C 41 3 
although both the rod^ and the pendulum with a 
bob, may be divided into such equal parts, that a 
given number of those parts, shall approximate the 
length of the common or English foot, within less 
than the lOOGOth part of an inch, yet the former is 
preferable, as a standard, because it is susceptible 
of more correct mechanical division than the latter. 
Sir Isaac Newton’s computation of the length of 
a pendulum, to vibrate seconds of time at the com^ 
pletion of the 45th degree of latitude, as stated by 
Mr, Jefferson, is 39. 14912 inches English meas¬ 
ure, and as a rod, to vibrate seconds in the same 
latitude, must be one half longer than the pendu¬ 
lum, the length of such a rod will be 58. 72368 
inches English measure. If this rod be divided in¬ 
to 587 -j equal parts, as Mr. Jefferson proposes, in 
that part of his report, where he supposes the pre¬ 
sent measures of length might be retained for the 
United States, each part will be so very nearly one 
tenth of an English inch, that 120 of these parts, 
tvill not exceed the English foot in length, more than 
the 1330th part of an inch ; but In that part of hi^ 
report, where be supposed a decimal series in meas¬ 
ures of length, capacity and weights might prevail, 
he proposes a division of the rod, into five equal 
parts, and that one of these parts should be deemed 
the American foot, or unit, from whence our meas¬ 
ures of length and capacity should be deduced, 
such a foot would be equal to 11. 744736 inches 
English measure, and the American inch would be 
