420 



THE POPULAR SCIENCE MONTHLY 



adepts in this fascinating study, and be has 

 evidently spared no pains in preparing his 

 manual, as his publisher has certainly spared 

 no expense in illustrating it. 



PUBLICATIONS KECEIYED. 



Education in Charleston, South Carolina. 

 The Disabilities of the Unaided South in Public 

 School Facilities. Published by the City Coun- 

 cil. 1881. Pp. 32. 



The Gesture Speech of Man. Address of 

 Colonel Garrick Mallery, U. S. Army, before the 

 American Association "for the Advancement of 

 Science. Salem, Massachusetts. 1881. Pp. 33. 

 . The Duties of Women. By Frances Power 

 Cobbe. Boston: George H. Kllis. 1S81. Pp. 

 193. 25 cents. 



Annual Report of the Surgeon-General of the 

 U. S. Army. Washington. 1881. Pp. 23. 



Reform in Medical Education. Annual Ad- 

 dress before the American Academy of Medicine 

 at New York. By Edward T. Caswell, M. D., 

 President. Philadelphia. 1881. Pp. 16. 



Circulars of Information from the Bureau of 

 Education, No. 3. 1881. Washington: Govern- 

 ment Printing-Office. Pp. 79. 



Study of the Sphecidte; List of the North 

 American Larradae ; Notes on the Philanthinse. 

 By W. H. I'atton. Pp. 28. 



Education and Crime, pp. 10; The Discipline 

 of the School, pp. 15. Bureau of Education. 

 Washington : Government Printing-Office. 1881. 



On the Filling of Amygdaloidal Cavities and 

 Veins in the Keweenaw District of Lake Supe- 

 rior. By M. E. Wadsworth, Ph. D. Pp. 12. 



The Areas of the United States : The Several 

 States and Territories and their Counties. By 

 Henry Gannett. E.M. Washington: Government 

 Printing-Office. 1881. Pp. 20. With Map. 



The Kinematics of Machinery. By Professor 

 Alexander B. W. Kennedy, C. E. With an In- 

 troduction by Professor R. H. Thurston, C. E. 

 New York : "D. Van Nostrand. 18S1. Pp. 88. 

 50 cents. 



Malaria : What it Means and how Avoided. 

 Bv Joseph F. Edwards, M. D. Philadelphia : 

 Presley Blakiston. 1881. Pp. 81. 



The Nature and Function of Art, more espe- 

 ciallv of Architecture. By Leopold Eidlitz. 

 New York: A. C.Armstrong & Son. 1881. Pp. 

 493. $4. 



The New Infirlelitv. By Augustus R. Grote. 

 New York : G. P. Putnam's Sons. 1881. Pp. 

 101. $1.25. 



Dangers to Health : A Pictorial Guide to Do- 

 mestic Sanitary Defects. Bv T. Pridgin Teale, 

 M. A. Third edition. Philadelphia: Presley 

 Blakiston. Pp.170. $3.50. 



The Honey Ants of the Garden of the Gods, 

 and the Occident Ants of the American Plain?. 

 By Henry C. McCook. D. D. Illustrated. With 

 ThirteenPlates. Philadelphia: J. B. Lippincott 

 & Co. 1882. Pp. 188. $2.50. 



Elements of Quaternions. By A. S. Hardv, 

 Ph.D. Boston: Giun A- Heath. 1881. Pp.230. 



A Study of the Pentateuch for Popular Read- 

 in %. Bv Knfus P. Stehbins, D. D. Boston : 

 George H. Ellis. 1881. Pp.233. $1.25. 



Ecce Spirit us. A Statement of the Spiritual 

 Principle of -Ti'sus ns the Law of Life. Boston : 

 II. Kills. 1881. Pp.238. $1.25. 



Sparks from a Geologist's Hammer. Bv Alex- 

 ander Winehell, LL. D. Chicago : S. C. "Griggs 

 & Co. 1881. Pp. 400. $2. 



'I'h e League of the Iroquois and other Le- 

 gends from the Indian Muse. By Benjamin 



Hathaway. Chicago : S. C. Griggs & Co. 1881. 

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Higher than the Church. An Art Legend of 

 Ancient Times. By Wilhelmiue von Hillern. 

 From the German by Mary J. Safford. New 

 York : William S. Gottsberger. 1881. Pp. 74. 



Mechanics' Liens. How Acquired and En- 

 forced. With an Appendix of Forms. By James 

 T. Hoyt, of the New York Bar. New York : P. 

 F. McBreen, printer. 1881. Pp. 310. 



Zoological Atlas, including Comparative 

 Anatomy, with Practical Directions and Ex- 

 planatory Text. By D. M-Alpine, F. C. S. With 

 231 Colored Figures and Diagrams. Vertebra ta. 

 Edinburgh and London : W. & A. K. Johnston. 

 1881. 



Report upon United States Geographical Sur- 

 veys west of the One Hundredth Meridian. Vol. 

 VII, Archaeology. By Frederick W. Putnam. 

 Washington : Government Printing-Office. 1879. 

 Pp. 497. Hlustrated. 



POPULAR MISCELLANY. 



Finding the Center of Popnlation. The 



computation of the center of population of 

 a country, as explained by Mr. F. D. Y. 

 Carpenter, who has performed the work for 

 the United States, for the census of 1880, is 

 not a simple or an easy process. As defined 

 in the " Statistical Atlas" of 1874, this center 

 is the point at which equilibrium would be 

 reached were the country taken as a plane 

 surface, itself without weight, but capable 

 of sustaining weight, and loaded with its 

 inhabitants, each individual being assumed 

 to be of the same gravity as every other, and 

 consequently to exert pressure on the pivot- 

 al point directly proportioned to his distance 

 therefrom. In other words, it is the center 

 of gravity of the population of the country. 

 It may be illustrated otherwise, by saying 

 that it is the point at which, if all the popu- 

 lation should assemble, the aggregate dis- 

 tance traveled by all those coming from any 

 two opposite points of the compass would 

 be respectively equal. It is found approxi- 

 mately by assuming a point as nearly as 

 possible to the true position of the center, 

 and then finding its north, south, east, and 

 west moments of population; that is, the 

 four aggregate products formed by multi- 

 plying the local populations by the distances 

 of their centers north and south of the as- 

 sumed parallel, and east and west of the as- 

 sumed meridian. The sums of the north 

 and south moments, and those of the east 

 and west moments should be severally equal 

 to each other. The differences which will 

 appear between the several sums in the 



