76 CONCHOLOGY. 



aqua fortis on the parts required to be 

 wrought on, and then it muft be froni 

 minute to minute, fteeped in clean water, 

 to hinder the acid from corroding it tOQ 

 much ; afterwards, hke other Shells, they 

 are to be polifhed, or pafled over with tri-^ 

 poly or emery : even then, all parts cannot 

 be clean alike, and gum-water or whites of 

 eggs muft be ufed to thofe lefs cleaned 

 parts, to render them vivid 3 elfe they 

 would Ihew but dull. 



The rubbing down of Shells re-pro^ 

 duces new ones, as they are called. Thus 

 the Volute, called by us the Purple or 

 Violet Tip, and by the French the Onyx, 

 has a brown epidermis, which being taken 

 off difcovers the ground colour to be a dull 

 yellow. When this is worked down to 

 beneath the cruft, or furface, it is of a 

 pure white, with the tip of a fine violet 

 colour. 



Th^ 



