September i, 1884.] THE TROPICAL AGRICULTURIST. 



23S 



Gokakelle (? Goxorakelle) estate, Badulla, gives 

 means for 7ij years of 93'20 inches and 157 Jays with »■ 

 rainfall of 4 80 iueheson30th-31st Jan. 1882. The figures 

 for 1883 are 90-46 inches on 170 clays, 330 inches having 

 fallen on 8th-9th May. 



Mausagalla estate, Badulla, has means for four 

 years of 93-35 inches and 163 days, with a rainstorm 

 of 4-95 inches on 29th-30th Jan. 18S2. The figures 

 for 1883 are 102-01 inches on 174 days, 310 inches 

 being fallen on 3rd-4th February. 



Leangolla estate, Madtjlkblb, has not supplied 

 complete returns for 18S3, but we see that 516 inches 

 fell on 8th-9th May against 7'55 on 5th-6th January. 

 1878. The means of 7J years aie 1 15" 10 inches on 

 197 clays. 



Kandanuwera estate, Elkadttwa (near Matale), has 

 established means in llgyears of 110-43 iuches and 

 158 days, with a rainstorm of 8'10 inches on 29th 30th 

 Jan. 1882. The figures for 1883 are 109'95 on 1S1 

 days, 6 '55 .inches having fallen on 8th-9th May. 



Samt.oowatte estate, Nawalapitiya, did not supply 

 the figures for the month of May, one of the rainiest, hut 

 of 33 36 iuches which fell in July, 5-50 fell on 12th-13th 

 The total without, May is 177-15 ou 191 days. Prob- 

 ably 200 inches on 200 clays will come near the mark, 

 20U inches being considerably exceeded here in previous 

 years. Tea flourishes with from 70 inches to over 250. 



Gammaduwa estate, Rattota, has in S!i years estab- 

 lished means of 116 6S and 123 clays. The figures for 

 1883 were 93-31 ou 89 days, with a rainstorm of 7 "41 

 iuciies on S'h-'Jth May. 



Kttai'olle estate, Matale, gave in 7 years means 

 of 95'10inches and 160 clave, 6 60 inches having fallen 

 on 15th-16th May 1S77. The figures for 1S83 were 

 80-03 inches on 197 days, 463 iuches falling on 

 8th- 9th May. 



Sau.mmuz estate, Udugama (in tho Southern 

 Province), is the last on the list. The figures are 

 185-25 inches on 248 days, which shows a first-rate 

 tea climate. 



We have thus ranged over climates in Ceylon, where 

 the rainfall in 1883 varied from under 29 inches, as 

 in the case of Hambantota, to nearly 186 in that 

 of Gikiyauakaudn. The contrasts are Btriking enough, 

 but they would be mora so, had not such places as 

 Templestowe, Ambagamuwa, disappeared from the list. 

 In many previous years, it showed a rainfall rang- 

 ing close on 250 iuches per annum, with 60 inches, 

 or 5 feet in one month. If observations taken some years 

 ago, at Padupolla, a Public Works Department station, 

 could be accepted as trustworthy, we should have 

 maximum tigures clooely approaching 300 inches as 

 against 30 at Hambantota. The range is certainly 

 from not much over 25 to fully 250 inches, a pretty 

 good range. And in our regions of heavy rainfall 

 saturation of the atmosphere with moisture, cloud and 

 mist have to be taken into account. Ceylon is in the 

 tropics and in the paths of the monsoons (the name 

 given to aggregations of cyclones aud their effects), aud 

 the deposition of moisture locally is mainly regulated 

 by the features of our mountain system. There are 

 places in Ceylon where rainless days are so rare as 

 to be remarkable, and other places where the rainy 

 days 'are noted as few and far between. Wo have, 

 consequently, salubrious zones (where the south-west tea 

 breezes have full play, and on the mountains, all ahoye 

 2,500 feet) and insalubrious, for we have terais and 

 terai fever at the bases of our hills. But ou the 

 whole Ceylon is highly favoured with a plentiful rain- 

 fall well-distributed, the secret of health iu human, 

 animal and vegetable life. 



