Conchology. 243 



inya, requires from twelve to fourteen hours. When the shells 

 have boiled the proper time, they should be washed over with 

 diluted muriatic acid, when the skin may be easily removed by 

 rubbing it off with the fingers. 



Though the art of polishing shells is a very valuable one, yet 

 it is very dangerous to the shells; for without the utmost care, the 

 means used to polish and beautify^a shell often wholly destroys it. 

 When a shell is to be polished, the first thing to be examined, 

 whether it have a naturally smooth surface, or to be covered with 

 tubercles or prominences. 



A shell which has a smooth surface, and a natural dull polish, 

 need only be rubbed with the hand, or with a piece of chamois 

 leather, with some tripoli, or fine rotten stone, and it will acquire 

 a perfectly bright and fine polish. Emery is not to be used on 

 this occasion, because it wears away too much of the shell. This 

 operation requires the hand of an experienced person, who knows 

 how superficial the work must be, and where he is to stop; for 

 in many of these shells the lines are only on the surface, and the 

 wearing away ever so little of the shells defaces them. A shell 

 that is rough, foul, and crusty, or covered with a tartareous coat, 

 must be left a whole day steeping in hot water : when it has im- 

 bibed a large quantity of this, it is to be rubbed with rough emery 

 on a stick, or with the blade of a knife, in order to get ofi:' the 

 coat. We have found different kinds of engraving instruments, 

 of much service in removing the crust and extraneous matter from 

 shells, particularly the parasitic species of shells which adhere to 

 them, such as serpulse and balansB. If done with caution, il will be 

 found by far the best mode; and, indeed, where there are spines, 

 they cannot be removed b}^ any other means, as by applying 

 acids they are often completely destroyed. After this, it may be 

 dipped in diluted aquafortis, spirit of salt, or any other acid; and 

 after remaining a few moments in it, be again plunged into com- 

 mon water. This will add greatly to the speed of the work. 

 After this it is to be well rubbed with linen cloths, impregnated 

 with common soap; and when by these several means it is made 

 perfectly clean, the polishing is to be finished with fine emery 

 and a hair brush. If after this the shell when dry appears not to 

 have so good a polish as was desired, it must be rubbed over with 

 a solution of gumarabic; and this will add greatly to its gloss, 

 without doing it the smallest injury'. The gum water must not 

 be too thick, and then it gives no sensible coat, only heightening 

 the colors. The white of an egg answers this purpose also very 

 well; but it is subject to turn yellow. If the shell has an epider- 

 mis, which will by no means admit to be polished, it is to be 



