PROCEEDINGS OF THE SOCIETY. 1087 



which a projecting fillet was cast, and which on being put together 

 allowed the arc to freely move between them, a brass set-screw 

 enabling it to be clamped rigidly in any desired position. In 

 this way the Microscope was well supported without any tendency 

 to tilt in any position. The next point was the fine adjustment, 

 which was made upon a plan which he believed was Mr. Zentmayer's, 

 but it was one wliich made it impossible for there to be any twist. 

 The third point was in having the draw tube so made as to take an 

 objective of much longer focus than usual; it was fitted with the 

 Society's screw, and would also take an amplifier if needed. 



The stage was simply a round plate of brass, but the method in 

 which the fork for holding the object was fitted to the stage gave it 

 almost the advantage of a revolving stage. The mode in which the 

 mirror was hung was also very satisfactory in a student's Microscope, 

 admitting as it did of being swung laterally in either direction, and 

 also — by means of a slide in the bar on which it was mounted — 

 of being moved up near to the objective so as to act as a condenser. 

 There was also an addition to the Microscope of great value, viz. an 

 iris diaphragm (see p. 1052) of very simple and ingenious construc- 

 tion (described and figured on the black board). 



Altogether the instrument was one which much pleased him, and he 

 had brought it under their notice in the hope that some of its points 

 might be taken up in this country, where the demand for efficient 

 student's Microscopes of good quality was becoming so great that it 

 would be worth while for any maker to bring out the best that could 

 be produced at a moderate cost. This Microscope could be supplied 

 in New York at about 71., but he thought it quite probable that it 

 might be made here for say IZ. less. 



The President expressed the thanks of the meeting to Dr. 

 Carpenter for his explanation. 



Dr. Edmunds pointed out that this most useful microscope-stand 

 would be vastly improved if only the arc upon which the body turns 

 were so constructed tliat the centre of the circle of which the arc 

 forms part wore made to coincide in position with the centre of the 

 stage. The object then would undergo no movement of translation, 

 either in rotating the stage or in turning the optical tube from the 

 vertical to the horizontal. In rotating the stage, the object would 

 turn upon the optic axis ; in moving the tube into various degrees 

 of oblicpiity from 0" to 90", the object would rotate upon its horizontal 

 axis. The result would be that, with a thin stage and a hemi- 

 spherical lens in immersion contact with the under surface of the slide, 

 all the complicated swinging substagcs ami other contrivances now 

 upon the table might be swept away, and every angle of illumination 

 c«)\ild be got by merely inclining tlie bo<ly of the Microscope upon its 

 sustaining arc. There wouhl only bo needed a lamp on a level with 

 the object with a condenser at its focal distance standing upon the 

 table in line between the lamp and the object. 



Dr. Carpenter said that another improvement had also occurred 

 to liini, and that was to construct tlie fork so that it would carry 

 round the object iu the axis of the Microscope. It did not do so as 



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