112 SUMMARY OF CURRENT RESEARCHES RELATING TO 



with the pillar support, so that when the Microscope is required to 

 be used much inclined the horse-shoe base can be turned round as 

 shown in the fig. This increases the stability of the Microscope, and 

 adds so little to the original cost that the makers of these inexpensive 

 forms may profitably adopt the suggestion. 



Mr. McLaren also uses a system of fine adjustment applied at 

 the nose-piece (shown in the fig.), consisting of a ring fitting in the 

 lower end of the body-tube, in which the nose-piece proper, carrying 

 the objective, is screwed by means of a very fine screw, 200 threads to 

 the inch. The focusing is effected by turning the nose-piece either 

 way, by which the objective is raised or depressed very slowly owing to 

 the fine pitch of the screw. By this system, which is also applied to 

 some old forms in our possession, the objective is made to rotate with 

 every movement of focusing, which cannot be commended. 



Sehieck's Revolver School and Drawing-room Microscope.— 

 Winter's and Harris's Revolver Microscopes. — F. W. Schieck has 

 just issued the Microscope shown in fig. 10 a and b, intended for 

 school and drawing-room demonstration. The peculiarities of the 

 instrument are fully set forth by Herr Schieck himself in the fol- 

 lowing statement (translated), which also includes some very original 

 directions for preparing objects : — 



" The management of a Microscope of the ordinary construction, 

 with fixed stage, movable tube, different eye-pieces, objectives, &c., 

 offers, in most cases, so many kinds of difficulties to the lay public, 

 especially to young students, in the inspection of the preparations 

 accompanying the Microscope, and in the adjustment of the image, 

 but especially in the self-preparation of objects, that this important 

 and interesting instrument has not yet attained that position either 

 among our intelligent youth, or in our drawing-rooms, as an object 

 of instructive entertainment, which befits its high ethical importance. 

 The management of the Microscope has even been found so intricate, 

 that in consequence (as I have had the opportunity of seeing on 

 numberless occasions) it has been very soon put aside again, after a 

 short trial. 



My new Microscope entirely removes this disadvantage. It is 

 of such simple construction, and its management so thoroughly easy, 

 that any one, even without any previous acquaintance with the use of 

 a Microscope, is able to observe with it, as well as to make for himself 

 beautiful microscopical preparations. 



The new Eevolver Microscope has, instead of a stage, a vertical 

 drum, turning on its axis (like the chambers of a revolver), in which 

 twenty different very beautiful and instructive preparations, from the 

 three natural kingdoms, are arranged, which, on turning the drum, 

 are brought successively into the field of view of the Microscope. 

 The movable mirror is in the centre of the drum, and is easily and 

 conveniently adjusted. 



The Microscope is provided with a hinge for inclining the 

 stand, so as to be able to observe conveniently whilst sitting. 



The twenty preparations are numbered, and an explanation of 

 them accompanies each Microscope. 



