1110 rnocEEDiNOs of the society. 



Mr. Crisp, referring to the interest which still attached to tho work 

 done by Lceuwenhoek with his Microscopes, exhibited two facsimiles 

 of those instruments. A collection of them was formerly in the 

 possession of the Eoyal Society, hut had disappeared, probably thrown 

 away by some one unfamiliar with their. form. The drawings of them 

 gave only a very poor idea of what they were like, and it had been 

 with much interest that some of the Fellows had had an opportunity 

 of inspecting one of the original Microscopes brought to England 

 during the recess by Prof. A. A. W. Hubrecbt, tho eminent Dutch 

 zoologist, who to other accomplishments added that of a most extra- 

 ordinary mastery over the English language both as regards grammar 

 and pronunciation. Copies of the Microscope had been made by Mr. 

 Mayall, which were so close a resemblance to the original that only 

 by the closest examination was it possible to say which was which. 



Mr. Crisp also exhibited Golfarelli's Micromctric Microscope for 

 the special use of watchmakers in examining the teeth of very fine 

 escapement wheels, and commented on the wide field that was opening 

 if special Microscopes were going to be made for the different purposes 

 to which they could be put. He also exhibited Cailletet's apparatus 

 for examining the effects produced upon minute aquatic organisms by 

 enormous pressures up to 650 atmospheres, necessitating great strength 

 in the apparatus. He also called attention to two " telescopic " 

 objectives belonging to Prof. Abbe, so arranged that the image of the 

 object was not altered in size by varying the length of the draw-tube, 

 a matter of importance in the case of micrometric measurements. 



Mr. J. Mayall, jun., called special attention to the exhibit of Mr. 

 T. Powell, who, not wishing to be behindhand in the matter of 

 objectives, had procured some of the new glass from Jena, and had 

 worked out an apochromatic 1/12 in. objective on his own formula. 

 In the result he had produced an objective which certainly compared 

 very favourably with those of Zeiss which had been exhibited in this 

 country. The Fellows could see for themselves how extremely well 

 this objective stood the tests applied to it, and it should be specially 

 remarked that the eye-piece used with it had a magnifying power of 

 40, and the lens showed no sign of breaking down under it. This it 

 would be remembered was a much higher power than the highest (27) 

 in the Zeiss series. He believed the eye-pieces were made on a 

 formula analogous to that of Zeiss, though not quite the same. The 

 formula of the objective was evidently less complex than that of 

 Zeiss ; there were fewer lenses and hence less difficulty in construc- 

 tion. The meeting would, he was sure, be gratified to know that 

 directly the new glass was available, one of their Fellows had put his 

 shoulder to the wheel, and produced such first-class work as the 

 sample before them. 



The President said he had had the opportunity that evening of 

 examining this new lens of Mr. Powell, and he could only say that he 

 was quite astonished at the definition which it gave. Even under the 



