Januahy 30, 1903.] 



SCIENCE. 



187 



on a telegraph key. For intervals bounded 

 by sounds the reproduced interval changed 

 from plus to minus at a point between inter- 

 vals of two and thi-ee seconds. There is very 

 little difierence between intervals bounded by 

 sounds and those bounded by lights; but a 

 considerable difference is given when the in- 

 terval is bounded by a sound followed by a 

 light or vice wrsa. The same interval 

 bounded by varied stimuli seemed to the sub- 

 jects to be longer than when bounded by like 

 stimuli. Memory of intervals bounded by 

 varied stimuli required more effort. Mr. 

 Miner believed that this represented the dif- 

 ference in difficulty of muscular adjustment 

 on which the memory of the time interval 

 depended. The increase in variability with 

 the longer intervals followed the law sug- 

 gested by Cattell and FuUerton, rather than 

 Weber's law. 



Mr. Miner also read a paper by Mr. J. H. 

 Bair, who was unable to be present, on the 

 general practice curve. The paper was based 

 on experiments made with a pack of 48 cards 

 (six different pictures, and eight of each pic- 

 ture). The cards when dealt in the same 

 order and then immediately after in a dif- 

 ferent order required a longer time for the 

 second order. If dealt 2, 3, 4, 5 ■ ■ ■ n times 

 in the same order before dealing in some new 

 order, the successive practices in the same 

 order followed the law of the practice curve, 

 which is an asymptotic approach to a physio- 

 logical limit; and at the same time dealing 

 the cards in any order required also less and 

 less time. This shows that practice in one 

 order gives practice ability in another order 

 antagonistic to it, and the more practice in 

 one order the greater the ability to respond 

 quickly to the new order. 



Professor MacDougal reported a series of 

 experiments showing the influence of varia- 

 tions in visual stimulation upon reactions to 

 auditory signals. Eeaction time was shorter 

 in darkness than in light, in weak light than 

 in strong light and in colored than in neutral 

 light. Reaction time was more constant 

 under neutral than under colored light; 

 changes of quality of light were followed 

 regularly by increased rapidity of reactions. 



These changes are apparently due to changes 

 in the attentive condition of the reactor, not 

 to any immediate organic influence of the 

 intensity or quality of the light. 



James E. Lough, 



Secretary. 



THE ACADEMY OF SCIENCE OF ST. LOUIS. 



October 20, iSOg.— Professor A. S. Chessin 

 presented for publication a paper on ' Some 

 Relations Between Bessel Functions of the 

 First and of the Second Kind.' 



Professor Wm. Trelease exhibited photo- 

 graphs showing the variations in the ring or 

 collar of Lepiota naucinoides, and a series of 

 lantern slides illustrating autumnal coloring 

 of foliage. 



November S, 1902. — Mr. G. G. Hedgcock 

 gave an illustrated account of ' The Sugar 

 Beet Industry in the United States and 

 Some of the Difficulties attending It.' 



Five persons were elected to active mem- 

 bership. 



November 17, 1902.— Dr. M. A. Goldstein 

 addressed the Academy on ' The Uses of the 

 Tuning Fork as a Means of Medical Diag- 

 nosis.' 



One person was elected to active member- 

 ship. 



December 1, 1902. — Dr. Adolf Alt delivered 

 an address on the ' Development of the Eye,' 

 illustrated by colored drawings and stereop- 

 ticon views made from sections prepared and 

 photographed by him. 



December 15, 1902. — A paper by C. F. 

 Baker, entitled ' A Revision of American 

 Siphonaptera,' was presented and read by 

 title. 



Dr. C. B. Curtis delivered an illustrated 

 address on ' Color PhotogTaphy,' outlining the 

 theory of color vision and the various ways 

 in which a given color sensation can be pro- 

 duced, and describing the processes by which 

 the natural colors of objects can be approxi- 

 mately reproduced by photographic means. 



Two persons were elected to active mem- 

 bership. 



January 5, 190S. — The reports of officers 

 for the year 1902 were received, and the fol- 

 lowing officers for 1903 installed: 



