386 MONTHLY WEATHER REVIEW SEPTEMBER, 1929
The Bulletin Quotidien de Renseignements in its sim-
plified form contains a 7 a. m. cha.rt for nort.hwest, Europe
and the eastern Atlantic, on which are ent,ered winds,
isobars, and lines showing the change of pressure in the past 24 hours. Beneath this map are forecast,s given
separately for the region around Paris and €or the whole
of France. On the reverse side there is a smaller map
showing changes of pressure in the past three hours wit,h large arrows indicating the direction of movement. of the
isallobaric systems; also charts of maximum and minimiini
temperature and rainfall. The different phases of the
systhme noageux, of which so much use is made in Frenc.h forecasting, are indicated on another map whic.h shows
the state of t'he sky a t 7 a. m., t.he regions in which the
several types of cloud formation prevail being indicated by
distinctive symbols. This report seems admirably to
fulfill its purpose of being a simple and (if we except the syst6me nuageus) nontechnical publication.
The Bulletin Quotidien d'Etudes in its new form com- mences with tables of readings a t 7 a. m., 1 p, ni., and 6
p. m., for French stations t,ogether with aerological
rep0rt.s) while the last page cont.ains a small table of
ships' reports from the Atlantic and Mediterranean. It is interesting to note that readings from foreign stations no longer find a place in the report,. More than one-half
of the eight pages are devoted to charts. I n the first of
these, whic.h is reproduced as the frontispiece of this number of the magazine, polar fronts appear for the
first time in the French daily weather report. The chart
is an ambitious one showing isobars and fronts over the
whole of that part of the Northern Hemisphere which extends from Europe in the east to eastern Canada, the
Great Lakes, and part of the United States in the west. The fronts are shown very clearly, by broken lines for a
warm front, and a row of black d o h for a cold front.
Front,s are often difficult, to locate; sometmimes their very
existence is doubtful. Further, they vary greatly in
intensity and importance and it therefore seems regret- table that no observations are entered on the chart to
help the shiident to judge of the nature of the fronts and
of their effect on the weather in the vicinity. The chart on which these fronts are shown is for 1 p. m. G. M. T. A Northern Hemisphere chart for 1 a. m. covering an
area centered a t the pole occupies most of the last page
of the report, and shows isobars but not fronts. The importance attached t80 isallobars in France is shown by the inclusion of six small charts of changes of
pressure in the periods of 24 hours, 12 hours and 3 hours
respectively, ending a t 7 a. m. and again for t,he same periods ending a t 6 p. m. The only forecasts contained
in this report are in the form of two charts, one for the anticipated changes of pressure in the 12 hours ending
at 7 a. m. the following morning and the other for the
state of the sky and the wind anticipated at t,his hour. Alongside these two charts are written an analysis of the
situation and some comments on the reasons which have
led to the deductions drawn. The report appears t'o be issued on the day following that t,o which it refers, as a
short critical discussion is included of t,he succ,ess or
otherwise obtained in the forecasts. Such a discussion
is likely to be of value by giving the reader an insight into the lines on which the forecasters work, and may in
addition be helpful to the forecasters themselves. Curves showing the daily march of temperature both a t the
summit of the Eiffel Tower and in the courtyard of the Office National MBtBorologique are also included in a
report, the form of which suggests a considerable appetite
for meteorological informa tion amongst French students
of meteorology.-J. 8. Dines.
Fire wenther incestiga,tions in. Wiscon.sin.-Foremost in importance in any plan t,o grow forest t,rees is the control
of fire, for upon such fire cont'rol depends t'he very
esiste.nce of t,he forest,. That weat,her conditions very largely determine the occurrence and severit,y of forest fires is obvious. Just) what, the, conditions are that spell
low or high hazard, however, hns never been de.finit'ely
determined for t>he Lake St8at,es region. To secure this informat,ion, a st,udy of fire we,at,he,r and t,he hazard
resulbing was st,art,ed in t'he spring of 1928 by the cooper- ating agencie,s.
Early in May t,eniporary field stations were est(ab1ished in northeastern Wisconsin in typical jack pine and hard-
wood areas. At e.ach of t'hese st8ations during t,he spring
fire season obserrations were made daily at 8 and 11
a. ni. and 2 and 5 p. m. of the conditions prevailing in the
open, in the forest, and on part'ially cut-over areas. The resulting inflammability and moisture content of the
lit,t'er was also determined a t frequent intervals. In addition, the occurrence of fiws in the prot,ect,ion districts
adjoining the stat,ions was noted and the behavior of going fires observed wherever poFsible, as was also the
character, nnioun t,, and dis t,ribu tion of inflaniniable material typical of the two forest t8ypes under observat,ion.
