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VI
PREFACE
I gladly take the opportunity of expressing my thanks to Mr. William Francis and Dr. T. Percy Nunn for their kindness in reading a large portion of the MS., to Prof. Alfred W. Porter, F.R.S., for reading all the proofs and for many valuable suggestions, and to the Publishers and the Printers for the care they have bestowed on my work.
L. S.
LONDON, April, 1914.
