8 



IIS^TRODUCTOEY. 



East Coast, Mocha and Aden in tlie E-ed Sea, tlie northern portion 

 of Madagascar, the Seychelles, the Madras Presidency, ISTorth- 

 ern India, Ceylon and the JSTicobar Islands, Sumatra, Siam, 

 Malacca, Singapore and the Straits Settlements, Cochin China, 

 the Phillippine Islands, Borneo, Celebes and the Moluccas, Java 

 and Madura, Banca, the Johore Archipelago, Timor and the 

 eastern group of Islands, with New Guinea^ a large portion 

 of Northern Australia, the Marquesas, Society's and other oceanic 

 islands. In South America the Republics of Peru, Bolivia, 

 Ecuador, New Grranada, and Venezuela, British, French and 

 Dutch Gruiana, and a large portion of the empire of Brazil ; 

 Trinidad, Barbados, and most of the islands in the Carribean 

 Sea. 



This zone has a mean temperature of 78^ to 82 J Eahrenheit. 



2. The tropical zone reaches from the 15th cleg, on each side of 

 the equ.ator to the tropics in 23 lat. The mean temperature is 

 73 J to 78f deg. Summer temperature 80 1 to 86 cleg. ; winter 

 temperature in the eastern coast districts, 59 deg. 



In this region is comprised the following countries : — Sandwich 

 Isles, Canton, in province of China, Burmah, Calcutta, and a portion 

 of the Bengal Presidency, the "Bombay Presidency, Madagascar, 

 Mauritius and Bourbon; the southern portion of Brazil, Cuba, 

 St. Domingo, Mexico, and Central America. 



3. The sub-tropical zone extends from the tropics 23 to 34 deg. 

 of latitude. There are a number of tropical fruits in this region. 

 The winters are mild and vegetation is green throughout the year. 

 In the northern division of the zone palms and bananas grow on 

 the plains. In this region is comprised all the extreme northern 

 portions of Africa, coasting the Mediterranean, comprising 

 Algiers and the Barbary States, Egypt, part of Persia, Cabool 

 and the Punjab ; the greater portion of China, Lower California, 

 Texas, the South- Western States of America, the Bermudas, the 

 Cape Colony and Natal, New South AVales, Southern and "Western 

 Australia — the Groverument settlements in the Northern Island 

 of New Zealand, the largest portion of Chile, Paraguay, Uruguay 

 and the Argentine Eepublics, the Provinces of Brazil from St. 

 Paul to B-io Grrande, Madeira and the Canary Isles. 



To define accurately the conditions of temperature which a 

 plant requires to maintain it in a flourishing condition we must 

 ascertain within what limits its period of vegetation, may vary, 

 and what quantity of heat it requires. This most remarkable 

 circumstance was first observed by Boussingault, but unfortunately 

 we do not as yet possess sufficiently accurate accounts of the con- 

 ditions of culture in the various regions of the earth, to enable us 

 to follow out this ingenious view in all its details. His theory is, 

 that the time required by a plant to arrive at maturity is as the 

 inverse ratio of the temperature ; therefore, knovTing the mean 

 temperature of any place, and the number of days which a plant 

 takes to ripen, the time required a.t any other poi]it more or 

 less elevated, can easily be ascertained. Peter Purry, a native of 



