UNCLE IN ENGLAND. 171 



gable Humboldt, having at last succeeded in 

 finding some of it undisturbed in the ground, 

 at once perceived that it had oozed out of 

 the roots of caoutchouc trees which were so 

 old that the interior had begun to decay. It is 

 white and brittle, till exposed to a strong heat ; 

 and when sufficiently beaten with a heavy club 

 it acquires great elasticity. The Indians make 

 their famous tennis balls of it ; it is also cut 

 into corks, which are very superior to those 

 made of the cork tree ; and it is worked up into 

 enormous drum-sticks the drum being merely 

 a hollow cylinder of wood about two feet long. 



" There is, however," my uncle observed, " a 

 species of fossil caoutchouc. It is, in fact, a bi- 

 tumen, but flexible and elastic ; and, as it has 

 the property of cleaning off pencil-marks ju the 

 same manner as Indian rubber, it has been 

 named mineral caoutchouc." 



I asked him if it might not be some of the da- 

 picho, which had lain buried in the ground, long 

 since the trees, from which it oozed, had pe- 

 rished ? 



" I have but two reasons, Bertha, to oppose 

 to your theory. It is only found near Castle- 

 town in Derbyshire, and you know the English 

 climate is not very well suited to those trees 

 and secondly, it is in the deep recesses of 

 a lead mine, surrounded by spar and lime- 

 stone." 



Q 2 



