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shades cast by lamps. It was obvious that the sensation of brilliancy 

 varied according to the proportion of white to black, and that it was 

 capable of being expressed arithmetically. It was also evident that a half 

 illuminated surface did not give anything like the same degree of sensa- 

 tion. The theory was that as when gravity acted on a pendulum, the force 

 required to swing it was in proportion to the square root of the gravity ; so 

 it was quite likely that light imparted a certain amount of motion to the 

 retina, by the energy passing from the particles of ether to the particles of 

 the retina, and that the periodic times of those vibrations or swings would 

 vary in proportion to the square root of the intensity of the light. These 

 appeared to be very likely analogies, and it might be looked upon as a very 

 pretty physiological theory, and one which had been arrived at by the use 

 of the microscope. He thought they were getting on in the use they made 

 of their instrument, and he looked forward to a time when it would become 

 an important help both to the chemist and the physicist as well as to the 

 physiologist. 



Dr. Matthews proposed a vote of thanks to Mr. Lowne for his address, to 

 which he felt sure all had listened with intense interest. He thought there 

 was one omission, and should be very glad if Mr. Lowne would supply it, by 

 stating what was the form of force employed ? 



Mr. Palmer did not observe any means of regulating or correcting for 

 temperature. 



Mr. Lowne said he did not indicate the nature of the force, or go into 

 that question further, because he was rather afraid of becoming, like his 

 tubes, a " long bore." The force had nothing to do with the heating of the 

 fluid, and no current whatever passed through it. The only correction 

 necessary to be applied was that ordinarily applied to the barometer, and 

 this was so small as to be hardly worth mentioning. 



The President then proposed votes of thanks to Mr. T. C. White, Mr. 

 Hailes, Mr. Lowne, and Mr. Ingpen for their communications. 



Votes of thanks were unanimously carried. 



The President said he had been requested to announce that the Soiree of 

 the Greenwich Microscopical Society would be held on the 14th of February, 

 at which the co-operation of members of the Quekett Microscopical Club 

 was invited. At their next meeting Dr. M. C. Cooke would give them a 

 lecture on " Black Moulds." 



The Secretary said that having had a good many complaints as to the 

 papers and meetings not being properly announced, he wished to state that 

 as they frequently could not get promises of papers or their titles until the 

 last moment, it was not always possible to announce them beforehand ; but 

 if given to him not later than the preceding " Gossip night," the announce- 

 ments would always appear in the "Echo " of the Monday before the ordinary 

 meeting, in the diary of the " Echo " the day before the meeting, and in the 

 eight Journals, which regularly inserted notices of scientific meetings for 

 the week, viz., " The Academy," " The Athenaeum," " The British Medical 

 Journal," " Iron," " The Lancet," " The Medical Times and Gazette," 

 " Nature," and " The Pharmaceutical Journal." 



