SABINE’S EXPERIMENTS. 35 
recently, to the determination of the length of the seconds pendulum in 
London and in Paris, by processes of great ingenuity and refinement. The 
interest with which these researches have been regarded has not been con- 
fined to Europe; it has prevailed especially in the United States, where the 
object has been justly considered—not merely of scientific value, but of na- 
tional importance ; and as such has excited the solicitude, and already a 
considerable portion of the attention of the Federal government. . 
Viewed in its connexion with national measures, the accurate determina- 
tion of the length of the Pendulum becomes of the first importance ; since 
it affords the only method yet known of identifying a‘standard, of recovering 
it if lost, and of transmitting it with certainty to the most distant posterity. 
Whatsoever may be the unit of linear measure in different states, whether 
assumed as a supposed aliquot part of the terrestrial meridian, as in France, 
or derived from accident rather than design, as in Great Britain, or originat- 
ing in a purely arbitrary assumption, it must be alike dependent on the Pen- 
dulum for its verification. 
It may be expected, therefore, that as governments shall be successively 
excited to place the measures of their respective dominions on a fixed and 
invariable basis, the length of the pendulum, vibrating some definite portion 
of time at a convenient place in each territory, will be determined by ex- 
periment, as a natural standard of reference and comparison for the na- 
tional scale. | 
The only states of Europe in which such experiments have hitherto been 
made, are those which have been already named ; the methods by which the 
determination has been effected in the two countries, differ from and are 
independent of each other; it is not necessary, on this occasion, to notice 
their respective merits, further than to observe that a high degree of skill 
and delicacy is. required in conducting them, and that their execution has 
afforded an adequate and very admirable display of these qualifications. 
There is a third mode, however, the accuracy of which is far less depend- 
ent on the skill of the conductor, by which, when the length of the pendu- 
lum, vibrating as above, has been ascertained at any one place, by either of 
the preceding methods, its relative length at any other station may be made 
