47s 



. f t he influence. In many places for- 



llers were supposed to favor 

 the out bum of severe storms, while in a small, -r 



tMT <>r pUrwe they were BMMffal t<> diminish 



the liabdity l them. The author could only 

 conclud. f.-> tl. observation that 



they have DO direct taflasoos on the propaffa- 

 Uoo of haiUtorm*. The preval n - of belief in 

 such influence in attributed to the prH|ii.-ii..n by 

 II--A! f.-.itur.-.- uf minor phenomena of iark and 

 iMQsmf^ooking cloud* which. while having no 

 real connect i<>n with it, are associated with what- 

 ever Storm may fchs time. It can not 



be denied. 'imt the production HIM! 



progress of storm* are affected by the features 

 of the earth's surface, but tin- influence such 

 feature* eiert i* only indirect, an. I consists es- 

 ssnUaJiy in changes that are caused in tin- atmos- 

 phere. 'Thus the differences in the temperature 

 iin<l moisture between the Alps ami tin- Lombard 

 plains south of them le.-id to the production of 

 rast atmospheric eddies and depressions which 

 have considerable effect on the climate of south- 

 ern Kiiro|M> and Africa. Similar disturb.. 

 but differing in intensity according to the pro- 



MH. may be produced by other lesser acci- 

 dents. The course of the storm, when it has 

 arisen, likewise does not appear to be governed 

 to any great extent by the mountain ranges, 

 val leys, and forests, but" rather bv the ordinary 

 laws of the direction of atmospheric current-. 

 If the pressure is even in a large area, the storm 

 will follow the n>ual course, from southwest to 



;tst ; if the pressure is uneven, the .tonn 

 will follow the general direction of the wind as 

 determined by that circumstance. 



pteof Mr. Keuchler, of Indianola, Texas, 

 to ascertain whether there was a connection be- 

 tween the extent of the year's growth of trees 

 as shown by the formation of rings and the sea- 

 son's rainfall showed that while thei 

 great variation- in the annual growth of the trees, 

 th y did not correspond with the seasonal rain- 

 fall. The conclusion is drawn from the observa- 

 tions that not rainfall alone or any single factor 

 governs the amount of the growth of the tree 

 during the season, but a combination of factors, 

 including, besides the amount of the supply of 

 moisture, evaporation, insolation, temperature, 

 and the character of the rainfall, whether it 

 conies in showers or continuously. 



It has been shown by long-continuod observa- 



tions made by J. E. Codman that the size of 



rain gauges (automatic) makes no practical dif- 



ference in the depth of rainfall collected by them. 



The largest gauge experimented with was 22 



inches, and the sm.il l.-t on.- _> inches in diam. -t.-r. 



.tuges were placed at different heights, 



uount* were collected 



bv the higher ones as those on the ground, pro- 

 Tided no counter-currents of air came in to 

 * the result. This result agrees with that 

 Joand hy Prof. Wcllmann in his experiments in 

 Ix-rlm. 



The following generalized results as to the 

 distribution of rainfall in the United States are 

 dducl by \V. Koppen from an investigation 

 of the rainfall charts published by the (I 

 meat. Thew are: 1. a district of continental 

 summer nun*, inclosed on both sides by littoral 

 rains, which, corresponding to the contrast of 



the yearly oscillation ..f temperature, an- much 



marked in the West than in li 

 district of isobaric rains in th- 

 equatorial sea winds in summer and \vr 

 ier in winter; :i. transit i. 

 trirts. in which both rainfall maxima o< -cur near 



t her. while the minima occur in 

 and autumn. Maxima after the e< 

 n here very well marked, but t he A ; 



"f Colorado and Kansas and the n 



- iperior are ind thnn 



With regard to the seasonal distribution 

 tropical /one. the difference* in 



nly a small part compared wit h that 



r.i-tropical regions; this resu 

 follows from the small variation of temp. 

 in the tn.j 



Winds. From the studies ,,f the relat 

 the diurnal rise and fall of the wind 

 I'nited States, b\ .Mr. Frank Waldo. 



results are derived that for.lanuan 



the wind toward the midday maximum i> ''. 



lowed by a more rapid fall over nearly the WHl 



of the United States. For .Inly the same lav 



ho). Is. except in the Western States, whs^^H 



morning rise is more rapid. The rise 



Mi--i-Hppi valley continues during about M-VM 



hours. On the Atlantic . 



creases from ten hours in the Nort h to fi\ 



on the coast of Florida. The rat- 



during the rise varies from 0*4 mil. 



per hour. 



A peculiar climatic feature of the r . 

 the United States between the ninety-fir 

 one hundred and second meridians i 

 rence in summer of hot winds, or current 

 with higher temperature than that of ti 

 oral winds. They attracted notice ii 

 tl|e twenty-three years ending in 1W 

 caused considerable damage to crops in t 

 four of those years. l'.\.n when severe, their 

 dest ructiveness, according to Mr. Isaac M 

 ('line, is confined to narrow limits T! 

 likely to occur U'twecri the middle 

 the middle of September, but are m 

 during July and August. The let 

 during which they are likely to pre \.-ii! \arn-- 

 from a few hours to three day< ! 

 tremely dry. Their direction 'is usually 

 the atmospheric movement near the 

 revailing at the time over th 

 which they occur, and their velocity 



ibly. It i- noticed a> on.- of th. 

 striking features that, while the atmosp 



rally and shows an exec- 

 at ure over the" territory affe< 

 heatetl narrow currents are often 

 tween which the air is much cooler. 

 these winds are always noted a 

 tion to wilt and droop, the m<,r. 

 ones burn ten.: on to a ci 



minutes, without reference to th> 

 moi-tnre prese.nt in the *oil orth. 

 mosphere; and some of the most destr 

 them have In-en known to occur wh 

 .rated with moisture. In stn! 

 tribution of pressure in conn. 

 winds.it i> f.,und. Mr. ('line says, that tin 

 mostly with low-pressure areas wlii'-h I 

 moved slowly from the north of Montana^^H 

 easterly along the eastern slope for thre< 



