I10                 The Meafure of the Eart1).

    found above a minute more or lefs than it ought to be, and which ofttn
    alfo happened within about 5 feconds of the juft account, fo that
    it was not necef~ary to carry a bigger Inflrument, of wxhich it was
    otherways impoffible to make ufe in fevcral occurrences.

                        ARTICLE              r I.

    T  H E diftance which was propofed to be meafured from Xalvoifine
    1T  to Sourdon,is found as'txxere parted into three Linesto w it, frot
    Malvoi/ne to MareWiil, from Maresil to Clermonf, and from Clermont
    to Sourlon. Thefe particular diftances were known by the means of
    13 Triangles, represented in the firif Figure of the 1&cond Plate.
    There were two of them which needcd no particular Obfervation,
    fo that one may account but i i principal Triangles, the other
    which are represented in the fecond Figure of the lamie Plate, ha-
    ving chiefly ferved for the verification. Here follows the lift of
    Stations and precife Places to which Obfervations have been made
    for formin, the Triangles.

    A Is the middle of the Mill of Villejuive.
    B The nearell Coin of the Pavillion of Juvify.
    C The point of the Steeple of Brie-Comte-Robert.
    D The middle of the Tower of Montlelhery.
    E The top of the Pavilion of Malvoifine.
    F A piece of Wood fir up purpofely on the top of the Raines of tke
      Tower of Monjay, and made larger with Straw tyed a/out it.
   G The middle of the Hil~ock of Mareuil, where 'twar veceJary to make
      a Fire for a mark.
   H  7The middle of the great Pavilion in the Oval of the CaJile of Damr
      martin.
   I The Steeple of S. Samfon of Clermont.
   K The Mill of Jonquiers near Compiegne.
   L The Steeple of Coyvrel.
   M A little Tree upon the Mountain of Boulogne near Montdidier.
   N The Steeple of Sourdon.
   O A little forked Tree upon the But of Griffon, near Villeneuve
      S. Georges.
    P The Steeple of Montmartre.
    Q_7 he Steeple of St. Chriftopher's, near Senlis.
    A B Is the fr/? Baft afiualy meafured, of 5663 Pabi/aln Toyf0es.
    X Y  Is a jecond Bafe of 3902 Toyfes, aqually meafured as the
    former.

      It can't be imagined that 'twas poffible to place a large Quadrant
   at the point of Steeples, and of fuch other Places as we made choice
   of for forming exadly the Triangles.
      But that we might have a remedy for this, we always had a
   care to obferve the apparent thicknefs of Objedfs towards which
                                                                 we