510 Notices respecting New Books. 



future edition might advantageously contain more copious reference 

 to colorimetric methods. These (though it is true they have a 

 probable error of about 2 per cent, per single determination) are 

 nevertheless quite accurate enough in numerous cases, and par- 

 ticularly for small quantities. The subject also of probable error is 

 a vital one in connection with accurate measurement. It would be 

 a great advantage to state the principal f ormulse required in quanti- 

 tative investigation. Though given in Merriman's and Airy's 

 special treatises and in Clarke's Eecalculation of the Atomic 

 Weights, they are not yet easily accessible to chemical inquirers. 

 Occasionally, also, the reader is desirous of forming an independent 

 judgment, and referring to an original memoir on a particular 

 process. It is much to be desired that in a future edition full 

 references be given. 



Any one who, like ourselves, has made a careful perusal of Mr. 

 Crookes's ' Select Methods/ has before him the necessary data for 

 answering the question, What are the general characteristics of 

 a good analytical process ? If, however, he should be inclined to 

 ask, "What is the general method of analytical discovery?" the 

 answer must be sought elsewhere. Laboratory work, laboratory 

 tradition, chemical environment, and a native chemical mind are 

 the necessary factors of a reply. But the idea of the ' Select 

 Methods' will be always at hand; and the volume itself will remain, 

 as we have said, unique in the history of chemical science. 



Fourth Annual Report of the United States Geological Survey, for 

 1882-83. By J. W. Powell, Director. 4to. Pages i-xxxii 

 and 1-473, with 48 maps and plates. Washington, 1884. 

 The Director's Eeport and the Eeports from the Heads of 

 Departments give general and in some respects special infor- 

 mation as to work and progress in the topographical, geological, 

 palseontological, chemical, and statistical branches of this extensive 

 and well- conducted Geological Survey. Plate I. indicates the extent 

 of work already done. The " Accompanying Papers " in this fine 

 volume are of great interest in many aspects, — the geographer, 

 miner, palaeontologist, and geologist finding useful matter to hand, 

 Capt. C. E. Dutton gives a full and richly illustrated account of 

 the Hawaiian Volcanoes (pp. 81-219, with 29 maps and plates). 

 Chapter XL, on " the Volcanic Problem," carefully thought out, is 

 very suggestive. An " Abstract of a Eeport on the Mining Geology 

 of the Eureka District, Nevada," by Mr. J. S. Curtis (pages 225- 

 251, with 3 plates of sections), comes next. The ores and their 

 position in Prospect Mountain and its spurs (Euby Hill in 

 particular) are treated of practically as to their occurrence and 

 hypothetically as to their sources and origin, whether as sulphurets, 

 oxides, carbonates, &c, or in a metallic state — the various ores 

 of lead, zinc, and iron, with silver and gold, being the subjects of 

 remark. 



Mr. Albert Williams, Jun., supplies a concise article on " Popular 



