4:56 Scientific Intelligence. 



finally attained. The prominent forms of regulators, devised 

 from time to time, are described fully and in historical order. 

 The various special problems which have arisen, as the division of 

 the electric light, the application of the light for signals at sea, 

 the relation of light intensity to distance of visibility, and so 

 on, are also treated in detail. The three parts now issued com- 

 plete about one-half of the work as planned. 



15. The new Knowledge : A popular Account of the new Phys- 

 ics and the new Chemistry in their Relation to the new Theory 

 of Matter • by Robert Kennedy Duncan. 263 pp., 8vo. New 

 York, 1905 (A. S. Barnes & Co.). — There is no reason why, at 

 the present day, the intelligent laymen should not acquire a 

 reasonably good knowledge of the progress that is being made 

 in the different branches of science, for books are not wanting 

 which put before him the facts in a form requiring a minimum 

 of preliminary training. The volume at hand is one having this 

 object, but its scope is broader than usual, and the nature of 

 matter, as now understood, and the light thrown upon the sub- 

 ject by the phenomena of electricity and radio-activity are pre- 

 sented with much system and clearness, and with a style to attract 

 the reader. The closing chapters reach out beyond the earth to 

 some of the problems of the stellar universe. 



16. Percentage Tables for Elementary Analysis ; by Leo F. 

 Guttmann, Ph.D. 43 pp. 8vo. New York and London, 1904 

 (Whittaker & Co.). — These tables, reproduced here from the 

 German edition, will be found most useful by the practical chem- 

 ist, as they give him at once with all necessary accuracy (to four 

 decimal places), from the amount of carbon dioxide and water 

 yielded on combustion by the substance under examination, the 

 percentage of carbon and hydrogen which it contains. A pro- 

 portional table opens the volume and one for the reduction of 

 volumes of nitrogen to grams is added at the end. 



II. Geology and Mineralogy. 



1. United States Geological Survey, Charles D. Walcott, 

 Director. — The following publications have been recently re- 

 ceived ; notices of some of them are deferred to a later number. 



Geologic Folios. No. 117. Casselton-Fargo Folio, North 

 Dakota-Minnesota ; by C. M. Hall and D. E. Willard. 



No. 118. Greeneville Folio, Tennessee-North Carolina ; by 

 Arthur Keith. 



No. 119. Fayetteville Folio, Arkansas-Missouri; by G. I. 

 Adams and E. O. Ulrich. 



Professional Papers. No. 32. Preliminary Report on the 

 Geology and Underground Water Resources of the Central Great 

 Plains; by N. H. Darton. 433 pp. 4to, 72 plates, 18 figures. 



No. 39. Forest Conditions in the Gila River Forest Reserve, 

 New Mexico ; by 'Theodore F. Rixon. 89 pp. with folded map 

 and diagram. 



