BIOGRAPHICAL NOTICE OF GEORGE F. BARKER. 695 



December, 1871, Professor Barker delivered a lecture before the Ameri- 

 can Institute in New York, upon the " Correlation of Vital and Physi- 

 cal Forces," which attracted very general attention. The lecture was 

 an attempt to show that, besides the ordinary psychological definition 

 of mind, another and a purely physiological one might be found, which 

 represented mind as solely the product of brain-action, and, as such, 

 entirely capable of being correlated with physical forces. In 1872 he 

 was Vice-President of the American Association at its Indianapolis 

 meeting. 



Having made the branch of toxicology the subject of special study, 

 Professor Barker was engaged quite generally in the investigation of 

 cases of criminal poisoning. Perhaps the most important of these 

 cases was the celebrated one in which Lydia Sherman was tried in 

 New Haven, in April, 1872, for poisoning her husband with arsenic. 

 Because the Wharton case, tried just before, had apparently left upon 

 the public mind the impression that chemical analysis in such cases 

 was unreliable, and hence had given the criminally disposed some 

 reason to believe that thejr might commit murder by poison with im- 

 punity, especial care was taken by Dr. Barker to present the chemical 

 and physiological evidence in the Sherman case in a fully conclusive 

 form. To the thoroughness of this preparation, and the completeness 

 of the chemical evidence, the conviction of the prisoner was largely 

 due. The chemical evidence in this trial, after correction by him, was 

 inserted in full, as a typical case, in the subsequent edition of Whar- 

 ton and Stille's " Medical Jurisprudence." 



In February, 1873, he was strongly urged to accept the chair of 

 Physics in the University of Pennsylvania, Philadelphia. After due 

 consideration and consultation the offer was accej)ted, and he removed 

 from New Haven to Philadelphia in April. The trustees having 

 placed a generous sum of money at his disposal, for the purpose of 

 providing the apparatus necessary for illustrating the science in a 

 proper manner, Professor Barker left in July for Europe, in order to 

 personally inspect the instruments he was about to purchase. The 

 result has justified this step. The collection of physical apparatus in 

 the university cabinet is certainly unsurpassed in this country, and in 

 some directions it is absolutely unique in the world. 



In the fall of 1876 Professor Barker had the distinguished honor 

 of being elected a member of the National Academy of Sciences. In 

 the summer of 1878, on invitation of Professor Henry Draper, he 

 accompanied the Draper Eclipse Expedition to Rawlins, Wyoming, 

 where he studied the total solar eclipse of July 29th, as spectroscopic 

 observer. The most important fact obtained by him was the con- 

 firmation of Janssen's observation of 1871, that the coronal spectrum 

 contained the dark solar lines of Fraunhofer. After the eclipse he 

 accompanied his friend Thomas A. Edison on a trip to California and 

 the Yosemite. He stopped on his return to attend the meeting of the 



