OOl 



NOTES. 



The Microscopes of Powell, Boss, and Smith. 

 By Edward M. Nelson. 



III. — JAMES SMITH AND HIS MICROSCOPES. 



When Mr. Joseph J. Lister gave the order to Mr. W. Tulley, the 

 celebrated telescope maker of Islington, for a Microscope to be made 

 according to his own working drawings, Mr. Tulley put it into the 

 hands of James Smith, a very expert philosophical instrument maker, 

 to execute. James Smith finished this Microscope on May 30th, 1826, 

 and therefore was the maker of the first achromatic Microscope in 

 this country. The object-glass for this Microscope was said to have 

 been made by Mr. Lister himself, a statement which is highly pro- 

 bable, as he practised lens-grinding so that he might be able to test 

 his own formulae. 



This Microscope, seen in fig. 146, has a draw-tube into which 

 the eye-piece was screwed; at the lower end of the draw-tube an 

 erector could be fitted ; rectangular movements were given to the 

 stag'e by means of the pinion heads shown in the fig., one being placed 

 in a vertical position. A substage is provided, and we are told that 

 a compound condenser was fitted to it ; it would be very interest- 

 ing to know the form of this compound condenser, because the 

 condensers of all previous Microscopes were very crude, being for the 

 most part composed of a single biconvex lens. The steadying rods 

 were of course suggested by the telescope mounts of that day, but the 

 folding tripod foot, which was the usual form for Microscopes at that 

 time, cannot now be commended. This Microscope differs from all 

 those immediately preceding it in one essential point, viz. that it is 

 solely a compound Microscope, whereas all Microscopes of that time 

 and for upwards of fifteen years afterwards, were both simple and 

 compound, or in the phraseology of that day, single and double. 

 Very old models, such as John Marshall's (1704), Culpeper's (1738), 

 Cuff's (1744), were solely compound Microscopes ; but those of 

 Benjamin Martin, Adams, Jones, Pritchard, Powell, and of Eoss even 

 as late as 1843, were both simple and compound ; so in this respect 

 this Microscope appears in strong contrast to those of its time. The 

 solid limb, which clearly predated those both of Eoss and Jackson, 

 was quite an original idea. 



About 1840 James Smith commenced business on his own account 

 at 50 Ironmonger Eow, Old Street, E.C., and here he made the first 

 Microscope, with his own name attached to it, for Mr. R. L. Beck ; this 

 Microscope (fig. 147) was finished on May 29th, 1839. This instru- 



