hoffman] BEAD-DRILLING 267 



as a starting point for the bristle drill used in perforating the entire 

 length of the bead. 



In several graves opened during the summer of 1884, there were 

 found, among other articles, bundles of the whiskers or bristles of the 

 sea lion (Zalophus californicus), which animal, together with one or two 

 species of seals, formerly abounded along the southern coast of Cali- 

 fornia and the islands of Santa Cruz, Santa Rosa, and others. The 

 bristles of this auimal are now highly i>rized by the Chinese of the 

 Pacific coast, who tip them with gold and use them as toothpicks on 

 account of their elasticity and strength. 



In investigating a large collection of long beads from the Pacific 

 coast, curved as cut from the shells themselves, the author found that 

 several of the specimens had been split longitudinally, exposing to view 

 an interesting interior, and suggesting a solution of the method em- 

 ployed in making the delicate perforations. The bead having received 

 a preliminary drilling at each end, as before mentioned, by using the 

 triangular fragment of hornstone— the ends of nearly all perforations 

 being rather flaring or of funnel shape — the bristle was next applied, 

 and twirled or rotated between the thumb and fingers, while, at the 

 point of contact with the shell, silicious silt or fine sand was applied to 

 aid in cutting away the calcareous matter of the shell. The soft stratum 

 between two layers of the harder enamel was naturally followed by the 

 drill, thus without the slightest difficulty causing the perforation to be 

 curved, from end to end, to conform to the convexity of the shell from 

 which the bead was made. 



In some of the shorter beads which have split longitudinally, exposing 

 the bore, it is shown that the drilling was accomplished from both ends, 

 the axis of the perforation from each end being in a perfectly straight 

 line, the two perforations meeting at or near the middle of the specimen. 

 In some examples the two perforations were shown to pass each other ; 

 in these instances the bead was thrown aside, and subsequent splitting 

 exposed to view the condition described. 



In shells of abnormal convexity and having a length of more than 3 

 or 4 inches, perforations in a straight line from either end would not 

 always reach the middle along the line of least resistance, as offered 

 by the softer calcareous stratum, but would sometimes emerge from 

 the sides, leaving a portion of the middle part of the bead solid. That 

 the bore followed the course of the curve of the bead, the bristle drill 

 continuing between the superior and inferior strata of harder enamel, 

 is shown in many examples. 1 



Substances having the texture of bristles, human skin, etc, are less 

 liable to destruction by erosion from the application of silt, or fine sand, 

 than harder mineralogic materials. This is demonstrated by tlie use 

 of the sand blast, and also by practical experiments in drilling with 

 bone, wood, and porcupine quills, and the whiskers or bristles of mam- 



1 Wheeler's report, etc, op. oit. 



