Submarine Appliances And Their Uses
Deep Sea Diving, &c., &c.

Ihe Mother-o’-Pearl Oyster (Maleagrina Margaritifera) produces the largest pearls, but is mainly valuable for the shells, a single pair often weighing, when cleaned and dried, as much as 14 lbs. These abound all over the Northern Coast of Australia, Western Australia, the Eastern Archipelago, Lower Burmah, New Guinea and the South Pacific Islands. The shells obtained are classified into four qualities : Young- shells, known to the trade as “chicken shell,” which are the most valuable, and average about 4,000 to the ton ; “ordinary sound ” quality, from 600 to 1,200 to the ton ; and “wormy”—i.e., worm-eaten and old—also 600 to 1,200 to the ton. Copyright. Photo No. 79. Shewing the various stages in the manufacture of a Mother-o’-Pearl Paper Knife, from the rough shell to the finished article. It is calculated that the annual take of a single boat is seven tons, of which five tons cover the outlay, and two tons may be reckoned as clear profit. The value per ton has a wide range, varying according- to the state of the home market, and may be estimated at from ^60 to /J200. Most of the pearls taken arc of poor quality and comparatively valueless, but occasionally gems are found realising- as much as ,£1,000, although some years ago a pair of Drop Pearls fetched over ^'15,000, another ^5,000, whilst the famous Southern Cross Pearl realised over 15,000. Coarse ones of extraordinary size are sometimes obtained. 154