938 PROCEEDINGS OF THE SOCIETY. 



(4) Zeiss's Micrometer Eje-piece ; (5) Millar's Multiple Stage-plate ; 



(6) Bauscli and Lomb Optical Co.'s Comjjressors (ante, p. 714); 



(7) Valentin's Hot Stage. 



Mr. Curties exliibited Aylward's Collecting Apparatus {supraj 

 P- 911). 



Mr. Stewart exhibited his simple Safety-stage. 

 Dr. Anthony said he had for the last thirty years, in the course of 

 his microscopical observations, attained the same result by simply 

 having the stage of the instrument made nan'ower than usual, so 

 that the slide slightly projected beyond the edge. When a high 

 power was used all that was necessary was to tilt the slide with the 

 finger, and it could be at once felt or heard when the objective came 

 in contact with it whilst focusing down. Boss had somewhat im- 

 proved upon this plan by having a very thin plate made, by means 

 of which the slide could be raised in a similar manner. 



The President said there was no doubt that in exhibiting objects 

 to a class of medical students something of this kind was very necessary, 

 and as they were not particularly careful or experienced, the plan of 

 tilting the slides was not of so much use, but he thought the admirable 

 little plan described by Mr. Stewart quite met the difficulty. For his 

 own pai't, he could say that he had some slides which he had never 

 ventured to show, because of the danger of getting them broken in 

 this way. 



Dr. Matthews said he had much felt the want of something of this 

 kind, for it was only during the previous week that he had demolished 

 a slide in that v/ay, and this not from any particular carelessness on 

 his part, but from inadvertence, the Microscope being shaded and the 

 lamp turned down, so that he was almost in the dark at the time. 



Mr. J. Mayall, jun., said that his objection to the use of safety- 

 stages was based on the fact that they were for the most part only of 

 any value when high powers were used, and as with high powers a 

 condenser was generally necessary, it frequently happened that when 

 the condenser was racked up and the objective down, the safety-stage 

 was squeezed between them. Mr. Stewart's device seemed to be a 

 very simple and efficient form, but he imagined it was only intended 

 for use by those who were not much accustomed to high powers. 



Mr. Stewart said it was intended entirely for rough purposes 

 when exhibiting slides to students and others who were not very 

 careful in such matters. 



Mr. Crisp said it was not unusual to hear derision of these safety- 

 stages, but it came from Fellows who were all experienced workers, 

 and to whom any such contrivance was superfluous. 



Dr. Coffin said that he had employed a similar contrivance for 

 some time, but it was simply made of a piece of brass wire bent into 

 a fork somewhat wider than the slide, the two ends of which were 

 bent back again, and across which the two indiarubber bands were 

 stretched. 



