xx Trans. Acad. Sci. of St. Louis. 



February 4, 1901. 



President Engler in the chair, thirty-eight persons present. 



An invitation from the K. K. zoologisch-botanische Gesell- 

 schaft, of Vienna, was presented, for the Academy to par- 

 ticipate in its fiftieth anniversary session on March 30, and on 

 motion the Corresponding Secretary was instructed to extend 

 the congratulations and well wishes of the Academy to the 

 officers of that Association, together with the Academy's 

 regret that it could not be personally represented at the 

 meeting. 



Professor F. E. Nipher showed, by means of the lantern, 

 positive and negative photographic pictures developed from 

 plates equally exposed, and positives reproduced from each. 

 He outlined briefly the character of the work which he is now 

 prosecuting on this subject, and stated that since his last com- 

 munication he had succeeded in still further shortening the 

 duration of the exposure necessary to secure good positives, 

 so that he appeared to be rapidly realizing his hope that it 

 will shortly be possible to convert any plate, which on the 

 beginning of the development in the dark room shows too 

 great exposure to yield a good negative, into a positive, by 

 leading it beyond the zero point and completing the develop- 

 ment in the light. 



Messrs. W. N. Graves and George C. Hitchcock, of St. 

 Louis, Dr. Lee E. Monroe, of Eureka, Missouri, and Mr. W. 

 L. Sachtleben, of Alton, Illinois, were elected to active mem- 

 bership. 



Two persons were proposed for active membership. 



February 18, 1901. 



President Engler in the chair, twenty -three persons present. 



The Council reported the resignation of Dr. L. C. McElwee. 



On behalf of a committee appointed at a previous meeting 

 to present a suitable memorial of the late Charles P. Chou- 

 teau, a charter member of the Academy, Dr. Green presented 



