718 MONTHLY WEATHER REVIEW. DECEMBER, 1920
Dr. Abbot’s summary of his report follows:
The ear hns l w n marked hv the practical completion for puhlica- tion of bolume Itr of the iinnals, bllt no all ropriatinn is vet available for ita publication. Close agreement of soEr variation \+as found for 1916 and 1919 between results of Mount Wilson, Calif.. and C‘alaniu. Chile, 6.000 miles apart. I further reniarkahle confirmation of the aolar variation conies froni a coniparknn of Sniithsonian nhwrvatinns in Chile with photoelectric ohservations of the brightness of Saturn I>> Dr. Guthnick. of the Berlin-RnIwlsl>erg Vbservatory. This coni- parison indicates that the nature of the rapid solar variation consists in the rotation with the sun of ravs of unequal brightness whirh strike the different planeta successivpli in the order of their lon&iides ancl fall one after the other upon the parth RS the sun by rotation lirings them into line nith us. -1 nvw nocturiial ratliatioii instruliient. y o - visionally called the “honeycomb pyranoniekr” 011 account of its cellular itruc t UP. and which eniplops the well-known hollow chanilm principle of the “absolutely black” body. but without loss of sensi- tiveness, has been successfully constructed ancl tried. By the Xener- caity of Mr. John -4. Roeblinq, of Kew Jeiwy, i t has IJcrn jiossilile to remove the Chile station to a mountain above the dust and smoke of ib fornier plateau location. and also to erect a building on the Harilua Rala Mountain, in Ari.mna. to whicli the Mount Wilson solar-constant work will be removetl in Xept.*inher, L99O.--If. 11. Ii.
DEOREE OF TEMPERATURE TO WHICH SOILS CAN BE COOLED WITHOUT FREEZING.
GEORGE ROUYOGCOS.
[Abstracted Irom J w r m l oJ d g r i r d b r a l Kcsearch. No\-. IS, 1920, Vnl. XS. Sn. 4,
pi’. :A7-.ZYiO.]
Careful tests showed that soil will not freeze at a tem- perature of - 1’ C. (30.2’ J?.) unless it.is vi orouslg agitated. If not disturbed, it will remain nt t is tcm- perature indefinitely witliou t frerzing. Dr. Bouyoucos found further that, if not disturbed, sand, loam, and clny soils may be cooled to -4.2’ C. (24.4’ F.), and peat and inuck to - 5’ C. (33’ F.) without freezing. The moisture content of the soils had no influence on the possible estent of supercooling. This explains why the soil need not be frozen even thou h the temperature of the air and of the soil itself ma %e considerably below 32’ F. $he author points out that by the method now in vo ue
the thermometer may give a record several de ees below the freezing point and yet the soils may not f e actually frozen. .
“Indeed,” he says, “the ability of soils to resist freez- ing even when their tem erature is much below the
regarding the temperature of soils in cold seasons and consequently upon the physical, chemical, and bac teri- ological processes going on in the soils during those seasons.’ -J. Wurren Smith..
for measuring the temperature of soils during cold weat % er
freezing point throws consic f erable new light. on questions
CLIMATE OF NEW ZEALAND.’
Ry Lieut. Col. D. C. BATES. Dominion Meteorologist.
(Review.]
This useful book a gives averages of temperatures, rainfall, and, in some cases, sunshine, for 11 stations in New Zea.land, ranging from Auckland in the north, with
I Reprinted from The Ne6corobgiraZ Malayariar London Urnernher, lkXIl, p. ?57.‘l
Prepared lor publication in the iVc‘e*v Zruland h.firiul 1’Enr-kook.
a superb subtropical climate, to Invercargill in the south with the climate of southwest England. The climatic features of each district are succinctly described, but we miss the generalized account of the meteorolo region which would bind the sections toget er and enable the reader to see how far the local characteristics are subservient to the prevailing winds and other far- reaching causes.
[NFLUENCE OF TEMPERATURE AND HUMIDITY ON THE
T Of the
GROWTH OF PSEUDOMONAS CITRl AND ITS HOST PLANTS AND ON INFECTION AND DEVELOPMENT OF THE DISEASE.
[Abstracted fro181 Joirrilol oj AgricuZtural Reamrch, Dec. 15, 1920, Vol. SS, No. 6, pp. 447-.m.]
This is a complete and -ralunhle study, not on1 of the effect of temperature and humidity on the deve P opment
of citrus diseases, but on the growth and clevelopment of the different citrus trees.
“Ivo t pes of rest periods are discussed: Winter dor-
when cell activity ceases to h p e a t estent, and the short rest periods which occur during the ,vl.owing season when
sonie of the cell functions mere1 slow up. With t,he tinie fnctor include([ the optimum tempern- ture for citrus p1ant.s lies between 20’ iuid 30” c. (65’
ant1 SO’ I+’.). Thrsc conditions nre essent,ial for diseuse infection- the presence of free moisture on the plant, a suitable tein eraturo, and an actively growing lant. TRe coliclitions for the most rapic Y del-elopment of citrus diseases are also those that, are most. favorable for the rowth of tho host dnnts.
on the relations of climate to citrus canker and scab, will make a valuable addition to our at present rather incomplete knowledge of the effect of climate and weather on plant diseases.--J. Wurr~n Rniltli,.
mancy, P Jrought about by the approach of cold weather
d i s stiicly, with allot \ ier that ur. Peltier is now making
CITRUS FRUIT FUMIGATION SAFEST I N DARK AND AT MODERATE TEMPERATURES.
While it ha.s long been known that the presence of light during fumigation of citrus fruit wit.h ligdroc ltnic acid
and foliage, it, has not been known that lioht before and after fumigation has a similar effect. h i s fact 1ias been disclosed by recent tosts conducted in California by specialists of the United States Department of l%i- culture, who have made a report of the experiments with suggedons for preventin injury, in department Bulle- tin 907, “Fumigation of Citrus Plants with Hydro- cyanic Acid : Conclit,ioiis Influencing Injury.’’ Moisture ancl tempera,ture, as well as light, influence fumigation injury, and experiments show that funiiga- tion is more safely ei-formecl a t t,emperatures below 80’ F.
exposure ten! greatly to increase plant injury. Trees in wet soil are likely to be more severely injured than healthy trees in dry soil.
is one of t,he factors which causes injury to t 0th fruit
Sudden than es o F temperature over R wide range during