DEVELOPMENT OF THE IDEA OF MEASURE. IGl 



hypotheses that have been ventured, on discorering that all 

 measures o^ extension and/brce originated from the lengths 

 and weights of organic bodies ; and all measures of time 

 from the periodic phenomena of either organic or inorganic 

 bodies. 



Thus, among linear measures, tlie cubit of the Hebrews 

 was the length of the forearm from the elbow to the end 

 of the middle finger ; and the smaller scriptural dimensions 

 are expressed in hand-breadths and spans. The Egyptian 

 cubit, which was similarly derived, was divided into digits, 

 which were finger-hreadths ; and each finger-breadth was 

 more definitely expressed as being equal to four grains of 

 barley placed breadthwise. Other ancient measures were 

 the orgyia or stretch of the arm,s^ the ^:>ace, and the palm. 

 So persistent has been the use of these natural units of 

 length in the East, that even now some of the Arabs mete 

 out cloth by the forearm. So, too, is it with European 

 measures. The foot prevails as a dimension throughout 

 Europe, and has done since the time of the Komans, by 

 whom, also, it was used: its lengths in different places va- 

 rying not much more than men's feet vary. The heights 

 of horses are still expressed in hands. The inch is the 

 length of the terminal joint of the thumb j as is clearly 

 shown in France, where ponce means both thumb and inch. 

 Then we have the inch divided into three barley-corns. 



So completely, indeed, have these organic dimensions 

 served as the substrata of all mensuration, that it is only 

 by means of them that we can form any estimate of some 

 of the ancient distances. For example, the length of a 

 degree on the Earth's surface, as determined by the Ara- 

 bian astronomers shortly after the death of Haroun-al-Ras- 

 chid, was fifty-six of their miles. We know nothing of 

 their mile further than that it was 4000 cubits ; and whether 

 these were sacred cubits or common cubits, would remain 

 ioubtful, but that the length of the cubit is given as twen- 



