130 MONTHLY WEATHER REVIEW. APRIL, 1909
tinuous layer around the earth, nor is there any reason to sup-
pose they should do so on Venus. Hence, if one of the clear
spaces should happen to be in the right position, we should
see through the gap, and the horn would be absent or broken.
Moreover it may be assumed that the planet is diversified by
mountains and valleys like our own, and that these are prob-
ably of similar stature and depth.
When the great air-currents flow over such features, up and
down movements are produced, which react upon any cloud
zones above, destroying the clouds by a descent in one place,
creating them or throwing them up to an abnormal height by
an ascent elsewhere.
We can thus esplain irregular or even periodic appearances
of projections of the bright surface, or the occurrence of dark
spaces in it, by attributing them to the passage of the cloud-
laden air over an uneven surface beneath. Projecting points
of light may well be thrown up to very great altitudes with-
out needing to suppose mountains so vast that they woulcl
flatten out under their own weight.
4. The acceleration of phase in eastern elongation is coin-
monly observed to vary from four to eight days-dichotomy,
or any special phase, being so much earlier than the theoreti-
cal time.
This can only mean that the surface along the sunrise ter-
minator is not at right angles to the planet's radius. but that
it slopes upward toward the sun, ancl that the slope is steep-
est in the equatorial regions, and diminishes toward the poles.
But this is exactly how the upper surface of a shell of rising
conveotion clouds should rise, and the fact alone is an almost
conclusive proof that the cloud theory is right.
The phenomenon is not limited to dichotomy, but can be
noticed at any time not far removed from greatest elongation.
The variation of the acceleration would imply a variation in
the slope such as would be a natural consequence of changes
in'the underlying surface due to the slow rotation relative to
the sun which has been postulated as essential to the perma-
nent maintenance of the clouds.
5. The retardation of phase in western elongation is rather
more pronounced. It can be explained as due to an even
greater slope of the mean surface of the clouds, due to the col-
lapse of the rising currents and breaking down of the clouds
toward sunset. On the earth the fall of the cloud levels in
the evening is distinctly more rapid than their morning rise.
The fact may be regarded as a proof confirmatory of the last.
6. The shading off of the terminator and,
7. The variable contour of the terminator would both be the
natural result of variations in the height to which the clouds
had reached in consequence of differences in the nature, and
therefore temperature or moisture of the surface beneath.
8. The smaller luminosity of the neighborhood of the ter-
minator.
Apart from the glittering margin, which has been attributed
to the cirrus veil, and apart from any definite darkening of a
particular region, this is perhaps the most obvious feature of
the planet.
Elsewhere we
look through it onto the suiiiniits of the convection clouds.
If, as appears to be almost certain, the individual cloucls have
on the whole a roughly pyramidal or pillared contour like our
cumulus and alto-cumulus castellatus, the body of the planet
would be brightest near the limb, where only the tips of the
clouds would be seen. On passing from the limb toward the
center of the disk, we should see farther and farther into the
shadows between them, and the proportion of shade should
increase as the sun's rays become more oblique.
9. The presence of a faint band of shade, approsimately
parallel to, but at some distance from, the terminator.
This can nearly always be seen. It is not sharply contoured,
but broad and ill-defined. Still a graduated shade, such as a
At the limb we see only the shining cirrus.
neutral tint wedge, will generally bring i t out. I t is best
seen in eastern elongation when the planet is near dichotomy,
or approaching its maximum brilliancy. It varies from time
to time in breadth and depth of shade, but always occupies
the same position relative to the terminator. It can not ap-
parently be followed into the shining ring near the limb. It
has been described by &I. Antoniadi in the Monthly Notices of
the Royal Astronomical Society for March, 1898, and its ap-
pearance is shown in Chart IS, figs. 4 and 5, which are, of
course, on different scales.
Surely this is a high-pressure ring, darker than the rest be-
cause we see deeper into it, and the spaces between the clouds
are larger. It is much less pronounced in western elongation,
aa we should expect should be the case from the difference
between the temperature gradients toward sunrise and sunset.
