PROCEEDINGS OF THE SOCIETY. 837 



swinging tail piece, whereas the male portion was on the end of the main 

 casting. Rods were fastened down firmly on the top of the castings 

 supporting the whole apparatus, ;md the camera slid along these on two 

 V-grooves on one side and on a plane surface on the other side. Both 

 the front and back of the camera were identically supported. 



The same method was adopted in that portion of the apparatus 

 carrying the illuminant and subsidiary lenses. 



In all cases the clamps were of simple character and consisted of a 

 metal bar which engaged on each side of the casting on winch it rested, 

 and which was tightened up by means of a quick-acting screw. On 

 manipulating the screw the bar was drawn against the side of the casting. 

 The camera itself was supported on vertical rods, firmly fixed on the geo- 

 metric slides. There Avas nothing peculiar about the camera portion as 

 such, except that on one side of it a small white screen was supported, 

 so that when the Microscope was thrown out of alignment an image might 

 be observed on the subsidiary screen. The final focusing, of course, had 

 to be done on a ground or clear glass screen in the usual manner. The 

 apparatus shown could be used equally well as an horizontal or vertical 

 camera, or it might, if required, be inclined at an angle of 45°. It 

 might be used for photographic specimens which required to be in a 

 horizontal or vertical position. 



Mr. Barnard said that he had wished also to refer to the method of 

 supporting the whole apparatus, but the Secretary would admit that he 

 had been a little hurried in bringing the apparatus forward, for it had 

 only been finished during the day. It was proposed that it should be 

 carried on two castings, one at each end. The one at the camera end 

 would, in fact, be of the character of a cradle. He was of opinion that 

 this method of supporting the apparatus might be carried even further, 

 as he had experimented with a somewhat larger arrangement in which 

 the camera was swung by short springs, so that in the case of anyone 

 working under trying conditions, the apparatus would be free from 

 extraneous vibrations. 



Mr. Shillinirton Scales said that it seemed to him that the most in- 

 teresting and ingenious point about this apparatus was, that so far as he 

 knew there was no other photomicrographic apparatus on which the 

 Microscope itself was made to move in the same optic axis as the optical 

 and camera adjustments, whether the camera were used in a vertical, hori- 

 zontal, or inclined position. He had listened carefully, and he did not 

 see that the optical adjustments themselves offered any advantage over 

 the optical bench. He presumed that the various optical fittings had to 

 be centred by screws. He thought the adjustments of the camera were 

 exceedingly clever ; the camera was not supported on any base, and could 

 be adjusted up and down. It had struck him on looking at the apparatus 

 that there might be a little lack of rigidity, but Mr. Barnard had ex- 

 plained that he had been hurried, which would adequately account for 

 this. The only other criticism he had to offer was in regard to the cost, 

 which he thought might perhaps be excessive. 



Dr. Spitta said it was, of course, a mere matter of detail, but was not 

 the distance between the illuminator and the Microscope somewhat short ? 



Mr. Barnard answered that, as it then stood, it might perhaps 



