XXX Trans. Acad. Sci. of St. Louis. 



the power of the motor once its weight is such that the weight of the 

 pilot and its accessories is small in comparison, and large machines 

 cannot expect to make greater speed than moderate sized ones. 



The architecture of the aeroplane is then seen to be the important 

 point for future investigation and machines with bodies so constructed 

 as to offer a minimum resistance for a given weight are the racing 

 planes of the future. 



The death of Mr. Ernest R. Buckley was reported. 



Febkuary 19, 1912. 



President Engler in the chair ; attendance 36. 



Dr. Chas. H. Turner addressed the Academy on ''Ex- 

 perimental Study of Color Vision and Pattern Vision of 

 Bees." 



To those whose interest in the interrelations of insects and flowers 

 has been stimulated by the work of Spengel, Darwin, Mueller, Robert- 

 son and others, the most logical theory that has yet been proposed to 

 account for the colors and color patterns of flowers is the one which 

 asserts that colored flowers are for the purpose of causing the cross- 

 fertilization of plants. 



This theory was held by practically all serious students until a 

 short time ago, when a reaction set in and a number of men came to 

 feel that, although the theory is plausible, there is not suflicient exper- 

 imental evidence to establish it. This change of view was brought 

 about by two things: first, the advent of the tropism theory of the 

 physiologists, and second, deductions based on morphological studies 

 of the insect eye. 



After a discussion of these two conceptions, Dr. Turner described 

 a series of experiments which he had made. Dr. Turner argued that 

 if bees can distinguish colors and color patterns it should be possible, 

 first, to train bees to collect from artifacts of a certain color, if such 

 artifacts contain something of value to the insect; second, once hav- 

 ing learned to collect from such artifacts, the bees should be able to 

 select artifacts of that color under each of the following conditions; 

 when the artifacts of that color pattern contain the thing of value 

 and none of the others do, when the artifacts of that color pattern 

 and some of the others contain the thing of value, when none of the 

 artifacts contain the thing of value. 



Dr. Turner conducted two sets of experiments; one, to determine 

 If bees can distinguish between plain colors and the other to test the 

 ability of bees to distinguish between color patterns. 



In the experiments of the first summer Dr. Turner found that 

 without a doubt bees can discriminate between solid colors, and his 

 experiments the second year proved conclusively that, after a bee 

 had learned, by experience, that artifacts bearing a certain color 

 pattern contained a more copious supply of easily obtained honey 

 than ordinary fiowers, it would select artifacts bearing that color 

 pattern from those marked in a different way. This was true: first, 



