DEVELOPMENT OF THE IDEA OF MEASURE. 203 



ty-seven inches, and each inch defined as the thickness of 

 six barley- grains. Thus one of the earliest measurements 

 of a degree comes down to us in barley-grains. Not only 

 did organic lengths furnish those approximate measures 

 which satisfied men s needs in ruder ages, but they fur 

 nished also the standard measures required in later 

 times. One instance occurs in our own history. To 

 remedy the irregularities then prevailing, Henry I. com 

 manded that the ulna, or ancient ell, which answers to 

 the modern yard, should be made of the exact length of 

 his own arm. 



Measures of weight again had a like derivation. Seeds 

 seem commonly to have supplied the unit. The original 

 of the carat used for weighing in India is a small bean. 

 Our own systems, both troy and avoirdupois, are derived 

 primarily from wheat- corns. Our smallest weight, the 

 grain, is a grain of wheat. This is not a speculation ; it is 

 an historically registered fact. Henry III. enacted that an 

 ounce should be the weight of 640 dry grains of wheat 

 from the middle of the ear. And as all the other weights 

 are multiples or sub-multiples of this, it follows that the 

 grain of wheat is the basis of our scale. So natural is it to 

 use organic bodies as weights, before artificial weights 

 have been established, or where they are not to be had, 

 that in some of the remoter parts of Ireland the people 

 are said to be in the habit, even now, of putting a man 

 into the scales to serve as a measure for heavy com 

 modities. 



Similarly with time. Astronomical periodicity, and the 

 periodicity of animal and vegetable life, are simultaneously 

 used in the first stages of progress for estimating epochs. 

 The simplest unit of time, the day, nature supplies ready 

 made. The next simplest period, the mooneth or month, 

 is also thrust upon men s notice by the conspicuous changes 

 constituting a lunation. For larger divisions than these, 



