QC wae, CoH 8s) Qc 925 5 sds CORNELL UNIVERSITY LIBRARY rin aia Library QC 925.3.C5J4 wl iON AMERICAN GEOGRAPHICAL SOCIETY RESEARCH SERIES NO. 7 THE RAINFALL OF CHILE BY Marx JEFFERSON AMERICAN GEOGRAPHICAL SOCIETY'S EXPEDITION TO a. B. ve. COUNTRIES IN 1918 NO. 2 NEW YORK OXFORD UNIVERSITY PRESS AMERICAN BRANCH: 35 West 32 STREET LONDON, TORONTO, MELBOURNE, AND BOMBAY 1921 w -D+y. Oc ee pa CS V4s COPYRIGHT, 1921 BY THE AMERICAN GEOGRAPHICAL SOCIETY OF NEW YORK COPYRIGHT IN GREAT BRITAIN PRINTED IN THE UNITED STATES OF AMERICA THE CONDE NAST PRESS GREENWICH, CONN, THE RAINFALL OF CHILE By Mark JEFFERSON As Chile is an agricultural country, its life is intimately bound up with the supply of rain; yet the distribution of this rainfall throughout Chile is quite misrepresented on all existing maps except as regards the general dryness of the north and the wetness of the south. THE THREE RAINFALL REGIONS OF CHILE The north of Chile is a hideous expanse of yellow sand and rock. At Iquique one millimeter of rain has fallen in the last five years (to the end of December, 1919). Of the last twenty years fourteen have had no drop of water from the sky. The whole catch of the twenty years has been 28 millimeters (a little over an inch). This is the nitrate desert. The drought does not begin to break until one reaches Copiapé, nearly 500 miles farther south. Here rainfall years are infrequent —i1910 and 1913 were such—but the average fall is only 17 millimeters a year (about two-thirds of an inch). The total rain- fall at Copiap6é in the last twenty-four years has been 408 millimeters, about one-third of what falls in New York in a year. At Ligua, less than 50 miles from Santiago, it rains every year, on an average 269 millimeters (between 10 and 11 inches). Though the country is still arid, the irrigated spots begin to attain significant size. The far south is as wet as the northis dry. It isa vast morass— where the rocks are not too steep to hold any soil—dripping, oozing, showering, with no roads possible but corduroy, where there are people enough to maintain corduroy. For 900 miles the woods are so wet that it is impossible to set a fire for clearing without constant relighting, even when all the people of the countryside turn out to attempt it. In the southernmost islands the attempt would be quite hopeless. “The inanimate works of nature—rock, ice, snow, wind, and water—all warring with each 2 THE RAINFALL OF CHILE other, yet combined against man—here reigned in absolute sovereignty.” ! The main home of the Chileans lies between these extremes, mostly in north-and-south valleys between the Andes and coastal mountains, from latitude 31° to 38° S. In this part of Chile are Santiago, Valparaiso, and Concepcién—the chief cities. The rain increases southward along these valleys from the scanty 269 millimeters at Ligua to'an abundant 1,250 millimeters at Temuco. Along the coastal mountains it is always greater, and here too it increases southward from 500 millimeters at Valparaiso to 2,700 millimeters at Valdivia. The Andean slopes are rainier than the coast in every latitude. The dryness of the interior valley and the wetness of the Andes is the novel feature of the new rainfall map, not recognizable on any of the old ones, though it is obvious on a brief journey in the country. Of clear sky and sunshine central Chile has an extraordinary amount. Evapora- tion must be very great. Rains TO WEST AND Rain SHADOW TO East The rains come from the Pacific. The valleys lie in the rain shadow of the coastal mountains, as the western Argentine plains lie in the greater rain shadow of the Andes. Always the western slopes are wet, the eastern ones dry. You see this in going from Valparaiso to Santiago by rail. Between Limache and Quillota the train moves northward at the foot of the coastal mountains, whose slopes are dotted with trees, poor-looking to one from a humid country but indicative of no little moisture. From Llai- Llai junction we go south to Santiago in a valley back of the coast range and find the eastern side of the range almost entirely sterile. There is a stream channel in the valley in which water must flow at times, for there is the work that water does—the channel carving, the boulders it drags along; but even after the rainy season has well set in in the south there are only pools of green, scummy water here and there in the stream bed. The hillsides have become bare. The brilliant sunshine is a delight; it 1 Charles Darwin: A Naturalist’s Voyage Round the World, London, 1886, p. 241. THE RELIEF OF CENTRAL CHILE 3 warms one gratefully on the winter days that are so chilly in the fireless houses. In this arid setting the brown water, rushing along in the steep irrigation ditches, evokes a luxuriant growth of alfalfa, grain, and vegetables to carpet every flat stretch between the tawny hills. The Chilean census of 1907 maps these irrigated fields of the central valley (Fig. 1). The water comes in abundance from the Andean slopes. I saw a much greater contrast in 1886, when crossing the Andes from Mendoza by the Iglesia pass on mule back. All the eastern Argentine slopes were sterile and bare. The only plant to be seen was a great candelabrum cactus; but 2,500 feet below the crest of the pass on the Chilean side graceful clumps of birches were scattered over the slopes. A little lower, at Ojos de Agua, beau- tiful, clear streams emerged from a bower of overhanging birches, very beautiful after the sterility of the Argentine slopes. The summit snows lie mainly on the western side of the range. They, too, must have come as water vapor from the Pacific. Shoreward there is more rain than in the valleys, but there is little soil, There are some dry cultivations on the rainier hills, but the main soils of central Chile lie in these intermontane valleys. Moistened by Andean waters, these soils nurture the best life of the land, unhampered by the forest cover that en- cumbers the earth farther south. In the latitude of Talca the forests are found only in the zone of heavier rains of the upper Andean slopes. A hundred miles south of Concepcién the forest clothes the whole country down to the sea. In this forest border the Araucanians maintained their long, successful struggle against Spaniard and Chilean. This is the Frontera. Tue RELIEF OF CENTRAL CHILE With his usual acuteness Darwin in 1834 called attention to the similarity of topography of central Chile and the southern archipelago. The coast ranges are not continuous ridges parallel to the Andes but just such irregular hill masses as the islands off the southern coast. The intermont basin plains are doubtless 4 THE RAINFALL OF CHILE “the bottoms of ancient inlets and deep bays, such as at the present day intersect every part of Tierra del Fuego and the western coast. . . . The resemblance was occasionally shown strikingly when a level fog bank covered, as with a mantle, all the lower parts of the country; the white vapor curling into the ravines beautifully represented little coves and bays; and here and there a solitary hillock peeping up showed that it had formerly stood there as an islet.” ? Most of the Chilean provinces extend across the narrow country from the Pacific to the summits of the Andes. But there are three (Fig. 1), Valparaiso, Maule, and Arauco, that have their greatest extension from north to south along the coast, with interior provinces behind them. It happens that in these thtee