282 MOTHER-O'-PEAUL. 



ESTHER. 



It is the Nautilus spirula. Those specimens which you 

 have generally seen have probably been broken; it being 

 usually, from its great fragility, found imperfect. In its 

 complete state it more resembles a crozier. This is the 

 Nautilus (N. pompilius} of which mamma has an ornament 

 on the chimney-piece. It is found in abundance at Manilla, 

 where the colored part of the shell is removed, and raised 

 white carved figures embossed upon it, and then two shells 

 being fastened together, the one aperture turned downwards, 

 the other upwards, it forms a graceful mother-o'-pearl cup or 

 chalice. 



HENRIETTA. 



Is mother-o'-pearl the same composition as pearls'? 



ESTHER. 



Precisely; there is no difference whatever. Shells have 

 been divided into two classes; porcellaneous and mother-o'- 

 pearl. The texture of the first is brittle, and resembling 

 porcelain; their surface is smooth and they are often beauti- 

 tifully variegated. They are composed of carbonate of lime 

 united to a very small portion of gelatine. Most of the 

 univalve shells, such as whelks, limpets, cowries, &c. belong 

 to this class. 



HENRIETTA. 



And the second class, or mother-o'-pearH 



ESTHER. 



These are mostly bivalves, the oyster and mussel belong to 

 it. In both classes, the hardening principle is carbonate of 

 lime; but in the mother-o'-pearl it is united with albumen, 

 but in larger quantities than the animal matter (gelatine) 

 exists in the porcellaneous shells.* 



HENRIETTA. 



But here, Esther, is a little mussel, which I suppose, by 

 mistake, is placed among the univalves. 

 * Brande's Chemistry. 



