Chas. V. Riley, President, in the chair. 



members present. 



Judge Holmes read letters from scientific societies in Rio Ja- 

 neiro, and Haarlem, Holland, requesting copies of the Transac- 

 tions of the Academy. These societies were accordingly placed 

 upon the exchange list. 



Mr. Wm. Lucas donated to the Academy the works of Sir \V. 

 Jones, 10 vols. 4to, and Say's American Entomology, 3 yols.. ori- 

 ginal edition. 



Mr. Nipher made the following communication tk On the Dis- 

 tribution of Errors in Numbers Written from Memory" : 



In writing logarithms which were read oft* to me, it was observed that 

 it appeared to be much more difficult to remember the figures in the mid- 

 dle of .the number than those at the extremes. In order to test this 

 point, numbers containing six digits were read to a person unaccustomed 

 to work with numerical tables. Each figure was separately named, the 

 interval between the names being the same, and all being spoken in a 

 monotone. After each number had been wholly given, the experimenter 

 immediately wrote them in proper order. The results here given are 

 obtained from 100 numbers. The whole number of errors was 125, occur- 

 ring in 59 numbers. For each 100 errors, the distribution throughout the 

 number is shown in the column e in the table below. 



Thus, out of 100 errors, 0.8 were in the digit first written. S.S in the 

 second, etc. The probability of error is greatest in the fourth digit. 



The probability in this case is the same as in the drawing of five balls 

 from an urn, containing a very large number of white and red balls in the 

 ratio of 3 to 2. In drawing five balls, six chances may occur, as shown in 

 the table above. 



According to the theory of probability, for each 100 draws, we should 

 draw all red, 1.0 time; one white and four red, 7.7 times, etc., as shown 

 in the third column. An actual experiment of 100 draws, gave the values 