While the clat,a secured have not yet been worked up
in detail, a very direct relat,ion between bhe inflamma- bility of the prevailing forest fire fuels and weather condi bions, particularly prec.ipitation and relative hu-
midity is obvious. For esample, each of hhe three
critical periods encountered this 'spring were preceded by from four to eight days without precipitation and with
a mid-day humidity of 40 per cent or less. The moisture cont,ent of the lit,ter during dry periods also was found to vary direct>ly witah the humidity, explaining why fires
burn more fiercely between noon and 4 p. ni. and are
more readily controlled in t,he, morning and late afternoon. Wind velocity was also found t'o be ah iniport,ant factor
when other conditions we.re favorable for the occurrence of forest fires, velocitie,s of seven miles per hour and over
causing fires to spread rapidly and making control difficult.
The spring fire season in nort,heastern Wisconsin this
year (192Sj was acute but not abnormal. * * * The lowest humidity obserwd was 21 per cent in the
open jack-pine country at 5 p. m. on June 6, the last bad fire day of the se.ason. While the humidity tended t o run somewhat, higher in the hardwood than in the jack-pine
coiintry, days with humidity of 30 per cent nnd less were
numerous at both stat,ions. Decidedly hig1ie.r humidities and a consequent higher moisture content, of the litter
normally prevailed a t the forest stations than in t,he open
in bot,h hardwood and pine, conditions in parbially cut- over stands being int,ermediate. This diffe.rence was par-
ticularly striking in the hardwood country after the leaves
had come out, but also prevailed consistent,ly in jac.k pine.
On the other hand, light rains were found to be more
effective in the open than in the forest, the forest cover
evidently preventing the prec.ipitation from reac.hing the
ground. As B result, norma.1 conditions were found to be
reversed by light rains, the litter in the forest) remaining
dry and hence more inflammable than that in the open.
* * * Just what conditions cause fires, apparently
dead beyond t.he possibility of revival, t'o flare up after
lying dormant for days is worth knowing. This spring a
fire of this kind occurred in northern Wisconsin in the area
that was being covered by this fire-hazard study.
As long as the relative humidity a t 8 a. m. was 50 per
cent or above the fire remained dormant. However, when the humidity dropped appreciably below 50 per cent
SEPTEMBER, 1929 MONTHLY WEATHER REVIEW 387
the fire flared up and required determined and siistained
effort to keep it under control. Light rainfall did not make the fire safe. A half inch of rain or more seems to be necessary to put a fire in a condition where it is no
longer a menace.-Forestry section, 1927-28, Annual
Report of the Director, agricultural experiment station, Uni-
versity of Wisconsin.
Count Rumford in meteorology.-In the course of a most
interesting biography of Count Rumford by Lyman C . Newell, published in Science, July 27, 1928, pages 67-73,
the following (pp. 69-70) is of historical interest in
dmerican meteorology :
One of his investigations was an elaborate series of unique experi-
ments on the heat-conducting power of fluids. He showed among many other things t h a t convection currents are the principal means by which heat is transferred through fluids, and described how, when a vessel of water is heated, there is generally an ascending
current in the center and a descending current all around the periph-
ery. Hence he concluded i t is only when a liquid expands by increase of temperature that a large mass can be readily heated from
below. He also pointed out the exceptional behavior of nater below 39' F., viz, i t contracts when heated and expands when
cooled. Then he proceeded t o explain how large bodies of water are prevented from freezing at great depths on account of the expansion which takes place on cooling below 39' F., and he men-
tions as an example that in the Lake of Geneva, a t a depth of a thousand feet, the temperatnre was found to be 40' F. He
emphasized the fundamental bearing of this unusual behavior of
water on climate everywhere, and on the preservation of trees,
fruits, and vegetables during the winter in cold countries. I n his experiments on the heat-conducting power of liquids, Count Ruinford * * * turned his conclusions to practical account in making warm clothing, not only of woven fabrics but also of feathers and fur. * * * I n another series of experiments devoted t o the radiating power of different surfaces he showed how the power varied with the nature
of the surface and illustrated the results by demonstrating the effect of a coating of lampblack in increasing the radiating power of a body.