places there are bits of a continuous coast range whose crest divides the coast province from the interior. In other places the hill masses are quite irregular. Each of these three provinces gets more rain than falls to leeward; but Valparaiso is unlike the others in including one of these old sea sounds, the broad trench of the Aconcagua at Quillota, so that there is enough level land for its waters to be used in effective agriculture. Thus it happens that Valparaiso has 6 per cent of its area irrigated, but neither Maule nor Arauco has a tenth of one per cent. They lack level land where their waters may be utilized. The interior provinces here, asarule, have 6 to 14 percent of theirsurface under irrigation. The western part of the province of Santiago lies in the rain shadow of the Valparaiso mountains. The city of Santiago has but 364 millimeters of rain (Fig. 2). The situation of the province of Maule on the 36th parallel is much the same, except that it includes lands beyond the crest of its coast range, as at Cau- quenes. The boundary that separates it from Linares and Nuble on the east runs along minor hills. Arauco, however, is walled off from Bio Bio and Malleco by the pronounced Cordillera of Nahuelbuta, with over 2,000 millimeters of rain on the windward slopes and only 500 or 600 in its immediate rain shadow in western Malleco. 2 Darwin, p. 255. LaSerena | Coquimbo | Valparaiso Santiago Rancagua Talca 7 Chillan Concepcion [32 3° 200 MILES Fig. 1 The Forests and the Irrigated lands of Central Chile. (From Census of 1907). The northern point of forest on the coast is in latitude 37 degrees 30° but in the Andes the forest continues to 35 degrees 40 minutes. dquimao o 250 VALPARA)SO! AMS Fig. 2 A new map of Rainfall in central Chile. Data by the Chilean Meteorological and Geo- physical Intsitute, including the year 1918. Isohyetals by Mark Jefferson. 7 B 7 76 =e 7 a 4 | {—~. \ Anal az q + + 2] e ¥ - + + a ’ ' a ' : 4 i ¥ i J =. te ‘ i: a / Aisa / + + age a _| a + - CO + 2] Taltal a ee * + + +o] © Copiaps + + + 1 cate * i + se 4) + + + +, ad + + + en el + + + + wl + + + + = ee ae eee ae MEAN ANNUAL RAINFALL a | oF CHILE PROXIMATE EPOCH 1900-1919 MARK JEFFERSON 1:10,000,000 aa COLOR SCHEME INCHES MILLIMETERS | Tess than 10(4_\less than 250 “| | 10-20 21250 - 500 i 20-40 (5) 500-1000 q 40-80 253/000-2000 80-200 GHB 2000-5000 (| over 200 ZB over 5000 | _ 45} 50 htr THE NEW RAINFALL MAP 5 THe New RainraLct Map SHOWING THE EFFECT OF THE RELIEF But all these items are quickest seen on the new rain map of Chile (Fig. 3), based on gauge records at 167 stations up to and including the year 1918. The doubling southward of all the isohyetals in the central valleys indicates the dryness of the interior. The rain falls during the prevalence of a northwesterly wind from the Pacific, laden with water vapor. Cooling alone is needed to precipitate the vapor as rain; and this occurs not only because the land is cold in winter but also as an accompaniment of the expansion of the air as it is pushed to higher levels on the slopes of the mountains. As the Andean slopes are much higher than all others, it is there that the strongest precipitation always occurs. If Pacific winds cross Nahuelbuta, they must descend on the eastern side and gain in warmth as the air rolls in above and compresses them. That it rains more.abundantly again on the Andean slopes is simply because of their greater height and of the greater expansion of air at those high levels if it is pushed up from the west. Settlement in central and southern Chile has always followed the interior valleys. This is, I think, partly a result of their greater dryness. The chief reason has been that the soils occur mostly in these valleys. But had there been more rainfall the whole valley would have been occupied by forest as far north as Santiago, which would have delayed settlement greatly. In the rainy south, where woods did actually occupy all the land, the less rainfall of the interior was a distinct advantage. It is curious that Darwin noted populous openings in these southern woods as early as 1834. “The llanos are the most fertile and thickly peopled parts of the country [Valdivia]; as they possess the immense advantage of being free from trees. . . . I have often noticed with surprise, in wooded undulatory districts, that the quite level parts have been destitute of trees.” It was in 1884 that it occurred to the governor of Arauco, Don Esteban Iriarte, to send a group of German domestics and 3 Darwin, p. 299. 6 THE RAINFALL OF CHILE mechanics from Berlin to the western slope of Nahuelbuta to settle there, with the idea that their presence might make those forest solitudes uncomfortable to certain Chilean cattle thieves. It must have seemed strange * that these Germans should have taken a route so roundabout—landing at Concepcién, going down the central valley of Malleco to Angol by rail, and thence by ox wagons over the trail to Los Sauces, Purén, and westward over the Nahuelbuta range—to reach a spot only twelve miles distant from the Pacific and on a slope leading down to it. The reason must have been that the trails were established in the drier valleys to the east and that there were none on the rainy western slopes. Even then we recall the two weeks’ wait at Purén till the mountain road became dry enough to pass. In other words, the effect of the heavy rains of southern Chile is to impede communications to an extraordinary degree, so that the roads follow the drier regions most carefully. Good soils in a wet region have their value greatly enhanced by roads through adjacent dry country. This is a most important element in the economic life of Contulmo and one that could not possibly be appreciated without some knowledge of the rain distribution of the region. Bowman has described identical rainfall relations with these of Chile for the south of Peru. The amounts involved in those desert regions are almost too small to measure, but their impor- tance is much enhanced by the desert environment® WINTER RAIN AND SUMMER DROUGHT The observations on which our rainfall map is founded are mostly recent, as we shall see, and the older values have been a good deal modified by Whitaker’s revision of 1915. It is an important fact in central Chilean agriculture that the rain falls mainly in the winter half year, April to September. Eighty-two per cent of the year’s total at La Serena falls in the three colder months, 73 per cent at Santiago and 61 per cent at 4See Mark Jefferson: Recent Colonization in Chile, New York, 1921, p. 35. 5 Isaiah Bowman: The Andes of Southern Peru, New York, 1916, p. 131. ! WINTER RAIN AND SUMMER DROUGHT 7 Concepci6én. In the three warm months, January, February, and March, the percentages are 0, 2, and 4. Chileans refer to this as a handicap, as it compels them to irri- gate. But if they had the same amount of rain in the summer months and had winter dry, they would still need irrigation, since the total amount of rain that falls is insufficient. Moreover, it isa great advantage to the farmer to have his water supply under control, as rainfall never is. The high yields that characterize Chilean agriculture are doubtless due to irrigation. The expense of putting water on the land precludes any but intensive methods of agriculture. Our data allow us to present a fairly complete table of the seasonal distribution of rain in Chile. It is curious that the three TaBLeE I—MONTHLY PERCENTAGES OF TOTAL ANNUAL RAINFALL STATIONS Lav. | 3| 2] 6] 2] @| 3) Bl 8) sl] 8/8 g ‘we, 5) 2) 2/3[8|3|8)3/2/8|8)2| A | wos La Serena . . 