396 POPULAR SCIENCE MONTHLY. 



known. The pound sterling continued to be the legal standard until 

 1496, when it was superseded by the pound troy. 



King Edward II., in 1324, provided by statute that the inch should 

 have the length of 'three barley corns, round and dry, laid end to end.' 

 Of these inches 13 were to make one foot, and 36 of them one yard. 

 The length of a barley corn must have been known to be quite as 

 variable as that of the royal arm. Yard sticks were indeed kept in the 

 royal exchequer, but care in preservation seems to have been quite as 

 unknown as methods of precision in construction. 



By the middle of the eighteenth century the influence of such men 

 as Sir Isaac Newton had produced a very perceptible effect on English 

 civilization. The Koyal Society of London, chartered in 1663 and 

 including all the scientific leaders of the kingdom, recognized the 

 chaotic condition of English weights and measures; and in 1743 a 

 standard yard was constructed by one of its members, George Graham, 

 who determined the ratio of its length to that of a pendulum beating 

 seconds. This pendulum length he found to be 39.14 inches. It is 

 most unfortunate that this length was not adopted as that of the yard, 

 even if its value was not known with the utmost precision. Had the 

 inch been defined as one fortieth part of this length, and the foot as ten 

 inches, not only would the foot have been made to accord with the 

 actual length of the average masculine foot, but a decimal division of 

 it would have been established. The binary division of the yard would 

 have been maintained, and its value would have been so nearly the 

 same as that of the meter, afterward adopted as an international unit 

 of length, that identification of the British and metric units would 

 have been easy. But the people were not seeking ideals. Graham's 

 yard was constructed for the Royal Society and there is no evidence of 

 its adoption by the government. The official standard until 1834 was 

 a brass rod made in 1570. It had been broken and mended so badly 

 that the joint was described to be 'nearly as loose as that of a pair of 

 tongs.' A copy of Graham's yard was made by Mr. Bird for a parlia- 

 mentary committee in 1758 and another in 1760, but not adopted until 

 1834. This was known as the ' imperial standard yard. ' At the same 

 time a brass weight which had been in the custody of the House of 

 Commons since 1758 was adopted as the 'imperial standard troy 

 pound.' But the avoirdupois pound was also officially recognized, the 

 difference between the two being that the troy pound was defined to 

 be 5,760 grains and the avoirdupois pound 7,000 grains. The 'im- 

 perial standard gallon' was made the official standard of capacity for 

 both liquid and dry measure. Under certain standard conditions of 

 measurement this was defined to be the volume of 10 avoirdupois 

 pounds of water, or 337.374 cubic inches. The wine gallon of 331 

 cubic inches had previously been the standard of capacity since 1706. 



