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ARTIFICIAL PEARLS.

of these calcareous productions is that which is found in theinside of the shell, whence that saying of Pliny , Quo appa-rel, nos uno concha; genera nasci.

From the transactions of the Swedish Academy , it appearsto he an opinion entertained by M. Lister, that the growthof pearls might be considerably promoted by impregnatingthe water, where the fish which produce pearls are bred,with calcareous matter for nourishment; but, we under-stand, the younger Linnaeus gave his opinion that his father’splan favoured of neither of these projected designs.

Under the appellation of artificial pearls, come thosesmall semi-transparent beads prepared by art so near toimitate the form, colour, and lustre of real pearls, that theyassume this name. It should appear, however, from thesilence of the ancients, and particularly Pliny on this sub-ject, that in h.is time it was not known; therefore this infe-rence furnishes us with a conclusion that this art is ofmodern invention.

Numerous modes have been resorted unto by the ingeniousto procure this imitation. xVt first it was conjectured, thatit was possible to manufacture large pearls from a numberof small or broken ones. Tzetzes speaks of this imaginedart in the following terms. Arte autem sic parant: e parvismargarilis comminutis alias majores in orhem effingunt.But all endeavours to effect this have failed; because artwanted the assistance of that menstruum which nature canalone supply,—that connecting medium which nature yetconceals and keeps to herself.

The idea of manufacturing globules of glass, coveringthem with a substance resembling the appearance of pearls,which art could supply, appears more congenial and co-rela-tive with the purposes of human ingenuity, whose theatre ofaction must be confined to an imitation of' those appearanceswe observe in nature. The nearer it can approximate to thereality, the more perfect is the arl. But the last mentionedmode was discovered soon to fail; because it was found thatsuch semblance, although at first it appeared to approachvery near to the original, yet when it was brought into theinfluence of heat, the beautiful pearly gloss was dissolved,which must have been the case, of necessity, to almost everykind of varnish in certain degrees of heat.

The next idea was certainly better calculated to answerthe purpose; although found on experience not entirelyto obviate the last mentioned difficulty. A French bead-maker, of the name of Jaquin, at length found out a method