BPBIL, 1908.
Even the so-called Plateau high,  an area of high pressure
that occasionally lodges over the Great Basin in winter, does
not persist on the average over two or three days. There are
times, of course, when it persists for a longer period, but on
these occasions it is believed that the endurance beyond the
average period is due to the inflow of cold air from the north-
west. In other words, the Great Basin, owing to the topo-
graphic surroundings, actually serves as a basin or reservoir in
which part of the cold air which has a slow eastward or south-
ward motion is entrapped.
One of the reasons for entertaining this view is the fact that
offshoots from the Plateau high  are frequently discharged
to the eastward or southeastward. After the discharge of an
offshoot the parent high soon disintegrates. It is also be-
lieved that owing to local radiation, and the drainage of cold
air into the valleys occupied by Weather Bureau stations, the
sea-level pressures for the Plateau region, are at times greatly
affected by these local surface temperature falls.
An area of high pressure firnily lodged over the Great Basin
is a most important asset to the forecaster, not only on the
Pacific slope, but eastward from the Rocky Mountains includ-
ing the Northern and Central States.
As I said before, according to my experience, there is no
distinct pressure formation in this country that approaches a
condition of subpermanency. There are times when the highs
and lows follow each other in nearly the same path. When
this condition prevails it is customary to say that a certain
type prevails. The same phenomenon has been observed in
Europe: See Nils Ekholm in the January, 1907, Meteorolo-
gische Zeitschrift, G c Uber die Unperiodische Luftdrucksch-
wankungen und einige damit zusammenhiingende Erschei-
nungen. (On the nonperiodic pressure variations and some
phenomena in connection therewith.)
. It seems to me that it would be profitable to study the daily
weather maps in periods of less than a month since the latter
period is too apt to include the records of more than one type.
It might be possible to do this for the Pacific coast where the
atmospherio movements are less complicated than in eastern
districts.
As an illustration of what one would meet in attempting to
correlate monthly mean pressures and weather conditions, I
submit, herewith, copies of the monthly mean pressures for
March, for the years 1902 to 1906, together with the paths of
highs and lows on the Pacific coast and over the Plateau
region. But one of these months (March, 1904) shows a steadiness in the movement of lows that would be useful to
the forecaster. (Charts SI to SV.)
Aside from the forecasting point of view considerable
interest attaches to this subject on account of its bearing upon
a rational explanation of climate. In this connection see
Bulletin Q, under  Seasonal variations of the weather.
In regard to Professor McAdies second proposition, I would
say that we are never certain that the pressure distribution
and the weather conditions existing at any moment of time
will match the actual conditions to the eastward in the nest
twenty-four hours.-A. J. H.
101
UAN W E PROTEUT AGAINST TOFWADOEST
A well-constructed conductor is a fairly reliable protection
against destruction by lightning, but one must be inside the
protected building, as there is no assurance of safety on the
outside. A dwelling may be so constructed as to pass unin-
jured thru a hurricane, tornado, earthquake, fiood, or fire, tho
it is rare that suah are built, and that which is safe against
one kind of visitation may not be so for another.
The following correspondence shows one phase of the ques-
tion of protection. We should like to have some one compile
15-3
enough data to give us a fairly correct idea as to whether it is
best to be frightened at every storm cloud and run to the
shelter of the c c tornado cave, or whether we may not as well
be brave and calmly await the dread visitation, since it is most
likely to pass us by. As the result of his extensive studies
Lieut. John P. Finley maintained that the best we oan do is
to watch the distant tornado, and if it seems to approach us
then move away toward the left; so far as we have learned,
this still continues to be the best rule.
(1) LETTER FROM A CORRESPONDENT TO THE CHIEF OF BUREAU.
I am going t o establish in this city a system which will give us warn- ing of the approach of tornadoes, which is as follows:
We will run a pole line around our city at a distance of four miles, which is connected to an alarm in the city by wires, using the very best
of wire and puttlng up the line in the most substantial manner. There will he two wires on this circuit around the town. We will place instru- ments a quarter of a mile apart on this line, to be adjusted to short- circuit the wires by making an electric contact, should a change in the atmosphere pressure (of as much as three-tenths of an inch) take plaae within flve minutes.
