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PROCEEDINGS OF THE SOCIETY. 
Meeting of 13th November, 1878, at King’s College, Strand, W.C. 
The President (H. J. Slack, Esq.) in the chair. 
The Minutes of the meeting of 9th October were read and con- 
firmed, and were signed by the President. 
The following List of the Donations since the last meeting was 
submitted, and the thanks of the Society given to the donors. 
From 
Annales des Sciences Naturelles (Zoologie). 14 vols. (1870 to 
1877) Mr. Frank Crisp. 
„ „ „ (Botanique). 13 vols. (1869 to 1877). Ditto. 
Henry, James. — ACneidea; or Critical, Exegetical, and .^sthetical 
Kemarks on the ASneis. 4 parts, 1873-8 Author. 
Papers of the Eastbourne Natural History Society, 1877 and 1878 Society. 
Wallich, Surgeon-Major G. C. — On the Radiolaria as an Order of the 
Protozoa. (From ‘ Popular Science Review ’) Author. 
Zeitschrift fiirwissenschaftliche Zoologie. 10 vols. (1869 to 1877). Mr. Frank Crisp. 
A special vote of thanks was on the suggestion of the President 
given to Mr. Crisp for his valuable donations. 
Dr. G. W. Koyston-Pigott, M.A., F.R.S., explained the leading 
points of a paper which he had sent to the Society, “ On a further 
Inquiry into the Limits of Microscopic Vision, and the delusive 
Application of Fraunhofer’s Optical Law of Vision.” The subject 
was illustrated by numerous diagrams. (The paper will be printed 
in the next number of the Journal.) 
The President read a paper by himself, “ On the Visibility and 
Optical Aspects of Hairs viewed from a Distance.” (The paper will 
be found at p. 318.) 
Mr. Charles Brooke, in reply to a question from the President, 
said that he thought the hair itself was not actually seen. On 
the occasion when being illuminated by the sun-light a bright line 
was perceived at the great distance of 173 feet, he considered that the 
perception of it was due to an optical effect similar to that produced by 
the heating of a platinum wire by a current of electricity, when the wire 
apparently increased in thickness the hotter and brighter it became. 
Mr. Henry Davis said that the phenomenon was well known to 
astronomical observers under the name of irradiation, and it applied 
generally to all bright objects. 
Mr. Stewart inquired whether in the course of these experiments 
there was anything like “ expectant attention ” on the part of the 
persons concerned in them ? Did they not know what they were to 
look for and exactly how they ought to see it, or were the hairs placed 
in positions vertically or otherwise without the persons knowing which 
way they were placed, so as to test whether they really did see them ? 
