220 



MICROSCOPE. 



single Mi- i s moveable along these wires by two little sockets fix- 



cioecopes. e( j to j t _ -p| le two U pp er p] a tes contain each a magni- 



"V"'' fying lens of different focal lengths, one of which keeps 



in their places the sharp point F, the small knife K, and 



the pliers P. 



Before using this microscope, we must unscrew the 

 upper lens and take out the point, the knife, and the 

 pliers; and having replaced the lens by screwing it on 

 again, the object is placed on the stage, and moved up 

 or down till it is seen distinctly. 



IV. Pocket Botanical and Universal Microscope. 



Pocket bo- This instrument, which is superior to Dr. Wither- 

 tanical and ing's, is represented in Fig. 15. A small arm AB car- 

 universal ries three lenses, two of which are fixed to the upper 

 niicrwcope. part at Bj allc j t h e ot her to the lower part at C ; and as 

 these three lenses may be either used separately or 

 combined, they afford us seven different magnifying 

 powers. A square pillar AK supports the arm AB. The 

 lower end of this pillar fits into the socket E of the base 

 FG. The stage DL, carrying the pliers M and a sharp 

 point N, constructed as formerly described, is made to 

 slide up and down the pillar IK. A reflecting mirror 

 H, moving round a horizontal and vertical axis, is fixed 

 into the base FG.. and reflects light through the object. 

 In using this microscope, the objects are placed on the 

 stage L : or, if they are put into ivory sliders, these 

 sliders pass under the stage L. The light is then 

 thrown upon the object by the mirror H, and distinct 

 vision obtained by the motion of the stage. Other ob- 

 ject ; may be fixed in the pliers M, N, and used as al- 

 ready described. 



The apparatus accompanying this instrument, con- 

 sists of three ivory sliders, a pair of nippers, a fiat glass, 

 and a concave lens, all of which are fitted to the stage 

 L. By taking out the pin E, the pillar IK may be turn- 

 ed half round, and the base FG used as a handle. The 

 stage DL, instead of being moved by the hand, is fre- 

 quently raised end depressed by an adjusting screw. 



V. Lyonet's Anatomical Microscope. 



Lyonet's The microscope represented in Fig. 16, was employ- 

 anatomical ed by M. Lyonet in his microscopical dissection of the 

 micro- caterpillar of the goat moth. It consists of an anatomi- 

 J5 01 ' e j B cal table AB, supported by a pillar ON, screwed into 

 the mahogany box DC. In the table AB, which is 

 prevented from turning round by two steady pins, is 

 an aperture G exactly over the mirror EF, for reflect- 

 ing light on the object. A fiat or concave glass is pla- 

 ced on the aperture G, for receiving the objects to he 

 dissected. An arm RXZ, composed of several balls 

 and sockets, by which it has an universal motion, is fix- 

 ed to the table AB by means of the screw H. The last 

 arm IZ carries a female screw for receiving a magnify- 

 ing lens, as shewn at Z. The lens is generally adjust- 

 ed to distinct vision of the object by the hand, though 

 a small motion may be given to it by the screw at H. 

 Another chain of balls and sockets is sometimes used 

 for holding an illuminating lens. The mirror EF can 

 also be taken from its place at K, and fixed by a clamp 

 to any part of the table AB. 



In using the dissecting table, the instrument should 

 stand upon a firm table, the left side of the observer 

 being near a light window, and the side DL towards 

 his breast. The observations should be made with the 

 left eye ; and in dissecting, the two elbows should be 

 supported on the table which holds the microscope, the 



hands resting against the board AB, to give it greater Single Mi- 

 steadiness. See Lyonet's Traitc Analomique de In Che- ""scopes. 

 niUe, fc. ""^ 



VI. Wilsoti's Pocket Microscope. 



The microscope invented by Mr. Wilson has been Wilson's 

 long in use. The body of it is represented by AB, P ock ct 

 Fig. 17. and is made either of brass, silver, or ivory. clo ^pe. 

 Another tube, with a long fine-threaded small screw 

 upon its circumference, screws unto the body AB. A 

 convex lens D is screwed into the end of the tube CC, 

 and its area may be increased or diminished by placing 

 upon it one or other of the two concave apertures of 

 thin brass, which are necessary when the highest mag- 

 nifiers are employed. Two thin plates of brass are 

 shewn at E, within the body of the microscope ; and 

 one of them is bent into an arched or semicylindrical 

 cavity, shewn in the figure, for the purpose of receiving 

 a tube of glass. At the eye- end G of the microscope 

 is a female screw for receiving the different magnifiers. 

 A spiral steel spring H, abutting with one extremity 

 against the end G and with the other against the plate 

 of brass E, serves to keep the plates in a proper position, 

 and to act against the long screw C. The microscope is 

 held by the ivory handle I. Seven different magni- 

 fying glasses, six of which are set in cells, as shewn at 

 K, are numbered from 1 to 6, the least numbers being 

 the highest magnifiers. The seventh, cr least magni- 

 fier, is set in a small tube, in order that it may be held 

 in the hand for viewing any large object. The objects 

 are held in an ivory slider M. Six sliders like this of 

 ivory, and one of brass, generally accompanying the 

 instrument. A brass slider, not represented in the fi- 

 gure, is sometimes added, for the purpose of confining 

 any small object, in order that it may be examined 

 without being crushed. A pair of forceps and a hair- 

 brush are used, as shewn at R and Q, Fig. 13. A glass 

 tube, for holding living objects, such as frogs, fishes, 

 &c. is shewn at P. 



In order to use this microscope, the slider containing 

 the object is thrust between the two flat brass plates 

 EF, care being taken to put the face of the slider where 

 the brass rings are farthest from the eye. The magni- 

 fying glass intended for use must then be screwed on 

 at G ; and while the eye looks through it against the 

 sky, or the light employed, the long screw CC is turned 

 till the objects in the slider are brought into the ante- 

 rior focus of the lens, when a distinct view of them 

 will be obtained. By moving the sliders between 

 the plates at E, different parts of the same object may 

 be brought into view, or different objects in the slider ; 

 but at every motion of the slider, vision should be made 

 distinct by a new adjustment with the screw. 



This instrument is sometimes placed upon a stand, Application 

 with a reflecting mirror, as shewn *n Fig. 15. In or- of jt to 

 der to see opaque objects with it in this case, an arm pP'^" 6 ob - 

 QR, Fig. 17. is screwed into the body of the microscope jec 

 at G. The proper magnifier is next screwed into the hole 

 at R, and putting the concave speculum S on the outside 

 of the ring R, the object is held upon the forceps, or 

 point of T, whose wire slips into a small hole, shewn 

 at u, in the body of the microscrope. The arm 11 is 

 then turned till the magnifier is brought over the ob- 

 ject, and distinct vision is obtained by turning the screw 

 C as formerly. 



VII. Ellis' s Aquatic Microscope. ^J^ 

 This microscope differs from the one shewn in Fig. microscope. 



