1895.] 475 [Frazer. 



The bearing of this latter feature upon the question of single or joint 

 production was obvious, because with a foreign hand touching the pen- 

 holder ever so lightly those movements which depended upon the exercise 

 or release of slight pressure could be producecd only in a very imperfect 

 manner. 



The tables will be found self-explanatory, but it may be worth while 

 to call attention to a method of utilizing their results which seems to be 

 important in proportion to the diversity and complexity of the factors 

 which enter into them. The extraction of information from tables of 

 statistics is frequently more difficult than the procuring of the statistics 

 themselves Let any one attempt to master, say the significance as life in- 

 surance tables of the necrological reports of the cities and of the country 

 at large, and he will appreciate the value of the art of Mrs. Glass after the 

 hare is caught. 



It may be stated as a general fact that the effect of minor components 

 of composite forces are more clearly distinguished when the ratios of 

 parts to each other and to the whole are considered. It is true that this 

 method of presentation is open to the objection that it magnifies very 

 small differences, but on the other hand it clearly distinguishes cases 

 which have resulted from closely similar conditions. The real table of 

 information, therefore, is a table representing the ratio to each other of 

 columns in the original table, and the percentages of difference between 

 measurements of objects whose origin is unknown or in doubt from those 

 of similar objects whose origin is known. It is in this way that the full 

 force of efTects produced as in this case by the resistance of a hand touch- 

 ing a moving penholder may be made manifest, as the tables herewith 

 given seem to show. (See the left-hand column of Table I, marked 

 -^^ or ratio of column A to column B). 



When this work had been done, further experiments in joint signature 

 marks by various persons were undertaken, in order that the conditions 

 peculiar to the above case might be replaced b}'' generalizations useful in 

 a wider field of inquiry. 



With this view over three thousand five hundred marks were produced 

 and examined, and the table which follows gives the percentages of the oc- 

 currence of various features in the free and in the joint marks respectively'. 

 Exception percentages such as 3 or 10 in the results indicate different de- 

 grees of uniformity in the occurrence or absence of a given characteristic 

 in a mark. Obviously, any feature to which there was not a single ex- 

 ception in the three thousand five hundred experiments, is of importance. 

 The only such feature discovered in these observations was the exist- 

 ence of ragged side terminals in some part, and usually throughout the 

 greater part of a joint mark. When a mark is entirely free from such an 

 appearance, therefore, it may be assumed, with a strong degree of prob- 

 ability, that it was not subjected to the influence of two hands. 



In the following summary, as well as in Table I, the letters R. U. mean 

 "right upper" (corner), and L. D. mean "left down" (or left lower cor- 



