=A.D. 1628.=--Leurechon (Jean), a student belonging to the Order of Jesuits (1591–1670), who became the confessor of Charles IV of Lorraine, publishes, under the name H. Van Etten, “La Récréation Mathématique,” carefully revised editions of which were made by Claude Mydorge and Denis Henrion in 1630, 1638 and 1661. In these, Leurechon alludes to the reported transmission of intelligence by the agency of a magnet or other like stone, saying: “The invention is beautiful, but I do not think there can be found in the world a magnet that has such virtue.” REFERENCES.--Georges Maupin, “Opinions touchant la mathématique,” Paris, 1898, pp. 20–24; Larousse, “Dict.,” Vol. X. p. 436; “Sc. Am. Suppl.,” Nos. 56, p. 881, and 384, p. 6125. The curious title-page of the English version of Leurechon’s work, published by T. Cotes in 1633, merits reproduction: “Mathematicall Recreations, or a Collection of sundrie Problemes, extracted out of the Ancient and Moderne Philosophers, as secrets in nature, and experiments in Arithmeticke, Geometrie, Cosmographie, Horologographie, Astronomie, Navigation, Musicke, Optickes, Chimestrie, Waterworkes, Fireworks, etc., Fit for Schollers, Students, and Gentlemen ... lately compiled in French by Henry Van Hetten. And now delivered in the English tongue.” Claude Mydorge, as stated in the “Biog. Gén.,” Vol. XXXVII. p. 87, was a French scientist (1585–1647), a very close friend of Descartes, and, according to Baillet, was next to Vieta, the foremost mathematician of his day. The second edition of his “Examen du livre des Récréations Mathématiques (du Père Leurechon),” contains notes of Denis Henrion following the observations of Père Mersenne in “Universæ ...” Paris, 1639 (see Bouillet, “Vie de Descartes,” Vol. I. pp. 36–37, 149–150, and Vol. II. pp. 43, 76, 78, 325). Denis Henrion was also a French mathematician, who died about 1640. He was the author of many very meritorious papers, notably of a “Traité des Globes et de leurs usages,” 1618, translated from the Latin of Robert Hues, 1593, 1594 (Larousse, “Dict. Univ.,” Vol. IX. p. 192). =A.D. 1629.=--Cabæus--Cabeo (Nicolaus), a learned Jesuit of Ferrara, describes (“Philosophia Magnetica”)[42] numerous experiments made by him to ascertain the possibility of two persons communicating intelligence by means of magnetized needles.