298 MONTHLY WEATHER REVIEW. AUQIJST, 1896
south, east, and west by a region of thunderstorm develop-
ment, as though the violent discharges from highly-electrified
air shaded off into gentler discharges in the distant regions, where the air was less highly electrified. A nia.ss of air (or
rather the moisture and dust contained i n i t ) niny carry a
charge of electricity a great distance, aiid may gradually get
rid of i t by a series of discharges, at first violent., as in the
lightning flash, but gradually diminishing, as in the luminous
or phosphorescent clouds aiid the most brilliant forms of au-
rora, until finally the discharges can give rise to only the
feehlest auroras. This gradual diminution in the intensity
of the discharge niay depend upon a corresponding gradual
diminution in the quantity of vapor in the air or on a grndual
change in the condition of the vapor, namely, the difference between aqueous vapor and ice vapor. In the Annntil Report
of the Chief Signal Officer for 1876 tlirz present Edit.or has
given a study of the aurora of April 7, 1874, and the following
quotations, from page 309 of that volume, are here given :
(a) The auroral light exists sometimes as patches or clouds, but more frequently as luminous lines [more or less closely packed together] inclined to the earths surface and approsimately parallel to the free magnetic needle.
(b ) The luminous lines are associated together, forming wave and cylindric surfaces ; such surfaces appear sharply defined in the por- tions where their tangent planes are directed toward the observer, giving rise to the appearance of beams or streamers which are, there- fore, 111 defined on one edge, but sharply defined on the other.
(e j The luminous Wave surfaces are themselves arranged parsllel to each other, giving rise to arches or belts across the sky which, when the observer is favorably situateil so that his lines of sight are nearly parallel to the luminous lines, are seen by him as striated belts or arches, each stria of which corres nds to an element of the wave surface, anrl which structure is wef? described by one observer as resembling the vertebrae and ribs of an animal. A slight curvature in
the luminous lines, or a >erspective effect, prevents the striated a pearance from being wch seen except near the meridian. When tEe luminous lines are quite straight, and es ecially when associated togetlier in perfect parallelism, ]Jut without feing grouped into wave surfaces, there ryults tlie corona srround the niagnetic zenith with merry dancers on all sides, as recorded by one observer. This phase of the aurora is probahly best. seen when the luminous lines are comparatively short. (a ) Inasmuch as tlie definite edge of a streamer is simply an optical effect produced by viewing those portions of a curved surface t,hat lie in the tangent plane that passes to tlie observer, it follows that another person at a distance, viewing the same wave surface will receive from
a slightly different portion thereof tlie impression of a definite streamer, if, iiiileed, he sees any at all. For a siniilar reason, that which appesrs to one person as a well defined arch or belt near his zenith will appear to an observer farther south as a collection of streamers which niay, in fact, essily become so faint or ill defined as to be scarcely noticeable, while the streamers which he does observe, as such, ma be formed by an entirely different set of luminous lines and surfaces. A[ third ollserrer farther to the north ancl looking south- ward may, with equal ease, be observing quit.e a different object from either of the others. The statement is, therefore, warranted that although the aiiroral light emanates from definite points and lines, yet the arches aiid streamers made up of these liave no proper locus. (e) The elementary luminous lines have motions both t,ransverse anrl parallel to their direction, but in adclition to this, slight chsn yes in the flexures or arrangement of the luminous surfaces, arrange& as they often are one Ijeliind the other, may ive rise to a complete change in
the appearance of tlie arches and &earns. Thus it resulk+ that the movements of the arches up and down, or north and sout.h, and the movements of t.he beams or stris, take place in a manner entirely diverse from the changes going on among the luminous lines.
v) A comparison of the apparent eastward and westward angular motion of the waves near the zenith of any station with the apparent nature of the streamers observed from stations farther south would, if the same objects were observed, afford an additional means of de- termining the arerage eleration of the general mass of light. The data at hand as to velocities are too crude to afford precise results in the present case. The general indications are, however, very stron ly in favor of the conclusion that the luminous lines were within 10 niifes of the earth.
