The San Francisco call., 1896-08-05
His Kites Struck Sunny Gains at
Only Eighteen Hundred
Feet.
WE'LL KNOW OUR WINDS YET.
Project to Measure Sea Breezes in
Cubic Miles Per Minute for
the Interior.

Forecast Official HammOn gave some
information yesterday which shows what
a low, groveling life the people of San
Francisco lead, albeit they vaunt much Of
many things.
Attached to this new reason why the
spirit of San Francisco mortals should not
be overproud is an interesting scientific
discovery. This discovery relates entirely
to the air.
Harmon has really discovered some
thing that nobody has known before, and
which is worth knowing these midsummer
days, as the nasty thirty-eig ht-mile gales
try to sweep the streets and to use the
eyes of citizens for dustpans. He has dis
covered that it is but just little way up
ward to airs that are warm and calm-not
as far as from Kearny street to the City
Hall.
He has sounded in an upward way the
listing gales which constitute this City s
characteristic summer winds, and has
found that the air current which sweeps in
through this gap in the Coast Range
whenever the interior is hot is much
smaller in vertical measurement than he
or anybody else who happened to think OF
at all has thought.
Harmon has recently measured this
the sea breeze was found to be only 1900
feet deep; all the other time it was $500
feet.
This is not very deep, or rather, very
high Tamalpais rises to 1900 feet and
Tam alpais is not very long measuring
pole when aerial exploration is consid-
cred. So the sea breezes that rush in
through the Golden Gate and over the low
peninsula are but surface disturbances
which San Francisco people suffer from
because they are so low.
Mr.. Hammon's discovery is really
worthy of consideration and it Is an
important scientific discovery. In one
sense the discovery is big one, and in an
other sense it is small one, 1t may be
the forerunner of extremely interesting
scientific discoveries. and it may be of
much practical importance in relation to
the forecasting of the summer weather
conditions of the great interior basin of
the State, which is geographically COM
posed OF the Sacramento ana San Joaquin
valleys.
1t may seem peculiar. but it is neverthe-
less true that the Weather Bureau may be
soon measuring in cubic miles per minute
the cold sea ar that blows into this great
interior basin, giving it whatever blessed
degree of GOODNESS the people therein may
receive. There is no place in the world
where such a possible problem and its
practical solution are possible.
The cooling air which this vast interior
basin gratefully receives in midsummer
comes to it mainly through this Golden
Gate gap in the Coast Range of mountains
which hem in the valley from Tehachapi
to Mount Shasta. This gap supplies cold
sea air to the interior just about as the
narrow Golden Gate supplies tide water to
the great expanse of inland waters which
comprise San Francisco, San Pablo and
Suisun bays and the sloughs about them.
The tide rushes in and out and its volume
may be measured at the Golden Gate.
In a similar way the cold sea air rushes
in through this gap and the sea breezes
which pour in ever the San Francisco
peninsula, between Mount Tamalpais on
the north and the San Bruno hills on the
south, supply nearly all the cooling air
which the Sacramento and San Joaquin
valleys receive, and determine and create
the day winds in those valleys. Little if
any sea air gets into these valleys over the
Coast Range north and south of San Fran
CISCO Through the Golden Gate the sea
air pours in, and it turns north in the Sac
ramento Valley, giving it southwest winds,
and it turns south into the San Joaquin
Valley, giving it its prevailing summer
northwest winds.
Neither the Weather Bureau nor any
body else knows anything about the
amount, times and character of the sea
breezes that may or may not creep into
this great interior basin over and through
other passes in the Coast Range. This
presents a new and wholly unworked
problem. But it is known that the great
body of cool air which pours into the
interior valley basin goes through the
Golden Gate gap in which San Francisco
lies.
Now one may realize the Importance and
interest of measuring the flow of air
through this gap. That is what Mr.. Ham
mon is trying to do and wants to do. and
if he were able to do it daily he would be
able to forecast much more accurately the
weather OF the interior. The problem
offered is simple though interesting. Its
solution needs a little money. If the
weather forecaster could every day tell
how many cubic miles of cold air per
minute or hour were flowing inward he
could tell more about the next days
weather.
For instance, the thermometer at the
surface gives the surface speed of the wind.
But the thermometer does not tell whether
the current is 1000 feet deep or $500 feet.
The tidal inflow o. water can be accu-
rately measured. A horizontal section of
the gap can be easily measured for any
altitude. Given the speed of the wind and
the height of the current and the cubic-air
measurement may be made. If the cur
rent moving IN at Lnlrty miles an EOUr Is
1000 feet in depth the amount of cool air
being supplied to the interior will be a
certain percentage OF that being supplied
if the current is $500 feet ia depth.
Now, this is one of the things Mr.. Ham
mon and Mr.. McAdie have been trying TO
get at with their Kites, and it is Mr.. Ham
mons long. somewhat dlscouraging but
persistent experiments which have re-
resulted in his two measurements of the
height of the sea breeze.
Both discoveries were the result of THE
CALLS interest and cooperation with Mr..
Hammo IS ex xperiments. Thanks to THE
CALL Mr.. Harmon has recently been en-
abled to send up focks of tandem kites and
add some degrees of success to his expert
ments On one occasion the kites went to
an altitude of $500 feet and showed that
the current in which they sailed extended
upward to that height. On the last occa-
sion, few days ago, a singular thing hap
pened. The first, or rather the last kite,
rose 10 about 1900 feet and stopped. The
second kite, hitched TO the string far be-
low it, also ascended to the same height
and stopped The third kite, 800 feet still
lower itself was carried to the same