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POPULAR SCIENCE MONTHLY. 



Seeley, H. C The Storv of the Earth. New 

 York : D. Appkton & Co. Pp. 186. 40 cents. 



Shaler, Nathaniel Southsate. Domesticated 

 Animals. New York : Charles Scribner's Sons. 

 Pp. 2C7. $2.50. 



Simeon, James. Discussions on the Gypsies, 

 and Do Snakes Swallow their Young ? Pp. 123. 

 And The Social Emancipation of the Gypsies. 

 Pp. 24. New York : Printed by E. O. Jenkins. 



Snyder, Charles Porter. The New Cosmology. 

 I'ublished by the author. Pp. 16. 



Stanley, William Ford. Notes on the Nebular 

 Theory. London : Kegan Paul, Trench, Trtib- 

 ner & Co. Pp. 257. ^s. 



Stedman, Thomas L. Twentieth Century 

 Practice. An International Encyclopsedia of Mod- 

 ern Medical Science in Twenty Volumes. New 

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Tarr, Ralph S. Elementary Physical Geogr.v 

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 Pp. 488. $1.40. 



Vulte, H. T., and Neustadt, George M. S. 

 Laboratory Manual of Inorganic Preparations. 

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Weekly Review, The. (Educational Periodi- 

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^ragtucwts ffi ^txtntt. 



A Device for Geological Teaching. It is 



now six years since there was issued a small 

 edition of an educational appliance invented 

 by James T. B. Ives, F. G. S., and appropri- 

 , ately named by him the Strata Map. Since 

 that time the inventor has made various im- 

 provements, and is now bringing out his map 

 in a more completely satisfactory form than 

 heretofore. Hanging on the wall it appears 

 as a geological map of the United States, east 

 of Denver, in the ten colors recommended 

 by the International Congress of Geologists 

 for the coloration of geological maps. On 

 touching the fastening at the upper edge of 

 the frame, the glazed front may be let down. 

 It is then found that the map consists of ten 

 cards, each of one color, all the cards being 

 cut away so that part of each is exposed to 

 view. The uppermost card represents the 

 Quaternary, and all is cut away except so 

 much as correctly represents the Quaternary 

 beds on the surface of the region. The next 

 card below it exhibits the Neocene areas in 

 the same manner, cropping out from under- 

 neath, and extending beyond, the Quaternary. 

 Then follows the Eocene, succeeded by the 

 Cretaceous, which again is underlaid by the 

 Jurasso-Triassic, and so forth. Finally, the 

 foundation represents the Archaean systems 

 collectively, and is seen exposed where the 

 well-known Archaean areas occur. The fact 

 of superposition of the formations is brought 

 home to the student by this device, while 

 denudation is illustrated by the cutting away 

 of parts of the several cards. Such resultant 

 phenomena as inliers and outliers are seen, 



also escarpments, the edge of each card form, 

 ing one in miniature ; while by tilting or 

 bending the cards, dip and strike with syn- 

 clinal and anticlinal folding may be illus- 

 trated as well as couformability of stratifi- 

 cation. One important advance which the 

 inventor has made since the earlier output of 

 his work is the embossing of the Archaean 

 foundation and all the superposed strata so 

 as to bring the whole to a plane surface. 



More recently Mr. Ives has been occupied 

 with the problem of constructing relief maps 

 combining strength and lightness with mod- 

 erate cost, printed maps being used to fur- 

 nish the geographical details in which relief 

 maps are often so deficient. One novel fea- 

 ture is the combination of distinctive colors, 

 to represent successive levels, with actual re- 

 lief. Regions that are less than one hundred 

 feet above sea level are colored buff ; from 

 one hundred to five hundred, light green, and 

 so on ; there being eight stages in all, repre- 

 sented by eight well-contrasted colors. 



These maps are made of specially pre- 

 pared paper, and the means by which the in- 

 ventor contrives to emboss them while still 

 retaining the register that is to say, making 

 the printing on the map exactly correspond 

 to the mountain peaks and river courses of 

 the embossed foundation is a secret not yet 

 divulged. 



The structural and artistic finish of these 

 maps exhibits the painstaking of one who 

 himself appreciates the value of his work. 

 They received a diploma and medal at tlie 

 Columbian Exposition, both in the Liberal 



S.. 