The magnetic apparatus for giving an alarm in the city is arranged 80
that if one or both the wires are broken it will cause an alarm to be given, or should the wires touch one another by being twisted together
it would give an alarm; also should the instrument short-circuit the wires by the sudden change in the air pressure, we would receive
alarm. We will have notice in advance of the tornado by the time it would take i t to travel from the instrument or pole line to the city, and
as the line is all around the city, at a distance of four miles, it would be uuable to reach the city from any direction without giving us an alarm.
I have kept in touch with the great work that your Bureau is doing under your able management, and I earnestly hope that you and your good workers may live to quite an old age, as you have done much to
overcome ignorance and superstition in regard to the many fake idem of the people in regard to forecasting the weather.
REPLY TO THE ABOVE LETTEB BY THE EDITOR.
You propose to surround your city by a double line of telegraph wire
inclosing an area about 8 miles in diameter or 25 miles in circumference.
A t every quarter mile of this circumference (100 stations in all) you will place an apparatus that will automatically shoi-kafrcuit the line whenever
the atmospheric pressure rises or falls at the rate of three-tenths of M
inch in flve minutes, or faster. The wires will also be short-circuited,
or an alarm given, i f either wire is broken or if the wires touch each other. You think that thls system of alarms will protect the city from
the unexpected arrival of a tornado. The statistics of tornado frequency show that a region of 1 square
mile any where in Missouri ie not very apt to experience a tornado, the probability being one-sixteenth of one per cent per century, so that a region 4 mlles square would have a probability of 1 per cent per century; that is to say, i t will presumably have a tornado once in ten thousand years. It is therefore probable that your system of wires and apparatus would have t o be kept In working order many years before it could be of use; and unless i t be kept in perfect repair, at great expense, i t will
be out of order and useless when the tornado comes. For these reasons many schemes analogous to yours which have been proposed in the last
forty years have been abandoned as impracticable. If you have any statistics showing that tornadoes are specially frequent in the neighbor-
hood of . . . . . . . . . . . . . . I should he glad to receive them and revise this calculation.
Ynu state that you are going to establish your system around . . . . . . . .: does this mean that you are going to do it at the expense of the city, or as a private enterprise?
(3) SECOND LETTER FROM A CORRESPONDENT.
In reply to your letter, I will say that I am unable to give you any additional information in regard t o the frequenoy of tornadoes in this
State, for the following reasons:
1. That most newspapers, as well as the public in general, call tornadoes
cyclones.
2. I have only been able to visit a few of the damaging storms to mcertain what they were.
3. That I believe that only a small per cent of the tornadoes reach the
earths surface, and i t seems to me that it would be dimcult on this account t o ascertain or even attempt to approximate the number of tor- nadoes in any locality. I quite agree with you that i t is only a small per cent of tornadoes
that do damage in this State, but there are so many dark, dangerous, and threatening-looking clouds that we will be uneasy, and this will
cause us to always keep our alarm system in the best of condition for fear that they are tornadoes. I have only this one life to live, and being healthy and enjoying it
there is no expense I would not undergo to protect it, 88 I prefer living
to any other state or condition I can imagine. We will not install this
102 MONTHLP WEATHER m m . APRIL, 1908
alarm system because we want frequent tornadoes, but quite on the con- trary because we do not, but want to be forewarned when there is one. The Weather Bureau omciala deserve credit for the work that they
have done in giving us facts and figures to work from, as well as the many wonderful discoveries they have made. They have taken an
uneducated people which had all kinds of superstitious ideas in regard
to foretelling the pending weather, based on myths and old traditions, until after a process of evolution and hard work on their part we have
now a Weather Bureau superior t o any in the world. They educated
themselves while educating the masses until they have reached this
state of proficiency. All this has-been accomplished within the last forty years, and if these same persons are kept in charge of this work,
I believe our Bureau will advance as much within the same time in the
future. While there is life there is room for progress.
