[CONTRIBUTIONFROM
THE
MASSACHUSETTSINSTITUTE OF TECHNOLOGY. ]
REVIEW OF AMERICAN CHEMICAL RESEARCH. VOL. IV.
No 5 .
ARTHURA:NOYES, Editor ; HENRY P. TALBOT, Associate Editor. REVIEWERS : Analytical Chemistry, H. P. Talbot and W. H. Walker ; Biological Chemistry, W. R. Whitney ; Carbohydrates, G. W. Rolfe ; General Chemistry, A. A. Noyes ; Geological and Mineralogical Chernistry, W. 0. Crosby ; Inorganic Chemistry, Henry Fay ; Metallurgical Chemistry and Assaying, H. 0. Hofman ; Organic Chemistry, J. F. Norr i s ; Physical Chemistry, H. M. Goodwin; Sanitary Chemistry, E. H. Richards ; Technical Chemistry, A. H. Gill aod F. H. Thorp.
GEOLOGICAL CHEMISTRY. W. 0. CROSBY.REVIEWER.
Geology of Canada. Ann.Rep. Geol. Survey, Can., 7, (1894). -In the section by F. D. Adanis on the Laurentian north of the St. Lawrence river, are given the analyses which were made to establish a criterion for the distinction of gneisses of igneous and sedimentary origin. These analyses formed the basis of a separate paper in the A m . 1.Sci. (July, 1895), which has been reviewed in these pages. Under the head of Economic Resources are also several analyses of iron ores. T h e section by G. Christian Hoffman, on Chemistry and Mineralogy, consists chiefly of miscellaneous analyses of a large variety of minerals, including coals, iron ores, celestite, graphite, galenite, tetrahedrite, nickeliferous pyrrhotite, niarls, mineral waters, and many assays of gold and silver ores. GENERAL AND PHYSICAL CHEMISTRY. A. A . N O Y E S , REVIEWER.
A Revision of the Atomic Weight of Zirconium. BY F. P. VENABLE.1. A m . Cltem. SOC., 20, 11g-128.-The ratio ZrOC1,. 3H,O : ZrO, was determined by heating the former substance at 100' in a current of hydrochloric acid to a constant weight and igniting it, first gently and then to the highest heat of the Bunsen burner for three or four days. T h e mean value of the atomic weight found is 90.78, that given by Clarke in his report of last year being 90.40. Five sources of error possibly affect-