In neither the tigures for annual nor monthly fa'ls of 

 ain can wo compare with some places on the ad j-iceut 

 ontinent, Cherrapunjee on the Khas-a Hills, a »pur 

 f the Himalayas facing the tea districts of Cachar 

 ud Sylhet, lor iustauce, those districts not getting 



the rainfall but feeling the effects in floods which 

 are occasionally destructive. Once in about ten years 

 we have exceptional floods in Ceylon, which severely 

 try all structures against which their waters are pro- 

 jected, especially irrigation works. But what would 

 our readers say to nenrly 41 inches of rain in one day 

 and 131 inches in one month ? In June 1876, from 

 12th to 16th, 114-14 inchis fell in live days: 22'84 

 on one day , 30 45 ou another, and 4080 on a third. 

 Between 1865 and 1SS0, the annual average established 

 was close on 500, the exact figures beiug 493*10 

 thus : — 



Inches. 



January ... ... ... 076 



February ... ... ... 2 '76 



March ... ... ... 8-7!) 



April ... ... ... 30-90 



May ... ... ... gi-43 



June ... ... ... 115-88 



July ... ... ... 130-84 



August ... ... ... 79-62 



September ... ... ... 5(H0 



October ... ... ... 1305 



November ... ... ... 2-23 



December ... ... ... 0-23 



Average annual rainfall ... ... 193J9 



If the rainfall registers of 1860 and 1861, abnormally 

 heavy rainfall years all over Bengal, could be trusted, 

 the figures for those two years would be 69973 and 

 90512 inches. But a maximum of 600 inches, or 50 

 feet, is probably nearer the mark. Mr. John Eliot, 

 M. A., Meteorological Reporter to the Government of 

 Bengal, thus notices the physical circumstances which 

 produce such a vast precipitation of moisture : — 



Oherrapunji is a small Indian station situated in the 

 south-west of Assam, on a small plateau forming the summit 

 of one of the spurs of Khasia hills. These hills, which 

 rise on the south with exceeding abruptness, have tho 

 Bengal plains and low lands at their base. Oherrapunji 

 stands on the summit of one of these hills at an elevation of 

 about 4,100 feet. The hill ou which it is situated rises 

 precipitously from the low lands of Cachar and Sylhet, which 

 are barely 100 feet above mean sea level. 



During ths south-west monsoon the lower atmospheric 

 current advancing across the coast of Bengal has a direction 

 varying between S.S.W. and S.E. in Lower and Central 

 Bengal. It thus advances almost directly towards the hills 

 of "Western Assam. 



The mountain ranges cause a very considerable deflec- 

 tion of the current. One portion of air is forced upwards 

 as an ascending current with a velocity directly depend- 

 ent upon' the strength of the current in the rear, and upon 

 other conditions which need not be enumerated. 



The rapid diminution of temperature which accompanies 

 expansion due to ascensional movement of air, is usually 

 followed by rapid condensation iu the case of a moist 

 current, such as the south-west monsoon current. 



The rainfall at Oherrapunji is not due to any abnormal 

 local conditions of atmospheric pressure, air movemeut, 

 &c, but simply and solely owing to the presence of a vast 

 mechanicial obstruction which converts horizontal air motion 

 into vertical air motion. 



This fall is very local ; at Silhet, not thirty miles further 

 south, it is under 100 inches ; at Gauhati, north of the 

 Khasia in Assam, it is under 80 inches ; and even on the 

 hills, twenty miles inland from Ohurra itself, the fall is 

 reduced to 200 inches. 



Oherrapunji is surrounded, or nearly so, by vertically 

 ascending currents of saturated air ; the dynamic cooling 

 of which is the cause of the enormous precipitation which 

 has made this place famous. 



Our readu-s will notice that the rain'all of the Indian 

 tea district of Sylhet is under 100 inches, while in 

 Assam it is under 80. But SO inchrs in Assam means 

 a heavy rainfall for four or five months, with dry and 

 even wintry weather for a considerable portion of the 

 year. In Ceylon, where the rainfall ranges from 70 

 to 200 inches, drought is rare, while frost and hail 

 are practically unknown. At any rate, we suppose a 



