904 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Fig. 165. 



fit inside the first. The only action required is then to push the one 

 into the other, and as they fit accurately there is quite sufiicient 

 adherence to keep the objective in its place. The centering of the 

 objectives is likely to be more accurate than 

 if they are screwed on in the usual way. 

 " It was of course just possible that a blow 

 might cause the objective to drop out, but this 

 in practice was hardly likely to happen." 



Mr. H. F. Hailes, referring to the analogy 

 between the fitting of an objective and the 

 chucks of a lathe, says that the proprietor of 

 large engineering works informed him that a 

 cone-fitting was the best for lathes that could 

 be used, and that he had done away with 

 screwed nose-pieces in favour of the cone. As 

 to its power of holding, Mr. Hailes saw a 1 in. 

 iron bolt screwed perfectly at one cut with 

 dies held in a chuck so fitted. 



Mr. E. M. Nelson, on the same subject, said that he believed 

 the cone " to be the best fitting in the world, and for his own part he 

 should be glad to see the whole system of screws swept away and the 

 cone substituted." 



Watson's Adapter Nose-piece. — To avoid the danger of the 

 objective dropping out of the cone-fitting of 

 Matthews' adajjter nose-piece, Messrs. Watson 

 have cut four slots in the coned tube of the 

 nose-piece to give it spring, and have applied 

 an outer screw-collar by which the tension of 

 the cone can be increased if required. An 

 adapter, coned externally, screws on the ob- 

 jective, where it may remain, as it presents no 

 obstacle to the use of the ordinary objective- 

 boxes. The screw-collar on the nose-piece can 

 be regulated to give just the required amount of 

 tension to prevent the objective from dropping 

 out ; and where additional precaution is thought 

 desirable, a quarter turn of the collar will grip 

 the objective as firmly as required, the reverse 

 movement releasing it. 



Boecker's Movable Stage.* — This (fig. 167) is yet another con- 

 trivance, of German origin, for moving an object on the stage in two 

 directions, described with a freshness and elaboration of detail which 

 carries one back some forty or fifty years in the history of cor- 

 responding contrivances for English Microscopes. 



The lower plate A is clamped to the stage, and the upper plate B 

 (with clips for the object) is moved by the screw S in a longitudinal 

 direction, M and B being connected. The movement of B from back 



Fig. 166. 



* Dippel's 'Das Mikroskop,' 2nd ed., 1882, pp. 649-51 (1 fig.). 



