MICROSCOPES OF THE FOUKTH CLASS 



233 



is presented, on a small scale, in fig. 186. It is admirably made, 

 and provides all that is required in coarse and fine adjustments ; 

 it is also provided with admirable sub-stage arrangements, and is 

 placed on a stand that, while it is of horseshoe pattern, has the 

 hind ' toe ' lengthened considerably, and is made so that the foot 

 can reverse as in the illustration, and lock, thus making a perfect 

 balance for the body, however it may be inclined. This admirably 

 made instrument is considerably under 51. in cost. 



Beck's ' British Student's ' microscope is of this class, as is also the 

 ' Star ' microscope by the same makers. The former has a firmly made 

 tripod, as fig. 187, representing this instrument, shows. It has a 

 spiral rack and pinion coarse adjustment, a fine-adjustment, a draw- 

 tube with mm. scale, and a focussing sub-stage which swings out when 

 not in use. The present 

 Editor can speak highly of 

 this instrument for elementary 

 class work, and with good 

 workmanship its price is ex- 

 ceedingly low. The ' Star ' 

 microscope is also a very re- 

 markable instrument, suffi- 

 ciently so to justify us in 

 departing from a rule to 

 point out that with two eye- 

 pieces, two objectives a 

 ^-inch and a ^-inch and an 

 iris diaphragm, the whole, 

 placed in a cabinet, is sold for 

 U. 15s. 



"We come now to micro- 

 scopes of the fourth class. 



A small, compact, and 

 thoroughly useful microscope, 

 specially adapted for medical 

 students and Biological 

 Schools, is made by Swift and 

 Son, and known as their 

 ' New Histological and Physio- 



FIG. 186. Ross's educational microscope 

 (1898). 



logical Microscope.' In its simplest form it is shown in fig. 188. 

 The stand is a firm tripod, the optical tube slides in a cloth-lined 

 fitting, the fine adjustment may be the differential screw actuated 

 by a large milled head, and capable of work with at least a ^th-inch 

 objective. It is beautifully swung, and is firm in any position. 

 The stage is large, and has the horseshoe opening. There are 

 several grades of this instrument, involving more or less complexity 

 and apparatus ; but it was designed to meet, and we believe does 

 meet, the needs of students who want a strong, practical, and well- 

 equipped instrument at a very moderate price. 



Another instrument of this class deserving the highest commen- 

 dation, and offering the student much more for the outlay involved 

 than we could have thought possible twenty years ago, is ' The 