10. The mottling or granulation of the surface, the appear-
ance of dark or bright spots moving over the terminator, and
the occurrence of bright points beyond it, are all phenomena
which should be visible, and receive obvious explanations.
11. The ring of light seen at inferior conjunction, and
usually attributed to atmospheric refraction, would more
probably be nothing but the edge of the illuminated shell of
cirrus. This stratum would, everywhere around the termina-
tor, be several miles above the cloucls, and perhaps 10 or 20
miles above the actual surface of the planet. Mere refraction
ought to give a ring of colored light, yellow, or even red.
But if the lower air is, as has been supposed, blocked by
heavy convection clouds, all colored rays would be stopped,
while the high cirrus would shine with the silvery light we
see.
At such altitudes atmospheric refraction would be almost
negligible, and a calculation based upon the position in which
the circle is complete would give the height at which these
delicate structures float, if only we knew how much to allow
for that rise of the lower clouds near the terminator to which
we have attributed the error of phase.
The phenomenon, then, may be regarded as only another
aspect of the same fact which also esplains the prolongation
of the cusps.
Finally, if we suppose that the convection clouds do not
form a continuous sheet, but are distributed broadcast with
clear intervals for the descending partial currents which
should accompany them, it becomes easy to believe that under
suitable circumstances ancl with sufficiently powerful optical
means, it may sometimes be possible to penetrate the veil,
and see at least some of the most salient features of the
planet's actual surface. On the other hand, the underlying
surface must react upon the clouds above, and it may well be
that those sharply defined markings which have been recorded
are nothing more than a result marked out upon the veil by
the features hidden beneath.
-
THE MOON BLAMELESS.
We print in full the following letter to the New York Herald
of May 31, 190'3, from the prominent and popular French as-
tronomer, Cammille Flammarion, as an influential contribution
to the constant warfare between superstition and truth. While
written particularly for the wine-growing districts of France,
every word applies with equal force to the corresponding dis-
tricts of this country. Even the general farmer would do well
to consider the application of these simple and rational espla-
nations to many of his problems and catastrophes.-C. A. .jr.
OBsEIiVAToRY OF .JTrvIsT,
PARIS, FRANi'E, itfay 11, 19)9.
TO THE EDITOR OF THE HERALD: The April moon again is astir with its peculiar influences. Radiant, warm afternoons, alluring as a tropical day almost, have been succeeded 1Jy nights quite as radiant, but as cold as in winter. At the end of April and the beginning of May we have been blessed with spring during the
h L , 1909. MONTHLY WEATHER REVIEW. 131
day, followed by winter at night. From a medium temperature of 2OoC
whilethe sun shone we have experienced afallof So or lo0, and tlie maximum of 250 has been followed by a minimum many degrces under
mro in the nocturnal hours. Congestion in many cases has been caused
by the heat at midday, and, on the other hand, in as many instances by
the uold of midnight.
In every district where fruit is grown, and especiallyin tlie vinecountry, serious damage has been done by the unseasonable frost. I n the chani-
pign country the thermometer registered 6OC below zero during the flrst nights of May and the vineyards suffered severely. Those of Touraine
and Anjou also were damaged, while from Bourgogne and from all points in the South of France we hear the same chorus of lamentation. Par- ticularly malign in its influence this year, the April moon ha.s scored iii-
numerable victims in the vegetable world. The loss is estimated at
many millions.
POOR MOON.
Poor moon ! It will be difflcult indeed to esonorate i t after such an
indictment. Set is i t more culpable, really, than its accueers?