I have read your articles in the WEIITHER REVIEW and have gained much information in regard t o lows and highs and the conditions accom- panying them, and it seems t o me that there is not much work left
undone. I also read what you write with special interest, because it impresses me that you are dealing with facts as you flnd them regardless of what theory they may upset or uphold; like all true scientists, you are seeking the truth. I am only a beginner, and any suggestions and information that you
will kindly give will be appreciated. I am open to conviction and believe that we all should 80 school ourselves aa to be a61e at the end of each
period to slough off the skin of preference or prejudice that may have hardened itself around us during the last period.
(4) REPLY SENT TO SECOND LETTER BY EDITOR.
I n reply to yours of July 27 I may thank you for saying that the Weather Bureau deserves credit for the work it has done in giving facts and flgures, and educating the people above superstitions and errors In regard to the weather; but our efforts t o benefit the people will be in vain
if, in spite of our facts and figures, you create an unnecessery dread or fright with regard to tornadoes in your locality. I see no reason to be-
lieve that your system of telegraph line and automatic signals will give any reliable forewarning of a tornado: and should advise you and the city not to waste money on it. You state your belief that only a small
per cent of tornadoes do damage at the earth's surface, in your State, and the rest do not reach the ground. You also add that you can not give any additional information about tornadoes, because the public gen- erally call them cyclones. Neither of these ideas is true; the use of two
terms, tornado " and 'L cyclone," need not produce any confusion in the statistics of frequency. The tornadoes that do damage et the earth's surface are the only ones that need to be counted in any efforts that you
make to provide against them; and, as I wrote before, them are so rare that a region four miles square need not expect to have more than one
in ten thousand years. If you count every destructive wind and every
imaginary tornado far above the ground in the dark and threatening clouds as a proper reaaon for fright and anxiety, you will produce a wholly
unnecessary state of uneasiness and alarm in the community.
You say there is no expense you would not undergo to protect your' life, but you do not protect it efficiently by your telegraph line and fore- warnings of tornadoes. The chance of your dying from a tornado is not the ten-thousandth part of your chance of dying from disease, accident, lightning, etc., and it would be a wiser policy t o spend your money to protect yourself against these. The mere forewarning of a tornado is no protection against its coming.
THE OBSERVATORY ON MOUNT ETNA.
Under date of May 16, 1907, at Messina, Sicily, Prof. G. B.
Rizzo, the director of the observatory recently built near the
summit of Mount Etna, wrote that he was about to start for
the summit and to occupy the observatory there for the sum-
mer, where he would make a series of observations on the
intensity of solar radiation, as measured by means of the Ang-
str6m pyrheliometer. This instrument is a duplicate of that
which has been used for the past five years by Mr. H. H. Kim-
ball, and on account of the special interest taken in this sub-
ject by American students Professor Rizzo proposes to com-
municate his results for publication in the MONTHLY WEATHER
REVIEW.
The importance of continuous meteorological work on
mountain summits is felt more and more as our knowledge of
meteorology progresses. The balloon work and kite work
must be supplemented by regular mountain stations; these
latter are practicable and inexpensive where balloon work
would be impracticable. There are many noble peaks on
ocean islands that still remain to be occupied, and even if they
o m not be oocupied immediately, yet the cloud phenomena
about their summits should be systematically observed.
The following description of the ascent of Mount Etna is
abbreviated from an account by Maj. Albert Woodcock, for-
merly United States Consul at Catania, Sicily, whose letter
was published in the Sportsman Tourist, Vol. LXI, New Pork,
July 25, 1903, which contains much interesting information,
but we have omitted that which is not appropriate to the
MONTHLY WEATHER REVIEW.
two stout horses left Catania to make the ascent of Mount Etna and
the descent into Val del Bove. A hammock beneath the carriage and a boot at the rear contained blankets, rugs, overcoats, and rations Por a
two days' campaign. We were soon looking down upon Catania with its thousands of lights, and upon the beautiful sea.
The moon was at i t s full. As we lscended t h e air grew fresher and more bracing; i t had been unm,mfortabiy warm in Catania when we left.
