134 THE ELEMENTS 



down with a knife ; when, ridges or 

 stria? can easily be imitated, if neces- 

 sary. The parts thus mended may be 

 coloured with common water colours, 

 and then brushed ; or if on a smooth 

 shell, polished with the palm of the 

 hand, and afterwards rubbed over 

 with Florence oil, which should be 

 well dried off with a piece of flannel. 

 If this mode is judiciously managed, 

 it may be examined, and never disco- 

 vered. 



Many shells, even when obtained 

 alive, are incrusted with extraneous 

 matter ; the best and safest means of 

 removing this is, first to steep them in 

 warm water, and then to scrape them 

 with a knife ; a little sand paper may 

 also be used, but care must be taken 

 not to injure the shell. When as much 

 of the crust is in this way removed, 

 as can with safety be done, recourse 

 should be had to muriatic acid, very 

 much diluted with water; by applying 



