xxii Trans. Acad. Sci. of St. Louis. 



As a young man, Charles P. Chouteau engaged in the trading enterprises 

 of the American Fur Company, in whose service he spent .nuch time in the 

 Territories of the Northwest. He was the fir-t and only navigator who took 

 steamboats up the Missouri river from St. Louis to Fort Beuton. Inherit- 

 ing property from his father, Pierre Chouteau, he added largely to it. He 

 became a large owner in the famous Iron Mountain and eugaged in the pro- 

 duction and working of iron on an expensive scale. Himself educated as 

 an engineer, he took a kindly interest in studious and progre-sive young 

 men and found pleasure in assisting them. During his long life his inter- 

 ests were identified with the growth and development of St. Louis; his 

 name wil! be remembered as one of her best and most honored citizens. 



As a benefactor and steadfast supporter of the Academy, from its incep- 

 tion, Charles P. Chouteau stands for u«, as a type of the busy and successful 

 man of affairs, endowed with a keen appreciation of what is highest and 

 best in human endeavor, and ever lending a willing hand to earnest workers 



in science. 



John Green, 



Enno Sander, 



Francis E. Niphbr. 



Professor J. L. Van Ornum addressed the Academy on The 

 progress made in engineering during the nineteenth century. 



A paper by Professor P. H. Rolfs, entitled Florida lichens, 

 was presented by title. 



Professor F. E. Nipher exhibited two photographic nega- 

 tives, developed by an ordinary pyro developer. One plate 

 had been exposed in a printing frame for 1,000 seconds at a 

 distance of a meter from a 300 candle lamp. It was then 

 treated for ten minutes in a chromic acid bath having ten 

 drops of an eight per cent, solution of chromic acid to three 

 ounces of water. This treatment was in the dark-room. The 

 plate was then developed in the dark-room. 



The exposure of the other plate had been equivalent to 

 a tenth of a second at the same distance from the lamp, 

 and was exposed under the same plate. This plate developed 

 normally in a pyro developer, having six drops of bromide 

 and six drops of potassium ferro-cyanide, both in ten per 

 cent, solutions. The over-exposed plate showed more of de- 

 tail, but the contrasts were less strong than iu the plate with 

 normal exposure. It looked like a slightly under-exposed 

 plate. 



"When a plate with this exposure is treated with the chromic 

 acid bath while in the light and is then developed in the light, 

 a positive picture results. The chromic acid bath may be 