We were ascending thru a highly cultivated region. Orchards of orange, lemon, almond, and flg and vineyards of grape grow luxuriantly upon
the slopes. I n an hour and a half we had ascended to Gravina, an un-
important village of low, lavve-constructed houses. Two miles higher up
we reached the quaint old town of Mascalucia. Perched high up on the side of Mount Etna, it commands flne views of the sea and landscepe
below. There twilight commenced to steal upon us, and the morning
star that had glowed with unusual brilliancy above the Calabrian peaks
began to pale. Still higher up we reached the lava village of Torredi
Grifo. We were now above the orange belt. I n this high altitude in
winter are heavy frosts and frequent snows. We now entered upon a barren waste of lava bed, which marks the eruption of 1637.
We arrived at Nicolosi. 2,265 feet above the sea, at 6 o'clock, a. m. Nlcolosi is an earthquake-rlven town, and has several times been shaken
to the ground. The lava, flood of May last approached within 1,ooO feet of it. It there stands a black, hideous mass, still hot and sending off sulphurous vapors. We rested at Nicolosi for an hour, refreshing
ourselves with cold coffee, bread, and cheese. Signor Orazlo Slivestri, professor of chemistry, geology, and miner- alogy of the Royal University of Catania, courteously tendered us the
use of the observatory. The dlrect road of ascent is covered by the lava flood of May last from 20 to a 100 feet deep. We were obliged to make
a detour around this hideous fleld of black desolation. We flanked Monti
Ross1 (the Red Mountains) on the south.
Soon after leaving the Red Mountains, we came to a spur of the lava bed of May last. It was insufferably hot. Our niules quickened their
pace in crossing. We had left the cultivated region at Nicolosi and were
now entering the wooded belt. The treeskere mostly of a young growth
of chestnuts. Wood being in great demand, the trees were cut before they reach the ordinary size. I n thls same wooded region, however, on the west side of Mouiit Etna, there are several monarchs of the forest
that have escaped the woodman's ax. They are said to be the oldest trees living and are without doubt 1,OOO years old.
Our ascent was very slow and tiresome to the mules. The last May eruption had covered the ground with volcanic sand. The trees seemed to rise from a black sandy desert, there being no green thing visible but
thelr ramage. We reached Casa del Bosco (House of the Woods) at 10
o'clock a. m., tired and voraciously hungry. We were now at an altitude
of 4,216 feet above the sea. Casa del Bosm is the last resting place be-
fore the final climb to the summit.
We wound around the east side of Mount Castello and ascended between Monti Agnuolo and
Frumento. We were above the habitable zone. All appearances of vege- tation had ceased. No bird fluttered by us, no cricket chirped. There were no signs of animal or insect life. All about u s was black desola-
tion. Sun-lit clouds were hanglng upon the crests below us. Our way waa over black volcanic sand and loose boulders of lava. We were soon upon Piano del Lago (the plains of the lake). Lava floods have filled it, and it has ceased to be a lake. Case Inglese is 9,652 feet above the sea. It is situated at the base of
the great cone. It was erected in 1811 by some omcers of the British
Army; the Engllsh at that time occupied Sicily. It is a low one-story building, constructed of lava rock, and stands east and west; in one of the three rooms isa flreplace. This building is the refuge of excursionists
to Etna. The observatory now (1886) is a low two-story building sur-
mounted by a dome. It is built of lava rocks, the walls being of unusual
thickness, to withstand the frequent shocks of earthquake. It is joined
to Casa Inglese, the latter being a lean-to on the south to the former.
A telescope and all other instruments requisite for making observations
in astronomy, meteorology, etc., have been purchased and will soon be mounted in the building. Owing t o the kindness of Professor Silvestri
(as before stated) we were in possession of the observatory. Here we found beds, bedding, table, chairs, etc., designed for the use of the
scientists: these, for the time being, were ours, and we were supremely comfortable. After an hour's rest our company mustered for the ascent
of the great cone. It towered into the heavens 1,900 feet above us, its sides being very steep. We finally reached the north rim of the crater. The grand old sea and
the Calabrian peaks lay outstretched before us. Sun-lit clouds in great
At 3 o'clock a. m. of August 14 last (1886), a large carriage drawn by.
The ascent became steeper and more difficult.