426 THE VARD, PENDULUM, AND METRE. 



any kind of medium magnitude, among multitudes of 

 objects of a like species which occur in nature. Such 

 must, of necessity, be chosen among organic structures 

 of the animal or vegetable kingdom (for among inor- 

 ganic masses of whatever kind, nature presents no in- 

 stance of a mean or typical magnitude, as distinct from 

 the average of a number accidentally assembled, which 

 may differ to any extent from an average similarly taken 

 of an equal number elsewhere collected). And among 

 the former classes of objects, even were it possible to as- 

 semble and measure them in sufficient numbers to afford 

 a true typical mean, we should have no security for its 

 identity in different ages and climates. 



(7.) We are driven then, in our choice of a universal 

 standard to the selection, either of some individual ob- 

 ject, (if such there be) natural or artificial, imperishable 

 in its nature, unsusceptible of variation by lapse of time 

 or decay, and indestructible by accident or else, to 

 some ideal or resultant length or magnitude (if such 

 there be), susceptible by its definition of being as it 

 were translated into a material expression, and marked 

 out as the result of some process which we are sure will, 

 in all ages and places reproduce the same identical 

 result. And besides these qualities of invariability, in- 

 destructibility and identical reproducibility it ought to 

 possess some obvious claim to general acceptation as of 

 common interest to all mankind, or at least to all the 

 civilized portion of it : an interest from which national 

 partialities and rivalries should be altogether excluded. 



(8.) The individual human type is at once excluded 



