_] 
January I, 1914] 
NATURE 
“6 
595 
The first part of the book tells the pathetic 
tale of the causes and factors of extermination, 
mainly of birds and mammals, in process all over 
the world, from the song-birds of Europe and 
the Southern States of America, to the pheasants 
of the east and the big game of Africa. In the 
second part he deals with the economic and other 
reasons for the preservation of species, with the 
laws that should be passed to achieve that end, 
with game reserves, &c. The book is well illus- 
trated with figures of many of the interesting 
species threatcned with extermination, and with 
maps showing their past and present distri- 
bution. 3 
“Trees in Winter ” (3) is essentially a work on 
arboriculture. By the term winter the authors 
mean that period when the tree is in its resting con- 
dition, a period which may ‘be considered to, 
extend from the shedding of the leaves in the fall 
to the bursting of the buds in the spring, 
which varies for different trees in different locali- 
ties. In the north-eastern United States, for in- 
stance, it may begin as early as the latter part 
of September, and may extend even into the 
middle of May. 
_.The subject-matter is divided into two parts. 
Part i.. deals with the buying, planting, and 
eare of trees mainly during their dormant con- 
dition, but it also contains much valuable informa- 
tion, and many important hints on spraying and 
_ the treatment of fungus growths and insect pests 
during the growing season. It was written 
primarily for the use of those who possess trees 
of their own in gardens or parks, and not for a 
municipal tree-planting commission.  Neverthe- 
less, it will be of inestimable service to those 
responsible for the well-being and upkeep of trees ' 
in the streets and public squares within city pre- 
cincts. This part was specially written at the 
_ request of the publishers as an economically useful 
» addition to part ii., the material of which first 
' appeared in pamphlet form as a bulletin of the 
| Storrs Agricultural Experiment Station, and 
| proved in such demand, especially for use in 
ore 
' schools, that it seemed desirable to issue it in book 
form, and thus render it more widely available 
than. would be the case if its circulation were 
_ | restricted to the limitation of a State publication. 
| 
} 
pe. 
ww 
! descriptions e  specit 
‘arranged, every. species being illustrated by photo- 
This part deals with the identification of trees.. 
It leads off with an analytical key to the genera 
and species; and this is followed by ‘detailed 
of the species, systematically 
graphs showing its mode of growth, its twigs, 
fruit, and other structural details. 
Although the trivial names employed are not 
always the same as those used in England—what 
we commonly know as the plane tree, for in- 
stance, is called the sycamore—this fact will in 
no way detract from the value of the book to 
arboriculturists in this country, because the admir- 
able descriptions and pictures make confusion of 
the species impossible. 
‘Roa BRL 
NO. 2305, VOL. 92] ; 
THE MINERAL RESOURCES OF THE 
UNITED STATES.) 
Sie record of the annual mineral production 
of the United States has now increased in 
size until it occupies two large volumes of 2242 
pages in all. These forma storehouse of informa- 
tion concerning a number of matters connected 
directly or indirectly with the mineral industry of 
America, whilst statistics of, and information 
about, the production of minerals in other parts 
of the world are given for the purpose of com- 
parison. The methods are the same as those 
employed in previous years, one of the two 
volumes being devoted to the metalliferous 
minerals and the other to the non-metals. From 
the economic point of view the latter are the 
more important, the value of the coal production 
of the United States being nearly one-third of the 
total value of the whole of the mineral products, 
this latter amounting to the huge sum of 
close upon 400,000,000]. As the population of 
the United States is just about 92 millions, the 
annual mineral production amounts to well over 
4l. per head of the population. 
_ The above total shows a small decrease, equal 
to 2°65 per cent., on the value of the production 
in 1910, in which latter year the record value 
attained in 1907 had again been nearly reached. 
Practically the whole of the above drop was due 
to a decline in the value of the pig-iron production, 
the statistics for the metalliferous minerals being 
based, as in previous years, upon the metals pro- 
duced from the ores, and not upon the ores them- 
selves. The production of pig-iron in 1911 was 
23,649,547 toms, as against 27,303,567 tons in 
1910, a decrease of 13°3 per cent., whilst the out- 
put of iron-ore declined simultaneously from 
51,155,437 tons to 40,989,808 tons, equal to a 
decrease of 23°4 per cent. The only cause that 
can be assigned for this decrease was over-pro- 
duction in 1910, which necessarily caused a de- 
creased demand in 1911. It is quite certain that 
this decrease was in no way due to natural causes, 
the capacity of the mines to produce the requisite 
supply of iron-ore being in no way diminished. 
The output of gold was practically unchanged, 
whilst that of silver showed a moderate increase ; 
in the same way there was but little difference 
in the copper production, whilst in the production 
of lead and zinc increases were shown, though in 
no case of .any great importance. 
. The coal output in 1911 was but little less than 
in 1910, namely, just over 496 millions of tons, 
as against about 5014 millions of tons in 1910. 
In 1911 the production of petroleum, on the other 
hand, showed an increase, namely, 2204 millions, 
as against 209} millions of barrels. 
In a similar way fluctuations, though not to 
any marked extent, occur in the less important 
mineral products, but the net result left by the 
perusal of these statistics is the distinct impression 
1 “The Mineral Resources of the United States, Calendar Year igrt. 
Part i. Metals. Pp. 1013. Part ii. Non-metals. Pp. 1224+maps. 
(Washington: United States Geological Survey, Government Printing 
Office, r912.) 
