EFFECTS OF FORESTS UPON CLIMATE: MAURITIUS. 305 



the rain-fall, have passed through considerable ranges of annual varia- 

 tions, and, as is thought, with a tendency to periodicity. 



The forests that have been cut since 1853 are from 8 to 20 miles dis- 

 tant from the observatory, and therefore the influence they may have 

 had, is not directly shown by its records. Mr. Charles Meldrum, the 

 director, in a letter dated August 16, 1877, informs us as follows : 



The general belief, in -which I agree, is that the humidity has considerably diminished 

 in the interior of the island, and probably the frequency of the rain-fall ; bnt observa- 

 tions have not been taken for a long enough period to enable ns to arrive at a satis- 

 factory conclusion as to the rate and amount of decrease. The local government have 

 lately commenced to replant some of the denuded localities, and in the coarse of time 

 the effect with regard to humidity will be known. 



I have little doubt that the destruction of the forests has produced serious eflfects as to 

 the sanitary and agricultural condition of the island. There have always been lakes 

 and lagoons on the low plains near the coast, formed by filtration from the high lands 

 of the interior. Formerly, when the interior was densely wooded, a large portion of 

 the rainwater was retained, and filtration went on gradually, so that even in the dry- 

 est years the lagoons received regular supplies of pure water. Bat now the greater 

 part of the rainwater is carried away to the sea, and hence in dry weather the sun's 

 rays beat down on slimy, foetid marshes. During torrential rains, also, the low lands 

 are flooded, and much stagnant water and vegetable dSbris is left behind. The conse- 

 quence is, that an island at one time noted for its salubrity, has become a hot-bed of 

 malaria. During the last ten years the mortality from fever has been very great. It 

 is during the process of evaporation after heavy rains, that the fever becomes epidemic, 

 and only then with a high temperature There was a severe drought from January to 

 April, 1875, followed by heavy raini in the latter part of April and in May ; but no in- 

 crease of fever took place, apparently because winter had set in before the rains ceased. 

 On the other hand, after a drought "Krhich took place in November, December, and Jan- 

 uary last, followed by torrential rainis, fever became general, and it continued to rage 

 through March, April, and May. 



Within the last 15 years many sugar plantations near the coast, in the leeward dis- 

 tricts, have been abandoned, mainly, it is said, through want of sufficient rain and 

 moisture.' 



It is more than a century since anxieties were first felt in Mauritius 

 in relation to the cutting oif of forests, and regulations were made with a 

 view of conservation. On the loth of November, 1769, the governor and 

 intendant — Desroches and Poivre — established a regulation founded 

 upon public policy and private inteiest, as well to protect the harvests 

 against the violence of the winds as to afford shelter from the burning 

 heat of the sun and exemption from drought. It was declared an im- 

 portant object of the administration, not only to protect the woodlands 

 in the places where they already existed, but to cause plantations to be 

 made in places where they had been destroyed. The measures then 

 proposed may be summarized as follows : 



The use of stone instead of wood in building. 



Forbidding the carrying of firebrands in the fields, roads, or -woods. 



Requiring the owners of lands to get licenses before clearing. 



Reservations of one-fourth of the concessions of land for forests, and especially the 

 woods growing upon ridges, bluffs, and hills, requiring the woodlands to be brought 

 up to this proportion by planting. 



Forbidding the clearing within ten perches along the banks of streams, except roads 

 and paths for coming to the water, or for passing along the bank, and ordering cleared 

 banks of streams to be planted. 



Forbidding the grantees of land along the sea-shore, from cutting any trees on the 

 King's reserves, or on their own land within ten perches, or, if cleared, requiring that 

 such lands should be planted. 



Forbidding the cutting of wood for forges or other establishments excepting under 

 the direction of a conservator, who was to reserve for high-forest sixteen young trees 

 per arpent. 



1 Brown's Forests and Moisture (1877), p. 124, cites other information concerning the 

 climate of Mauritius, confirming the above. 



See also N. Pike's Sub-tropical Rambles in the Land of the Aphanopteryx (1873), p. 422 ; 

 Thornton's History of India; Transactions of the Scottish Meteorological Society, 1866; 

 Transactions of the Royal Society of Mauritius, &c 

 20 F 



