Jum, 1906. MONTHLY WEB
THE STRUCTURE OF HAILSTONES.
Ry 1). S LArmr*, ib.lstant Vhseriel. Dated Fw t Wdvrth, Te\ , J u l ) 11, l(rffi.
On the evening of the 20th of June the observer at Fort
Worth had an unprecedented opportunity to esamine hail-
stones with reference to the formation of the centers. The
hail fell for fifty minutes, and the stones were plentiful for
several hours after the storm had passed. The hnilstones of
this storm were very symmetrical, the prevailiug form beiug
an oblate spheroid about two and a qiiarter inches in the long
diameter by one and three quarter inches in the short axis.
The largest stones had nine definitely marked concentric
layers outside of the central nucleus. Three other styles of
formation were in evidence, yiz, those having three. five, and
seven layers. These layers were clistinguishable by being
cemented, or congealed, together by sheaths of A thin zshite
amorphous ice so devoid of thickness as not to be onllecl a
layer, yet in the cross bections the lines of separtition were as
well marked as those of the layers of an onion.
It was noted that every stone had an odd number of layers
in its formation, the series running three, five, se%en, or nine
layers. The outside surfaces of all stones were quite smooth
and of crystal ice. In the seven- ancl nine-layer hailstones
the layer nest to the surface layer was snowy, something of
the nature of a snowball dipped into water and slightly com-
pressed, forming a sort of mushy amorphous ice, usually very
white. I n the five-, sez en-, and nine-layer formations, the third
layer, counting from the nucleus outward, was an enwrapment
of snow so definite in structure as to admit of no doubt of its
being moist snow. This third layer was about as thick as
heavy blotting paper. I n the seven- and nine-layer forma-
tions the nucleus and all layers were crystal ice, excepting the
third and the lager next to the surface layer.
FIG. 2. FIG. 3.
Figs. 1, 2, and 3 show the foriuatioos of hailstooes haviug flw. seven, and nine layers, respectively, outside the central nucleus. The stippled
dark portions represeot snow of R defiuite form, granular in a few
iostances, but not compact, as amorphous ice usually appears.
In the five-layer formations there mere variations from the
seven- and nine-layer stones, i.e., the five-layer formations always
had a soft center or nucleus of either aniorphous ice or snow.
In two instances the centers presented such feathery frost
needles that the contents could be shaken out by gently tap-
ping the ruptured stone with a lead pencil, leaving a spher-
ical cup of crystal ice, ragged and pit,ted within.
Another feature of this hailstorm, probably having some
significance with reference to the altitudes at which these
hailstones had been formed, was that at intervals of allout
ten seconds from the time a loud peal of near-by thunder was
heard there would be a tlownpour of nine-layer hailstones,
followed two seconds later by an increased shower of the
seven-layer formations, and one second after these came the
LTHER REVIEW. 277
five-layer formations, immediately followed by the small three-
layer pellets of ice.
During the storm the wind was blowing a gale, and the
direction of descent of all stones was the same, except for
the nine-layer formations. At intervals only, these came from
a direction almost opposite to the course of the wind; the
remainder of the time they caiiie quartering with the wind.
During the reverse action of the stones against the wind the
descent was at an angle of about 60°, but at other times the
descent was nivre nearly perpendicular.
The test for the presence of sir within the stones showed
that whenever a snowy or amorphous ice layer was reached
air bubbles were in evidence. No air bubbles were given oE
frola the three-lager stones, nor from the centers of the seven-
ancl nine-layer formations. Whenever the five-layer centers
mere reached air bubbles were present, plainly showing the
presence of enlocked air.
The snowy centers of the five-layer formations seem to have
originated in a snow zone. The other nuclei must have been
formed without the snow zone. The snowy layers, or anlor-
phous ice contlitions, noted in the seven- and nine-layer forma-
tions, indicate that the snow zone must have heen passed
twice.
I n view of the observations macle during this hailstorin i t
seems wrong to assert that the center of a hailstone is either
crystal ice, or amorphous ice. It seems that the centers, or
nuclei, are variable quantities, dependent upon the conditions
of temperature and moisture, and the altitude at which the
nucleus forms. With these factors in mind it is evident that
the center of one stone might be crystal ice, another be anlor-
phous ice, or mushy, like snow, while others cau be dry snow,
claiiip snow, or even frost itself.