(g The electric phenomena of the atmosphere embrace on the one
rora attending cirrus or stra6us and haze, and in both cases the electrifi- cation of the atmosphere is eviilent,ly primarily due to the inductive influence of the earth. Between these comes a third class of electric discharges, that, namely, which gives rise to the phosphorescence of
han h lightning attending cumulus clouds, and, on the other, the au-
clouds. Such phosphorescence was noted durin the present aurora on A mil 7, 1871, at two stations. It has been otserved by myself in dashington on occasions too numerous to enumerate, when the whole heavens were obscured and rain or snow imminent: especially has it been remarkably dist,inct on the edge# of the banks of clouds advanc- ing from the northwest, and immediately preceding a sudden change from warm, moist,, southerly to cold, dry northerly or northwesterly winds. It has also been frequently recorded in r.onnect,ion with the lightning and rain of hurricanes. I n fact the luminous or phosphores-
cent cloud due to the silent discharge of electricity between its compo- nent atoms is a far inore frequent phenomenon in these latitudes than either light,ning or auroras, and connects together all the luminous electric phenomena of the at.mosphere in such a way as to show that while the electricity may be clue tc, the induction of the earth. the form of the discharge is due to the state in which t.he atmi.ispheric moisture exists at the time. (h ) It accords with the prcceding views t.hat we find the bettins and arches higher above t,he ground and far less numerous and brilliant in the west than in the east., and th:it, in general, the lower Lakes and New England liave ever been distinguished by brilliant, auroral dis- plays, ,&ice here not. only mount,aiiis with their high electric tension, but, moisture and rapid alternirtions of temperat,ure 1jredominat.e.
T l i ~ above long quotatioii shows that we may espwt local auroras whenever dry, cold air separates two regions of
highly electrified air. The extent and brightnres of the
auroral display depends upon details t.hat we can not yet
enumerate.
As illustrating the weather cmdit.ions n.nd thunderstorm
phenomena over the a.urora1 region that! lay het.weeu bhe local
stornis of the Ohio Valley and the hurricane south of Cuba
on the evenings of August 25 and 26, we give t.he follow-
ing quotat.ion from the letter of Mr. H. W. 0. Mnrgary, volun-
t,ary ohserver a t Eustie, T.nke Co., Fla.
DATA OF ELEOTRICbL STORM AS SEEN FROM OBRERYATORY GROVE,
$USTI(;, FLA., AUGUST 25, 189.5.
6.30 p. in.-Local time. Wind light iiorblieast. Electrical st.orm in southwest with const,ant. lightning :imong two or niore sOrata of clouds
as if from one to the ot.lier strata, with an occasional flash to the hori- zon. Another dense bank of clouils slowly approaching it from the north, aiid also a bank high up in northeast,. i.00 11. ni.-Rain began to fall in west from clotiils, with clear space to horizon below, showing clearly in several places on t.he clear sky of western horizon. Numerous small cloiiils moving frmi different direc- tions toward main borly of clouds in sunt.liwest~. 7.15 p. m.-Clouils rapidly &hering from all c uarters t,ow:ircl the southwest,; very dense; lightning in southwest and north. The chief point from which t,lie li htning conies is a black, fleecy cloud in s0ut.h- west, about 50 to 60 avjove the sonthwestrrn horizon. Rain increas- ing along western horizon in spots. Win11 get,ting easterly but very light, at times up to 5 or G miles an how. Lig1it.ning increasing in east. Wind getting puffy and very distant thundw at times, but inore con- tinuous than heretofore, ancl gett.ing louder.
7.30 p..m.--bppears to be raining heavily in nest-southwest and a shower in tlie west and northwest., but all separate; wind still light northeast to east. 7.35 p. m.-A heavy belt of black, tongue-like, ragged cloud movin up slowly from south and snut,heast; lightning now principally in nort% along horizon; three northern clouds, that passed partly to westward, seem t,o be absorbing the elect.rica1 clouds in soiit.hwest,. 7.50 p. m.-Wind conies from west, and very light, and, at 7.53, back again to east; variable from east and west; light Guffs. 8.90 p. m.-Storm passing off to northwest, as the clouds from it have
absorbed those in southwest ancl carried them Do northwest,; lightning still quite vivid in north.
