MINUTES OF SECTION A. 



August 12, 1909. — Miscellaneous scientific business, 

 presentation of specimens, etc. An old map of Delaware 

 County, original author unknown, dated 1810, recently found 

 among the archives of the Institute, was exhibited. Among 

 other things, T. Chalkley Palmer made a report of a micro- 

 scropic examination of a sample of Media drinking water, 

 which at this time was exceedingly offensive in taste and 

 odor. The result of the examination may be found in full 

 among the records of the Section, and shows a numerous 

 growth of animal and vegetable organisms. Chemical anal- 

 ysis by C. M. Broomall confirmed the bad character of the 

 water. Subsequently, it may be noted, after a thorough 

 cleaning of the reservoir, the water returned to its original 

 first class quality. A simple apparatus for comparing the 

 intensity of two lights, consisting of a cube of white par- 

 affine divided by an opaque septum, was exhibited. Albert 

 S. Barker exhibited a microscopic collection of hairs from 

 the mouse, elk, rabbit, bat. camel, monkey, etc. 



August 19, 1909. — Miscellaneous scientific discussion 

 and presentation of specimens. Albert S. Barker exhibited 

 a varied collection of interesting microscopic objects, includ- 

 ing brown aphides, Vaucheria, Spirogyra in conjugation, 

 Chelifer cancroidcs , etc. 



August 26, 1909. — General discussion and exhibition of 

 specimens. C. E. Ogden and Sanford Omensetter spoke at 

 length on the habits of the chimney swallow in this locality. 

 Dr. B. M. Underhill presented specimens of crinoids and 

 fossil ferns and spoke of their position in geological history. 

 The following specimens were presented and discussed : — 

 Digger wasp, diatoms, insect eyes, etc. Albert S. Barker 

 showed a live plant louse found on a beech tree, where large 

 black ants were caressing it in an effort to obtain lioney dew. 



