ZOOLOG-Y AND E0TA2TY, MICEOSCOPY, ETC. 



293 



EJ://<il^ 



adjustment. It is to this fine-adjustment that the instrument owes its 

 origin. The moment Mr. CampheU explained to me the principle of his 

 fine-adjustment, I foresaw the construction of an efficient sfcodent^s Micro- 

 scope. The direct-acting screw is only suitable for low powers and small 

 apertures. I will put it 



even stronger : delicate Fig. 41. 



work with high powers 

 and wide apertures is 

 not possible with any 

 Microscope having a 

 direct-acting screw fine- 

 adjustment. 



The stage is of the 

 cut horseshoe form. . . . 

 The principal object of 

 it is to enable you to 

 feel your working dis- 

 tance. Let me point 

 out a great improve- 

 ment in the sliding bar. 

 Its guiding lugs are 

 stowed away underneath 

 the stage ; I have no 

 hesitation in saying 

 that next to a perfect 

 mechanical stage this is 

 the best. Most of the 

 mechanical stages are 

 so defective in design, 

 and so scamped in their workmanship, as to be worse than useles?. 



The substage is fitted with a tube, having a spiral .slot for f.oo.sir.^. . . . 

 There is a novel feature about the stops for dark-gxoui-d illur:.::!.::."-,; ,;o, viz. 

 there is a three-legged carrier which holds them all. This carrio: .oas a 

 pin in the centre of it on which the various sized discs fit. T„o st r.-, 

 diaphragms, &c., have a separate tube-fitting for them, so that it is i:i.- 

 necessary to move your condenser when changing either a stop or a 

 diaphragm. This substage will carry either of Ir^f, Acbo s o:r.i.oivors. or 

 a cheap condenser made especially for this Microscope. Ti.e 'veigi-t of the 

 Microscope is 7 lbs. complete." 



The instrument is made by Mr. C. Baker, of High Holbom, and has 

 been brought out under the personal superintendence of JMr, 0. L. Corfcies. 

 Since the original issue, Mr. Baker has added to the completeness of the 

 design by the application of a rack and centering movements to the sub- 

 stage, and also Mayall's removable mechanical stage. 



Lindsay's Simple Microscope. — In the Journal for 1883, p. 708, we 

 reproduced from a German publication two figures of Lindsay's ^licroscope, 

 which we have since found were probably taken from the specification of 

 the patent granted to George Lindsay in 1742, the first patent known in 

 England relating to a Microscope. As the general design of the instrument 

 is not readily understood by inspection of those figures, we here give a 

 perspective view (fig. 42) of a highly finished model in silver by Lindsay, 

 which we met with in our recent visit to Italy. 



The optical arrangement consists {!) of a low-power lens provided 

 with a Lieberkiihn (one of the earliest applications of this device after its 



