Measurement of a Baje on iTounfiow- Heath. 395, 
extremities of each ; and two caft-fteel pins, or axes, fuited to 5 ' 
the diameters of the holes, which ferve to conned the. adjoin- 
noo links- together. The holes in the fhort plates are made 
roughi o>r jagged with, a file ;; fo that when, they have embraced 
the ends of two- adjoining, long ones, and the pins have pafled. 
through all the holes, in rive.tting their extremities, they are. 
made perfectly fail,, and as it were united to the fhort plates 
while the embraced ends of the long ones turn freely round 
on the middle part of the pins. 
At every tenth link the joint,, juft, now defcribed, has a 
pofition at right-angles to the former ; that is to lay, the fhort 
plates lie here horizontally, and the pins palling through 
them hand vertically,. Thus, there being in the whole chain 
two hundred calf, -heel pins, one hundred, and eighty lie hori- 
zontally ; and twenty, including the two by which the han- 
dles are attached, hand vertically, Thefe crols- joints, which 
were chiefly intended that the chain might fold up in a fmaller 
eompafs, by returning upon itfelf at every tenth link, are 
likewife ufeful in prefenting a horizontal lurface,. to which 
fin all circular pieces of brafs are fcrewed, with, figures 1 , 2, 3, 
&c. to 9, engraved on them,., denoting the decimal parts of the 
length. Thus the. middle crofs-joint, or that which feparates- 
the 50th from the 5.1ft link,., is fhewn in the Plate with the 
figure 5 upon it. 
The chain, in its fir ft conftruction (for We -are now to point 
out Tome alterations that were afterwards made in it), was one 
hundred, feet in length, including the two brafs handles ; in 
the extremity of each of which there was a femi- circular hole, 
of the fame diameter with the fteel arrows fuccelfively fixed 
in the ground, and ferving to keep the account of the number 
of chains, when applied to common meafurement, In. this its 
fi r ft: 
