Si VEGETABLE SUBSTANCES, 



tropical countries is vefy remarkable, Humboldt 

 describes the third zone of the Peak of Teneriffe, the 

 region of firs, as at nine hundred toises of absolute 

 height (about five thousand seven hundred and sixty 

 feet) ; and he says that, in the Cordilleras of New 

 Spain, under the torrid zone, the Mexican pines reach 

 as high as two thousand toises (about twelve thou- 

 sand eight hundred feet). 



The Silver Fir (Pinvs picea), so called from two 

 lines of white on the under side of the leaves, is a 

 majestic tree, and grows with great rapidity. It is a 

 native of the south of Europe and the Levant, the 

 silver firs upon mount Olympus being the most 

 nlagnificent trees in that country. Requiring a richer 

 soil and a warmer climate than the pine and the larch, 

 it cannot be so well cultivated in bleak situations as 

 those species. The timber which it produces is softer 

 and less durable than that of either of them ; and, 

 therefore, it is not so well adapted for general pur- 

 poses : but its lightness renders it a very fit material 

 for boats, and planks made of it are said to have the 

 property of not shrinking. It has been introduced 

 into this country as an ornamental tree, for more 

 than a century ; but it has not been hitherto, and pro- 

 bably never will be, extensively cultivated for profit. 

 Nearly allied to the Silver Fir, though inferior to it as a 

 •grower, is the Bahn of Gilead Fir (Pinus balsameaj. 

 It is a native of America ; but although it has been 

 in this country for more than a century and a half, 

 the only place where it has grown, even to moderate 

 dimensions, is Woburn Abbey. 