He also investigated the absorption of heat by different surfaces. His results led t o the law that good radiators are good absorbers and the recommendation that vessels in which water is t o be heated
should be blackened on the outside. I n speculating on the function of the coloring matter in the skin of the negro, he said:
" Were I called to inhabit a very hot country, nothing should
prevent me from making the experiment of blackening my skin, or, at least, of wearing a black shirt, in the shade and especially at night, in order to find out if by those means I could contrive t o make myself inore comfortable.''
-e. F. B.
New rainfall record f o r Canal 7one.-Rainfall in this
consular district during the months of July, August, and
September was considerably greater than during the corre-
sponding months of the year.1928. A notable feature was a precipitation in the space of one hour of 5.16 inches.
The total rainfall in the Colon consular district during the month of Bugust was 33.78 inches.
BIBLIOGRAPHY
C. FITZHUGH TALMAN, in Charge of Library
RECENT ADDITIONS
The following have been selected from among the titles of books recently received as representing those most
likely to be useful to Weather Bureau officials in their
meteorological work and studies :
American society of civil engineers. Flood control with special reference t o t h e Mississippi river.
A symposium . . . p. 657-969. illus. 23 cm. (Repr.: Trans. v. 93. 1929. Paper no. 1709.)
Brooks, C. E. P. Formation of hail. p. 305-308. illus. 28 cm. (Discovery. London. v. 10, Sept., 1929.)
Dannmeyer, F., & Riittenauer, A.
Grundlegende Untersuchungen an Gliihlanipen mit ultravio- lettdurchlassigem Glase. 19 p. figs. 21 cm. (Mitt. Licht- forschungsinst des Allgemein. Krankenhauses, und der
Studienges. fiir elektr. Beleuchtung.)
Defant, Albert. Meteorologie. 5t,e., umgearb. Aufl. unt.er Benutzung der 3. Aufl. der Bearbeit. von W. Trahert,. Berlin. 1929. 140 p.
illus. 16 cni. (Sammlung Goschen.)
Deutsche Forschung. Aus der Arbeit der Not,gemeinschaft der
deutschen Wissenschaft. (Deutsche Forschungsgenieinschaft.) Heft 4. Geophysik und Aerologie. Berlin. 1928. 91 p.
figs. 23 cm.
International geodetic and geophysical union. Section of meteor-
Troisieme assemblke gbnkrale: Prague, 1927. I. Report on photometers for a survey of .the reflectivity of the earth's surface, by L. F. Richardson. 11. Atmospheric dust: ob-
servations with the Owens dust-counter. 1. United Stat,es,
Washington, January 1925 t o July 1927. 2. Australia,
Melbourne, September 1924 t o June 1927. 3. Finland. (Aitken dust-counter.) Report. by Dr. G. Melander.
Cambridge. 1928. 48 p. illus. ,25 cm.
ology.
Ivanow, Sergius.
Die Klimaten des Erdballs und die chernische Tatigkeit der
Pflanzen. Berlin. 1929. 39 p. 3536 cm. (Fortschr. der naturwissensch. Forsch. Neue Folge, H. 5.)
Japan. Central meteorological observatory. /
Climatic atlas of Japan and her neighbouring countries.
Tokyo. [1929.] 37 p. 95 plates. 42 cm.
Kahler, K.
Einfiihrung in die atniosphlrische Elektrizitlt. Berlin. 1929.
vi, 244 p. illus. 25!$ cm. (Sammlung geophys. Schrif- ten. Nr. 9.)
Meyer, Rudolf.
2336 cm.
Die Haloerscheinungen. Hamburg. 1929. viii, 168 p. figs.
(Probleme der kosmischen Physik. 12.)
PakHtas, Kazys.
. . . Le climat de la Lit.uanie . . . Klaipkda.
illus. charts. tables. diagrs. 2236 cm. 1926. 137 p.
Scherschevsky, A. B. Die Raket,e fiir Fahrt und Flug. Eine allgemeine verstandliche
Einfiihrung in das Raket,enprobleni. Berlin. 1929. 134
p. illus. 21 cm.
Schmauss, August, R- Wigand, Albert. Die AtniosphLre als Iiolloid. Braunschweig. 1929. 74 p.
illus. 2231 cni. (Sammlung, Vieweg. Heft 96.)
Sion, J. Asie des moussons. 2 v. Paris. 1928-1929. figs. plates.
29 cm. (Geog. univ. T. 9.)
Southern California. University. Compilation of papers read before the water supply section,
school of citizenship and public administration. Short course, June 17 t o 21, inclusive. Los Angeles [1929.] 163 p. figs. plates (fold.) 23 crn. [Papers on hydrology.]