The record-union., 1899-04-11
A RAINFALL CHART.
RAINFALL FOR FIFTY YEARS
AT SAN FRANCISCO.
Are the Seasons and is the Climate
Changing?-The Data Gives
Negative Answer.

There has been issued a chart show
ing the rainfall at the city OF san
Francisco for every month and season
from that of 1S49-50 to 1S9S-99. The
charting is done in an elaborate man
ner and with detail quite exhaustive.
The period covered is fifty years and
thus data is furnished for rational ana
reasonably safe judgment as to the nat
ural and recurring rainfall seasons IL
is quite impossible to indicate briefly
and satisfactorily the character OF the
charting. 1t must suffice for US to say
that it is upon a scale and after
method presenting the subject to the
eye with ease and to the mind with
convincing force.
The chart was compiled by Herman
Schuealer, C. E., and is issued by the
directorate of the Central Pacific Rail-
road Company, being adopted by that
body March %, 1899.
The value of this chart can scarcely
be overestimated 1t gives information
in a form readily absorbed, that VIII
go exceedingly far in correcting erron-
eous Judgment and removing fears not
justified by fact, but largely enter
tanned.
Accompanying this valuable chart is
corner chapter, written by William II.
Mills, more clearly to- indicate the worth
and exposition of the chart we quote
that chapter, as the deductions are full
of interest:
THE memory of man relating to me-
teoric phenomena in past seasons is
wholly unreliable. The occurrence OF
two or three seasons of unusual preclp-
itation or of drouth frequently gives
rise to apprehension relating to perma-
nent changes of climate. Moreover
two or three strikingly cold or warm
winters win be the occasion for pre-
dictions of permanent changes relating
to the severity or clemency of the Win
ter seasons If no meteorological rec
ords could be appealed to; if all past
observation rested merely in the mem
ory Of man, the more recent seasons
still within the horizon of memory
would be accepted as the standard OF
permanent climatic conditions.
There are no instances of sudden
charges of climate. The denudation Of
forests in certain portions of the world
has brought about a gradual decline OF
annual precipitation of moisture and
wrought changes in the observation of
thermal conditions: but such changes
are very gradual and before they can
be accepted as evidence of permanently
changed or changing conditions, they
must extend over periods embracing
centuries.
The two drouth years of 1S62-63 and
1SG3-64 occasioned apprehensions con-
cerning the permanent decline in the
quantity of seasonal rainfall. The set
tlenent of this State at that time was
comparatively recent and no records
had been kept prior to the American
occupancy. Unusual phenomena in new
countries create greater apprehension
in the minds of their occupants than
like phenomena in the older settled re-
gions of the earth. The default of a
seasons rainfall, an unusually hard
winter, the total failure of crops in a
country but recently occupied by civil
ized man, are the occasion of greater
distrust than the same conditions in
older settled regions, because the re-
corded precedent of restoration to nor
NAL conditions in the new country is
wanting.
'The extraordinary drouth of the
rainy season of 1S97-9S in California,
with the threatened drouth of 1898 90,
which was happily broken by the rain
fall which commenced on the 14th day
of March, gave rise to much discourage
ment relating to the probability of per-
manent climatic changes
Since the past meteorological his
tory of any climate may be accepted as
prophetic Of the immediate future his
tory, this rain chart for every month of
fifty years and the seasonal rain chart
fer the same period becomes valuable
as affording assurance of future condi-
tions.
THE student of the chart will find for
himself many interesting facts. but will
find none to justify the conclusion that
the climate' of California has undergone
OF is undergoing any changed condi-
tons which would justify any appre-
hension as to future floods or drouth.
To some of the more obvious facts at
tention is called.
ta) Inc drouth of the greatest Sc
verify occurred in the season of 1870
1851, when the precipitation at san
Francisco was only 7.4O inches. Thir-
Teen years later drouth analogous to
that of the former season occurred in
" ISOo-Ot, WHen the DrGclDI-
tation was but 1929 inches. Thirteen
years later in the season of 1867 q
partial drouth occurred, when the pre-
cipitation was 11.04 inches. The sea-
sonal chart will disclose the fact that
from the season of 1S76-77 to the sea-
son or lS97-9S, period of twenty one
years, no drouth is recorded. the lowest
precipitation for any season during that
entire period being 1914 inches.
"(b) In period of fifty years there
have been but two drouth seasons an
proximately equal in severity, that OF
lSoO-5l and that of 1S97-9S They are
forty-eight years distant from each
other in point of time.
"(c) Dividing the fifty years into two
equal periods of twenty-five each, we
find the aggregate rainfall for the
first twenty-five years to be 595. II
inches, and the aggregate for the last
twenty-five years, or to the end of this
season. to be 569S5 inches. showing a
remarkable evenness, and presenting no
difference possessing any significance.
"(d) Dividing the forty-eight seasons
from 1S49-50 to 1S96-97 into four equal
periods of twelve years each, gives the
following results:
From 1s4s to 1851. twelve seasons. .26s. 81
From 1861 to 1873, twelve seasons. .30I 81
From 1873 to 1885, twelve seasons 2S2. 81
From 1888 to 1896, twelve seasons. .2S7. ii
'(e) The last group of twelve seasons
L., 4 ty1n nl,A<.