July 2, 1909] 



SCIENCE 



27 



binite are safe up to a certain point while 

 nitroglycerine and blasting gelatine are not. 

 The French Commission decided that an ex- 

 plosive whose temperature of explosion, as 

 calculated by certain thermochemical data, 

 was below 1,500° C, could be licensed for use 

 in fiery mines, yet carbonite, which is one of 

 the safest of all, and several others in use, 

 have a temperature of explosion considerably 

 above 1,500° C. Bichel and Mettegang, whose 

 investigations in this field are highly praised, 

 require slow detonation as one of the charac- 

 teristics of a safe explosive, yet " the velocity 

 of detonation can not, however, be considered 

 to be a determining factor under all circum- 

 stances. Certain nitroglycerine explosives, 

 amongst which we may also include carbonite, 

 explode much more rapidly than, say bob- 

 binite, and yet show themselves to be much 

 safer when tested." Even in making firing 

 tests in galleries, as is now being done by 

 several governments and organizations, the 

 author finds that the results differ with the 

 shape and dimensions of the galleries, so that 

 each gallery may have its own ignition tem- 

 perature which would affect the results ob- 

 tained. 



In discussing this topic the author says: 

 " It has been known for a long time that coal 

 dust as well as pit gas is highly explosive," 

 while he knows perfectly well that neither coal 

 dust nor pit gas is explosive by itself, 

 though they may form explosive mixtures with 

 the air. Also in discussing " smokeless," 

 " flameless " and " safety " explosives he fails 

 to point out that these terms are used in the 

 art in a purely relative sense and that an 

 explosive possessing these purely negative 

 qualities absolutely does not exist. Justice 

 requires us to state, however, that when dis- 

 cussing catastrophes in explosive works he 

 says : " The author has always warned manu- 

 facturers and users alike that the function of 

 an explosive is to explode, and that although 

 certain compositions are almost insensitive to 

 ordinary impulses, such as blows, friction, 

 etc., yet he never believed that any explosive 

 existed which under favorable conditions and 

 by proper means could not be made to ex- 



plode," but this point is emphasized because 

 in a publication such as this, which may be 

 cited as authority in litigation in which im- 

 portant interests are involved, care should be 

 taken that no loose terms or unqualified 

 phrases regarding the properties of matter are 

 used. 



Surprise is expressed at the extent to which 

 black powder is still being used, it being stated 

 that 7,000 tons of it were used in the mines 

 and quarries of Great Britain, and 3,597 tons 

 exported in 1907, making 10,597 tons in all. 

 This is markedly less than the output of the 

 United States, where the production of black 

 powder at the census of 1900 was 62,412 short 

 tons and at that of 1905 was 107,910 short 

 tons. In fact, since the statistics of this in- 

 dustry in the United States were first sepa- 

 rately taken, at the census of 1840 there has 

 been a constant increase at each decade, and 

 this failure of " smokeless " powder to sup- 

 plant black powder was commented on with 

 fullness in the Census Bulletin for 1900. 



The book is filled with information, much 

 of which is quite up to date, and it bristles 

 with references, a large part of which are to 

 British patents. A defect is in its limited 

 use of American sources, patent or other 

 readily accessible literature, for a country 

 which produced 363,748,097 pounds of ex- 

 plosives of all kinds in the census year 1905 

 can not have failed to have made useful con- 

 tributions to the progress of the art. Never- 

 theless, the book is a good one. It is more 

 than a compilation, for it is thoughtful, crit- 

 ical and sometimes controversial. Every one 

 of the many who possess the parent volumes 

 must also acquire this and they will be pleased 

 to have done so. 



Charles E. Munroe 



Birds of the World. By Erank H. Knowl- 

 TON, Ph.D., with a Chapter on the Anatomy 

 of Birds by Erederic A. Lucas. The whole 

 edited by Robert Ridgway. With 16 col- 

 ored plates and 236 other illustrations. 

 American Nature Series, Group 1, Natural 

 History, pp. i-xiv, 1-874. New York, 

 Henry Holt & Co. 1909. 



