PROCEEDINGS OF THE SOCIETY. 421 



sections with both single as well as double staining, others exhibiting 



the "fall of a leaf " and the formation of the "abscissa" layer; insects 

 whole or compressed, the Crustacean Astacus longicornis, or wood-boring 



animal of the ocean; different ferns and plants, showing their varied 

 method of carrying pollen, seeds and spicules ; the membrane behind and 

 in front of the lens in the eye of the newly-born kitten : groups of 

 flowers formed by insects" scales ; and finally, examples of a moth and of 

 a butterfly, and two groups of daffodils. 



At the conclusion, Mr. Spitta said he would be only too pleased to 

 explain to any Fellow of the Society his method of producing the slides, 

 the plates used, and so on — in fact, anything relating to the photo- 

 graphic side of the subject, and that he would give Mr. Parsons the 

 name and address of the artist, for he felt sure that some might like to 

 avail themselves of this method of rendering contrast by colour, which 

 gave such very superior differentiation to that obtainable by ordinary 

 photographic methods. 



The President gathered that the method used was that of painting 

 over a specially taken photograph, and he presumed that the process em- 

 ployed by Mr. Spitta for colouring photographs was entirely new, and as 

 yet unpublished. He had seen very beautiful results obtained actually 

 with the stained specimen itself, though of course only up to a certain 

 degree of magnification. He returned the heartiest thanks of the Society 

 to Mr. Spitta for his demonstration. 



In reply to the President's supposition that the process employed by 

 the artist for colouring the slides was entirely new and as yet unpublished, 

 Mr. Spitta replied that this was so, at least so far as he knew. 



The vote of thanks accorded to Mr. Spitta for his demonstration was 

 carried with acclamation. 



Mr. Spitta was then asked to communicate his " Report on the 

 Grayson's Ruling presented by Mr. Conrad Beck to the Royal Micro- 

 scopical Society." 



Before reading the report, 



Mr. Spitta said that Mr. Beck had been kind enough to give to the 

 Society two rulings, an inch divided into hundredths, and a millimetre 

 with divisions of 0*25. He did not propose to read the paper in its 

 entirety, for it was of a very dull nature, and not fit for the purpose. 

 There were several difficulties which became apparent after commence- 

 ment which did not strike him before. One was to make a suitable 

 arrangement, one that would not shift during the somewhat protracted 

 time occupied by making several thousand observations. The stand had 

 to be of the most rigid kind — indeed, he had to cast aside a very large 

 number of readings on this account, some 1500 or 1(500, if not more. 

 Then, again, owing to the size of the rulings many arrangements of 

 objectives and oculars had to be experimented with bo as to avoid errors 

 of curvature of field, and such like troubles. The details of the 

 examination were set forth in the paper, but he might say the rulings 

 were in themselves most remarkably fine and perfect over the halves of 

 the scales under observation, but that a peculiar error manifested itself 