129° 54/|10| o} of 2/24]/24/27/31/14| 1124] 0} o 98% Santiago . 133° 27/10] 0} 34) 2] 2/22/25/26/13] 4] 3] 1] 134] 90 Concepcién . 136° 50’|10] x| 2| 5} 6/16/2q4l2z}rx] 7] 4} 2] 83 Valdivia. . 139° 48/|10] 2| 3] 5) 8)r2ir7}rsir4iro} 6] 5] 3 qI Puerto Montt . |41° 28’/10] 6] 6) 7| 8}12/r0]z6] 9] 7] 6] 7] 5 62 GuafoIsland . [43° 34’| 9| 6! 6] 6! o/z3]/r2/zz/13| 7] 5] 6] 5 64 Melinka . . . 143° 54'| 6] 4] 5) 6] 8/13]12]/13]z0] Oo} 7] 7] 7 61 Refiihue . . . 142° 34’] 4] 8] 3] 7| 7/z2/13]11] 9}ro} 5] 8] 7 59 San Miguel - 153° 43’| 3] 7| 8} 8|13]/10} 8] 9} 6] 5] 9) 8) o 54 Bahia Harris. {53° 50’| 5] 6] o]zz/rz/z0] 8] 7| 8} 8] 6] 7] 9 55 Bahia Douglas . |55° 9’| 4/10] 6] 9] 9/11] 9|rz| 6] 4] 5/12) 7 56 Punta Arenas . |53° 10’| 9} 6] 6/10/11/14) 8{ro0} 8} 8| 5) 7] 7 61 Dungenes .. . [52° 24’| 9/10) 5] 8/14] 9] 9/10] 8] 6] 4) 4/13 58 Cape Raper. 146° 50’! 7| 9} 7| 8} 9} 8} 8 8] 8} 8] 8) ojz0 49 Evangelistas . 152° 24’) 9/10] 9|/zo|10| 8] 7| 8} 6) 8} 8| 8] 8 49 Bahia Félix . 58° 58] 5| g/ro]zz} 9] 9] 6} 8] 5] 8) 8| 8) 9 48 * The last column indicates the percentage of the annual amount that falls in the six winter months, April to September inclusive. It is obtained from the winter rain in millimeters and does not quite agree with the sum of the (approximate) winter percentages. 8 THE RAINFALL OF CHILE southwesternmost stations in the archipelago have a slight excess of summer (December, January) rain, but the fact is of course without economic significance on account of the lack of inhabitants. Similarly summer thunderstorms occur in the Andes east of Atacama. There exists a map of rainfall on the Pacific, published by the Ham- burg Seewarte, that gives the distribution of rainfall by seasons on the basis of the numbers of rainy days observed, gauge read- ings for rain measure not being practicable on a moving deck. From this (Fig. 4) we learn that the rainless region of Peruand Chile extends only one or two hundred miles from the coast, as if it kept over the Humboldt Current. Alittle farther out there is rain in winter time reaching as far as the equator on the sea, though on land it is lis ‘10 20 30 / Fic. 4—Distribution of rain on the Pacific according to a count of days of rain atsea. The shaded area (1) rarely hasany rain. It seems that the aridity of the coast extends less than 200 miles out to sea, lying over the Humboldt Current; the area marked 2 has rain only in winter; the area marked 3 has some winter rain; and the area marked 4 has rain more than half the time in every month. The stars are placed on the stippled area on land because it is too far inland. Summer thunder- showers are common in northeastern Chile. (Stiller Ozean: Ein Atlas, etc., Deutsche Seewarte, Hamburg, 1896, Pl. 25.) DATA FOR A NEW RAINFALL MAP 9 confined to central Chile. Later observations place the land- ward margin of the stippled area farther west than here rep- resented, One result of the heavy rainfall of the south is a slightly diminished specific gravity of the waters of the Pacific from 39° to 53° S. and as far west as 85° on the 5oth parallel, 1.026 as compared with 1.027 just beyond. That means slightly fresher water.® Data AVAILABLE FOR A NEw RAINFALL Map A total of 167 stations are now available for the study of Chilean rainfall. One hundred and thirty-four of these—up to 1915—are reported in a work by the Chilean meteorological service,’ which contains a careful compilation and summation of all rainfall observations in the country from 1849 to 1915 by Miguel Whitaker, chief of the rainfall service. Quite a number more are added by the annual reports for 1916, 1917, and 1918. Ten of these, having only their latitude given, were not used in drawing the rainfall map, but the longitudes of all but Cuyurran- quil and El Suefio have since been found and put in the list at the end of this paper. They agree well with the isohyetals. Los Guindos and Pehuenco point to heavy mountain rainfall on the 38th parallel where I had drawn the isohyetal broken.8 In a note at the end of Publicacién No. 20 Whitaker says “Isohyetals, . . . lines of equal precipitation, are not pub- lished, . . . for the number of stations established up to date does not indicate even approximately the distribution of rainfall in the country.” There is a good deal of truth in the statement; however, isohyetals have been drawn which are based on data very much less adequate than what we now possess, and these isohyetals . Stiller Ozean: Ein Atlas, etc., Deutsche Seewarte, Hamburg, 1896, Pl. 5. 7 Recopilacién de sumas de agua caida en Chile 1849-1915, Inst. Meteorol. y Geofisico de Chile, Seccién Lluvias, Publ. No. 20, Santiago de Chile, 1917. 8 They are: La Pampa (28° 59’), 250 mm.; Tongoy (30° 15’), 98 mm.; Perales de Marga-Marga (33° 9’), 563 mm.; S. José del Carmen (34° 33’), 541 mm.; Millahue (34° 38’), 607 mm.; Cuyurranquil (35° 38’), 1,508 mm.; Los Guindos (38° 3’), 3,169 mm.; Pehuenco (38° 23’), 2,293 mm.; El Suefio (39° 15’), 2,894 mm.; Ponsonby (52° 40’), 339 mm. 10 THE RAINFALL OF CHILE are in wide and constant use today. The stations now established suffice in my opinion to give us lines with some approximation .to the truth, especially in the settled part of the country, central Chile. That is not true of the maps now extant. That is the only reason for undertaking at this distance from Chile a task that doubtless will be better done some day by the Chilean meteoro- logical office. Chile has one rain gauge to every 737 square miles of area. That is not much, compared with Switzerland, which has one to 48; or with the United Kingdom, where, it being good form for a wealthy landowner to maintain a rain gauge, there is one to 31. Something, however, can be done. The records are of very different length, from 1 to 68 years (16 of more than 20 years, 20 of 10 to 19 years, 34 of 5 to 9 years, 14 of 4 years, 21 of 3 years, 12 of 2 years, 50 of I year); but even the short series help. The country is so uneven of surface that the rainfall usually varies more from point to point than from year to year. Most of the stations are in the better-settled regions of the central valleys. It is difficult to keep up stations in the Andes,. which occupy fully half the country on the east. Nevertheless the Meteorological and Geophysical Institute has 19 stations in the Andes or in the foothills well to the eastward of the peopled valleys. They invariably show much greater precipita- tion than the valleys. The comparison of the rainfall at these mountain stations with those of the valley just west of them, given in the numbers of the last column of Table II, abundantly establishes the great rainfall of the Andean slopes. This is the first correction of the older maps, all of which made the central valley wetter in these lati- tudes than the Andes or the Pacific coast mountains. While longer series of observations are highly desirable at all these stations, there can be no doubt that they will confirm the general relation here brought out. “REDUCTION” OF SHORT SERIES OF OBSERVATIONS It will be noted that a number of stations have but one year of record. The greatest defect of a single year’s observation as “REDUCTION” OF OBSERVATIONS II TABLE II—RAINFALL STATIONS IN THE ANDES Ane tw RAINFALL|RAINFALL IN Yrs. STATION Lat. | Lone. . IN MILLI-| THE VALLEY METERS METERS |TO THE WEST I |Portillo 32° 51/170° 12) 2,885 | 1,552 300 6 |Apoquindo 33° 25'170° 32’ 782 510 3 |Maitenes 33° 18'|70° 22’) —— 50S 6 |Florida Alta 33° 33/|70° 33’) —— 516 400 4 |La Obra 33° 35/170° 30'| 799 692 6 |S. José de Maipo |33° 38'}70° 22’ 957 651 2 |Volcdn 33° 49’|70° 11’| 1,500 | 1,436 528 7 \EIl Teniente 34° 6'170° 38’| 2,134 | 1,153 405 4 |Lonquimay 38° 26/71° 14’ 970 | 1,890 I |Selva Obscura [38° 22’172° 8’ 438 | 2,022 I,200-1,300 rt |Curacautin 38° 26'|71° 50’ 544 | 1,841 1 |Pucén 39° 16//71° 58’ 230 | 1,378 No distinct 5 |Panguipulli 39° 40'|72° 17’ 140 | 2,697 valley here 2 {Los Riscos Ar’ 13/|71° 41’ 60 | 2,298 - 5 |Bahia del Volcan |41° 11'}72° 31 60 | 2,172 3 |Puntiagudo 41° 5/172° 17’ 190 | 3,319 I,200-1,300 2 |Peulla 41° 5/\72° 7! 