High Frequency Apparatus Page viii

viii PREFACE vegetables. The sixth section is devoted to a comprehensive discussion of apparatus of large size for use upon the stage in spectacular productions. An appendix giving the current prices of the parts and materials required for the construction of the apparatus described has been added with a view to expediting the purchase of the necessary goods. I wish to acknowledge my indebtedness to the following concerns and individuals for assistance rendered in the preparation of this volume: Victor Electric Company for illustrations of standard electro-therapeutic apparatus; Clapp-Eastham Company for illustrations and the list of parts and materials; Mr. Melville Eastham for a practical working knowledge of magnetic leakage transformer design and construction; and, last, but not by any means least, Prof. Wm. C. Houghton, for many ideas and suggestions, and much unselfish manual labor during the course of experiments which made this treatise possible. THOMAS STANLEY CURTIS. Aeolian Hall, New York City. February, 1916. માં ત