NEW STAGE FOE THE MICEOSCOPE. 277 



NEW TRAVERSING STAGE FOR THE MICROSCOPE. 



BY PATEICK PEEELAND, 



REGISTRAR, TORONTO UNIVERSITY. 



Head before tlie Canadian Institute, 21st February, 1857. 



The high position now occupied by the microscope, both as an 

 instrument of scientific research and as a means of obtaining use- 

 ful recreation, as well as the great attention given to it, in order to 

 bring it as near as possible to perfection, render unnecessary any 

 apology from me in bringing under the notice of the Canadian 

 Institute what I conceive to be an improvement in the construction 

 of the stage, or the apparatus used for holding the object while 

 under examination, and for moving it about so as to bring at 

 pleasure any portion of it into the centre of the field of view. The 

 importance of being able to move the stage plate of the microscope 

 in every direction easily and with precision, is well known to every 

 inicroscopist, and many methods of doing so, each having its own 

 peculiar merits or delects, have been adopted. 



In 1831, Mr. Cornelius Varley constructed the first microscope 

 with a lever stage movement, for which he subsequently received the 

 gold Isis medal, awarded to him by the Society of Arts of London. — 

 But the application of the lever in Mr- Varley's microscope was 

 soon found to be objectionable, its fulcrum was attached to the 

 stage itself, and the lever projected downwards under it. thus 

 removing the hand to a considerable distance from the focus adjust- 

 u ent, while the whole arrangement was complicated. It was how- 

 ever, subsequently much improved by Mr. Alfred White, who 

 simplified very much the whole stage movement, and entirely dis- 

 pensed with a great deal of what encumbered Mr. Varley's. Instead 

 of having it below the stage, Mr. White brought the lever above, 

 and placed its fulcrum on a stout arm projecting from the upright 

 which carried the compound body ; and in this form the lever stage 

 is still mostly used — this stage is described by Mr. White in the 

 first volume of the Transactions of the Microscopical Society. It 

 consists like almost all traversing stages, of three plates of brass laid 

 one above the other, the lowest one being fixed and the other two 

 provided with dovetailed guides and slides, so that each may be 



