174 
POPULAR SCIENCE REVIEW. 
to the student of Petrology, who, as the author himself remarks, must hear 
in mind that he cannot become acquainted with this subject by reading 
alone, and that the work before him does not pretend to be more than a 
systematic rudimentary guide. 
WATTS’S DICTIONARY OF CHEMISTRY.— Third Supplement.* 
T HE present Supplement brings the general Record of Chemical Discovery 
down to the end of the year 1877, and includes some of the more 
important discoveries of 1878. As, however, it comprises an unusually long 
interval of time, it has been found necessary, in consequence of its large 
size, to publish it in Two Parts. 
The author acknowledges his obligations to Professor E. J. Mills, F.R.S., 
for an article on Cumulative Resolution ; to Professor J. E. Thorpe, F.R.S., 
for one on Flame ; and to Mr. R. Warrington, F.C.S., for articles on Forest- 
trees and on Barley. 
Among the more important articles on Inorganic Chemistry are those on 
Alum, Anorthite, Antimony, Arsenic, Barium, Bismuth, Boron, Borates, 
Cadmium, Caesium and Rubidium, Cerite Metals, Chlorine, Chromium, 
•Chrysocolla, Clays, Cobalt, Copper and its Alloys, Corundum, Didymium, 
Enstatite, and Felspars. 
The portion relating to Organic Chemistry comprehends articles on 
Acetamide, Acetic Acid, Ammonia derivatives of Acetone, Acrolein, Amyl, 
Alcohols, Anthracine, Alizarin, Benzamide, Benzine, Benzoic Acid, Butyl 
Alcohols and Ethers, Chrvsoidine, Cinchona, Cinchonine Group, Citric Acid, 
Cumene, Cyanamide Cyanates, Cymene, Diamenes, Diconic Acid, Dye Stuffs, 
Ethers, and Fermentation. 
The article on Arsenic comprehends a list of the sulphur-salts of that 
metal which are produced when hydrosulphides are saturated with arsenic 
-pentasulphide. Under the heading of Copper, the Hunt and Douglas 
process for the wet extraction of that metal from its ores is described, as 
well as the employment of phosphorus in the process of copper-refining. 
The methods used by Ilautfeuille for the production of artificial crystals 
of orthoclases and albite are given under the head of Felspar, as well as a 
large number of recent analyses of the different members of this important 
mineral group. The views of Tschermak and Yom Rath on the one hand, 
and those of Descloizeaux and Petersen on the other, relative to the 
constitution of the triclinic felspars, are concisely and clearly stated ; and 
this article may be regarded as affording a lucid summary of the present 
state of our knowledge on this subject. 
The articles on Organic Chemistry have been prepared with the care and 
•exhaustiveness for which Mr. Watts is so distinguished ; while Mr. 
Warrington’s article, of twenty-five pages, on Forest- trees is a valuable 
monograph on that important and interesting subject. 
• “A Dictionary of Chemistry and the Allied Branches of other 
Sciences.” By Henry Watts, B.A., F.R.S., &c. Third Supplement, 
Parti. London: Longmans, 1879. 
