70 SABINE’S EXPERIMENTS. 
if even with such skilfulness, identity is not ensured, then is the measurement . 
not invariable, and it would have no effective value as a standard, since the 
invariability of the measurement is no less important for such purpose than 
that of the length itself. The preference which appears to be generally given 
to the method of determining the length of the seconds pendulum invented 
by Captain Kater, over that of Messieurs Borda and Biot, may be principally 
attributed to the result of the former being less dependant on individual skill 
than that of the latter ; with regard to the first part of the process, especially, 
it can scarcely be doubted that the pendulum with convertible axes of suspen- 
sion affords a certain means of reproducing at pleasure a determinate length ; 
it is in the second part of the process, namely, in the measurement of this 
length on the national scale, that a proof of the identity or repetition would be 
a most satisfactory testimony; perhaps a more decisive one could not be 
furnished than by a repetition in the United States, where the artists would 
be guided in the construction of the necessary instruments, and the experi- 
mentor in the mode of employing them, solely by the report of the original 
proceedings ; the perspicuity and sufficient fullness of which would thereby 
be submitted to the tests of experience. 
It has been presumed in these concluding observations, in conformity with 
the recommendation contained in the report on weights and measures made 
by the Secretary of State to the senate in 1821, that the United States are, or 
shortly will be, in possession of a standard linear measure, which has been 
compared with the French or British scales with the utmost attainable instru- 
mental accuracy ; and if with either, then effectively with both, since the va- 
lue of each, in parts of the other, has been correctly ascertained. 
It may, finally, be observed, that bya repetition of the original experiments 
at New-York, this comparison wouid be assured; the standard measures of 
both nations would receive reciprocal confirmation ; and would descend to fu- 
ture ages as having been referred to a standard in nature, which is not only 
supposed, but has actually been proved, to be reproducible. 
