158 Captain Sabine on the 



simple standard, and which is of determinate and determinable 

 magnitude, is the pendulum of a particular spot ; it being under- 

 stood that all future repetitions, designed to produce identical re- 

 sults, should be made identically at the same place. 



We consider, that Captain Sabine has gone far towards proving 

 that, in this view, the pendulum is applicable to the proposed ob- 

 ject ; that with proper precautions, and by adopting the method 

 of experimenting which he has pointed out, different observers, 

 using different instruments, may arrive with certainty at identi- 

 cal conclusions : at least so nearly identical as not to differ in the 

 fourth place of decimals of a British inch. But he has also 

 shewn (pages 213 to 233,) that the method which was previously 

 adopted, and employed in the experiments which are considered 

 by the act of parliament to have determined the length of the se- 

 conds pendulum in the latitude of London, does by no means en- 

 sure identity on repetition within the limits declared in the act ; 

 because the method is not independent of individual peculiarity, 

 or of accidental circumstance. The conviction is thus forced 

 upon us, of how essential the experiment itself of repetition is ; 

 and that it is expedient to prove that a method will produce iden- 

 tical results in other hands than the original experimenter, before 

 it is officially bequeathed for such purpose to posterity. 



The selection of a spot, the pendulum of which is to supply an 

 invariable length in perpetuity, and which will require to be re- 

 ferred to, not less by foreign nations of the present day, who may 

 desire to compare their standards with that of Great Britain, 

 than by those of more distant ages who may seek the recovery of 

 the British measures, is by no means an indifferent consideration, 

 It has happened accidentally that the original experiments were 

 made in a private house in London : a circumstance which in it- 

 self, must sooner or later have obliged their repetition elsewhere. 

 But if the length of the pendulum is affected by natural local 

 circumstances, to the amount we have stated, (and we think the 

 fact too clearly made out by Captain Sabine to be questioned,) may 

 not even artificial changes in the character of the place of experi- 

 ment produce a similar result, although in a less degree ? Can 

 we be assured that the vibrations of a pendulum, in Mr. Browne's 

 house in Portland Place, are the same now, as when, not more 

 than two centuries ago, its site was nearly a mile without the 

 limits of the city ? Nor are either of these times identical with 

 that which would be found, were the future observer compelled to 

 seek for the spot amongst masses of rubbish. Nor is this last 

 view of the subject, however improbable or distant, one that is to 

 be entirely neglected. The language, the arts, and the sciences, 

 which are the boast of Great Britain at the present day, are founded 

 upon a basis more secure than that of empire, and will exercise an 

 intellectual supremacy over future ages, should even the fate that 



