REVIEWS 377 



ordinary interest, and the volume will be useful to all who are interested 

 in the manufacture of cement. 



The various methods of making chemical analyses of the raw materials 

 are given in detail. Following the chemical analyses is a series of mechan- 

 ical analyses. These mechanical analyses are given because the physical 

 character of the clay has an influence on its chemical activity when the 

 cement is burned. 



The chapter on "The Nature of Portland Cement" contains the results 

 of investigations since 1887. The preparation of this summary must 

 have required considerable labor, for many of the original papers are 

 printed in French or German. The results of the author's investigations 

 form a valuable contribution to the subject. 



Every detail of cement manufacture is explained from the mining 

 of the raw materials to the pulverizing and testing of the finished product. 

 One of the most important features of the volume is the series of contri- 

 butions made by the author to various problems of cement manufacture. 



On pp. 155-57 the author gives a list of the unsolved problems connected 

 with the chemical and physical analysis of cements. A perusal of this 

 list indicates that there is a large field open to the investigator who has a 

 thorough knowledge of chemistry and physics. 



A few pages are devoted to a description of Ohio cement plants, with a 

 statement of the raw materials used and the size and capacity of each plant. 



G. C. M. 



Preliminary Report on the Ohio Co-operative Topographic Survey, 

 November 15, 1903. By C. E. Sherman. Pp. 227. 



This work has been in progress three years, the average appropriation 

 by the state being $25,000 per year. To this appropriation the United 

 States Geological Survey adds an equal amount, besides bearing all the 

 expense of engraving and printing the maps. It is estimated that the 

 entire state will be mapped within five years at a cost, to the state, of 

 $25,000 per year. 



The maps are made in accordance with the general plan of the United 



States Geological Survey, the only exceptional feature being the numbering 



of the sections. It is proposed to indicate the areas of woodland after 



the maps are printed. Numbering the sections and indicating the wooded 



areas will add much to the value of the maps. 



G. C. M. 



