Taylor.] OOD [Oct. 21, 



of the French system to have lurnished such a standard for the benefit 

 of all mankind. * * * In the establishment of the French system, the 

 pendulum, as well as the meridian, has been measured ; but the standard 

 was, after a long deliberation, after a cool and impartial estimate of the 

 comparative advantages and inconveniences of both, definitively assigned 

 to the arc of the meridian, in departure from an original prepossession in 

 favor of the pendulum." A writer in the Edinburgh Review for January, 

 1807, remarks: "Three different units fell under the consideration of 

 these philosophers, to wit, the length of the pendulum, the quadrant of 

 the meridian, and the quadrant of the equator. If the first of these was 

 to be adopted, the commissioners were of opinion that the pendulum vibra- 

 ting seconds in the parallel of 45 degrees deserved the preference, because 

 it is the arithmetical mean between the like pendulums in all other lati- 

 tudes. They observed, however, that the pendulum involves one element 

 which is heterogeneous, to wit, time ; and another which is arbitrary, to 

 wit, the division of the day into 86,400 seconds. It seemed to them better 

 that the unit of length should not depend on a quantity, of a kind differ- 

 ent from itself, nor on anything that was arbitrarily assumed. The com- 

 missioners therefore were brought to deliberate between the quadrant of 

 the equator, and the quadrant of the meridian ; and they were determined 

 to fix on the latter, because it is most accessible, and because it can be 

 ascertained with the most precision" {Edinburgh Review, Vol. ix, p. 379).* 



That this selection was wise at the time it was made, cannot be doubted. 

 That it would be wiser now to select the equator, can, perhaps, be made 

 equally evident. By the modern methods of electro-magnetic determina- 

 tion of longitude, an arc of the equator could now be ascertained with as 

 much accuracy, as one of a meridian, and perhaps with even greater pre- 

 cision. A national, or what would be far nobler, an international com- 

 mission, liberally endowed with every needed equipment, for measuring 

 in South America, and in Africa, arcs of the equator — if possible entirely 

 across either continent ; and also (what would be very important) one 

 through the opposite island Borneo — is an enterprise due to the enlightened 

 spirit and scientific progress of the age, and would be one worthy of the 

 united wisdom and resources of the three greatest nations of the world. 

 The determination of the precise figure and dimensions of our globe — that 

 fundamental problem of practical astronomy — is one of such transcendent 

 importance, that no outlays should be regarded as injudicious or misap- 

 plied that would ofler the prospect of even a slight improvement in the 

 accuracy of our results. 



The equator is, in the first place, undoubtedly the true girth and measure 

 of the earth ; and the circumference should always be understood to be 

 this natural measure, unless otherwise specified. In the next place, the 

 meridian not being a circle (owing to the polar flattening of the earth) no 

 two degrees of its quadrant have exactly the same value ; which renders 

 the estimates of its degrees exceedingly awkward. According to the com- 



* See note C, page 360. 



