act, tains of Peru antly lost incloud t team often o  , ted one of t nearly impossible terrains on Earto tado —“muced”—and t most certainly is. t only to scale some of t cains—mountainst defeated even t to reacains to ford , nearly all of it unced andfar from any source of supplies. But Bouguer and La Condamine tenacious, and tuck to task for nine and a ered years.

    Sly before concluding t, t a second Frenceam, takingmeasurements in nortable discomforts of to dangerous ice floes),  a degree  longer near ton y-ters stouter op to bottom around the poles.

    Bouguer and La Condamine t nearly a decade o t o learn no t even t to find it. Listlessly, ted t t Frenceam . till notspeaking, turned to t and took separate ships home.

    Sometured by Ne a plumb bob ain ain, affected by tain’sgravitational mass as . If youmeasured tion accurately and  tain, you couldcalculate tational constant—t is, ty, kno th.

    Bouguer and La Condamine ried t C ed by botecies and tion laydormant for anoty years until resurrected in England by Nevil Maskelyne, tronomer royal. In Dava Sobel’s popular book Longitude, Maskelyne is presented as a ninnyand villain for failing to appreciate t ed to  mentioned in  least foro ain of sufficiently regular so judge its mass.

    At y agreed to engage a reliable figure to tour tiso see if sucain could be found. Maskelyne kne sucronomer and surveyor C to measure an astronomical event of great importance:

    t Venus across tireless Edmond ed y