875, Mr. Tolles made and sold the instrument described 

 in the following sjtecification for a patent (the application for which 

 was filed in July 1877 1) : — 



• Note. 



"TOLI.ES" LAIiOEST MICROSCOPE. 



******* Can bo furnished with radial arm 

 to carry accessory apparatus at any angle for $50." 



— C. St'Kldir's Price I-ist for 1S72, jjaj^e •'>. 

 t AcconlinR to tlio U.S. Patent Law, an invintor haa two yours njUr the lirst 

 instrument is sold in wliirh tu apj)ly for a patint. 



