MEMORANDA. 199 



forms of stand, each instrument difiering not only in 

 size, but in construction also. The greatest novelty exhibited 

 by them, is what is termed a museum microscope, and 

 which might also be named a monster microscope. This 

 extraordinary instrument consists of a large brass cylinder, 

 with a microscope body seated on it ; and in the interior of 

 the large cylinder are eight others, upon which are fixed, 

 in all, 504 objects, each cylinder being devoted to a special 

 class of objects. By simply turning a nut at one end of the 

 outer cylinder, each of the objects in the series to which 

 it belongs is successively brought into the field of view, whilst 

 at the same time, its name appears on a small label. By 

 very simple means the position of the internal cylinders can 

 be changed; and thus, in succession, all the objects may, one 

 after another, be brought into view. The object sought in 

 the construction of this machine is to afford an easy means 

 of exhibiting, to numerous persons, microscopic objects in 

 museums, lecture-rooms, &c. ; and it is constructed in such 

 a substantial manner, and, at the same time, is so easy of 

 employment, that it is not liable to injury by the uninformed 

 observer, like a common microscope. 



Among the minor novelties exhibited by Messrs. Smith and 

 Beck, is an ingenious little apparatus for the support of 

 objects under the simple microscope or when viewed as opaque 

 objects in the compound, and by means of which any part of 

 the object can be turned into view with the utmost ease.^ 



In the other stands Ave do not notice anything of striking 

 novelty, though in all it is pleasing to remark the general 

 excellence of workmanship, and ingenuity of contrivance. 

 Mr. Baker has a good display of instruments of various kinds, 

 and in one Ave notice a very neat mode of supporting three 

 different objectives on a circular plate, a mode which seems 

 more compact, at any rate, than that usually adopted by means 

 of one or more arms. 



But there is one feature more in which the present Exhibi- 

 tion shows a considerable advance over the former one, viz., 

 in the numerous specimens of microscopes of a cheaper form 

 than the splendid instruments Ave have above referred to. 

 Nothing shows so strongly the increased popularity of micro- 

 scopic pursuits than the earnest efforts made by almost every 

 optician to produce an instrument capable, from its price, of 

 being brought Avithin the reach of the great mass of the people. 

 Among the more conspicuous of those Avho have striven for 

 this useful object, it is needless to refer again to Messrs. Smith 



* A description of this useful little instrument is given in the ' Trans. 

 Mic. Soe.' in the present number. 



