Page:ONCE A WEEK JUL TO DEC 1860.pdf/87

14, 1860.] is rather wrong there; it can be imitated, and wonderfully imitated too,) “either in beauty of form or brilliancy of lustre, is the abortive egg of an oyster enveloped in its own nacre, who will not be struck with wonder and astonishment?" Wonder and astonishment are words which scarcely exist now. Science has shown so many wonders that we are hardly astonished at anything; but Sir Everard’s assertion admits of proof. A pearl cut in two exhibits the concentric layers like an onion, as may be seen through a strong glass; and in the centre is a round hole, very minute it may be, but wherein the ovum has been deposited.

Sometimes the ovum, or sand, or enclosed substance has attached itself to the shell, and has then been covered with mucus, forming a pearl which cannot be separated from the shell. There are several specimens of such pearls in the British Museum.

The great beauty in pearls is their opalescence, and a lustre which, however clever men are, they have never yet given to artificial pearls. Sir Everard Home supposes that this lustre arises from the highly polished coat of the centre cell, the pearl itself being diaphanous. Sir David Brewster accounts for it by the pearl and mother-of-pearl having a grooved substance on its surface resembling the minute corrugations often seen on substances covered with oil, paint, or varnish. Philosophers are sometimes not very explanatory. Sir David means to say that beneath the immediate polish of the pearl there are certain wavelets and dimples from which the light is reflected. “The direction of the grooves,” again to quote Sir David, “is in every case at right angles to the line joining the coloured image; hence, in irregularly formed mother-of-pearl, where the grooves are often circular, and have every possible direction, the coloured images appear irregularly scattered round the ordinary image.”

In the regular pearl these are crowded, from its spherical form, into a small space; hence its marvellous appearance of white unformed light; and hence its beauty and value.

To prove the translucency of the pearl, we have only to hold a split pearl to a candle, where, by interposing coloured substance or light, we shall have the colour transmitted through the pearl. Curious as is the formation of the pearl, we have yet a cognate substance to it. What we call bezoar, and the Hindoos faduj, is a concretion of a deepish olive green colour found in the stomach of goats, dogs, cows, or other animals; the hog bezoar, the bovine bezoar, and the camel bezoar; this last the Hindoos turn into a yellow paint; but the harder substances the Hindoo jewellers