694 THE POPULAR SCIENCE MONTHLY. 



auspices of the Western University of Pennsylvania. In the summer 

 of 1860 he again visited Europe, spending his time while abroad 

 mainly in studying the scientific collections, institutions, and resources 

 of London and Paris. 



During the month of August, 1861, on the recommendation of his 

 friend President Hitchcock, of Amherst College, he was tendered the 

 professorship of Natural Science in Wheaton College, Illinois. This 

 he accepted, and dischai'ged the duties of the chair for the subse- 

 quent college year. In September, 1862, he went to Albany, at the 

 solicitation of his friend Professor C. H. Porter, to act as his substi- 

 tute in the chair of Chemistry in the Albany Medical College, Pro- 

 fessor Porter having entered the army as Assistant Surgeon of Volun- 

 teers. While thus acting, he pursued regularly his medical studies, 

 and was graduated therefrom as a Doctor of Medicine in 1863. After 

 a third course of chemical lectures in Albany, given in the fall of 1864, 

 Professor Barker went to Pittsburg as Professor of Natural Science 

 in the Western University, remaining there during one year. 



In the winter of 1865-66, while preparing to enter the service of 

 the United States as an Assistant Surgeon of Volunteers, having been 

 offered a commission by Dr. Quackenbush, then Surgeon-General of 

 the State of New York, he was offered by Professor Silliman the po- 

 sition of Demonstrator of Chemistry in the Yale Medical College. 

 This offer was accepted, and he entered immediately upon his duties. 

 Early in the spring of 1866 Professor Barker wrote the first part of a 

 text-book, intended as a new edition of Silliman's " Chemistry." In 

 this book, the modern nomenclature and notation appeared in a text- 

 book for the first time in this country. The theory of types was made 

 use of as a basis of classification, and the book was used with the 

 senior class in Yale College. 



During the absence of Professor Silliman in California in 1866-67, 

 the entire instruction in chemistry, in the Academical Department of 

 Yale, was given by Dr. Barker. At the commencement in 1867, he 

 was appointed Professor of Physiological Chemistry and Toxicology 

 in the Medical Institution of Yale College. The chemical lectures in 

 Williams College, in the absence of an instructor in that science, were 

 given by him in the spring of the years 1868 and 1869. In the sum- 

 mer of 1870 he wrote a chemical manual entitled "A Text-book of 

 Elementary Chemistry," which was published in September. In this 

 book it was assumed that one philosophy was broad enough for the 

 whole of chemical science ; and hence the subject was divided into 

 four sections Theoretical, Inorganic, Organic, and Physiological only 

 the first two of which were presented in the volume mentioned. It 

 achieved a very considerable success, about ten thousand copies hav- 

 ing been sold within the five years after its publication, and transla- 

 tions of it into French and into Japanese having been made. It was 

 adopted as the text-book in the University of Tokio, Japan. In 



