XXX. PRESSURE FRACTURE PROCESSES 



THE statement that stone is snsceptible of fracture by pres- 

 sure and may even be elaborately shaped by pressure proc- 

 esses is usually received with decided incredulity by the 

 uninitiated, and that the work can be done by means of bone tools is 

 still further beyond the limits of ready belief. But primitive man 

 devised numerous methods which enabled him, with the aid of bits 

 of horn, bone, antler, or ivory, to carry the manufacture of objects 

 of brittle stone by means of pressure fracture to a degree of refine- 

 ment not readily attainable by any other known means. Pressure 

 shaping is limited, however, in its capabilities, since it can be oper- 

 ated successfully only where brittle stone is utilized, and even then 

 with slight success, except with comparatively small objects. The 

 several varieties of pressure processes have been tested in recent 

 years by luunerous students, in many cases with marked success. 

 Some have imagined themselves the discoverers of entirely new 

 methods or the rediscoverers of methods practiced in ancient times 

 and now classed among the lost arts. But examination of the 

 literature of pioneer days and the reports of observers who have 

 come into familiar contact with primitive peoples, disclose the fact 

 that most of the now known processes were practiced by the tribes 

 in various parts of America up to the time of the introduction of 

 iron and steel. This is amply shown by the numerous citations 

 brought together in subsequent pages. It may bo added that prob- 

 ably a majority of the methods are still i^'acticed by remote tribes in 

 different parts of the world. 



Two varieties of the i)ressure-shaping arts are recognized — the 

 free-hand and the rest processes. These processes are, for the most 

 part, not si)ecifically distinct, since the implement used, so far as its 

 operating point is concerned, is practically the same in all forms of 

 the work, the distinction being due to differences in the mounting 

 and api)lication of the point. In the rest method the fixed position 

 of the stone worked permits of the application of greater force than 

 the free-hand method, while the haft of the implement may be so 

 lengthened as to be set against the chest or under the arm of the 

 operator, thus greatly increasing the fracturing power. 



The following brief summary of the several kinds of pressure 

 shai)ing work will be convenient for reference for those who may not 

 desire to take up the subject in greater detail. 

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