The elliptic functions introduced by Professor K. Weierstrass of Berlin are best known through the admirable pages of Professor H. A. Schwarz's Formeln und Lehrsätze zum Gebrauche der elliptischen Functionen, Göttingen, 1885. These pages have been translated literally into French by Dr Henri Padé, Paris, 1894. Halphen's well-known three-volumed treatise on elliptic functions is devoted almost entirely to the Weierstrassian forms. In the English language, the following references may be useful:—Whittaker, Modern Analysis; Greenhill, Elliptic Functions; Harkness and Morley, Theory of Functions; Forsyth, Theory of Functions.