1895.] 47o [Frazer. 



Evidences of the action of two hands in joint signature marks. 



By Persifor Frazer. 



From the committee appointed by the Society to investigate the various methods for 

 the examination of documents. 



{Read before the American Philosophical Society, December SO, 1S95.) 



If it be conceded that the effect of a given individual's will on that 

 individual's mechanism of bones, muscles, nerves, etc., with which it has 

 been associated in all acts of the possessor of both, results in the produc- 

 tion of a script characteristic of that individual and of no other ; it ought 

 to follow that whatever be the pattern traced, whether a simple cross or a 

 more complex series of conventional signs as in hand-writing, it should 

 contain characteristics of the writer. In the case of a simple cross, these 

 characteristics are much more difficult to discover than in that of ordinary 

 writing or name-signing, but that they exist no one will deny who has 

 taken into consideration the invariable tendency of mankind to contract 

 habits in the performance of all acts which it repeats during a longperiod, 

 and tlie growth of a habit in any organized being from constantly tak- 

 ing the easiest method under existing conditions to accomplisii what the 

 will has commanded. 



The fact that simple marks, made by persons ignorant of the art of wri- 

 ting or deprived of some organ or faculty possessed by the majority of 

 their race, contain characteristics of the individuals who make them, is a 

 logical sequence of the principles of grammapheny,*and is susceptible of 

 actual demonstration. 



It is not the object of this paper to treat of marks of this kind, but of 

 those which are made by one person while another touches the pen- 

 holder. 



If great difficulties are encountered in dealing with the first kind of 

 marks the difficulties in those of this second kind are vastly greater and 

 might well be considered insurmountable in so far as the problem is con- 

 cerned with the establishment of individual character from the traces of 

 resistance to free pen movement observable in the joint mark. 



The undersigned speaks thus cautiously of the possibility of establish- 

 ing the characteristics of one person from the traces of his interference 

 with the free work of the actual holder of the pen, a problem comparable 

 to the determination of the orbit and mass and of an unknown planet from 

 the effect of the latter on the movements of a known planet, because it is 

 not possible to state how far legitimate investigation may be extended in 

 the future by new devices and larger knowledge. 



* This word has been used by the writer in his treatise on Bihhotics; or The Study oj 

 Documents (J. B. Lippincott Co., Philadelphia, 1894), to express the "elucidation of the 

 individual character of hand-writing, or that by which it distinguishes itself from every 

 other hand-writiug." 



