( 133 ) 

 PROCEEDINGS OF THE SOCIETY. 



Meeting of 14:Th December, 1881, at King's College, Strand, W.C, 

 The President (Professor P. Martin Duncan, F.E.S.) in the 

 Chair. 



The Minutes of the meeting of 9t]i November last were read and 

 confirmed, and were signed by the President. 



The List of Donations (exclusive of exchanges and reprints) 

 received since the last meeting was submitted, and the thanks of the 

 Society given to the donor. 



From 

 MicrograpMc Dictionary. 4th ed. Parts 4-6 Mr. Van Voorst. 



Mr. Crisp exhibited Parkes' Drawing-room Microscope with 

 magnetic stage, and two bottles from Professor H. Van Heurck, of 

 Antwerp, containing new fluids for use with homogeneous-immersion 

 lenses; one (" liquide homogene a la tacamaque") with a refractive 

 index of 1'510, and a dispersive power of -0072, and the other (" a 

 I'oliban) of the same index, but with a dispersive power of • 0077. 



Mr. John Mayall, jun., exhibited Mr. Deby's method of turning 

 the correction-collar of objectives, the chief peculiarity of which was, 

 that the collar was worked by a tangent screw (with a long arm) 

 acting upon a worm-wheel, instead of by the ordinary collar-adjust- 

 ment, which Mr. Deby had found to be inconvenient (see p. 107). As 

 at present made, it would not go into an ordinary box, but (as had 

 been pointed out by Mr. Beck) the screw pinion might be con- 

 siderably shortened, so as to admit of its being put in a box in the 

 usual way. 



Mr. Beck said that it must be borne in mind that in adjusting an 

 object-glass it was often desirable to get a sudden adjustment, which 

 could not be very well done with this form. 



Mr. T. Charters White described, by means of black-board 

 drawings, a new form of growing or circulation slide which he had 

 recently devised, and exhibited the slide in action under a Microscope 

 (see p. 19). 



Mr. James Smith said he had been trying himself to work out 

 some better form of growing-slide than those in common use, but his 

 attempts had hitherto proved abortive. He was, however, very much 

 pleased with the one now shown by Mr. White, the great advantage 

 of which was its extreme simplicity, and its capability of keeping 

 objects alive for any length of time. 



The President thought that its only disadvantage would be that 

 when carefully examining one particular individual, others might be 



