NATURE 
241 
THURSDAY, JANUARY 10, 1907. 
INDIAN CLIMATOLOGY. 
Climatological Atlas of India. Published by the 
Authority of the Government of India, under the 
Direction of Sir John Eliot, K.C.I.E., F.R.S. 
Pp. xxxii+120 plates. (Issued by the Indian 
Meteorological Department, 1906.) Price 36s. 
HE Indian network of meteorological observ- 
ations is the greatest individual organisation 
within the tropics, and it has, therefore, attained the 
greatest importance in the pursuit of meteorology and 
climatology. Founded in the year 1875, it can now 
look back upon more than thirty years of uninter- 
ruptedly successful activity, having during this period 
had the peculiarly good fortune to be presided over 
by two distinguished meteorologists—Henry F. Blan- 
ford and Sir John Eliot. From the commencement 
the author of this review has followed with sympa- 
thetic interest the development and the active work 
of the organisation, has been in constant association 
with its director, and has also, as far as possible, 
~made use of the immense volume of information. In 
-no meteorological organisation in the world are there 
such comprehensive records, as well of a statistical 
as of a scientific nature, as in the Indian one; 
only the much older Russian one can compare with it. 
Beginning with the smaller, but very valuable, scien- 
tific essays of Blanford in the Proceedings of the 
Asiatic Society of Bengal, it grew into the huge folio 
volumes of the Indian Meteorological Memoirs, of 
which the seventeenth volume is completed and pub- 
lished. Then came monographs relating to individual 
cyclones, Blanford’s ‘‘ Indian Meteorologist’s Vade 
Mecum”*’ (Calcutta, 1877), and especially the five 
volumes of cyclone memoirs by Sir John Eliot, and 
his ‘*‘ Handbook of Cyclonic Storms in the Bay of 
Bengal ”’ (second edition, Calcutta, 1900). 
The introductory text to the ‘‘ Climatological] Atlas ”’ 
gives a summary of the publications of the Meteor- 
ological Department, relates the history of the de- 
velopment of the department, and describes its objects 
and aims. Reference may here be permitted to an 
older publication, ‘‘ Memoirs of the Indian Surveys,”’ 
by Sir Clements R. Markham, K.C.B., F.R:S. (second 
edition, London, 1878, xvi., pp. 275-310), in which 
is minutely described the beginnings of meteorological 
efforts in India, down to the establishment under 
Blanford of a single organisation; it also gives a very 
good analysis of the meteorological work until the 
year 1875. The text of the ‘“‘ Atlas’? contains the 
“most important facts as to the principles on which 
tthe construction of the charts is based; the means 
‘are critically derived from the observations of the 
iwenty-five years 1876-1900. 
The Indian network of meteorological observations 
extends from about latitude 6° N., in the tropical 
Indian Ocean, to the prodigious plateaus of the Hima- 
layas, under 35° N. It includes, in the south as well 
1 The complete numerical values are found in various volumes of the 
Indian Meteorological Memoirs. 
NO. 1941, VOL. 75] 
as in the north, hill stations at and above 6000 feet 
above sea-level, which supply information the 
upper strata of the atmosphere. The region contains 
the hottest and the most rainy parts of the world, and 
it is the scene of one of the most peculiar meteor- 
ological phenomena—the south-west monsoon—in 
which the wind régimes of the two hemispheres meet 
between 30° S. and about 30° N. 
From the accumulated meteorological records in 
on 
this highly interesting region we have now this 
splendid chartographic production, the ‘‘ Climato- 
logical Atlas of India.’’ This work excels in its 
completeness even the similar work the ‘ Atlas 
Climatologique de l’Empire de Russie’’ (St. Peters- 
burg, 1goo). In a certain sense these two great 
works are complementary to each other, giving us 
such a very extensive picture of the climatic variations 
over the largest continental area of the world—Asia 
and Europe—as one would hardly have hoped for a 
short time ago. The ‘‘ Indian Climatological Atlas ’” 
contains a very valuable peculiarity—it takes into 
consideration the daily variation of the meteorological 
elements, explaining their extension over the country 
during the extreme day hours 8 a.m. (10 a.m. for 
pressure) and 4 p.m., and also the daily variations of 
pressure and temperature. In India these daily vari- 
ations play a most important part. The smaller 
charts complete in a clear manner the information on 
the large charts, and they are of very great practical 
value. 
The ‘Atlas ’’ contains 120 charts in perfect tech- 
nical finish, as is expected from Bartholomew’s Geo- 
graphical Institute. The first chart (double) exhibits 
in a very excellent manner the orographical features 
of the Indian Empire, the knowledge of which is 
very important for the understanding of the pro- 
gress of meteorological phenomena over them. 
Another two-page chart shows the political divisions 
of India, influencing the selection of the meteor- 
ological stations. Then come four smaller maps, 
showing the rainfall divisions according to Blan- 
ford and Eliot respectively, the medical provinces, 
and the meteorological divisions for the Daily 
Weather Report. Upon these introductory repre- 
sentations follow a couple of double-page maps 
showing the distribution of the pressure and the 
winds in the opposite months January and July. 
These charts embrace the whole of India and the 
East African and Australian monsoon regions, ex- 
tending from 35° S. to nearly 50° N., from Asia Minor 
and East Africa in the west to Japan and the greater 
part of Australia in the east. With these we are in 
a position to see at a glance the distribution of pres- 
sure with the north-east and with the south-west 
monsoons. Both charts are very instructive, and par- 
ticularly the July one, for it shows the origin and 
advance of the south-west monsoon of western India, 
which Sir John Eliot first completely explained. A 
uniform decrease of pressure prevails then from the 
south Indian Ocean, under 30° S., up to the foot of 
the Himalayas, in 30° N., with a difference of pres- 
sure of close upon an inch (30.3 inches in the south 
and 29-4 inches in the Punjab). The wind systems of 
M 
