The Pottery Tree of Para. 51 



The bark seldom grows more than half an inch thick, and is 

 covered with a skin or epidermis frequently covered with 

 lichens. A superficial examination shows nothing out of the 

 common; the fresh bark, however, cuts somewhat similar to a 

 soft sandstone, but, when dry, it is very brittle and flint-like, 

 and sometimes difficult to break. By biting a piece of the 

 bark the presence of silex can be well ascertained, as it grates 

 between the teeth like fine sand. If we examine a section 

 under the microscope, we find all the cells of the different 

 tissues or layers are more or less silicated, the silex forming 

 in the cells while the bark is very young. In the inner bark 

 the silex or flint is deposited in a very regular manner, as will 

 be seen by Fig. 1. The flint, however, from the ash of a 

 porous cell of the bark assumes a very different appearance, 

 as shown in Fig. 2. Fig. 3 shows a porous cell macerated, 

 and Fig. 4 is a flint skeleton from a similar cell. The bark 

 of young trees and branches contain a much larger quantity of 

 water than that of old trees ; the proportion of water, however, 

 are more equal in the old and young woods. From an analysis 

 made of both the old and young barks, the old was found to 

 give 30.8 per cent, of ash, and the young bark 23.30. Of the 

 different layers of the old bark, the outer gave 17.15 per cent., 

 the middle 37.65, and the inner 31. A larger percentage of 

 ash was yielded by the bark of an old branch, which was found 

 to give 77. In comparison to the bark the wood is relatively 

 poor in silex, the duramen, or old wood of an old trunk, giving 

 only 2.5 per cent., and the alburnum, or young wood, 2 per 

 cent. only. 



The wood, bark, ash, and various specimens of the manu- 

 factured pottery, may be seen in the Kew Museum. 