As a matter of tact, what 1s the April moon? Generally, the deflnition
that I gave a long t h e ago has been adopted; i. e., i t is the moon
whlch rises after Easter. I gave this deflnition in consonance with the popular idea, contrary to the dictum of the Annual of the Bureau of Longitudes, because it is the
only one which is acceptable. The definition of the Annual is, in effect,
this: The name April moon is given to the moon wliicli rises in its flrst
quarter in April and is full either at the end of the month or, more ordi-
narily, in the early part of May. Nbw the moon may rlse in Aprll. for instance. on the l s t , ad, or 3d and
be full neither at the end of the month nor in the beginning of May, for it would be afull moon the 15th, 16th, or 17th. Such a deflnition as that
quoted is, therefore, not only not correct, but i t iniplies a contradiction.
and it may easily be seen what a degree of uncertainty and confusion may
arise from it. In 1905 i t is noted that the April moon appeared April 4, Bnlshing its course May 4.
If any definition is t o be held free from popular prejudice i t certainly must be in harmony with i t s own terms. Gardeners, horticulturists, and
all cultivators of the soil are imbued with this prejudice, because they
fear the frosts of the last half of April and of the lirst two weeks of May. These are for them the most critical periods, which they believe arc ad- ministered by the disastrous April nioon and which, according to this
definition, they have long associated with the feast of Easter. This festival is determined for tlie Sunday following the first full moon after March 21 (the spring equlnos). Easter can not conie hefore BIarch 22,
and the new moon following can not rise before April 6 . I n this delini-
tion of the April moon this liinatioii begins at i t s very earliest only on April 5 and ends on May 5, never beginning .4pril 4, 3. 2, or 1. Yet gen-
erally, the full moon rises at the end of April or in the first days of May. When Easter is late (its date varies between March 22 and April 26), the
April moon appears in May. Note particularly that Easter is determined
and its date fixed by astronomy. This year, 1909, the April moon appeared April 50 aud was gone May
19. Thislunation, so much dreaded, i s not designed to arouse our fears. but it serves rather as a convenient point from which to contemplate a
characterietic time of the year, that in which takes place the struggle of spring to overcome t h e last onslaughts of winter. If icr the v h m p OJ
&?aaana that iR alone reaponaible fur dnmnge to wegetatiotr, mid evrry year 2
& the 8am r)o fur UB t h h phase qf the $car ia coacenud.
This is in contradiction to the definition.
TEMPERATDEES AXE DCFFEREAT.
If the night is clear there is a great deal of radiation from tlie earth
into space. whence there results a sensible lowering of tlie temperature of the ground reaching many degrees below zero (centigrade), while the
ambient air is maintained at a temperature some degrees above. It has been proved that objects can acquire in the nocturnal hours a tempera-
ture differing from that of the atmosphere which envelopes them. For example, if you suspend ln the air in the evening small balls of cotton
you will often find that their temperature is Go, 7O, and even Sot! below
that of the surrounding atmosphere. Vegetable growth is subjoct to the same effects. Thus a plant may be frozen hard while the thermometer hanging near by indicates a temperature much above OOC.
When it Is cloudy this phenomenon does not occur. The temperature of the atmosphere, the earth, plants, etc., reniains the same. The clouds
form & screen or veil and prevent the heat stored in the ground during the day from escaping and ascending toward the celestial vault at night.
On the contrary, if no obstacle be opposed to i t the nocturnal radiation dissipates the heat and the temperature of the ground is lowered rapidly.
Soon the frost seizes in its cruel grip tlie plants that are still frail, the
too delicate flowere and the young shootson tree and shrub; the waterr
juices, which are very abundant in newly formed vegetable tissues, he-
come frozen, are enlarged in volume and burst the receptacle in which
they are contained. I n the morning the solar rays caress the flowers and the buds mortally hurt by the cold of the night, giving them a pale
yellow hue, which precedes their iinal dissolution in a very few days. The result would be the same if the moon did not exist. This is so true
that sometimes a very simple precaution only is necessary to save the
young cultures during this disastrous lunation; a veil of mist, a cloud
of smoke. or even a little sheet of paper may serve as protection against the cold, perhaps averting a heavy loss.
