Figure 9-9. Illustration of the use of the card-index method of identifying an unknown. 



only the strongest line of the pattern can be used as a guide for selecting the 

 group of cards for comparison. All of the lines on each card of the selected 

 group are compared with the pattern of the unknown ; bearing in mind, of course, 

 that at least all the strongest lines must be found in the pattern of the unknown, 

 with proper relative intensity. Checking of only a few lines on a card is usually 

 sufficient to indicate whether or not agreement exists. When a card identifies 



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