* 366 Tue MIcroscopr. 
NOTES ON THE MICROSCOPE STAND AND SOME OF 
ITS ACCESSORIES. 
AN AMATEUR. 
IN. 
THE STAGE. 
HE form of the stage, whether circular, square, or oblong, 
matters little, provided it is large enough. A stage barely 
of sufficient width to receive the slide, or even smaller, as I have 
actually seen, is not desirable. The microscopist never feels 
comfortable while manipulating the slide, if he is restricted in 
the freedom of his movements by a small stage. Neither is the 
material from which it is formed of great importance, although 
there is really not much margin for choice or criticism, since the 
material is either brass or glass, or a combination of both. If 
the stage is firm, steady, strong and large, it may be of almost 
any form, or of any material that will supply these essentials. 
For advanced work there are advantages in circular stages, 
since they are capable of a complete rotation so as to change 
the position of the object in relation to the light, instead of a 
change in the position of the mirror, since it is often necessary to 
examine the object under varying conditions and directions of 
the illumination. A rotating stage is therefore a convenience, 
since, on first class stands, it may he accurately centred by 
certain appliances supplied to the instrument by the maker, and 
the object may then be rotated with the stage, and kept at or 
near the centre of the field of view. This centring of the stage 
is important when it is to be rotated under an objective of high 
power, where the field is small, and the difficulty of retaining 
a rotating object within it is correspondingly great, <A few of 
the cheaper stands have rotating stages, but in order that this 
accessory shall be ‘satisfactory, the workmanship must be good, 
and the stage should be supplied with the means for centring, as 
after a few rotations, the accuracy is lost and the wabbling be- 
gins. If the stage can not be centred at the beginning of this 
kind of work, it will rotate, but it will also rotate the object out 
of the field. No stand, however, should be rejected because it 
has a stage that will not rotate. A circular rotating stage is not 
a necessity, but is a desirable luxury. 
The margin of the circular stage on the best stands is bevelled, 