Rj' \vELLlNI.TON SMITH. h t e d hfifflintIBWn, Pa., JUly %, 1906.
We had a very severe hailstorm on Saturday, July 28, at 5
p. m. The stones were quite small at first, but at the end of
twenty minutes they became large. They were flat and ob-
long, regnlarly corrugated froin the center toward the circum-
ference. They were from one inch to two inches in their
longest diameter, and less, by one-third to one-fourth of
these dimensions, in their shortest diameter. They were from
one-half to three-fourths of an inch thick. They all were
dished, or hollowed, toward the center, and some had holes.
We gathered about a dozen stones from the board walk and
placed them in ordinary pump water, but no one could see any
bubldes ascend. Then we gathered some that fell on the
heavy grass of the lawn, and these in a few minutes gave up
very small bubbles. We then placed some more in a number
of vessels of water, and bubbles were seen to ascend rapidly
to the surface of the water. Most of these bubbles were ex-
ceedingly small, not larger than a grain of eagle powder, but
I noticed quite a number as large as a common pin head.
There was no mistake about the ascending bubbles of air, as
every one in the house olmerved them.
The Fitchburg Sentinel of June 4 contains an account of a
remarkable hailstorni occurring in the southern part of the
town of Fitzwilliam, N. H., on Saturday afternoon, probably
June 2. The storm cloud approached from the south about
4 1). m. Heavy rain, thunder, and lightning accompanied the
hail. As the storm progressed the hailstones steadily increased
in size, until a t the end of ten minutes they were two inches
in diameter. At 4:30 p. 111. the storm was over, and observers
beg,zn collecting the hailstones. which mere generally either
egg-shaped or round. Seventeen such stones filled a quart
measure. The larger stones were buried their full depth in the
earth. Most of the stones, if not all, had large, pure white,
snowy nuclei, surrounded by a ring of transparent ice that
was exceedingly hard.
276 MONTHLY WEATHEX REVIEW. JUNE, 1906
The oenter of the storm seemed to be over a hill near Laurel
Lake, as the hailstones were smaller in other parts of the town.
From a cottage on this hill the observer seemed to see the
southwest wind drive the storm toward Wachusett Mountain,
25 miles southeast, then a countercurrent of east wind blew
the cloucl back directly toward the hill and the cottage;
ancl tlie sultry afternoon was followed by the storm. which
began with cool winds from the aoutheast and the northwest at
almost the same time.
Hailstones having very iuteresting corrugations are pictured
in the MIJNTHLY WE~THER RETIEW, for April, 1677. (See fig. 4.)
These fell at Morgantown, W. Va., April 2A, 1677; they were
about two by one and one-half inches, and the average volume
- was 0.873 culiic inch.
FIG. 4-Corrugated hailstone.
-C! -4.
SUGGESTIONS TO OBSERVERS OF HAILSTONES.
In connection with the excellent article by Mr. Landis it
m:ty be ailded that future observers of large hailstones shoulcl,
if possible, note the following points:
1. Examine many nuclei and ascertain what proportion of
t,lieiii are (a) clear ice, (h ) dry snow crystals, (c ) a mushy mis-
ture of snow or ice with or without air bubbles.
2. Devise some method of approximately measuring the
temperature of the nucleus, as distinguished from the ou tsicle
lager. The difference of temperature between the inside and
outside may be quickly ascertained by thermo-electric methods.
The average temperature of a whole hailstone, as well as of
its several parts, can be determined by delicate calorimetric
methods.
3. Measiire the volumes of the successive layers and the
nucleus. This is best done by making careful drawings of
sections of the hail before i t melts, and measuring from these
drawings afterwards at leisure.
4. Observe whether the air bubbles in the respective layers
are elongated radially, or have any other systematic armnge-
ment.
5. Note the time which elapsed between lightning and thun-
der and the fall of hail, i f any, apparently attending them; the
connection is undoubtedly purely accidental, and the observa-
tions should bring out this fact.