190 | 3,263 rt |Casapangue 41° 3/|/71° 55’ 320 | 4,110 4 |Refiihue 42° 34'|72° 27' bo || Saxe E337 an indication of the amount of the rainfall at any place is the possibility of an unusually wet or dry year. Such a year, it happens, was 1914 in most of Chile. It was unusually rainy. Also it was the only year in which the rainfall was measured at a number of stations, among them the important one at Portillo, high in the Andes to the northeast of Santiago. I note the rain for seven years in succession at five stations in the region of Santiago in Table III. For each place the year 1914 was two or three times as rainy as the other years of the seven. For 66 years of observations at Valparaiso the mean is 515 millimeters; for 68 years at Santiago, 364; which is close to the values for the seven years at those places. Beyond all doubt 1914 was unusually rainy. The rainfall 12 THE RAINFALL OF CHILE TABLE ITI—RAINFALL IN THE REGION OF SANTIAGO STATION ro12 | 1913 | 1914 | 1915 | 1916 | 1917 | 1918 | MEAN Ovalle "3 38 308 93 34 74 108 104 Los Andes 618 276 600 234 110 187 212 320 Valparaiso 500 325 | 1.273 407 200 382 466 493 Santiago 201 268 700 237 225 204 377 329 El! Teniente 953 963 | 2,229 888 630 582 | 1,043 | 1,041 Total 2,435 | 1,870 | 5,0r0 | 1,859 | 1,199 | 1,429] 2,206 | 2,287 measured at Portillo that year was 2,755 millimeters, of course much higher than usual, though we have no other measure at Portillo than that. It would not be fair to use a value like that, which we know is too large. The only thing to do is to “reduce” it by the observed values at the nearest station, Los Andes. There 600 millimeters fell in 1914 compared with an average value of 338. It is not unreasonable to say that something like 338 =, Of 2,735 millimeters is the mean rainfall at Portillo. Some idea of the validity of this procedure may be had from the values in the above table. Suppose we had only one observation of the rain at Ovalle and that it was the one for 1914, 308 millimeters. The nearest station is Valparaiso. Comparing with Valparaiso 493 we should say eae of 308, or 121, is the probable mean rain- fall for Ovalle, as Valparaiso had a mean for the seven years of 493 and a catch of 1,173 in 1914. But the actual catch of the seven years was 104. The reduction has given us, in 121, a very fair approximation to the actual mean, much better than the observed 308. Or suppose we had only the value 600, caught in 1914 at Los Andes. Reducing by Santiago we should get 282 for the Los Andes mean. Or the Valparaiso value for 1914, if alone, would, when reduced by Santiago, give 551 for the Val- paraiso mean, in each case a better value than the observed one. All short series of rainfall observations need reduction for epoch in this manner; and this has been done in every case in the present study. In Table II Volcdn’s two observations are for SWITZERLAND AND CHILE 13 the years 1904 and 1905; Santiago had 616 and 682 for those years, twice her mean value of 364, so we have reduced the Volcan observations, 2,224 and 2,913, by Santiago to 1,436. The three observations at Maitenes were made in the years 1900, 1913, and 1914, the first and last rainy years and the second rather dry. The straight mean would have been 828 millimeters. The “reduced” value is 505. The single observation of each of the three stations Selva Obscura, Curacautin, and Casapangue, was in 1918, a rather wet year; and so all the observed values were slightly reduced from 2,248, 2,045, and 4,569, to 2,022, 1,841, and 4,110. It so happens that Los Riscos, with observed values for 1913 and 1914 of 1,996 and 1,997 millimeters, was the only station of those listed in Table II to have its value raised by “reduction.” That is chance, of course, the chance that most of the one or two year stations happen to have records for wet years. But it is important to bring out the fact that “reduction” of the observations at these mountain stations is not the cause of their large rain measures, since in every case but one the re- duction has diminished the actual catch, as more than the cus- tomary rainfall at that place. Further, there can be no doubt that the reduced values are fairly like those that future observa- tions will discover. THE Swiss RAINFALL MAP AND THE CHILEAN DATA In the Chilean archipelago it is certain that the lines of equal rainfall must be of very complicated pattern—too complicated probably ever to be drawn in full detail, unless some day the region should become inhabited. Every mountainous island must have heavier rain on its western, windward side, than on the eastern. Where a sound stretches out broadly to the east of an island, the rain must fall off a great deal, to increase again on the next island or on the mainland. There must be many isolated patches of smaller and of greater rainfall strewn through- out the archipelago. The fairly well-known isohyetals for Switzerland offer some interesting analogies. The Chilean archi- pelago is a partly submerged belt of mountains. If Switzerland 14 THE RAINFALL OF CHILE were depressed a thousand meters, the seas would invade the land, giving it the irregular coasts and islands shown on Figure 5 by shading the parts of the country above 1,000 meters. On this I have drawn Billwiller’s isohyetals? made from 334 rain- gauge stations. The Jura appears mostly as islands whose western outliers have less than 1,500 millimeters of rain. But the larger, higher “islands” get 1,500 and more, and then the rain falls off steadily to the eastward to 1,200 and goo on the “sound” between Fic. 5—Precipitation in Switzerland compared with that of Chile by shading regions above 1,000 meters. If the rest of Switzerland were beneath the sea Switzer- Jand would be in some degree comparable with southern Chile, and the well- observed facts of rainfall in Switzerland help us understand the little-studied Chilean Archipelago. the Jura and the Alps. On the Alps again the western outliers get 1,200 millimeters, but the slopes of the main range get 1,500 and 2,000 as the winds—here too from the west—are lifted to higher levels on the mountain sides. The contouring of isohyetals here shown about the mountain masses is doubtless present in the Chilean archipelago. Our handful of observations does not 9 Atlas der Schweiz, No. 26. RAINFALL SECTIONS ACROSS CHILE 15 enable us to go into such detail, but the Swiss analogy shows what the general scheme must be. All observers agree that the great rains of the archipelago come with winds from the north- west. The windward exposure there is therefore to the north- west, whereas in Switzerland it is to southwest. THREE RAINFALL SEctTIONs Across CHILE Our data accord perfectly with the