lxvi Trans. Acad. Sci. of St. Louis. 



as co-ordinates. The zero condition was represented by a line, 

 and the conditions for producing direct and reversed pictures 

 were represented by areas. 



He also exposed and developed > in a common bath, in the 

 lighted audience room, negatives printed from negatives, and 

 positives printed from positives. 



The value of radio-active substances acting upon the 

 developing plate in place of or in addition to light was 

 referred to as a most promising field for study. 



Professor Nipher stated that he had done no work with the 

 plates of other makers, since he found on trial that one such 

 plate did not give good results with the treatment that had 

 succeeded with the Cramer plates. 



Mr. H. J. Gerling, of St. Louis, was elected to active 

 membership. 



Three persons were proposed for active membership. 



Reports of Officers for the Year 1900. 

 Submitted January 8, 1900. 



The President addressed the Academy as follows : — 



Members of the Academy: In rising to accept the honor which you have 

 again conferred upon me in electing me President of the Academy, I would 

 take the opportunity to make a few remarks upon the work which the Acad- 

 emy has attempted to do during the past year. 



It is needless for me to say that the general policy of the Academy which 

 has been followed for several years past has also been followed during the 

 year which has just closed. No new departures have been attempted, partly 

 because the policy which we had been following was thought to be a good 

 one, ;md partly because we were restricted in our facilities and opportuni- 

 ties for attempting new work. 



All of the meetings of the Academy which have been assigned by the 

 Council at the beginning of the j-ear have been held upon the dates appointed, 

 to the number of sixteen. The record shows that the attendance at the 

 meetings has been better than in any previous year. I think this fact is 

 siguiiicant in showing that the Academy is gradually beginning to interest a 

 larger constituency, and it is important that such means should be taken by 

 the Council as to continually enlarge that constituency, because it is from 

 those interested in the Academy's work that we must expect to derive our 

 sustenance. 



