PROFESSOR F. J. CHESHIRE 45 



of the most modern types, attended by unskilled labour; the whole 

 of these activities being directed by the highest technical knowledge 

 and skill. Thirdly, a well designed microscope must confer the 

 greatest happiness upon the greatest number of its users. In other 

 words, it must meet to the fullest possible extent, the needs and 

 demands of its users. But these demands are constantly changing 

 and increasing. Demands resulting from war experience, for ex- 

 ample, are already of a formidable nature, and are certain to become 

 greater. One fundamental difFiculty in design must be noted. A 

 good design having been evolved to meet existing requirements, 

 there is always a strong temptation to meet new requirements by 

 a modification of the old design. In any particular case this may 

 or may not be satisfactory, but one is often inclined to wonder 

 whether this subservience to tradition has not resulted in the per- 

 petuation of designs which, however good they may have been at 

 one time, are now ill-adapted to meet more exacting requirements. 

 A thorough overhaul of the design of the microscope by thoroughly 

 skilled mechanicians, without reference to old and traditional 

 designs, might lead to startling and valuable results. This is a 

 point of great importance to the trade. So long as a manufacturer 

 confines himself to the production of well-known designs, he must 

 of necessity meet with keen competition. Should he, however, be 

 successful in introducing new and valuable features, his chance 

 of success is very greatly increased. This danger of too close an 

 observance of traditional designs is unfortunately enhanced by mass 

 production, because when a manufacturer has laid down expensive 

 plant to produce a given design, it often pays him — or he thinks it 

 does — to buy up patents for improvements upon it, and throw them 

 into the waste-paper basket. 



Again, in the elaboration of a standard design we all agree that 

 the faddist must not be considered — the greatest happiness of the 

 greatest number must be sought for. Here, again, the matter is 

 not so easy in practice. We are now told that the bullet which 

 eventually brought down the ZepiDclin so ignominiously was, in the 

 first case, refused as the suggestion of a crank. Many valuable sug- 

 gestions for the improvement of the microscope must also have been 

 turned down for the same reason in the past. 



Time, unfortunately, does not permit of any consideration or 

 criticism of the design of the details of the microscope, but there 

 is one matter of some importance to which I should like to draw 

 your attention. In the early days of the microscope the illuminating 

 apparatus was of the simplest kind, generally nothing more than 

 t.he sky or a common lamp, the light from which was thrown upon 

 the object by a simple mirror. Modern work, however, demands 

 a well-corrected condenser of large aperture — or it may be a dark- 

 ground illuminator — working in conjunction with a small and intense 

 light source accurately adjusted in the axis of the complete illumin- 

 ating and observing systems. Now this adjustment of the light 

 source is tiresome in the case of an expert, and difficult in the 

 case of a tyro, and, when made, a touch of the mirror, or a slight 

 accidental displacement of the microscope or the lamp, necessitates 

 the work being done again. This difficulty could be largely removed 

 by the simple expedient of resting the microscope and the lamp on 

 geometrical bearings of the three-radiating groove type. In the 