Swiss analogy to point to heavy rains on the western islands, ranging from one meter at Guafo (43° 34’ S.) to two meters at Cape Raper (46° 50’) and three meters at Evangelistas islet off the western entrance to the Strait of Magellan (52° 24’). This increases to eastward on what we may call the main slopes of the Andes to five meters at Refiihue (42° 34’) and Bahia Félix (52° 58’). These last two stations, where the Chilean rainfall culminates, are 700 miles apart. There are no stations between. Even these are new, the records being for the years 1914-1918 at Refiihue and 1915-1918 at Bahfa Félix. Also they are accordant, Refiihue 5,336, 5,104, 4,748, and 5,738 millimeters; Bahia Félix 5,648, 6,160, and 5,183 millimeters. They nearly double the amounts of rainfall known from any earlier observations, and they accord abso- lutely with rainfall theory, which the older maps defy. The only one of the land masses in the archipelago that has observations on both sides, windward and leeward, is the Brunswick peninsula, that southernmost projection of the mainland of South America which pushes the middle of the Strait of Magellan 60 miles south of its eastern and western entrances. San Miguel to windward has 1,286 millimeters, and San Isidro and Punta Arenas to leeward have 813 and 470 respectively, exactly as theory requires. The height of the peninsula is about 800 or goo feet. A very good rainfall section may be drawn the length of the Strait (Fig. 6). The values of precipitation from west to east are 3,018 at Evan- gelistas, a rocky islet out in the Pacific, 5,479 at Bahia Félix on the windward exposure of Desolation island, which rises to 1,300 and 1,500 feet with loftier lands that reach 2,000 to 3,000 feet just to the east. About 150 miles further to the southeast 16 THE RAINFALL OF CHILE along the Strait is San Miguel, just beyond the axial line of the Andean summits, which reach 29 2 OUNGENESS: 8 e 3,100 feet. San Miguel itself is at sea level. Ps The rainfall there is 1,286 millimeters. Another 81 d 60 miles brings us around the corner of the Brunswick peninsula to San Isidro, with only lowlands to the east. The rain is 813 milli- meters. Thirty-five miles almost due north is Punta Arenas with rather similar conditions except that it is more definitely under a lee slope. Its rainfall is 470 millimeters. From here eastward to theAtlantic entrance among eleva- tions never exceeding 200 feet, the rainfall is from 200 to 370 millimeters. It is likely that greater values than any of those observed occur between Bahia Félix and San Isidro, on the western slope of the crest, for instance. This is undoubtedly one of the wettest regions in the world. The values are fairly well ascer- tained, only Bahia Félix and San Miguel having as little as three years of observations, while Dungenes has 16, Evangelistas 20, and Punta Arenas 35. A much more complete rainfall section across Chile can be made at the Pérez Rosales Pass in latitude 41° (Fig. 7). This is not far south of the inhabited parts of Chile. There is no coast station exactly opposite; but Punta Galera (40°) had a rainfall of 2,221 millimeters, and Punta Corona (41° 47’) 1,986. In the hollow east of the coast ranges Osorno has but 1,328 millimeters. It stands in the rain shadow of the mountains, in the interior valley that throughout Chile contains the railway and most of the cities. Lake Llanquihue lies at the eastern margin of the valley and has the * “PECKET HARBOR: 1. MAGDALENA PTA.ARENAS, gellan, showing the increase of rain to the east, west of the ‘S.1SIDRO 'S MIGUEL BAHIA FELIX Fic. 6—Rainfall along the profile of the lands beside the Strait of Ma VERTICAL SCALE 12 X HORIZONTAL continental divide. 3018 a EVANGELISTAS. RAINFALL SECTIONS ACROSS CHILE volcanoes Osorno and Calbuco close to the east. The level of the lake is but 90 meters, but the west winds here feel the uplift im- posed by the slopes farther east. Frutillar, on the western shore of the lake, has 1,758 millimeters; Los Riscos and Bahia del Volcin on the eastern shore have 2,298 and 2,112. From Lake Llanquihue the trail over the Andes leads to Lake Todos los Santos at 190 meters, though it lies among lofty moun- tains, a scene as grand as any fiord in Norway. At Puntiagudo near the western part of the lake the rainfall is 3,319 millimeters, at Peulla to the east it is 3,263. Casapangue, in the approach to the pass, with an elevation of 320 meters, has a rainfall of 4,110 millimeters. Puerto Blest, at 750 meters on the eastward slope, has 3,590 millimeters; and Bariloche, near the eastern end of the Argentine Lake Nahuelhuagi, has 931. The summit height of the Pérez Rosales Pass is but 1,050 meters, but the Andes here range about 2,000 meters in height as a very level crest line, a plateau level above which tower the great volcanic cones Tronador (3,320 meters), Osorno (2,680), and Puntiagudo (2,499). The in- crease of the rainfall to the eastward across Chile here is due to the uplifting of the west winds against the slopes of coast mountains and the Andes, plainly perceived at stations which are not themselves on these slopes but in valleys far below them. It is not to be supposed that a narrow westward-facing valley in the mountains gets no other increase of rainfall than that which corresponds to the ascent eastward of its valley floor. Everything RANGES COAST wsoos wLcin, enue PLLA CASAPANGUE PTOBLEST PyaTucuod rte ‘Osorno S.JUAN DELA COSTA PUATA COROMA iARGENTINE i CHILE showing heavy rain on the coast range, diminished BERUICAL SCALE TWICE MORIRONTAL a 17 The increased rainfall on the windward slopes is striking, as 41°S., Fic. 7—Profile and rainfall along a section across Chile in latitude rain in the valley, and increasing rain toward the crest of the Andes. well as its diminution to leeward. 18 THE RAINFALL OF CHILE indicates that it shares to some extent in the increased rainfall due to the sloping countryside in which it is situated. Of course valley stations do not receive as much rain as the slopes above. It is well known that moun- tain streams when gauged are found to deliver much more water than is measured at valley rain stations in their basins. This is our most complete section of Chilean rainfall. We depend on it especially to confirm the theory that all Chilean hills have increased rain to windward and diminished rain to leeward. This is just the opposite of the distribution expressed on the current maps of rainfall in Chile. The records are very brief and of irregular period. Punta Corona has 17 years, Osorno 10. Only for 1913 and 1918 is there anything like simultaneity of observations. I give the records for those years in Table IV. TABLE IV—RAINFALL IN A CROSS SECTION OF CHILE AT LATITUDE 40° S. STATIONS 1913 | 1914 | I915 | 1916 | 1917 | 1918 | MEAN Punta Corona 2,131 | 2,398 | 2,206 | 1,776 | 1,412 | 2,294 | 1,986 San Juan de la Costa 1,253 | 1,620 | 1,524* Osorno 1,646 | 1,604 | —— 2328* Frutillar 1,990 | 1,707 | ——— | 1,613 | 1,440 | 2,025 | 1,755 Los Riscos 1,996 | 1,997 2,298* Volcan 1,938 2,595 | 1,915 | 1,761 | 2,351 | 2,112* Puntiagudo 3,638 | 3,876 | 3,167 3.316* Peulla —— } 3,907 | —— —— | 3,804 | 3,263* Casapangue —— | | | | er | oo are Puerto Blest — | — | — | — | — ] 3.992 | 3,590* The starred values have been reduced for epoch and differ from the observed values, reduction being made by Punta Corona and Puerto Montt. It may be repeated that they would have shown the effect of slopes more