Page:Popular Science Monthly Volume 80.djvu/98

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struction. In these descriptions we have the unconscious beginnings of comparative anatomy. In them all careful comparison is made with similar parts in the body of man as well as with the bodies of other animals. Volume IV. contains an essay by M. du Clos on the principles of natural mixtures and observations on the character and location of the mineral waters found in the different provinces of France. Of these waters 67 varieties were examined in addition to the waters of Spa. In an essay by M, Dodort, written as a contribution to the history of plants, careful descriptions are given of many common, and of not a few rare plants. Volume V. is noted for the variety of subjects treated. M, Frenicle explains a method for solving problems by means of exclusion. There is in this volume a brief treatise on right-angled triangles and a table of magic squares. M. Blondel suggests a solution for the four cardinal problems of architecture. But one must turn the pages of this volume for one's self in order to see what subjects interested scientific men during the last quarter of the seventeenth century. In this volume one will find abundant proof of the scientific ability of M. Frenicle. In Volume VI. there are special treatises by M. de Roberval and M de l'Abbé Picard, though the astronomical works of M. Picard are contained in Volume VII. A large portion of this volume was published as an independent treatise in 1698. Volume VII. contains, in addition to the works of Picard, essays by Huyghens and astronomical letters from M. Auzout first published in 1665. An essay by M. Picard, now very difficult to obtain, written in 1671, to go with an atlas which appeared in folio form, is found in this volume. Other observations are described which were made for a folio volume printed at the Louvre and appearing in 1693. From a letter from M. Auzout to an Italian observer and instrument-maker contained in this volume, we learn the method then used for determining the diameter of the planets. There is also a description of a journey by M. Richer to Cayenne in the interests of astronomy and physics. Special journeys were made by de la Hire and others to different sections of France in order to secure accuracy in a proposed map. These were continued from 1672 to 1684. The accounts of these journeys are of considerable interest. The volume contains tables by which to find, on any day of the year, the time when the polar star passes the meridian, its horizontal declination and the height of the pole at any point on the earth's surface. There are accounts, too, of observations, physical and mathematical, made by the Jesuit fathers in India, Siam and China, and of the use made of the observations by the academy. Vol, VIII. is filled with the miscellaneous works of M. I. D. Cassini. A few of the suggestive titles are of interest: Origin and progress of astronomy, and its use in geography and navigation; elements of astronomy, verified by observations made