OF ARTS AND SCIENCES. 521 



In 1877 he was made an associate editor of the American Journal 

 of Science, and contributed to it then and afterward several excellent 

 reviews of important papers. 



In 1881 he collected a number of his essays and addresses in an in- 

 teresting little volume entitled " Scientific Culture and other Essays." 

 The address which gives its name to the book, and the two which fol- 

 low, " The Nobility of Knowledge," and " The Elementary Teaching 

 of Physical Science," display the penetrating insight and good judg- 

 ment which he brought to bear on the problems of education ; they 

 are full of wise advice and inspiration. The book also contains 

 appreciative biographical notices of Graham and W. H. Miller, and a 

 paper on the radiometer, dwelling on the scientific principles brought 

 out by this instrument. The careful and enthusiastic study of the 

 radiometer, which led to this article, is exceedingly characteristic of 

 the man. Whenever a striking new discovery was announced, he at 

 once threw himself into the study of it with the greatest ardor. Thus 

 he was probably the first to take calotypes in America, and later 

 became an expert photographer, as I have already said. Shortly 

 after Bunsen and KirchhofF's great invention, he constructed the most 

 powerful spectroscope of that time, inventing many ingenious contriv- 

 ances for making the necessary adjustments ; sevei'al of his papers 

 owe their origin to this work on spectrum analysis, and he was on 

 the point of making a discovery of the first order, the method of 

 seeing the solar prominences in spite of the full glare of the sun, 

 when he was anticipated by two other observers. In the same way 

 he mastered the new science of electrical measurements, procured the 

 necessary apparatus, gave instruction in this subject to voluntary 

 students, and wrote a popular account of its principles. 



In 1880 his father died, at a great age, and in the following year, 

 after the graduation of his nephew 0. W. Huntington from Harvard 

 College, he went to Europe with his family, and passed the winter in 

 Egypt. This was the last and longest of his many foreign journeys, 

 and was rendered more noteworthy by the fact that on his return to 

 England in the summer of 1882 the University of Cambridge con- 

 ferred on him the honorary degree of Doctor of Laws. 



In 1887 he returned to the field of Natural Theology in a course 

 of lectures before the Union Theological Seminary of New York, 

 which was repeated before the Lowell Institute of Boston, and pub- 

 lished in 1888 under the title, " The Credentials of Science the War- 

 rant of Faith." This book, which has passed through two editions, 

 was intended for students of divinity, and the argument therefore is 



