324 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



which the ichneumon is held by the ancient Egyptians. 13 

 A, May 16, 1874, 545. 



ORIGIN AND FORMATION OF DOUBLE MONSTERS. 



An elaborate paper by Dareste upon the origin and mode 

 of formation of double monsters discusses the subject in all 

 its details. He comes to the conclusion that these, among 

 the vertebrate animals, always result from the union, or more 

 or less complete confusion, of two embryos produced upon a 

 single cicatricule. Duthiers* Archives, 1874, i., 118. 



HEIGHT OF THE HUMAN SPECIES. 



M. Silberman shows that the average height of the male 

 and female population of France, taken in a certain position 

 which he names the "geometric," is 1.600040 meters, or two 

 meters if, in the same position, the hands are comfortably ex- 

 tended over the head. Two individuals laid lengthwise, with 

 fingers touching, will thus measure four meters ; and this he 

 terms the base of the harmonic proportions of the human race. 

 Thus this harmonic base is four times one meter, just as the 

 meridian is four times ten million meters, and the relation of 

 the two integers is as 1 to 10,000,000. From these consider- 

 ations he draws proof of the equality of the sexes, as they ex- 

 hibit woman, not as a complement to the male portion of the 

 race, but as constituting normally, and by right, half of the 

 human family. M. Silberman arrives at the conclusion, as the 

 result of his various investigations and studies, that the aver- 

 age height of the human race has remained unchanged since 

 the Chaldean epoch, 4000 years ago. 



THE THEORY OF ERRORS OF OBSERVATION. 



Mr. C. S. Peirce, in an interesting article on the laws of 

 errors of observation, and the nature of the so-called personal 

 equation, gives the results of some experiments made upon 

 an entirely untrained observer, a young man about eighteen 

 years of age, who had had no previous experience whatever 

 in observations. He was required to answer a signal con- 

 sisting of a sharp sound like a rap, his answer being made by 

 tapping upon a telegraph operator's key nicely adjusted. 

 Both the original rap and the observer's tap were recorded 

 by means of a delicate chromoscope, and five hundred ob- 



