The lunarians do not, as Butler has it "When the sun shines hot at noon, Inhabit cellars under ground, Of eight miles deep and eighty round.

Pearl is, in fact, a calcareous secretion by the fish of bivalve shells; and principally by such as inhabit shells of foliated structure, as sea and fresh water muscles, oysters, &c. A pearl consists of carbonate of lime, in the form of nacre, and animal matter arranged in concentric layers around a nucleus; the solution indicating no trace of any phosphate of lime.