xl INTRODUCTION. 



shells in a natural state, there are others who wish 

 to see their beauties revealed. To remove this epi- 

 dermis, it should be first soaked for a day or two in 

 water, and then rubbed firmly with a hard brush, 

 armed with finely powdered pumice-stone. It will 

 often be difficult to remove every part of the pel- 

 licle ; but, by diligently persevering, it may be done. 



It is not unusual, when the colours of the shells 

 are rather dull, to revive them with varnish. This 

 may reasonably be allowed, since it only imitates 

 their appearance when wet out of the sea. The 

 best varnish for the purpose is a simple solution of 

 gum Arabic, in water, which can be laid on with a 

 camel-hair pencil, and easily washed off again, at 

 any time, without injuring the shell. 



Collectors are sometimes imposed upon b}^ a trick, 

 which was first practised in Holland, where two or 

 more shells are sold as distinct species, which are 

 precisely the same, except that one of them has 

 had its external coat taken off, by grinding the shell 

 on a wheel charged with oil and emery. Many 

 shells by this process assume a new appearance. 

 The common cowry becomes violet; the nautilus, 

 which has broad tawny stripes on its sides, rubs 

 down to a fine mother-of-pearl ; and many of the 

 limpets become so altered in their colours, that 

 they lose all resemblance to the original shell. 



