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THE POPULAR SCIENCE MONTHLY. 



DKSCRimvE America. A Geographical and 

 Industrial ilouthly Magazine ; L. P. 

 Brockett, Editor. Pp. 32. Price, $5 a 

 year ; oO cents a number. 



Each number of this publication is de- 

 voted to a particular State. Tlie number 

 before U9, which is marlted Vol. I, No. 6, 

 is given to Georgia. It includes a fine map 

 of the State, a list of cities, towns, villages, 

 and stations, an editorial article on interna- 

 tional exhibitions, and chapters describing 

 the State in general and relating to cotton 

 and rice culture, lauds, population, immi- 

 gration, education, the representative men, 

 the religious condition, government, finances, 

 debt, and taxation and history of the State, 

 with a statistical table of counties. Several 

 of these articles are furnished by men disl 

 tinguished or representative in the specia- 

 fields to which the papers respectively relate. 



Van Nostrand's Science Series. New 

 York : D. Van Nostrand. Price, 50 

 cents each. 



No. 73. Symbolic Algebra ; or, The Al- 

 gebra of Algebraic Numbers. By Professor 

 William Cain. Pp. 131. The object of 

 this essay is the discussion of negative 

 quantities of algebra, with the purpose of 

 finding a logically developed system that 

 shall include such quantities as special 

 cases. The volume also includes some criti- 

 cal notes on the methods of reasoning em- 

 ployed in geometry. 



No. 74. Testing-Machines : Their His- 

 tory, Construction, and Use. By Arthur V. 

 Abbott. Pp. 190. Mr. Abbott has been 

 engaged for several years in developing and 

 applying methods of testing the strength of 

 materials, and in this book explains such of 

 his most successful methods as seem likely 

 to be generally useful and interesting. 



No. 75. Recent Progress in Dynamo- 

 Electric Machines. By Professor Silva- 

 Kus P. Thompson. Pp. 113. This is are- 

 print of lectures delivered before the Eng- 

 lish Society of Arts on the subject indicated 

 in the title, which were supplementary to a 

 previous series of lectures on the theory of 

 the dynamo and its functions as a mechani- 

 cal motor. 



No. 77. SrAniA-ScRTEYiNa. By Arthur 

 Wi.NSLOw. Pp. 148. This hand-book con- 

 tains a complete exposition of the theory 

 of stadia measurements, with directions for 



its application in the field. Tables for the 

 reduction of observations are added which 

 the author has used in the Geological Sur- 

 vey of Pennsylvania, and with them tho 

 trigonometrical four-place tables. 



No. 78. The Steam-Engixe Indicator. 

 By William Barxet Le Van. Pp. 169. 

 In this book the indicator and its object are 

 described ; its construction and action are 

 explained ; and the method of calculating 

 the horse-power of engines is illustrated. 

 An endeavor has also been made to explain 

 the most important parts of the theory and 

 action of steam, and to show the modes of 

 working engines that have been found to 

 be most advantageous. 



No. 79. The Figcre of the Earth. By 

 Frank C. Roberts, C. E. Pp. 95. In this 

 book the historical data in connection with 

 the figure of the earth are presented, and 

 the important mathematical principles for 

 the deduction of it upon the spheroidal hy- 

 pothesis arc arranged in a compact form. 



No. 80. Healthy Foundations for 

 Houses. By Glenn Brown. Pp. 143. This 

 is a reprint of a serial paper published in 

 the " Sanitary Engineer " during 1884, with 

 fifty one illustrations from drawings made 

 for the articles by the author. 



Maps of the Dominion of Canada. Tele- 

 graph and Signal Service. Sir Hector 

 L. Langevin, Minister of Public Works. 

 In sheets. 



These maps arc intended to be full, and 

 are very handsomely executed. The group 

 now under notice contains two sheets of the 

 Eastern section, two of the West-Central 

 section, two of the Western or Pacific coast 

 section, with a Mcrcator chart of telegraphic 

 lines and electric-cable connections through- 

 out the world ; and a map on a spherical 

 projection showing the world's submarine 

 cables and principal telegraph lines. 



Notes from the Physiological Laboratory 

 OF THE University of Pennsylvania. 

 Edited by N. A. Randolph and Samukl 

 G. Dixon. Philadelphia. Pp. 88. 



A collection of '■ brief records of facta 

 of interest brought to light in the course of 

 physiological study." The constant aim of 

 the writers has been to present these facta 

 with the greatest conciseness compatible 

 with scientific accuracy. 