To resume, let us say that the destruction of vegetation takes place
when the atmosphere is transparent and the nocturnal radiation is in. tense. It is under the same circumstances, that is, when the heavens
are serene and pure, that the moon sheds her white light upon the earth. But the moon is wholly innocent of the mischief that is attributed to her
influence. Moreover, the great thermometric variations that are observed, especi-
ally at this season of the year, attract our attention principally because
of their grievous results. Nevertheless, such variations are to be noticed
quite as niuch throughout the year. Ancient proverbs must not be taken
too literally. For example, these three days, May 11, 12, and 13 are
known by the names of the * saints of the ice, Saint Marmentius, Saint Pancras, and Saint Gervals. Now these salnts of the ice are no more ex- istent than the April moon, and the dates mentioned exhibit cold or warmth indifferently without any regularity. Neither in the one case or
the other is there the least sign of an astronomical phenomenon.-Cam- milk Flamrntarinti.
SCIENTIFIC TRESPASS.
In his admirable address1 on Earthquakes before the Ameri-
can Association of Geographers, Dr. G. IC. Gilbert, as geolo-
gist, offered the following remarks, which apply equally well
to meteoroiogists.
You are not to infer that an apology is made because I trespass on
flelds t o which I have no title, for I am an advocate of the prlnclple of scientiflc trespass. The specialist who forever stays at home and digs and delves within his private inclosure has all the ad\-aatages of inten-
Hive cultivation- except one; and the thing he misses is cross-fertiliza-
tion. Trespass is one of the ways of securing cross-fertilization for his
own crops and of carrying cross-fertilization to the paddock he invades.
Hypotheses, the trial theories which compete for development Into flnal theories, spring by the principle of analogy from earlier and successful
theories, and the broader the investigators knowledge of explanatory sclence the greater his opportunity to discover hypotheses that may be
applied to his own problems. Progress is ever through the interaction of the sciences one on another; and scientiflc trespass is one of the proflt- able modes of interaction. The trespasser brings with him a mental
attitucle and a mental equipment which are new to the subject,,Fnd
whether or no the idea he contributes eventually makes good, its
contribution creates a new (ategory for observation auld opens a new avenue of inquiry. And he carries back with him the pollen of new ideas.
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WHAT IS HE CHINOOK WIND?
<The history of words is the history of the nation. The
truth of this quotation from an early philologist is well exein-
plified by the following paragraph quoted from the Portland
Oregonian:
In Its present acceptation a chinook is the equatorial trade wind
that blows during the winter months from the southwest and, laden with moisture, strikes tlie Paciflc coast from the northern boundary of Cali-
fornia to the Alaskan Archipelago. It is now the local name for the soft,
balmy, south wind. In early days in Oregon, and even as late as the early seventies, our summer wind from the northwest was called a
1 chinook, so named because i t blew into the Willamette Valley from
the coast region inhabited by the Chinook Indians north of the entrance of the Columbia. Among the pioneers and their descendants a chinook wind was a  clearing up  wind. Now it signifies precisely the opposlte,
i. e., a wind from tlie south followed by rain. Within the past twenty-five years the word has been grafted into the
speech and the written language of the vast territory east of the Cascade
Mountains, and circulates freely throughout Wyoming. It has been carried into western Nebraska. In recent years i t has crept into Boston
newspapers with local application. Any soft, balmy wind that springs
U ~J in winter is called a chinook. Thus we see in an age of high civilization and universal knowledge
the vkissitudes of written words. chinook  has been turned  end for end.
The changes perpetually going on in the spelling of words
are paralleled by equally radical changes in their meanings.
The movament for simplified spelling represents the modern
scientific, economical, labor-saving and socialistic spirit as
contrasted with the individualistic, autocratic, and arbitrary
spirit of the past generations. There is no continuous per-
I Sce Science, 1509, 2Q (11. s.) : 122.
But i t is a misnomer.
Within thirty years
. . . ... .-. . .