OF THE UNITED STATES. 311 



such length as to bring the top e of the signal aliout eight or 

 nine feet above the ground at g. 'Ihe tin cone is liclcl stea- 

 dy in its vertical position bv two iron wires fastened at tiie 

 lower rim aa of the cone, in diametrically opposite places, 

 and wound lound the pole, and making right angles with 

 each otlier. 



To place a signal, a hole was dug in the sroutul to the 

 depth of about three or four feet, and of proportional width, 

 and a j)ernianent mark was then placed properly centred 

 in the station. These maiks consisted of truncated hollow 

 cones of liard baked stonewaie open at top and bottom, tlieir 

 height ed equal to sixteen inches, the inner diameter at the 

 top cc equal to six inches, the lower diameter (]d equal to 

 twelve inches. They were at such a distance below the 

 surface of the ground as to be perfectly secured from acci- 

 dents arising from jiloughing, ^'c. 



Tlie signals can be pulled out of these cones perpendicu- 

 larly, and the holes filled with eartli so as to leave no appa- 

 rent mark; while at any future time the cones can be easily 

 uncovered ; and being emptied of earth, without being dis- 

 placed, they will be prepared to receive other siu;nals, 



'I'hcsc signals answered in every respect perfectly well, 

 and though constructed of apparently costlier materials than 

 rough signals, the expense attending them, with the pertna- 

 nent mark in the ground, h^z. amounted only to aliout three 

 dollars and a half each, — a sum for which no pyramid, or 

 any thing similar, could be constructed. 



In favourable circumstances, these signals appeared like 

 a stromj; luminous point, often requiring, wlien the signals 

 were near, the use of a dark glass before the eye. Their 

 form then became as distinctly visil>le as the limbs of a pla- 

 net. 



In distances ofthiity to forty miles, they presented a dis- 

 tinct luminous point, when the sun was in such a situation 

 as to reflect its rays directly to the observer, wliich time is 

 ofsuflRcicnt duration. 



2 