strongly if not reduced. The reduction is not made to “doctor” values, in order to get values as we wish them, but to remove the extreme values of observa- tions made in very dry or very wet years. Five complete years of simultaneous observations would be more satisfactory than RAINFALL SECTIONS ACROSS CHILE ° 19 this but not much more convincing, inasmuch as the observa- tions we have fall well into a system of values. A somewhat more complex accordance between relief and rainfall is afforded by the section across the great volcanoes Llaima and Lonquimay, that loom so majestically above the 73 4 7'2 7 7 50 0 50 100M L L ane Fic. 8—Malleco, the only interior province of Chile, with the Cordillera of Nahuelbuta on the west and a spur of the Andes carrying the great volcano Llaima On the east. Andean table-land in the vicinity of Temuco or Collipulli, for here two interior valleys are crossed between the Andes and the sea (Fig. 8). Mention was made above of the three coastal provinces Valparaiso, Maule, and Arauco, walled off from interior Chile by a definite mountain range parallel to the coast. Malleco, one of the-two provinces that Arauco shuts in from the Pacific, 20 ANDES NAHUELBUTA (LAWUMINE, LONQUIMAY ‘SELVA OBSCURA = CURACAUTIN rez 1204 825 LOS SAUCES, VICTORIA ‘COLUPULE ANGOL caucd WERIICAL SCALE TWICE HORIZONTAL, LAVAPIE Fic. 9—Profile with rainfall records along a section across Malleco province near latitude 38° S., showing in every case increased rainfall on the western slopes and diminished rainfall in the rain shadow on the east. THE RAINFALL OF CHILE is also walled off from the Andes by a part of the province of Bio Bio, so that it is unique among all the provinces of the country in having no contact with the outer boundaries of the land. It is Chile’s only interior province, with the Sierra Nahuelbuta on the west, and on the east a spur of the Andes which projects to the northwestward from a point in the province of Cautin and carries on its broad back the two volcanic cones. Tracing a section here to the southeastward from Punta Lavapié (Fig. 9), we have gauges at Lavapié and Colicé in Arauco on the rainy, windward slope of Nahuelbuta; at Angol, Los Sauces, Traiguén, Collipulli, Victoria, Selva Obscura, and Curacautin in Malleco, in the interior valley; the first three deep in the rain shadow of Nahuelbuta, the last four on the windward slopes of the Andean spur, with Selva Obscura and Curacautin in eastern Malleco, Lonquimay in Bio Bio province, in the upper valley of the Bio Bio and in the rain shadow of the spur referred to, and finally Lake Alumine beyond the Andes in the Argen- tine Republic. Figure 8 locates the points men- tioned and notes the rainfall at each station, in centimeters. Always there is increased rainfall to windward, and lessened to leeward, with the maximum catch on the slopes of the Andes. Although there are no other sections that can be carried so well across the country as_ this, except perhaps at Santiago, where both. the Andean stations have but one year of observation as yet, there can be no doubt that the same relations are in fact repeated up and down the whole great length of the country. The disap- pearance of forest in the high altitudes of south- SHORT OBSERVATION SERIES 21 ern Llanquihue, shown in Figure 1, suggests a limiting height above which the rain diminishes on the Andean slopes instead of increasing further, just as happens in the Himalayas and other lofty mountains. TREATMENT OF SHORT OBSERVATION SERIES The fact that our series of observations vary in length from I year to 68 gives the different series of observations very different dates. Attention has been already called to the necessity and method of “reducing” observations for epoch, when the series is a short one. It usually happens at any place that a few wet years are followed by a few dry ones. Table V illustrates this by giving the average rain for the last six pentads for 21 stations in Chile. TABLE V—A. AVERAGE RAINFALL IN MILLIMETERS IN THE LAST StX PENTADS VI Vv IV Ill IL I TOTAL STATIONS Ig18— | 1913—| 1908— | 1903- | 1898-} 1893- YEARS I914 | 1909 | 1904 | 1899 | 1894 |} 1889 28 |Caldera 13 12 2I 5r |La Serena 46 184 203 120 | II9 33 |Coquimbo 98 38 176 188 — 83 12 |Los Andes 269 408 20 |Punta Angeles 560 360 565 642 66 |Valparaiso 526 380 703 837 499 | 404 14 |Pefiuelas 690 414 949 68 {Santiago 349 241 413 536 330] 286 17 |S. Fernando 766 521 I5 {Punta Carranza oxy 628 674 I5 |Punta Tumbes 304 —_ 587 39 |Concepcién 1,337 | 1,033 | 1,435 | 1,763 | 1,352 17 |Contulmo 1,889 | 1,618 | 2,036 19 |Mocha West 1,238 gir | 1,156 48 |Valdivia 2,615 | 2,278 | 2,970 20 |Punta Galera 2,017 —| 1,045 ir {Isla Guafo 969 | 1,212 16 |Punta Dungenes 252 _— 188 15 |Islas Evangelistas 3,087 | 3,337 | 2,406 | 2,907 35 |Punta Arenas 552 557 _ _ —| 372 22 THE RAINFALL OF CHILE The five years 1899-1903 were the rainy ones at all stations north of the island of Mocha.!° Valparaiso, for instance, had more than B. Same, INDEX NuMBERS (CALLING VALUES OF PENTAD VI = 100) VI Vv IV III II I STATIONS 1918— | 1913—| 1908—]| 1903— | 1898— | 1893-— I9I4 | 1909 | 1904 | 1899 | 1894 | 1889 Caldera 100 92 162 La Serena Coquimbo 100 38 179 192 —_ 84 & Los Andes 100 152 Punta Angeles 100 “64 IOI II5 Valparaiso 100 72) 134 Is9 95 77 Pefiuelas 100 60 137 Santiago 100 69 119 154 94 82 b San Fernando 100 68 Punta Carranza 100 86 92 Punta Tumbes 100 _ 149 Concepci6n 100 61 I07 132 IOI Contulmo 100 86 108 ¢ Mocha West 100 74 93 Valdivia 100 87 II4 Punta Galera 100 83 98 133 Punta Corona 100 —_— 96 Isla Guafo I00 125 d Punta Dungenes 100 —_ 75 Islas Evangelistas} 100 108 78 94 67 Punta Arenas 100 IOI _ _ — C. Same, Group MEANS a |North 100 88 144 155 95 80 b Center 100 71 124 154 94 82 c South 100 78 104 132 Ior| — d_ |Archipelago 100 TIt 83 94 _— 67 10 Mocha, in latitude 38° 15’, is regarded as the turning point in Chilean climate. South of it is the zone of the prevailing westerly winds; north of it the Humboldt Current sets to northward along the coast, and increasing aridity characterizes the climate (Carl Martin: Landeskunde von Chile, Hamburg, 1909, p. 228). SHORT OBSERVATION SERIES 23 half as much again of rain in the five years 1899-1903 as in 1914— 1918, 159 per cent as much, as the sub-table B shows. Or the six stations about Valparaiso, group a, had 155 per cent as much in that pentad as in 1914-1918. The catch of only five years, therefore, would mean very different things according as the years were earlier or later ones. And the difference between the averages given by five-year, ten-year, fifteen-year, and twenty- year records is not merely due to the greater accuracy of the longer period but in part to the fact that the rainfall itself varies from year to year. Where the average for group a is 100 for the last five years, for the last ten it would be gale woot $8 or 94; for the last fifteen T°+884™44 Oo. yyy: for the BS twenty 122; for the last twenty-five 116; and for the last thirty 110. Herbertson speaks " of the trouble he took in combining ob- servations of what he calls “different periods,” by which he means periods of different length. There is no explicit mention in his work that he recognized the difference here referred to, which is really one of epoch, since one decade or twenty-year period may differ widely from another. Even among professed students of rainfall there is insufficient recognition of the irregularity of at- mospheric precipitation in time. It is this variation of the rainfall from epoch to epoch that makes simultaneous series of observations so desirable and, in their absence, reduction to a common epoch so essential. This reduction has been made. To be ideal a reduction should be made by means of another station that is near and similarly situated. We do not always find one near in Chile, and very rarely are they similarly situated to the one to be reduced. We use the best available, but there has been no pretense even of reducing all the observations to one fixed epoch. The data at hand do not warrant the undertaking. As an example of re- duction Ligua may serve. Six years of record, 1912-1918, with 1914 lost, give an average of 198 millimeters. The average at Valparaiso and Punta Angeles combined for the same six years 1 A.J. Herbertson: The Distribution of RainfallOvertheLand, London, 1901, p.7. 