IV. 



Prof. Nipher illustrated a method of preparing large resistance 

 standards for electrical measurements b}' films of graphite on a 

 ground-glass plate. A set of standards from 50,030 to 1,000,000 

 ohms was exhibited, and the statement was made that the results 

 of experiments now in progress on the resistance of the glass of 

 the Holtz electrical machine would be reported to the Academy 

 in detail on their completion. 



Dr. Hambach exhibited specimens of Cycas revoluta from the 

 greenhouse of Mr. D. Brown that were apparently maturing their 

 fruit, although the species is dicEcious, and no male plants were 

 known to be in bloom in the vicinity. The plant from which they 

 were taken has already bloomed several times, but the pistils had 

 heretofore remained small. 



Prof. Trelease remarked briefly that the fruit exhibited was not 

 yet full grown, nor in the specimens examined had the formation 

 of an embryo begun. Statements referring to the occasional de- 

 velopment of sterile fruit of this species without pollination were 

 quoted, and the tardiness attending the development of its embryo 

 was contrasted with that of certain couifow. notably Piiius and 

 Salisburia. 



November 1st, 1886. 



President Nipher in the chair ; ten members present. 



Dr. Todd made some remarks on the soaring of buzzards^ 

 the pelican, and other birds, attempting to explain the ability 

 of the bird to soar and fly without any apparent movement of 

 the wings. He oflered the theory that it was due to the sculling 

 movement of the extreme feathers, which he finds tlie birds have 

 the ability to slowly rotate, though he has been unable to detect 

 any motion from a limited study with glasses. Attention was 

 also called to the great development of the breast muscles of birds, 

 by which they do their flying, and to their very limited develop- 

 ment in man. If flying machines were ever to be made a success 

 they must be worked by legs, where tliere is the greatest muscu- 

 lar development. 



Prof. Nipher gave a mathematical discussion of the efiiciency 

 of the shunt form of dynamos, illustrating the curve of efiiciency 

 by models. 



