528 PROCESSES INFERRED FROM INDIRECT OBSERVATION 



Loeb and Koranyi. A drawing-board is made up of alternate strips 

 of metal and wood and is carefully polished so that the junction of the 

 strips is as nearly as possible indistinguishable to the touch. The 

 metallic strips are connected together in a circuit which includes a signal- 

 magnet and a metallic pencil. When a line is drawn upon the board 

 with the metallic pencil the moment at which the pencil touches or 

 leaves a metallic strip is indicated upon a cylinder of smoked paper by 

 the signal-magnet (Fig. 46) . In this way the length of line traversed at 

 any instant in the entire process can very readily be determined. It is 

 convenient to provide a ruler, firmly affixed to the board, to guide the 

 movements of the pencil and to start the line from a check or crotch 

 in the ruler, the position of which on the board with reference to the 

 nearest succeeding metallic strip has been accurately determined. 



When the relationship between the time and the extent of movement 

 in drawing a straight line is investigated in this way it is found that the 

 Autocatalytic Formula: 



log = ka(t - ti) 

 a x 



applies with remarkable accuracy, "a" being the total length of the 

 line, "x" the length of line drawn at time "t" after the motion of the 

 pencil first began, and "t," the time taken to reach the middle of the 

 line. The following is an illustrative result: 



Subject R.M.M.rf Formula: log -^ = k (t - 38.75) 



ol . x 



. x t k 



inches. 1/100 sees. 



1 10.00 0.051 



2 15.50 0.050 



3 17.50 0.046 



4 21.00 0.047 



5 ............ 22.50 0.044 



6 , ... 25.00 0.045 



7 ....... 26.00 0.042 



8 . , . . . ... . . . . 27.50 0.041 



9 29.00 0.040 



10 30.75 0.040 



11 32.00 0.038 



12 33.50 0.038 



13 35.00 0.038 



14 , . i 36.50 0.037 



15 38.00 0.037 



16 39.50 0.037 



17 40.75 0.042 



18 42.00 0.043 



19 43.50 0.042 



20 . ... . . . . . . ... . 45.00 0.041 



............. 47.00 . 0.039 



22 ..... . . . ... 48.25 0.041 



23 v * . . . . . . . 50.00 0.041 



24 . -:.'.'.'. . . 52.00 0.044 



25 V '. ."' . . ... . . 53.75 0.041 



26 :.. 55.50 0.043 



27 57.50 0.044 



28 59.50 0.049 



29 61.75 0.050 



30 



66.00 0.054 