24 ? \ Santiago \ THE RAINFALL OF CHILE q (00 200M Valparaiso \ Talca \ Punta Carranza Punta Tumbes Isla Santa Maria Lota Mocha West Mocha East Punta Niebla Valdivia Punta Galera Puerta Montt Evangelistas is 385 millimeters. As the series mean for Valparaiso and Punta Angeles is 523, it is assumed that the true mean for Ligua would be 533 of 198, or 269. The obvious dependence of the rainfall on the topography has not been allowed to influ- ence the drawing of the iso- hyetals. These have been placed where the figures of the record demand. The result is quite unlike any previous rainfall map of Chile; and, whatever may be thought of the adequacy of the data now, it is certain that never before was anything like an adequate body of rain measurements at hand. Voss’ RAINFALL Map OF 1907 The last revision, by Voss” was made in 1907 and was very much generalized, the scale of the published map being I:40,000,000; and there were but 21 stations available for all Chile. There was a_ gap in the archipelago from the northern end of the island of 2 E. L. Voss: Die Niederschlagsver- haltnisse von Siidamerika, Petermanns Mitt. Ergdnzungsheft No. 157, 1907. Fig. 10—The annual rainfall of Chile after Voss. VOSS’ RAINFALL MAP 25 Chiloé to the western entrance of the Strait of Magellan, a dis- tance of 700 miles. Voss had no observations on the Andean slopes, where we have listed 19; he had no sections across the country, and all but two of his stations for measuring the rain TABLE VI—STATIONS WITH THEIR RAINFALL AS GIVEN BY VOSS AND AS OBSERVED TO DATE Voss, OBSERVATIONS| JEFFERSON, OBSERVATIONS oe ewes | “2 | vous Sea METERS METERS Iquique ..... 5 3 19 0.6 Caldera “4h 16 28 16 Copiapé . : 4 8 24 17 Isla Chafiaral . . 4 Or a 70 La Serena 4 38 51 147 Punta Tortuga 5 168 44 126 (Coquimbo) Valparaiso . . 10 497 66 515 Santiago 37 325 68 364 Talca 4 505 27 686 Punta Carranza . 3 363 15 744 Punta Tumbes 3 742 Is 461 Isla S, Maria 4 767 12 807 Lota, « r 1,817 5 E312 Mocha East 3 1,695 rf 1,215 Mocha West 4 1,376 19 1,130 Valdivia . 22 2,900 46 2,698 Punta Niebla . 3 1,588 s 2,800 Punta Galera . 5 2,882 18 2,221 Puerto Montt 26 2,300 33 2,160 Ancud..... 6 2,383 23 2,092 Islas Evangelistas 5 2,918 18 3,018 were on the seacoast. The only inland stations were Santiago and Talca. His stations had an average of 8 years of record where we have 26 for the same places. Finally the present values have had the great advantage of Mr. Whitaker's critical revision. In Table VI are given the old values and the new ones. The observations recorded for Punta Niebla for 1901, 1902, 26 THE RAINFALL OF CHILE and 1903 appear to be erroneous. We have observations at ‘near-by Valdivia—only 12 miles away—for those same years, as well as many others, and the differences between the rainfall noted at the two places is incredibly large. Further, observa- tions were made again at Punta Niebla in 1918 and 1917 which show no such discrepancy. The old records for Punta Niebla were probably badly made. They have been rejected. 1918 IQI7 1903 1902 IQOL Punta Niebla . 2,054 2,085 1,314* 1,318* 1,843* Valdivia : 2,778 2,083 1,933 2,942 2,991 Difference +176 +2 —619 |—1,624 |—1,148 The values Voss used for Punta Carranza and Talca were quite erroneous and were the grounds of the false delineation of the rainfall in central Chile on all current maps, with the suffh- cient-to-abundant rainfall (500-1,000 millimeters) in the central valley and less on the coast ranges and Andes alike. As we see on Figures 2 and 3, the isohyetals of 250 millimeters and 500 milli- meters project southward, not northward, along the central valley on the evidence of numerous stations. The only records of Voss that indicate a wetter valley are Talca in the valley, with 505 millimeters, and Punta Carranza on the coast with 363 milli- meters. For Talca he states he had 4 years of record, giving him a mean rainfall of 505 millimeters. Miguel Whitaker’s revision of Chilean rain data gives us two series of gauge records at Talca which are here given in detail: 1869-92—549, 374, 666, 424, 540, 831, 576, 658, 1,064, 667, 554, 1,266, 714, 607, 566, 644, 220, 552, 520, 1,158, 304; 1910-18 —493, 577) 674, 744, 1,524, 680, 464, 765, 737- The first series of 21 observations was made long before Voss did his work but does not seem to have been accessible to him. In all there are but six records as small as his average of 505 millimeters. The average of the series may be regarded as well VOSS’ RAINFALL MAP 27 determined by the 30 years of observation at 686 millimeters. That is more rain at Talca in the valley than Voss supposed, but it is not so much as falls at Punta Carranza. For Punta Carranza he had 3 years of record, and this value should be more than doubled. There are 18 years of record in Whitaker's list from 1901 to 1918: 660, 749, 296, 1,296, 1,105, 751, 647, 572, 345, 633, 799, 567, 796, 1,141, 574, 563, 568, 809. The mean is, 744. Only two years have values as small as 363, which Voss gives as the mean. No three years in the series would have given 363 millimeters. The value is certainly quite erroneous. Equally false is the delineation in the archipelago, and its sole foundation is the one gauge at Evangelistas Islet. The rain was plainly greater on that islet than in the Argentine Republic east of the Andes. He drew the system of isohyetals that is everywhere reproduced, showing an increase of rain all the way from the Atlantic to the Pacific. This had no sufficient founda- ticn in his two points of observation and could have no justifica- tion in theory. The increase of rainfall from west to east which is observed in the Chilean archipelago is demanded by the con- ception of moist west winds cooled by uplift on hill and mountain slopes. List OF CHILEAN RAINFALL STATIONS USED IN THIS ARTICLE, WITH THEIR LATITUDE, LONGITUDE, ALTITUDE, AND THE VALUE OF THE RAINFALL ADOPTED IN MILLIMETERS. (FROM Inst. Meteorol. y Geofisico de Chile, Secci6n Lluvias, Publs. Nos. 20, 23, 24, and 29) No. NAME Yrs.| Lat. |Lonec. Ee pea ance 1. |Tacna r {18° 0/!70° 18’ 560 oO 2. |Arica I§ |18° 28/|70° 20’ 5 a 3. |Iquique Ig |20° 12/70° 11’ 9 6 4. |Oyahue 3 |21° 13'/68° 16] 3,696 200 5. |Chuquicamata r [22° 18'168° 55’| 2,710 ? 6. |Calama 2 |22° 27'168° 56'| 2,260 oO 28 THE RAINFALL OF CHILE No. NAME Yrs.