794 



SUMMARY OP CURRENT RESEARCHES RELATINQ TO 



Fio. 122. 



Microscope, which is stated to bo 12 in. high, stage 4 in. by 4 in., 

 " woifht 2'} kilo." The tail-jncce attached to the under side of the 

 6ta"e turns on an axis projecting hiterally from the standard, the latter 

 having a diagonal stop-piece at the bottom, against which the end of 

 the tail-piece, which is sloped off as shown in the fig., abuts when the 

 instrument is upright. 



Schieck's Travelling Microscope. — We are reminded that Herr 

 Schieck some years ago brought out the Microscope shown in fig. 122, 



which anticipates those of Dr. Zeiss 

 described ante, p. G37, inasmuch as the 

 prolongation of the stem beneath the 

 stage slides in a socket on the base, and 

 can be clamped at any i>oint. 



The object of this device was stated 

 to be to enable the instrument to go 

 into a case of reduced dimensions for 

 travelling. 



Zeiss's Ila Microscope— Babuchin's 

 Microscope. — In the description of these 

 Microscopes, ante, p. 637, wo should 

 have exjjlained that by moans of the 

 screw at the back of the limb, the fine- 

 adjustment can be thrown out of gear 

 when travelling, thus preventing tho 

 point of tho micrometer-screw from 

 getting damaged. 



Leitz's Demonstration Microscope- 

 Old Demonstration Microscope. — The 

 design of this Microscope sufficiently 

 appears from fig. 123. The form of the 

 frame in which the body-tube socket 

 screws, is devised to enable it to be held 

 in the hand and passed round for class 

 demonstration (tho object being viewed 

 by transmitted light), and at the same 

 time to allow of its being rested on the table when not in use. 



We are forcibly reminded by this Microscope of the tendency to the 

 repetition — with more or less modifications — of antique forms. On page 

 109 we reproduced a figure from the ' Acta Eruditorum ' (1686), illus- 

 trating the employment of Campani's C()mi)ound Microscope on opaque 

 and transparent objects, and it is evident that Leitz's Demonstration 

 Microscope might bo substituted for Campani's, the difference of form 

 being only a simplification certainly not suggestive of an interval of 

 upwards of two centuries in their ctmstruction. 



Fig. 124 shows what appears to have been a Demonstration Microscope 

 of the last century. It is constructed of wood and cardboard, and is 

 apparently a modification of Culpeper and Scarlet's IMicroscope figured 

 in Dr. Robert Smith's ' Opticks ' (Cambridge, 1738, 2 vols. 4to.). The 

 body-tube slides in a socket for focusing, and has a draw-tube in which 

 the lenses of a Huyghenian eye-piece are applied respectively above and 

 below, the draw-tube serving not only to increase the amplification, but 

 also (probably) as a means of focusing the image more accurately, as in 

 some of the modern " miniature " Microscopes. Mounted transparent 



