ROAYL MICROSCOPICAL SOCIETY. 309 



mendation, while others by Gundlach and Nachet were also 

 described as good. None by English makei's had come under his 

 notice. 



March 4th, 1874. 

 Charles Brooke, Esq., F.R.S., President, in the chair. 



Mr. Alfred Saunders read a paper entitled " A. Contribution 

 towards a Knowledge of Appendicularia," in which he minutely 

 described the appearance and structure of specimens found at 

 Torquay and Weymouth. A paper by Dr. lloyston-Pigott, F.R.S., 

 entitled " A Note on the Verification of Structure by the Motion of 

 Compressed Fluid," and another by the same author on "A Note on 

 the President's Remarks on Dr. Pigott's Searcher for Aplanatic 

 Images," were read. 



The first paper gave an account of some appearances produced 

 in the "beads" and other minute structures of certain microscopic 

 objects by the movements and currents in the fluid produced by 

 pressure applied to the covering glass. The objects were immersed 

 in various fluids, such as Rangoon oil, glycerine containing 

 chloride of gold in solution, &c., and pressure applied by the 

 direct contact of the objective (a ^ or ^) with the cover glass. 

 The method was chiefly applied to determine certain points in the 

 structure of the Podura scale. 



In his second paper Dr. Pigott gave an explanation of his 

 'aplanatic searcher,' which he defined as being a new expedient for 

 balancing spherical and chromatic aberration, being on a large 

 scale precisely what the adjusting screw collar of an objective is on 

 a minute scale. The collar separates the front lens by thousandths 

 of an inch. The searcher traverses inches. 



April 1st, 18/4. 

 F. H. Weniiam, Esq., Vice-President, in the chair. 



A paper by Dr. Anthony, " On the Structure of a Lepisma 

 Scale," was read by the Secretary, &c. 



Mr. Wenham made a communication on an instrument for 

 excluding extraneous rays in measuring apertures of microscope 

 object-glasses, and demonstrated his method to the Society. 



Mr. S. J. Mclntire read a "Note on a curious proboscis of an 

 unknown Moth." The proboscis ended in a hard chitinous point, 

 and was furnished with several formidable recurved spines, so as to 

 be fitted, apparently, both for penetration and retention. The spe- 

 cimen came from Western Africa. 



A "scientific evening" was held on April l.oth, in the great 

 Hall of King's College, when a number of interesting objects were 

 exhibited. 