OPTICAL PHENOMENON.
It may be interesting to puhlish and explain t.he following
phenomenon, specially comniuiiicuted, from the Ohio Weather
and Crop Report., by Mr. Sumuel W. Courtright., voluntary
observer a t Circleville, Ohio. He states t h t -
On February 13, 1895. a1JOUt 9.30 1). m., a beautiful phenomenon was witnessed in the heavens, almost in the zenith. It resembled a dis- tinct and perfect rainbow, and the nioon, which had risen to a height of about 4 5 O , was in t.he center of a beautiful cross of bright, light yellow bars. These bars crossed each ot.her at right angles on the face of the moon. The horizontal bars described an arc of about one-f0urt.h of the heavens, ancl at about 15O on either side of the moon was a similar cross in fainter outlines. The eastern sky was mist aiid heavy, while the western sky was clear and the stars shining brigbtly. The phenomenon was witnessed by a great many of our people.
AUQUIT, 1896. MONTHLY WEATHER REVIEW. e99
We gather from the above report that on this occasion tht
principal phenomena observed were : ( 1 ) A distinct and per.
fect rainbow partially encircling the zenith, and so higt
above the moon as to be almost in the zenith. (3) A beautiful cross of horizontal and vertical bars of a brighl
light yellow intersecting each other on the face of the moon
(3) Two similar fainter crosses a t about 16O to the right and
the left of the moon.
The general explanation of optical phenomena seen aboul
the sun and moon was given on page 14 of this REVIEW fol
January, and page 56 of this REVIEW for February, 1595
( 1) The arc of colored light or horizontal rainbow concentric
with the zenith is caused by rays of sunlight that enter and
leave the little vertical prisms of ice that are slowly settling
down through the atmosphere. The top and bottom facets 01
faces of these crysta.ls are inclined to each other and the re-
fraction through these faces produces prismatic colors just aE
in an ordinary prism. The diameter of the rainbow circle
around the zenith is smaller in proportion as tlie sun or niooii
is higher above tlie horizon. (8 ) The large cross of light
yellow bars is due to the simple reflection of the nioonlight
froni the outside facets of innumerable cryst.als of ice, all of
which are slowly settling with their axes vertical. (3) The
small and fainter crosses on either side of the moon are due
to two reflections from the interior surfaces of crystals.
A complete study of the phenomena of parhelia can be
made by preparing a number of hollow prisms made in the
exact shape of the crystals of snow and ice that occur in na-
ture. These prisms should be made of thin plates of glass
cemented together a.t the edges, and should be filled with
water, whose refruckive nncl dispersive powers are of course
very nearly the same as those of ice. Let such a prism be
suspended in the sunlight in various positions with reference
to the zenith, and in the position that i t assumes when falling
slowly through the air. Set i t to revolving rapidly, 8s i t may
do when falling freely. If a special bright reflection is seen
when viewed from a certain direction then this represents the
position of a mock siin due to total reflection within the
prism. If prisxnat.ic colors are seen this represents the posi-
tion of a rainbow. If a moderately bright reflection from an
external surface is seen this gives the location of some one of
the numerous h i i d s of light that may occur.
THE COLD SUMMER OF 1816.
An article in the New York Sun copied into the Iowa
Monthly Review for July, 1895, gives some det.ails about the
remarkable summer of 181 8, as remembered by James Win-
chester of Vermont. It is said that in June of that year
snow fell to the depth of three inches in New York, Pennsyl-
vania, and New Jersey 011 the 17th; five inches in all the
New England States, except three inches in Vernion t. There
was snow and ice in every month of this year. The storm of June 17 was as severe as any that ever occurred in the
depth of winter; it began about noon, increasing in fury
until night, by which time the roads were impassable by
reason of the snow drifts; many were bewildered in the
blinding storm and frozen t,o dea.th. During June, .July, a.nd
August the wind was continuously from the north, fierce and
cold ; July was colder than June, and August. colder than
J L ~Y ; there was a heavy snowstorm August 30th. The first
two weeks in September brought the first warm weather of
the year, but on the 16th of that month the cold weat.her sucl-
denly returned and continued increasing until winter. The
year 1816 had neither spring, summer, nor autumn. The only crop of born raised in that part of Vermont th& suni-
mer wa.8 saved by keeping bonfires burning around the corn-
field night and day. The crop of 1117 was raised from the
seed of 1515. The sunimer of 1117 was one of the hottest-
and driest ever known in that region.
