STANDARD - Survey Instrument Antique Center!

234
Plain Polar Plaiiimeter.
This Planimeter is of German silver, with adjustable tracer arm fully graduated,
about 9 inches long, in polished mahogany box with proving bar.
Price of instrument when rated ... .
not rated but with all the improvements
Precision Plaiiimeters.
. . $31.00
27.00
These Planimeters are very much more accurate than the ordinary Polar Planimeters.
The graduated rollers do not touch the paper at all, but roll, instead, on a
hard, highly polished surface of steel, thus eliminating all errors due to the irregularities
of the paper surface.
No. 1O9. Large Suspended Ball Plaiiimeter.
Not kept in stock.
This instrument is capable of doing very accurate work. The tracer arm is 11|
Inches long, the pole arm is 6 inches long, and the diameter of the toothed circle on
the pole is 6 inches. The angular motion of the tracer arm is about 90.
Surfaces from 2 x 4 inches to 7 x 10 inches can be measured without moving the
pole.
Price of instrument complete packed in morocco box . . . $75.00
No. 11O. Large Rolling Ball Planimeter.
The Planimeter illustrated above is made of German silver and
bronzed brass, and enables to obtain results of greater accuracy than
any other Planimeter yet made, both on large and small surfaces The
tracer arm is graduated throughout and has a length of 12 inches which can
be increased by a lengthener to 22 inches. Its angular motion is about 00
Ihe two rollers are made of exactly equal diameters, ensuring a motion of the
instrument, as a whole, in a straight line. A surface of any length and a width of
20 inches can be measured with the 22 inch tracer arm.
Price of instrument, with testing bar enabling to check areas
of known radii, and table of settings, in velvet-lined morocco box
with lock
$9O.OO