6. Split the hailstones carefully with a sharp knife and note
whether they have special planes of easy cleavage.-6‘. A.
WEATHER BUREAU MEN AS EDUCATORS.
The following lectures and addresses by Weather Bureau
men have been reported:
Mr. JosephL. Cline, June 12,1906, on “Elements of the Earth’s
Atmosphere ” ; also June 27, on Electricity, Atmospheric
Disturbances, Weather Forecasting, and the General Work
of the U. S. Weather Bureau ”, illustrated with stereopticon
views, both before the Summer Normal School, Corpus
Christi, Texas.
Mr. P. Connor, April 10, 1905, at the monthly dinner of the
Kansas City Implement and Vehicle Club, on ‘‘ Weather
Bureau Work ”; also June 9, 1905, before the Kelvin Cluib of
the Central High School, on “The Weather Bureau, Storms,
and Forecasting ”; also November 16, 1905, before the Tech-
nological Society of Kansas City, on ‘I The Equipment of
Stations, Weather and Weather Forecasting ”; also December
12, 1905, before the Bancroft C‘lub, on Climate and the
TITeather ”; also February 9. 1906, before the teachers and
p q i l s of the High School, Kansas City, Iians., on <‘ Weather
Topics ”; also April 11, 1906, before the Atheniturn, on ‘I The
Success of TITeather Forecasting ”.
Mr. D. A. Seeley, October 36 and 27, 1905, before a class of
10 students in phrsics, Bradley Polytechnic Institute, Peoria,
Ill., on “The Barometer ”.
Mr. A. H. Thiessen. June 27, 1906, before the class in geog-
raphy, at the Summer School, State Agricultural and Mechani-
cal College, Raleigh. N. C., on “The Weather Map ancl Fore-
casting the Weather ”.
Classes from colleges, scliools, acadeniies, members of teach-
ers’ institutes, etc., haye visited Weather Bureau offices, to
study the instruments and equipment ancl receive informal
instruction, as reported froiii the following ofices:
Buffalo, N. Y., June 5 and 6, 1906, a class of 35 students
from the Teachers’ Training School No. 10.
Evansville, I d ., June 18, 1906, the graduating class of tlie
Baker Avenue Public School.
Kansas City, Mo., April 15,1905, pupils and teachers from the
High School, Argentine, Iians.; June 6,1905, a class from the
Central High School; October 24, 1905, a class from Loretto
Academy; October 24 and 35, pupils from the High School,
Iiansas City, Hans.; January 30, 1906, principals of local
schools; April 24, 190G, sonie of the Sisters and B large class
from Loretto Academy.
Moorhead, Minn., JLIW 30,1906, pupils of the local Siiinmer
School.
Oklahoma, Okla., June 22, 1906, about forty members of the
Oklahoma County Teachers’ Institute.
Peoria, Ill., August 29 to September 1, 1!)05, 75 teachers,
attending a local teachers’ institute; November 6,1905, a class
of 12 students from Iinox College, Galesburg, Ill.; May 2,
1906, tlie “As You Like It” Club of Peoria; June 15, 1906
(the annual .‘ Open Night ” at the Bradley Polytechnic Insti-
tute), more than a thousnnd persons.
Raleigh, N. C., June 26, l !)O G , geography class from the
Summer School, Agricultural and Mechanical College.
Sioux City, Iowa, January 16 and 17, also June 7 nncl 6,
1906, classes from the Sioux City High School, in all about
one hundred fifty pupils.
Vicksburg, Miss., June 27, 1906, the junior and senior
classes of the Vicksburg High School.
RECENT ADDITIONS TO THE WEATHER BUREAU LLBRARY.
H. H. PIarBdLL. Librarian.
The following titles have been selected from among the books
recently received, as representing those most likely to be useful
to Weather Bureau officials in their meteorological work and
studies. Most of them can be loaned for a limited time to
officials and employees who make application for them.
American Climatological Association.
Chile. LPervicio Meteorolojico de la Direccion del Territorio
Transactions. ssxi, 218, 1s pp. Elo. Detroit. 1905.
Anunrio. 1904. 390 p l ~. do. Valparaiw. 1905. Maritimo.