140 



SCIENCE. 



[N. S. Vol. XV. No. 369. 



being as indicated above, but limited by cir- 

 ciimstances in many instances. The metals 

 that have been in use from earliest times, 

 either in native state or in ores, naturally 

 occupy more space than those of comparatively 

 recent origin; especially since in the former 

 class is included the development of metallur- 

 gical operations used at different periods to 

 make the metals available. 



The occurrence in nature of many of the 

 metals is very fully shown by lists of localities 

 and of ores, or minerals, the latter accom- 

 panied in many cases by f ormulEe giving their 

 chemical composition. References to authori- 

 ties cited occupy footnotes on nearly every 

 page, and as an example of their thoroughness 

 may be mentioned a note calling attention to a 

 'peculiarly American and wonderful' company 

 for extracting gold from sea-water, formed in 

 Connecticut. The history and exposure of this 

 fraud is well known to the readers of Science. 



In sketching the history of processes for ex- 

 tracting metals from their ores, the modern 

 extensive application of electricity has not 

 been neglected, especially with reference to 

 aluminium, antimony, gold, copper, silver and 

 zinc. In this connection German, British and 

 American patents are occasionally cited. 



Unusual forms or conditions of some metals 

 are named, and their chemical preparation de- 

 sci'ibed — colloidal mercury discovered by Lot- 

 termoser, and Leo's colloidal silver, but the 

 researches of Carey-Lea seem to be unknown 

 to the author. 



Among the most valuable features of this 

 work should be mentioned the statistics of 

 production and the prices; when possible the 

 figures are given for the entire nineteenth cen- 

 tury in five-year averages; and a study of 

 them brings out some striking features. The 

 contrasts in production and price of alumin- 

 ium are especially notable; from 1858 (three 

 years after the labors of St. Clair Deville had 

 made it an article of commerce) to 1884 a 

 kilogram of aluminium was quoted at 100 

 marks, during the year 1890 the price per 

 kilo fell from 27.6 to 15.2 mks., and in the fol- 

 lowing year it fell to 5 mks.; the price in 

 1897 was 2.5 mks., and the output amounted 

 to three and four tenths millions of kilos, of 



which nearly two millions were produced in 

 the United States. Sodium was quoted at 

 32.5 mks. per kilo in 1866, and at 5 mks. in 

 1897. Manganese has suffered an extraordi- 

 nary fall in price, showing that as soon as an 

 article is positively demanded by commerce, 

 means for securing it cheaply are devised; in 

 1886 manganese was quoted at 550 mks. per 

 kilo, and four years later at 40 miss.; it fell 

 in 1896 to 16 mks. per kilo. 



The price of metallic sodium in 1879 was 

 20. mks. per kilo, and it had fallen to 5 mks. 

 in 1897. Some metals of minor importance 

 maintain a relatively uniform price, as anti- 

 mony and palladium; while that of platinum 

 has risen from 500 mks. per kilo in 1870 to 

 1297 mks. in 1895, and largely owing to the 

 demand made for it by electrical apparatus. 



In pleasing contrast to these rapid fluctua- 

 tions in price is the steady behavior of the 

 king of metals — gold; the figures (in part) 

 are as follows: 



1801-05, 2736.8 mks. per kilo. 



1846-50, 2736.3 



1876-80, 2730.7 " " 



1891, 2736.3 " 



1892, 2743.2 



The important bearing of this is obvious 

 to students of monetary science. 



The author is to be commended for the pains 

 he has taken to prepare a valuable work of 

 reference; the reviewer regrets that he feels 

 obliged to point out a blemish in the manufac- 

 ture of the volume, for which the publisher is 

 primarily responsible. The running-head 

 lines, particularly important in a dictionary 

 or a book on the alphabetic plan, have been 

 omitted and their place is inadequately filled 

 by the page numbers ; this makes it difiicult to 

 find a given metal readily, although in alpha- 

 betic order, except by scanning the text closely 

 on a given page, or by examining the table of 

 contents. This economy by publishers is to be 

 deprecated. Henry Caerington Bolton. 



Practical Marine Engineering, for Marine 

 Engineers and Students, and with Aids for 

 the Applicants for Marine Engineers' 

 Licenses. By Wm. F. Durand, Professor of 

 Marine Engineering, Cornell University. 

 New York, Marine Engineering Co. 8vo. 



