April 4, 1902.] 



SCIENCE. 



547 



tions were found penetrating into the olivines 

 and along the lines of fracture, it was also 

 assumed that the iron was altogether second- 

 ary and posterior to the shattering of the sili- 

 cate. 



The meteorite will be described in detail in 

 the Proceedings of the U. S. National Mu- 

 seum. 



Alfred H. Brooks, 



Secretary. 



NEW YORK ACADEMY OF SCIENCES. 

 SECTION OF ANTHROPOLOGY AND PSYCHOLOGY. 



A MEETING was held on February 28. Mr. 

 J. H. Bair reported on some quantitative stud- 

 ies in sensory and motor association. His 

 experiments have been carried out by aid of a 

 typewriter, the subject reacting to different 

 stimuli by striking different keys. Curves 

 were presented showing the rate of formation 

 of association. If, after the stimuli have been 

 presented many times in the same order, the 

 order is then changed, the association is inter- 

 fered with, and the more so the firmer it has 

 become. If the typewriter keys are inter- 

 changed, so that the reaction to each stimulus 

 must be changed, this interferes still more 

 with the association. These results showed, 

 then, that the association of definite sense im- 

 pressions with definite motor reactions was 

 more persistent than the association of sense 

 impressions with other sense impressions fol- 

 lowing in serial order, or than the association 

 of movements with other movements following 

 in serial order. 



In the discussion of this paper, several other 

 facts were mentioned, showing the importance 

 of motor reactions in the formation of asso- 

 ciation. Professor Thorndike had observed that 

 good visualizers, who are able to picture men- 

 tally a page of printed matter that they have 

 read, yet cannot read off the pictured words ; 

 apparently because the visual images are not 

 associated with motor responses. 



Mr. J. B. Miner spoke on ' Involuntary 

 Muscular, Responses to Rhythmic Stimuli.' 

 He described some experiments conducted by 

 himself at Columbia and Minnesota univer- 

 sities, in which tracings were obtained for non- 

 voluntary hand and head movements when the 



subjects listened to a series of uniform 

 sounds. It has been noted by Thaddeus L. 

 Bolton and others in their investigation of 

 rhythm that such a series of sounds appears 

 not uniform, but as if coming in groups of 

 two or more sounds. The muscle responses 

 obtained corresisond with this perception of 

 rliythm, one wave coinciding with each rhyth- 

 mic group. The movements recorded strik- 

 ingly agree with another phenomenon of 

 rhythm in that a motor wave shows for each 

 stimulus when the sounds came slowly (forty 

 per minute), but when the rapidity of the 

 sounds was increased the wave encompassed 

 two, three and even foiir sounds. This agrees 

 with the introspective observation that the 

 subjective group includes more units as the 

 sounds come more rapidly. On the basis of 

 the data of muscular responses Mr. Miner 

 believes that an adequate physiological ex- 

 planation of rh;fthm may be formulated, while 

 organic rhythms alone would not furnish a 

 completely correlated activity. 



Dr. Clark Wissler reported some ergograph . 

 experiments showing that the contracting 

 muscle presents a power series which is con- 

 stant, whether the resistance is applied by a 

 spring or by a weight. While this power 

 series is weakened by fatigue, the resistance 

 value of any point in the muscle series is the 

 same for a weight or for a spring. In other 

 words, there appears no difference between the 

 fatigue produced by weights and springs when 

 estimated in terms of the muscle series. 



E. S. WOODWORTH, 



Secretary. 



SECTION OF ASTRONOMY, PHYSICS AND 

 CHEMISTRY. 



The Section met at the Chemist Club on 

 the evening of March 3. The first paper of 

 the evening was by Mr. Charles C. Trow- 

 bridge, on the 'Physical Nature of Persistent 

 Meteor Trains.' Mr. Trowbridge gave a list 

 of forty meteor trains which had remained 

 visible to the naked eye for from two minutes 

 to more than one hour. The trains were all 

 seen by reliable observers. Several tables 

 were exhibited, giving the size, shape and 

 color of recently observed meteor trains. 



