LECTURE XI. 
177 
ducing this substance into the inside of finely- 
blown glass beads, slightly tinged with opaline 
hues, a perfect imitation of real pearls might be 
made : (for an attempt of a similar nature had 
some years before been made in Italy, by filling 
glass bubbles with quicksilver; but which was im- 
mediately discouraged; first, on account of the 
pearls so prepared wanting the true colour, and 
because they were judged to be dangerous by the 
physicians.) Jacquin was at first put to great dif- 
ficulty in preserving the silver-coloured powder, 
which, if not used quickly, becomes putrid, and dif- 
fuses an intolerable smell. Attempts were made 
to preserve it in spirits, but by this method the 
lustre w'as entirely destroyed. It was at length 
found, that volatile alkali possessed the power of 
preserving the substance without injury to its co- 
lour. Many years elapsed before the false pearls 
became very common ; and even so late as the 
reign of Louis the Fourteenth it is said that a 
French Marquis who possessed very little property, 
but who was violently in love with a particular 
lady, gained her affections by presenting her with a 
rich string of these pearls, which cost him but three 
Louis’s, but which the Lady, supposing them to 
LECT. II. 
