MINUTES OF. SECTION A. 



February 17, 1910. — Dr. B. M. Underbill exhibited 

 four specimens of pigs' feet with solid instead of cloven hoofs. 

 These feet were taken from a two days old pig, one of a litter 

 all showing the same characteristic. He also exhibited a dis- 

 sected specimen of one of the hoofs. It was stated that this 

 breed of hog was becoming quite common by artificial selec- 

 tion and that it was somewhat difficult to reconcile the exist- 

 ence of the solid hoof with the recognized laws of evolution. 

 T. Chalkley Palmer gave an interesting talk on diatoms, and 

 showed specimens under the microscope. C. M. Broomall 

 called attention to the laws of reflection governing the con- 

 centration of energy in the Thwing high temperature thermo- 

 meter. Adolphus Leland exhibited some microscopic quartz 

 crystals. Adjourned. 



March 10, 1910. — Illustrated lecture, "Theories and 

 Facts Concerning Arthropodal Vision," by Albert S. Barker. 

 Mr. Barker's remarks upon this subject are set forth in Vol- 

 ume V, Number 2, of these Proceedings. 



March 31, 1910. — Henry L. Broomall and others gave 

 descriptions of various optical effects at sea. C. Edgar 

 Ogden related an interesting account of a recent trip to 

 Florida, and presented a number of mineralogical and botan- 

 ical specimens. Mention was made of a recent article describ- 

 ing a white rainbow. CM. Broomall gave a short talk on 

 the theory of wind vanes and their accompanying eddy cur- 

 rents. A. H. Moon mentioned a number of optical illusions 

 and mathematical puzzles. Adjourned. 



April 21, 1910. — C. M. Broomall described the methyl- 

 ene blue test of the bacterial stability of water and exhibited 



