1084 



PROCEEDINGS OF THE SOCIETY. 



reduced size of the condensers ; and 3rd, in the sectors being remov- 

 able, so that they could be replaced by the ordinary substage if 

 desired. 



Mr. Jno. Mayall, jun., exhibited " the Thury-Nachet Traverse 

 Substage," one of the earliest forms of what was now called the 

 " Swinging Substage " (made by M. Nachet in 1855 for M. Thury), 

 and described the peculiarities of its construction (see p. 1059). 



Mr. Crisp exhibited and described Messrs. Parkes's frog-plate 

 (see p. 1041). 



Mr. Teesdale's description of the Pearson-Teesdale microtome 

 was read, and the instrument exhibited (see p. 1034). 



Mr. G. C. Morris's letter as to what was supposed to be a fungus 

 on human hair was read, together with a communication from Dr. 

 Cooke, to whom the specimens had been submitted. 



Lr. Stolterfoth's paper " On the Diatomacere in the Llyn Arenig 

 Bach Deposit " (see p. 913) was read, and a slide in illustration 

 exhibited. Several packets of the deposit referred to were also 

 placed upon the table for distribution amongst the Fellows. 



Dr. Matthews said that he visited the place some few years ago, 

 and then found some pipe-clay works upon the spot. No one at that 

 time thought that the deposit was diatomaceous earth, but pipe-clay, 

 and it was used as such. 



Mr. Crisp read some recent communications from Prof. Hamilton 

 L. Smith, in which he recommended the abandonment of the wax cell 

 (see p. 861), and the use of paper dipped in shellac varnish for 

 making rings (see p. 1038). 



Mr. James Smith said he had described these rings some fifteen 

 years ago, and a notice of it appeared in the ' Transactions ' at the 

 time (see p. 1039). 



Dr. Braithwaite said he had used them twenty-five years ago. 



Mr. Stewart described the observations of M. Eobin on a species 

 of Podophrya (see p. 817), in connection with Mr. Badcock's paper on 

 Acinetina (see j). 561), and drew figures in illustration on the board. 



Mr. A, A, Bragdon's letter on fluid for homogeneous-immersion 

 objectives was read (see p. 1051), and a discussion enstied, in the 

 course of which 



Mr. T. Powell said it was his decided opinion that such objectives 

 were better constructed with a collar adjustment ; if made so as to be 

 at the right jjoint when the collar was screwed home they could not 

 go far wrong ; and 



Mr. Stephenson again reminded the Meeting that if the objects 



