348 



CONCEUNING THE TEAK TREE. 



angles of re- 

 flection pecu- 

 liar to each. 

 It isesFential 

 to the reflect- 

 ing force. 



All the hypo- 

 theses to ex- 

 plain reflec- 

 tion are insuf- 

 ficient. 



That within and beyond this angle the light receives this modifi- 

 cation in a less complete manner. 



Polished metallic bodies, which reflect more light than trans- 

 parent bodies, do also polarise it in a greater degree. This mo- 

 dification is essential to the forces which produce reflection. 



Lastlyj these new phenomena have advanced us one step 

 nearer the truth, by confirming the insufficiency of all the hy- 

 potheses which philosophers have formed in order to explain 

 the reflection of light. For example, it is certain, that not one 

 of them tend to explain, why the most intense ray of light, 

 when it is polarised, can, under a certain inclination, pass through 

 a transparent body, and be totally deprived of the partial re- 

 flection to which ordinary light is subject. 



IV. 



Some Account of the Teak Tree of the East Indies. 

 William Roxburgh. 



By Dr. 



Introduction. nT^HE durability of Teak wood for ship-building is well 

 -JJL known to every one in India^ and its qualities are so much 

 valued in England, that considerable quantities are imported. 

 The Society for Encouragement of Arts, from whose 30th 

 volume the following paper is extracted, express their opinion, 

 that this tree may be successfully cultivated in our West Indian 

 and African settlements. And though it must be admitted, 

 that the true national policy of an empire must ever be to esta- 

 blish those public resources which are least subject to the contin- 

 gent events arising from the local distance of colonies, and con- 

 sequently, that our great eflforts ought to be to encourage the 

 growth of native oak j yet it must be nevertheless admitted, 

 that every possible me^ns of insuring our supplies, and encou- 

 raging our settlements, ought to be adopted. 



The timber of the teak tree is in India what oak is in Ener- 

 Great value of , , . . , , , . ^ 



the teak tree ^^^^ 5 '^ 's, however, unnecessary to enlarge on their compa- 



of the East rative value, because oak will not grow in India : our attention 



ought, therefore, to be confined to teak alone, not only as being 



by 



Indies. 



