CONSTRUCTION OF THE MICROSCOPE. 65 



Microscope. he Objectives supplied with it are of great excellence and 

 very moderate cost, and are quite adequate for all the ordinary purposes 

 of scientific investigation. 



62. Browning's Rotating Microscope. The peculiarity of this instru- 

 ment is that, as in many of the Continental models, the object-platform 

 (B), with the limb carrying the body above it, revolves together; whilst 

 the lower plate of the stage (c), with any apparatus fitted into it, as like- 

 wise the mirror, remains fixed. Thus the object is enabled to receive 

 illumination in every azimuth without any derangement either in its cen- 

 tering, or in its focal adjustment. The body is supported, as in the Jack- 

 son model, upon a limb, A, which is firjnly fixed to the rotating plate B of 

 the stage. In the simplest form of the instrument, shown in the figure, 

 the rotation is effected by pressing a finger on the projecting pins attached 

 to B; but if required, B can be made to move by a pinion and toothed 

 wheel, with graduated scale attached; and a sub-stage for carrying illumi- 

 nating apparatus can be fixed to an arm below c. This Microscope is fur- 

 ther characterized by the solidity of its several parts, and the care taken in 

 its construction to secure it against derangement from an accidental strain. 

 It is particularly adapted to the use of those who work with high powers 

 upon objects requiring the varied illumination for which this rotating 

 arrangement gives special facilities. 



63. CroucJi's Student's Binocular. This instrument (Plate in.) was 

 devised at a time when the construction of the Binocular was still almost 

 exclusively confined to the makers of First-class instruments; and it had 

 the great merit of bringing within reach of the Student a convenient and 

 well-constructed Binocular, at a moderate cost. "With the improvements 

 it has since received, it still remains one of the best instruments of its 

 class; and the Author, after considerable use of it, can strongly recom- 

 mend it to such as desire to possess a Binocular at once cheap, good, and 

 portable. Its general arrangement is shown in Plate in. , but a mechani- 

 cal stage can be substituted, if desired. The rotating stage and object- 

 holder resemble those of MM. Nachet's Microscope (Fig. 45). An Achro- 

 matic Condenser, Paraboloid, Polarizing apparatus, etc., can be added to 

 this instrument; or it may be fitted with Mr. Crouch's ' Universal Sub- 

 stage Illuminator,' which, like that of Mr. Swift (Fig. 85), combines 

 the different Accessories ordinarily required for the examination of trans- 

 parent objects. ' 



64. Baker's Student's Erecting Binocular. With a special view to 

 the wants of Students in various departments of Biology, Messrs. Baker 

 have adapted a Stephenson Binocular ( 35) to the stand of their 

 Student's Microscope, as shown in Fig. 47; with which the stand of 

 their Laboratory Dissecting Microscope (Fig. 35) may be so combined as 

 to afford the requisite support to the hands, when they are engaged in 

 dissecting (or otherwise manipulating) objects on the stage of the Binocu- 

 lar. An ordinary Monocular body may be readily substituted for the 

 Binocular; and the same Eye-pieces and Objectives serve for both. The 

 low cost at which this instrument is made, will doubtless cause many to 

 possess themselves of it, whose pursuits will be specially facilitated by its 



1 The price of this instrument, with one pair of Eye-pieces, two Objectives (a 

 best 1-inch and a l-4th of 110), and a Condenser for opaque objects, in case, is 

 12 15s. Od. 



2 The price of this Binocular, with one pair of Eye-pieces, a dividing Objective 

 of 1 inch and 2 inches, and a l-4th inch of 70, in Case, is 10 guineas. 

 5 