| Lat. |Lonc. wana a 4. |Antofagasta Ir |23° 39'}70° 25’ 4 4 8. |Cachinal 1 |24° 58//69° 34’ 2.005 z 9. |Refresco 5 125° 15'169° 52’ 1,850 5 ro. |Taltal 5 |25° 25'170° 34, 39 15 rr. |Caldera 28 |27° 3’)70° 53’ 2 16 12. |Copiapé 24 |27° 21'l70° 21’| _ 37° 17 13. |La Junta (Copiapé) I [28° 3'169° 58’ 21200) 48 14. |Vallenar 4 |28° 35'|70° 47’ 379 80 15. |La Pampa I }28° 59']70° 15’ m2 08: 250 16. |Isla Chafiaral 4 |29° 171° 37' = 70 17. [Isla de PAjaros I }29° 35’|71° 33’ (100) 18. |Serena SI |29° 54’|71° 15’ 35 147 19. |Coquimbo 33 [20° §6’\71° 22’ a7 126 20. |PuntaTortuga(Sameasi9)|_ I |29° 56’|71° 21’ 27 126 a1, |Rivadavia 3 |20° 58'170° 34’ 818 171 22. |Vicuiia I |30° 2’171° 40’ 606 170 23. |Paiguano 2 130° 2’/70° 32’! 1,004 130 24. |Tongoy a 130° rgy"l77? 25" 4 98 25. Lengua de Vaca 5 }30° 16’]/71° 37’ 42 90 26. |Ovalle 7 130° 36'|71° 12’ 250 104 27. |La Junta Ovalle 3. |30° 43/]70° 53’ 505 70 28. |Quilimari I |32° 6'171° 31’ 25 300 29. |Chincolco I |32° 13'}70° 50’ 715 135 30. |Cabildo 2 |32° 25'/71° 6’ 177 240 gi. |Ligua 6 |32° 27’|71° 16’ 58 269 32. |Putaendo I 132° 38'170° 40’ 825 260 33. |San Felipe 14 |32° 45'170° 44'| 636 238 34. {La Calera 5 132° 48’|71° 13’ 217 336 35. |Ocampo I |32° 48'170° 56’| 457 174 36. |Chagres (Catemu) 2 |32° 48'170° 50’ 412 274 37. |Los Andes 12 |g2° so’l70? 37" 816 338 38. |Portillo I 132° 51'170° 12’| 2,885 1,552 39. |Liaillay I ige* sz'iyoP 53" 385 203 40. |Quillota 4 132° 53'/71° 16’ 128 345 41. |Limache 3 133° 1'}71° 18’ 88 402 42. |Punta Angeles (Val- paraiso) ao ig3° x lyr 98" AI 532 43. |Valparaiso 66 133° 2')72° 36° Io 515 44. |Quilpué I |33° 4'|71° 30’ IOI 561 45. |Tiltil 6 133° 5’|70° 56’ 578 384 THE RAINFALL DATA 29 ALT. In| MILii- No NAME Yrs.| Lat. |LONG. Mermus| (Meters 46. |Curaumilla 6 |33° 6/}71° 44’ 85 316 47. |Perales de Marga-Marga I 133° 9/)70° 21’ 220 563 48. |\Pefiuelas 14 |33° 11//71° 29’| 360 620 49. |Colina 6 133° 18/|70° 46’ 486 233 so. |Casablanca I 133° 19'/72° 33'| 230 570 51. |Maitenes 3 133° 18/}70° 22") — 505 52. |Apoquindo 6 133° 25/|70° 32’ 782 510 $3. Santiago 68 |33° 27'|70° 42’ 520 364 54. |Nufioa I 133° 28'170° 36) — 408 55. |Maipa I |33° 32/}70° 40’ 488 378 56. |Florida Alta 6 133° 33/170° 33) — 516 57. |Lo Espejo 3 133° 34’|70° 42’ 580 427 58. |San Antonio I 133° 34/171° 30’ 4 509 59. |La Obra 4 133° 35']70° 30] 799 692 60. |San Bernardo 4 |33° 36}70° 43° 573 392 61. |Malloco (Lindenan) I |33° 36/170° 52’ 400 428 62. |San José de Maipo 6 133° 38’|70° 22’ 947 661 63. |Talagante I |33° 40'170° 56’ 343 513 64. |Melipilla r [33° 41/|71° 18’ 169 543 65. |Buin 1 |33° 44'|70° 44] 488 4l7 66. |Volc4n 2 133° 49/170° 11‘ 1,500 1,436 67. |Hospital 2 133° 51/}70° 45} 384 528 68. |Corneche I 133° 57'171° 37) 699 69. |San Francisco I [33° 58'|70° 45’ 471 628 70. |El Teniente 7 134° 6'170° 38'| 2,134 1,153 71. |Rancagua 14 [34° 10/170° 45’ 500 379 72. |Requinoa t 134° 17/170° 45’ 421 516 73. |Calleuque r |34° 21/171° 31’ 106 493 74. |Rengo I 134° 24')70° 52'| 319 536 75. |Pichilemu 7 134° 25'172° 00'| 9 — 881 76. |San José del Carmen rt {34° 33'170° 46’ 138 541 77. \San Fernando 17 134° 35']71° 00} 350 739 78. |Millahue I ]34° 38'/71° 5’ 170 618 79. |Querelema r [34° 51/172? x’) — 988 80. |Curicd 17 134° 59'|71° 14’ 211 681 81. |Talca 30 |35° 26'/71° 40) 107 686 82. |Punta Carranza 18 |35° 36/|72° 38’ 30 744 83. |Cuyurranquil r 135° 38’ 160 1,508 84. |Chanco 5 135° 42/)72° 32’ 37 814 85. |Linares 4 |35° 50'171° 36) 157 873 30 THE RAINFALL OF CHILE No. NAME Yrs.| Lat. |Lonc. Sct te 86. |Cauquenes 6 135° 58'172° 201 142 630 87. |Copihué (Fundo) 3 136° 4/72? '52'| -— 77 88. |Longavi (Matancillas) I 136° 06'171° 42’ 170 1,187 89. /San Carlos 2 136° 25'/72° §7° 172 528 90. |Quiriquina Isla 23 136° 36//73° 2’ 20 881 ot. |Chillan I0 136° 37/172° 6’ II4 1,042 92. |Punta Tumbes 17 136° 37/173° 6’ OL 461 93. |Nebuco I [36° 39/172° 13’ oo 924 94. |Penco (Cerro Verde) 5 [36° 43/173° 0” TS: I,O51 95. |Bulnes I 136° 45'172° 19’ 83 993 96. |Santa Clara bp [g6° Bo'|72* 22) 93 975 97. |Concepcién 39 136° 50173° 3’ 15 1,296 98. jIsla Santa Maria 12 136° 59173° 32’ 78 807 99. }Punta Puchoco 4 134° 1'173° 12" 18 1,071 roo. |Lota 5 137° 573° 10’ Io 1,312 ror. |Punta Lavapié 14 137° 81173° 35’ 46 785 o2. |Yumbel 7 137° 9/)72° 32’ 80 1,022 03. |Yumbel (San Cristébal) 5 137° 10']72° 31’ III 983 04. |Laja I 37° 16')72° 42’ 45 833 105. |Colico 3 137° 24'|72° 21’ 134 2,129 106. |Los Angeles 3 137° 28']72° 21’ 160 576 107. |Nacimiento 4 137° 30'|72° 41’ 57 1,089 108. |Angol 3 |37° 48']72° 41’ 72 1,204 10g. |Collipulli 3 137° 57'|72° 26] 244 1,632 110. |Los Sauces 5 137° 59'172° 49" III 625 rrr. |Contulmo rz [38° 273° 12" 50 1,869 112. |Los Guindos 3 138° 378% 10" 44 3,169 113. |Victoria 5 138° 14/173° 18’ 351 2,006 114. |Quidico r 438° xg"173° 25" 26 1,801 115. |Traiguén 6 138° 15172° 40’ 177 1,099 116. |Mocha West FG 138° ar’\73° 58’ 20 1,130 117. |Mocha East 7 138° 22'173° 54’ 40 1,215 118. |Selva Obscura rt |38° 22"\72" 8° 438 2,023 119. |Pehuenco I 138° 23'}71° 16’ 650 2,203 120. |Lonquimay A 138° 26"\7r* 14" 970 1,890 raz. |Curacautin t 138° 267/74" 50° 544 1,841 122. |Quillén £ 8" .28'\92" 35” 278 1,326 123. |Carahue 2 138° 43173° 9’ 10 1,250 124. |Temuco ~f 138° 451172° 35’ 102 I,250 125. |Padre Las Casas , i 38° 46/172° 37')| — 1,250 THE RAINFALL DATA 31 No. NaME Yrs.| Lat. |Lonc. SE METERS| METERS 126. |Puerto Saavedra 3 |38° 46/173° 22) — 1,352 127. |Boroa (estaci6n) I 138° 46'}73° 15’ 45 1,373 128. |Boroa (misién) I 138° 50'}73° 10° 130 1,583 129. |Puerto Dominguez 4 138° 54/1739 14) — 2,315 130. |Araucania de Freire 3 [98° 57'l72° 36° 103 1,794 131. |Pitrufquén I 138° 50/172° 38’ 95 2,256 132. |Toltén 3 139° 13/173° 13’ 5 1,981 133. |E] Suefio I |39° 15’ 260 2,804 134. |Pucén I |39° 16'/71° 58’ 230 1,378 135. |Loncoche I |39° 22'172° 50’ 112 2,768 136. |Panguipulli 5 139° 40//72° 17’ 140 2,697 137. |Vladivia 48 139° 48'173° 14’ 1s 2,698 138. |Punta Niebla 2 130° 52'173° 24’ 40 2,800 139. |Corral 13 |39° 53’173° 25’ 5 3,101 140. |Punta Galera 20 {40° 1'173° 44’ 40 2,221 141. |Rio Bueno 4 |40° 19/|72° 55" 58 1,359 142. |Trumag 5 140° 21173° 7’ II 1,273 143. |San Juan de la Costa 2 140° 31/]72° 32’ 500? 1,524 144. |Osorno ro |40° 35'173° 9’ 24 1,328 145. |Casma ¥ j4e* 1's? 5° 123 2,081 146. |Puerto Blest r |4r° 1'|71° 50’ 756 3,590 147. |Casapangue r l4r° 3/]71° 55’ 320 4,110 148. |Puntiagudo 3 141° 5'172° 17’ 190 3,319 149. |Peulla 2 lar? 5'|\y2? 7) 190 3,263 150. |Frutillar 5 |41° 7'172° 50’ 139 1,755 151. |Bahia del Volcan 5 |4r° 11/|72° 31’ 60 a,r12 152. |Los Riscos 2 141° 13/|72° 41’ 60 2,298 153. |Puerto Montt 34 [41° 28'172° 57’ 5 2,160 154. |Abtao r |4x° 24'172° 55’ 107 1,033 155. |Punta Carona 17 |4r° 47/173° 52’ 48 1,986 156. |Punta Ahui A 141° 491173° 51’ 40 2,116 157. |Tres Cruces 5 |4r° 50/173° 20’ 25 2,260 "158. |Ancud 23 |41° 52/173° 49’ 20 2,092 159. |Morro Lobos 6 142° 4/173° 24’ 60 3,052 160. |Castro r |42° 29'173° 45’ 4 1,337 161. |Pillan de Refiihue 4 |42° 34/1729 27") — 5,231 162. |Isla Guafo zr |43° 34'174° 45’ 140 1,075 163. |Melinka 6 143° 54/173° 46" 5 3,258 164. |Cabo Raper 3 |46° 50175° 35') — 1,933 165. |Cabo Posesién 4 |52° 18'168° 57’ 80 333 32 THE RAINFALL OF CHILE No NAME Yrs.| Lat. | Lone. oo oe 166, |Punta Dungenes 16 [52° 24’|68° 26’ 5 219 167. |Islas Evangelistas 20 |52° 24'175° 6’ 55 3,078 168. |Punta Delgada 4 152° 28’169° 34’ 5 300 169. |Ponsonby t [52° 40'|72° 12’ —_ 339 170. |Pecket Harbour I 52° 47'170° 50’) — 364 171. [Isla Magdalena 3 |§a° S5"l70° 33° 30 ays 172. |Bahia Félix 3 152° 58174° 4’ 15 51479 173. |Punta Arenas 35 |53° 10’170° 54’ 4 470 174. |San Miguel 3 153° 43171° 54’ — 1,286 175. |Cabo San Isidro 5 153° 47/]70° 58’ 20 813 176. |Bahia Harris 2 153° 50'|70° 25’ I2 719 177. |Bahia Douglas 3 155° 9//68° 8’ _— 884