316 CULTIVATED VEGETABLES. 



erfully than in the latter. It is farther re- 

 marked, that the silver when filled a second 

 time, produces worse tea than the earthen- 

 ware ; and that it is advisable to use the 

 crockeryware, unless a silver vessel can be 

 procured sufficiently large to contain at once 

 all that may be required. These facts are 

 readily explained, by considering that the 

 action of heat, retained in the silver vessel, 

 so far exhausts the herb, as to leave little 

 flavour for a second dilution ; whereas the 

 reduced temperature of the water in the 

 earthenware, by extracting only a small por- 

 tion at first, leaves some for the action of 

 subsequent dilutions. It is supposed that 

 the infusion is stronger in a globular vessel, 

 than in one of a different form ; and this must 

 be the case, since it is demonstrated that a 

 sphere contains a given measure under less 

 surface than any other solid ; from which it 

 follows, that where there are two vessels of 

 equal capacity, one globular, and the other 

 square, oblong, elliptic, or cylindric, the sphe- 

 rical vessel, having less surface than the other, 

 must throw off less heat ; and that, conse- 

 quently, the effect will be greater in the 

 former case than in the latter. 



The reason for pouring boiling water into 



