44 PROCEEDINGS OF SOCIETIES. 



In the meantime your contributor has touched on an important 

 point in stating that our excellence (which he grudgingly says may be 

 assumed for the present) is partly due to the greater intensity of the 

 rays of light we transmit. He may now forestall the Paris savant, 

 in whose conversation the statement and demonstration of these in- 

 vestigations has formed an integral element during ten years to my 

 knowledge, and show experimentally and mathematically that the 

 theory of the production of the minutest oiitical images requires the 

 gi-eatest possible preponderance of peripheral over central rays in the 

 objective : that the immersion principle greatly assists in the attain- 

 ment of this condition : that we thus inherently possess greater freedom 

 from errors of diffraction that necessarily exist in the Dry Objectives. 



At this date, with lenses already made on the Immersion principle 

 of focal lengths varying from ^th to J^th of an inch, we do not ask 

 to have our merits assumed ; we point to our series of Dr. Woodward's 

 photographs as conclusively proving that we possess photometric 

 powers and other qualities most highly valued in microscopic defini- 

 tion, in a degree quite beyond those of Dry Objectives. 



I am, Sir, your obedient servant, 



Immersion Lens. 



PEOCEEDINGS OF SOCIETIES. 



KoYAL Microscopical Society. 



King's College, June 3, 1874. 



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



The minutes of the preceding meeting were read and confirmed. 



A list of donations to the Society siuce the last meeting was read 

 by the Secretary, and the thanks of the meeting were voted to the 

 donors. 



The President announced that the reading room and library of 

 the Society would be closed during the month of August. He also 

 regretted to inform them that a i:)aper which it was expected would 

 have been read before the meeting that evening, had unfortimately 

 been lost in transmission through the post, and they were consequently 

 unable to read it. 



The Secretary called attention to a slide exhibited by Mr. Baker, 

 just received from Herr MoUer, and a very remarkable specimen of 

 his extraordinary skill. In a square, with sides only yV^h of an iuch, 

 were 80 clear circular sj)aces in a dark framework of phutography, 

 and in each space a fine specimen of a diatom, wdth its name, and the 

 authority for the name, plainly photograj^hed below it. The whole 

 series could be well seen at one glance under a 1 J-inch objective, and 

 the names read, though very small with that power unless a B eye- 

 piece was employed. Beck's ith had a considerably larger field than 

 one of the spaces, and Powell and Lealand's immersion -J th just took 

 one in, and showed in one view a name as long as " Triceratium for- 

 mosum," the letters being beautifully sharp with that magnification. 