Fh7-3
NoTE.-The preceding statement agrees with what we may
gather from the interesting book by Charles Peirce, published
in Philadelphia in 1147, entitled A Meteorological Account
of the Weather in Philadelphia, from January 1, 1790 to
January 1, 1847. A record was begun by Peirce, a t Ports-
mouth, N. H., in 1793, and was continued in Philadelphia,
where he had access to numerous other journals. According
to this work the mean temperatures at Philadelphia during
tlie year 1816 were the lowest on record, and were as follows :
January, 3 2 O ; February, 2 8 O ; March, 3G0 ; April, 47O ; May,
5i0 ; June, 64O ; July, 68O ; August, 66O ; September, 62O ; Oc-
tober, 52O ; November, 45O ; December, 32O.
On page 247 Mr. Peirce says :
The temperature of the whole year was only 4 9 O , it being the coldest year we have on our record. Although there was no uncommonly cold weather during the three winter months, yet there was ice during every month in the year, not excepting June, July, and August. There was scarcely a ve etable came to perfection north and east of the Potomac. The cofd weather during the slimmer not only extended through America, but throughout Europe. One of the most celebrated Yeteorologists in England, on reviewing the weather of the ear, said :
It would ever be remembered that 1816 was a ear in wbch there was no summer, and the temperahre of the year [as a whole) was the lowest ever known. It was also the coldest Rummer ever known in the West Indies and in Africa. The medium temperature of the whole year in Philadelphia was only 49O.
A POPULAR SUBSTITUTE FOR THE BAROMETER.
In The Weather and Crops, published by t.he Illinois State
Went.her Service, we find a short deecriptiou of a simple in-
strument that serves the purpose of showing approximately
the changes that may be going on in the pressure of the air.
The descript.ion rea.ds as follows :
If it large-mouthed glass jar-fruit or pickle jar will do-be filled about two-thirds full of water, and in it be placed, inverted, a smaller long-necked flask, with mouth entering the water, the increasing or de- creasingpressure of the outer atmosphere will cause the water to rise or fall within the flask. Clear, fine weather will be foretold by the yater rising in the flask; stormy, wet, or bad weather by the water fall- ing.
The device thus explained will, undoubtedly, show varia-
tions in atmospheric pressure, and all the more correctly in
proportion as the temperature of the air within the flask
remains stationary. If we wish to be at all accurate, or if we
wish not to he misled by the effects of changes of tenipera-
ture we must either keep the temperature constant or else
make a numerical allowance for the effect of its variations.
If tlie temperature within the flask rises 1 degree Fahren-
heit, its confined air will expand by of its volume, and the
water in the neck of the flask will be pushed down to a cor-
responding amount. On the other hand, if tlie atniospheric
pressure should diminish by 0.06 of an inch below a normal
pressure of 30 inches, the a.ir within the flask being slightly
relieved of its pressure would expand by the & part of its
volume, and the water in the neck pushed down as before. In
30 far as we cannot rely upon the constant temperature of the
rtir within the flask we must therefore make an allowance of
3.06 for each degree of change. As this apparatus is so sensi-
tive to temperature i t niay therefore be considered as a ther-
nionieter when the atmospheric pressure is constant. In fact.
t.his is known as the firet form of air thermonieter which was
wed by the physician Snnctorius, who learned i t from Galileo
in 1596, and it was the study of the fluctuations of this ap-
paratus that contributed greatly toward the discovery of the
pressure of the air and the invention of mercurial barometers
irid the ordinary spirit thermometer. If one wishes to use
:,his apparat,us ES a barometer, and needs, therefore, to know
.t,s temperature correctly to within a degree, he will find i t
)est to fasten the smaller flask and its long neck, or, still bet-
;er, a long glass tube, permanently within theouter glass jnr
ind fill the latter with water so that the wholeflask is cov-