lU THE WEALTH OF THE SEA 



made from tubing, with the hole of a size suitable 

 for the hole through the bead. Appropriate lengths 

 are cut off, the holes are plugged with a refractory 

 material, such as fire-clay or graphite, and the pieces 

 are then heated to the softening point in a revolving 

 iron drum partially filled with powdered talc. The 

 dram is revolved until the beads are all shaped: the 

 heating is then stopped, but the revolution of the 

 drum is continued until they are cooled. 



H. F. Taylor, formerly of the United States 

 Bureau of Fisheries, has recentlv devised a very 



•'to' w 



simple method ^ of preparing a pearl lacquer which 

 possesses certain advantages over other methods. 

 According to his process the fish scales are rubbed 

 in water to remove the valuable lustrous particles. 

 The suspension obtained is drained off and allowed 

 to settle, and the supernatant water, containing 

 whatever blood has been present, is decanted off. The 

 remaining heavy suspension, containing the lustrous 

 particles of guanine, is treated with a digestion mix- 

 ture of pepsin and glacial acetic acid, and allowed 

 to act forty-eight hours. This completely digests and 

 removes all the proteinaceous matter from the 

 guanine crystals. After the digestion, the surfaces 

 of the crystals are clean, and they now possess the 

 peculiar property of being more readily wetted by 

 ether and certain other non-aqueous solvents. Ad- 

 vantage is taken of this property to obtain clean 

 crystals suspended in solvents of nitrocellulose lac- 

 quer : ether is poured into the digestion mixture and 



^ "Pearl Essence : Its History, Chemistry, and Technology ," by 

 Harden F. Taylor, Bureau of Fisheries Document 9S9 (195o). 



