1062 PROOEEDINQS OF THE SOCIETY. 



worked from tlic oiiposito cud, an ordinary eyc-picco being iiGcd for the 

 purpose of focusing. 



Mr. Pringlo said that the camera upon the table was exceedingly 

 similar to the one which he had first used for the purpose of i)hoto- 

 micrography, resembling it in the most remarkable manner because of 

 the objective being fixed to the body. The arrangement was one which 

 he soon gave up, because ho found it to be inconvenient, doubtful, and 

 uncertain as to getting the object in the centre, and although the inten- 

 tion was to save trouble, ho really found it gave a great deal more. Now 

 he used a Microscope and light fixed upon a moving table, which turned 

 upon a pivot, and had a stop by which it could be clamped if required ; 

 this was never out of centre to any great extent. He found the best 

 plan for getting the object arranged was to use first a piece of ground 

 glass and then plain glass with ruled lines. 



Mr. J. Mayall, jun., said that in his opinion, when photograjihy was 

 to be used in connection witli the Microscope, it was best to combine a 

 really good Microscope with a substantial and well-made camera. It 

 was only courting difticulty to build up such a photomicrographic appa- 

 ratus as that under discussion, in which, however good the arrangements 

 might be for the photography, those for the microscopy were wholly 

 defective. No provision had been made to enable the worker to adjust 

 the object at all conveniently, for the stage would ordinarily be out of 

 reach when the image was being viewed. Microscopes were in general 

 use to suit every class of work, and therefore it was sheer waste of 

 ingenuity to construct photomicrographic apparatus with the intention 

 of supplanting the use of a Microscope. If low-power work only were 

 required, then a Microscope of moderate pretensions could be easily 

 combined with a camera ; but where high-power work was to be done, 

 the highest class of Microscope must bo employed, and special means 

 were necessary to facilitate the centering of the imago on the screen, 

 and, above all, to enable the worker to control all the adjustments 

 readily, and to assure himself, by direct inspection in the Microscope, 

 that the image was such as he desired to photograph. These were 

 the points sought to bo embodied in the photomicrograi)hic appa- 

 ratus of Dr. Zeiss, Mr. Nelson, and others. The ajqjaratus recently 

 exhibited at the Society by Mr. C. L. Curties — in the designing of which 

 he (Mr. Mayall) understood Mr. Nelson had assisted — was a praiseworthy 

 attempt to construct a good and serviceable arrangement for combining 

 a Microscope with a camera at a very moderate cost. The aim was 

 distinctly practical, and based on a full knowledge of what had been 

 done previously in that direction by other designers ; but the apparatus 

 designed by Lord Edward Churchill presented no points that he (Mr. 

 Mayall) could commend, and was clearly a step in the wrong direction. 



Mr. J. Mayall, jun., said that it would be remembered that some 

 time ago Mr. E. H. Griffith, of the United States, sent a very pretty 

 Microscope with a lamp attached to it ; he had now sent another some- 

 what similar in appearance, but in which the chief novelty was the fine- 

 adjustment. Mr. Ladd had devised one on somewhat the same general 

 principle, that is, with the lever attached to the coarse-adjustment ; but 

 the action was here produced by a worm-wheel and a tangent screw that 

 could be readily clamped to act on the coarse-adjustment. He thought, 



