During the preparation of this investigation of Standard Measures a large
number of authorities were examined, including the following: Kelly’s
“Universal Cambist,” Maunder’s “Weights and Measures,” “Encyclopædia
Britannica,” “Chambers’ Encyclopædia,” Williams’ “Geodesy,” Hymer’s
works, “Smithsonian Reports,” “Coast Survey Reports,” Herschel’s
“Astronomy,” etc. The only concise and clear statement I found was J. E.
Hilgard’s report to the Coast Survey on standards in 1876, which I was
gratified to find coincides with my deductions.