NOVEMBER 12, 1897. ] 
‘dichotamous’ system, now so generally and so 
deservedly popular. They are based primarily 
on length of wing, and there are usually sev- 
eral successive categories of equal rank. The 
objections to this arrangement are partly over- 
come by the use of very large type for the 
main headings. 
The books are intended primarily for sports- 
men and others ‘‘who are interested in birds 
and would like to know their names, but often 
find it no easy task to identify them by the 
‘bird books.’’’ That they fulfill this*purpose 
admirably will be evident to all who use them. 
The paper and press work are good and the 
prices remarkably low. 
Mr. Cory has made many contributions to 
ornithology, the most important of which re- 
late to the ‘Birds of the West Indies.’ His 
entertaining ‘ Hunting and Fishing in Florida,’ 
published about a year ago, gained him a wider 
circle of readers, but it is doubtful if any of 
his writings will prove so helpful to so large a 
class as the two that form the subject of this 
review. 
C.H. M, 
Les gaz de Vatmosphére. Par H. HENRIET. 
Paris, Gauthier- Villars et Fils ; Masson et Cie. 
This short treatise presents the reader in con- 
cise form a great deal of useful information 
with regard to the composition, methods of 
analysis, and réle played by the various con- 
stituents, of the atmosphere. While the refer- 
ences to recent work would seem to indicate 
that the book is abreast of the times, the fact 
that, with few exceptions, the investigations 
noted are those by French scientists only is 
not calculated to inspire confidence in the au- 
thor’s conclusions. In the text, although the 
names of others than Frenchmen occasionally 
appear, there is no reference to any paper not 
printed in a French journal. Ina bibliography 
whose length should guarantee its complete- 
ness, there is the title of one English book and 
that of one Italian memoir; the remainder are 
all French. On the other hand, as the book is 
evidently written for Frenchmen, it may be that 
the author gave only such references as would 
be readily available in almost any public library 
in France. On the whole, this defect will mili- 
SCIENCE. 
743 
tate against the use of M. Henriet’s convenient 
little book by others than his fellow-countrymen. 
Argon, a New Constituent of the Atmosphere. By 
Lorp RAYLEIGH and PROFESSOR WILLIAM 
Ramsay. Washington, The Smithsonian 
Institution. 1896. 
This paper is published by the Smithsonian 
Institution in the form in which it was presented 
in competition for one of the Hodgkins Fund 
prizes. It remains but to notice that it differs 
from the abstract which appeared in the Pro- 
ceedings of the Royal Society,* in that it contains 
detailed accounts of experiments and results 
omitted in many cases from the abstract ; and 
from the fuller paper in the Transactions,} 
since the latter incorporates the results of later 
experiments in several directions. 
It may be as well to call attention to a typo- 
graphical error in the formula (p. 35) which in- 
dicates the relation between the velocity of 
sound in a gas and the ratio of the specific 
heats: ‘N’ should be ‘ /.’ W. W. R. 
Atmospheric Actinometry and the Actinic Con- 
stitution of the Atmosphere. By BH. DUCLAUX. 
Washington, The Smithsonian Institution. 
1896. 
This paper is a translation of that presented 
by M. Duclaux in competition for one of the 
Hodgkins Fund prizes. It represents an en- 
deavor to measure the quantity and effect of 
the actinic solar rays, as distinguished from the 
luminous and calorific, under varying atmos- 
pheric and climatic conditions. 
The reagent employed for these measure- 
ments is a solution of oxalic acid ; this is rapidly 
oxidized by actinic rays, is not affected by the 
luminous rays and scarcely at all by the calo- 
rific, while the reaction is but slightly exother- 
mic. From the summary of results the following 
may be noted as of special interest: The ‘ daily 
combustion’ yaries from one day to another 
much more than any other meteorological phe- 
nomenon. Itshows the influence of the seasons 
and manifestly exhibits a maximum in the 
* Vol. 57, p. 265. This paper also was published 
in this country, e. g., American Chemical Journal, Vol. 
17, p. 225. 
+ Vol. 186, p. 187. 
