94 THE POPULAR SCIENCE MONTHLY 



struction. In these descriptions we have the unconscious beginnings 

 of comparative anatomy. In them all careful comparison is made vv^ith 

 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 prin- 

 ciples of natural mixtures and observations on the character and loca- 

 tion 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 sub- 

 jects 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 sug- 

 gests 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 Eoberval and M de I'Abbe 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. Eicher 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 observa- 

 tions 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 



