78 Sir George Shuckburgh's Account 
mentioned is inclosed by a circular frame, or rail of mahogany, 
14, 15, which is supported by ten balusters, 16, 17, 18, 19, 20, 
si, 22, 23, 24, 25, and serves to protect the brass circle from 
any accidental injury in passing by it, without depriving it of ex- 
posure to the general temperature of the room. It, at the same 
time, affords means of support to a small lamp, 13, which, by 
reflection from the perforated speculum at the bottom of the 
microscopes, to be seen in that marked X, throws light upon 
the divisions by night. 2 6, 26, and 27, are iron rods, that, by 
being attached to the wooden case, 9, 10, give steadiness to the 
upright balusters, and the circular frame that they support. 
1, and 2, are large stout brass cones, firmly fixed into the frame 
3, 4> 5 > 6, 7> 8, before mentioned, and whose use is to carry the 
microscopes W, X ; any degree of pliancy or flexure in these 
cones would be readily discernible in the microscopes, and 
extremely detrimental to the observations, they are therefore 
made as stiff as possible, y, is a plane forming the upper 
side of the frame 3, 4, 5, 6, &c. and consisting of 3 plates, 
two moveable in grooves, and one fixed, furnished with suit- 
able screws, one giving the extremity of the axis a motion 
upward or downward, and the other a motion to the right or 
left : this latter is procured by a rod passing through the cone 
2, one end screwing into the plate below L, near the centre, 
and the other turned by an occasional handle fixed on 
near X ; the former motion, viz. of elevating or depressing 
the axis, is procured by a handle fixed on to a screw near e, 
QR is another circle, of the same dimensions with the former, 
graduated in the same manner, and held together by eight 
conical radii, firmly screwed to a circular centre piece, which 
serves as a base to a large conical axis, 2 feet 3 inches long, 
