284 SUMMARY or CURRENT RESEARCHES RELATING TO 



little outlay in the matter of accurate bearings. It was, however, 

 abandoned in favour of the usual Jackson slides and rack. 



Another feature in the design of the stand, which we have found 

 convenient in practice, was the greater bend of the limb than usual, 

 by which the space above the stage was left free for manipulations 

 with either hand. This latter feature has been maintained in all the 

 later models of Microscopes issued by Mr. Tolles. 



Winter's, Harris's, or Rubergall's Revolver Microscopes.— Mr. 



Harris of Great Eussell Street, W.O., informs us that Thomas Winter 

 was the " first and true inventor " of these instruments (described 

 ante, pp 114-5) more than 56 years ago, when Mr. Harris inherited 

 the business. 



The one described as a simple Microscope bears the name of 

 " T. Winter, No. 9, New Bond Street, London," while that figured at 

 page 115 has, it appears, engraved on the cross arm carrying the 

 body-tube, "Thomas Eubergall, Optician to H.E.H. the Duke of 

 Clarence, 24, Coventry Street, London." Winter worked for Mr. 

 Harris, and sold the first model to him (the simple form mentioned 

 ante, pp. 114-5). Later Winter made some for Eubergall, probably 

 the compound one (fig. 11). He also made some much smaller ones, 

 which were sold for a few shillings. 



Geneva Go's. Nose-piece Adapters. — This (fig. 33) consists of two 

 pieces of brass hinged together at the back. The upper is immovably 

 attached to the nose-piece of the Microscope ; the lower terminates in 

 a fork, which lies just under the nose-piece. The two plates are kept 

 together by a set-screw, acting on a spiral spring, which can be 

 tightened or loosened as required. The objectives are screwed to the 

 collar shown in the fig., which slides in the fork. When the 

 objective is centered with the optic axis, a slight projecting rim on the 

 upper plate drops into the aperture of the adapter ; the objective is 

 then held fast, but is readily removed on applying a moderate down- 

 ward pressure, which depresses the forked plate 

 Fig. 33. and enables the collar to be slipped out. By 



the set-screw the amount of pressure required 

 to be applied can be varied. 



The above form is a fixture on the Micro- 

 scope, but the Company make another which is 

 removable. It does not appear, however, to 

 diflfer in principle from the nose-pieces of Nachet 

 and Verick (see this Journal, i. (1881) pp. 

 661-2). 



The advantages of such arrangements are 

 explained by the Geneva Company to be (1) 

 economy of time, (2) " a mechanical centering 

 of the objective much more perfect than can be 

 obtained with a screw, the defects of the centering being immediately 

 recognized can be partly corrected, and (3) we can readily choose 

 the side of the objective which gives the best images, when oblique 

 illumination is used." 



