PROCEEDINGS OF THE SOCIETY. 147 



with the work of the late Dr. Wallich would be acceptable to the 

 Council. 



The number of slides iu the Cabinet now amounts to 7699. 



The printed catalogue published in 1865, edited by the late R. J. 

 Farrants, contains 1300 slides. 



INSTRUMENTS AND APPARATUS. 



During the past year the President has made a careful examination 

 of the various eye-pieces and other apparatus in the collection, and has 

 classified these with the Microscopes to which they belong. 



Pending the conclusion of this work, not much progress has been 

 made with the Catalogue, but it has now been taken in hand, and will be 

 completed during the coming Session. 



Messrs. Powell, Beck, and Baker have very generously and kindly 

 cleaned all the objectives in the collection free of all charge, and the 

 apparatus is now in very excellent condition. 



The following additions have been made to the collection during the 

 past year : — 



February 15. — An old Microscope (No. 33) and a 1/4-in. Objective by 

 Andrew Ross. Presented by Messrs. W. Watson and Sons. 



April 19. — An old Microscope by Adams. Presented by Mr. J. M. 

 Offord. An old Microscope, attributed to Benjamin Martin. Presented 

 by Dr. W. H. Dallinger. 



July 21. — A 1/8-in. Objective (1838) by Andrew Ross, made for the 

 late Prof. Lindley. Presented by the Right Hon. Sir Nathaniel Lindley, 

 Master of the Rolls. 



October 18. — A Gillett Condenser with fine adjustment, by Andrew 

 Ross (registered July 20, 1849). Presented by the President. A 

 Model of Reichert's new Fine Adjustment. Presented by the President. 



STANDARDISATION OF THE SUBSTAGE, AND OP THE INTERNAL 

 DIAMETERS OF THE DRAW-TUBES OF MICROSCOPES. 



The following Resolutions were adopted by the Council on December 

 20th 1899 :— 



(1) That the Standards adopted by the Council in 1882 be witn 

 drawn. 



(2) That the Standard size for the inside diameter of the substage- 

 fitting be 1-527 in. = 38-786 mm. 



(3) That the gauges for standardising eye-pieces be the internal 

 diameters of the draw-tubes, the tightness of the fit being left to the 

 discretion of the manufacturers. 



(4) That the following four sizes of the internal diameters of the 

 draw-tubes be adopted : — 



R.M.S. No. 1, -9173 in. = 23-300 mm. 

 „ No. 2, 1-04 „ = 26-416 „ 

 „ No. 3, 1-27 „ =32-258 „ 

 „ No. 4, 1-41 a „ =135-814 „ 



