THE ART OF WEIGHING AM) MEASURING. 619 



aud space before which the huinaD mind shrinks back in dismay. The 

 science of the eighteeuth century sought to render itself immortal by 

 basing its standard units upon tlie solid earth, but the science of the 

 nineteenth century soars far beyond the solar system and connects its 

 units with the ultimate atoms which constitute the universe itself. 



Note A. 



The appended table exhibits the principal comparisons hitherto made 

 of the more important early English standards of length. The signifi- 

 cations of the reference numbers, and the authorities for the descriptions 

 of the standards, are as follows : 



No. 1. Standard yard of Henry VII (1490); an end measure formed 

 of an octagonal brass rod half an inch in diameter. 



No. 2. Standard yard of Queen Elizabeth (1588); an end measure 

 formed of a brass rod six-tenths of an inch square. 



No. 3. Matrix to Queen Elizabeth's standard yard (1588) ; of brass, 

 1^ inches wide, 1 inch thick, aud 49 inches long. 



No. 4. Standard ell of Queen Elizabeth (1588) ; an end measure of 

 brass, six-tenths of an inch square. 



No. 5. Standard yard of the Clock- makers' Company (1671); a matrix 

 formed by two pins in an octagonal brass rod half an inch in diameter. 



No. 6. Standard yard at the Tower ; a line measure marked on a 

 brass bar sev^en-tenths of an inch square and 41 inches long. 



No. 7. Graham's Royal Society scale (1742); a line measure, on a 

 brass bar half an inch wide, one-quarter of un inch thick, and 42 inches 

 long. Line marked E. Mem. Roy. Ast. Soc, vol. 9, p. 82. 



No. 8. Ditto. Line marked Exch. 



No. 9. Ditto. Paris half toise; marked F. 



Numbers 1 to 9 are described in the Philosophical Transactions, 1743, 

 pp. 547-550. 



No. 10. Bird's standard yard of 1758; a line measure, on a brass bar 

 1.01 inches square, and 39.00 inches long. Mem. Roy. Ast. Soc, vol. 9, 

 p. 80. 



No. 11. Bird's standard yard of 17G0; a line measure, on a brass bar 

 1.05 inches square, and 39.73 inches long. Mem. Roy. Ast. Soc, vol. 9, 

 pp. 80-82. 



No. 12. General Roy's scale; a line measure, upon a brass bar 0.55 

 of an inch broad, about 0.2-5 of an inch thick, and 42.8 inches long; 

 divided by Bird. Phil. Tnms., 1785, p. 401, and Measurement of Lough 

 Eoyle Base, p. 73. 



No. 13. Ramsden's bar, used in the trigonometrical survey of Great 

 Britain. Phil. Trans.. 1821, p. 91, and Measurement of Lough Foyle 

 Base, pp. 73-74, 



