312 SCIENCE PROGRESS 



as rapidly as it had risen, until now there is only a very trifling 

 quantity sent out of the island. 



Other importations made in Thwaites' time were the rubber- 

 trees of South America. These were introduced in 1875-6. Ceara 

 rubber (Manihot glaziovii) became the source of a small industry in 

 the early eighties; but was rapidly given up, as it did not prove 

 profitable, and because tea was then coming in as the standard 

 Ceylon crop. Para rubber (Hevea brasiliensis) did not seed so 

 early or so freely, and was very slow in coming into cultivation. 

 Until 1898 seed could only be obtained in small quantity, but 

 since that time the planting has gone on very rapidly, until now 

 there are probably 60,000 acres or more in Ceylon, and an equal 

 quantity in the Federated Malay States, the profits of the early 

 pioneers having proved to be enormous. 



The great industry which has arisen in Ceylon in recent 

 years is of course tea. This was introduced by the Botanic 

 Gardens early in the last century, but was not touched until 

 about 1870, and did not really begin to develop into an impor- 

 tant industry until the return of the Commission sent to Assam 

 to investigate methods, and provided with questions mainly by 

 Dr. Thwaites. The Botanic Gardens, therefore, may claim to 

 have had some considerable share in starting this industry also. 



Thwaites retired in 1880, and was succeeded by Henry Trimen. 

 The really important introductions of useful plants from abroad 

 were by this time practically over, and Trimen hardly intro- 

 duced anything in his sixteen years of work that is likely to 

 prove of more than minor interest or value. But he devoted 

 himself to spreading the use and cultivation of those useful 

 plants which had already been introduced, more especially 

 cinchona, cacao, and cardamoms, and to the writing of a 

 complete flora of Ceylon, whose publication was begun in 

 1893. Unfortunately Trimen died in 1896, when only three 

 volumes of the five of which the flora consists were published, 

 but its completion was generously undertaken by the veteran 

 Sir Joseph Hooker, and the last volume appeared in 1900. 



In many respects the last twenty years of last century 

 mark a check in the progress of the Ceylon Botanic Gardens, 

 and it will be well, before resuming the history, to deal with 

 what had been accomplished elsewhere. The other British 

 gardens were in general (except Calcutta) simply inferior 

 editions of those of Ceylon, and it is to the Dutch possessions 



