154 Dr. G. A. Campbell on 



received its proper share of records. It does not seem pro- 

 bable that this influenced the results to any considerable 

 extent. As far as such an effect occurred it would corre- 

 spond in a general way to the condition obtaining in the 

 practical use of the telephone, where the subject matter and 

 the preceding syllables give some clue as to the syllable 

 which may be expected. 



The telephonic network included regular common battery 

 subscribers' sets at each end, common battery transformers 

 and cord circuits at the central offices, and a line of about 

 one hundred miles of loaded No. 16 or No. 14 B. and S. 

 gauge cable, with the addition of from three to sixteen miles 

 of non-loaded No. 19 B. and S. gauge cable. The series of 

 tests over this connexion included twelve thousand records. 



For comparison, tests were also made with direct trans- 

 mission through the air, the same observers facing each other 

 with no intervening obstruction but not looking at each 

 other. The observers were fifteen feet apart in a quiet room. 

 This series contained two thousand records. 



Table I. shows the distribution of all records. Where 

 there are two figures in a square the upper refers to the test 

 made through the air. The syllables have been arranged in 

 such an order as to bring those which are most frequently 

 mistaken for each other as near together as possible. This 

 brings the surds or voiceless consonants,/, s, h, sh, ch, k, t, 

 and p together. The remaining consonants are all voice 

 consonants with the exception of th. The occurrence of th 

 among the voice consonants may be accounted for by the 

 fact that th is liable to confusion with the voice consonant dh 

 as in thee, and it is possible that in these tests the distinction 

 between the two was not properly made. In an earlier 

 series of tests which included dh in place of th the same 

 mistakes were made as in the present series with th, that is, 

 dh was confused with v on one side and z on the other. In 

 the table the voiceless explosives k, t, and p come together, 

 also the voice explosives g, d, and b, and the nasals m and n. 



A blank square indicates that no record was made by 

 either observer corresponding to that case. The table shows 

 156 such squares, and therefore of the possible incorrect 

 cases only 59 per cent, occurred. A zero indicates that not 

 over one-half of one per cent, of the total records for that 

 syllable fell within that square. Had the distribution of 

 records been entirely haphazard the average number in each 

 square would have been 5 per cent. The table actually shows 

 only 34 squares with 5 per cent, or more incorrect records, 

 therefore only 9 per cent, of the incorrect cases occurred 

 with a frequency equal to or greater than the probability 

 corresponding to a perfectly haphazard distribution of records. 





