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"Mr. Hopkins has rendered a valuable service to experimental physics."
--_Evening Post._
"The book is one of very practical character, and no one of a
scientific turn of mind could fail to find in its pages a fund of
valuable information."--_Electric Age._
"The work bears the stamp of a writer who writes nothing but with
certainty of action and result, and of a teacher who imparts
scientific information in an attractive and fascinating
manner."--_American Engineer._
"It should be found in every library."--_English Mechanic._
"The book would be a most judicious holiday gift."--_Engineering and
Mining Journal._
Mr. Thomas A. Edison says: "The practical character of the physical
apparatus, the clearness of the descriptive matter, and its entire
freedom from mathematics, give the work a value in my mind superior to
any other work on elementary physics of which I am aware."
Prof. D. W. Hering, University of the City of New York, says: "I know
of no work that is at the same time so popular in style and so
scientific in character."
Prof. W. J. Rolfe, of Cambridgeport, Mass., writes: "The book is by
far the best thing of the kind I have seen, and I can commend it most
cordially and emphatically."
HUNDREDS OF CORDIAL RECOMMENDATIONS FROM EMINENT PROFESSORS AND
SCIENTIFIC MEN.