The Abney Level Useful for simple slope profiles, horizon diagrams and height measurements Eyepiece Scale (in degrees) Level bubble Rotating Arm. : http://slideplayer.com/slide/4508172/
Many Abney levels will feature items such as stadia and will have a feature to focus items at different distances. Some even have a magnification feature. Abney levels are easier to use and inexpensive. They are used to measure degrees, percent of grade and topographic elevation. The user can then determine height, volume and grade through manipulating the readings with trigonometry. : http://www.engineersupply.com/Hand-Levels-and-Abney-Levels-and-Dumpy-Levels.aspx
This is one of the popular instruments of the surveyor''s kit. It is not a precise instrument by any means, angles of slope are read to within two minutes, in the larger size, and to within ten minutes in the smaller size. : http://www.xnatmap.org/adnm/ops/specs/raftrain/chaps.htm
Abney level surveying : http://www.nzdl.org/gsdlmod?e=d-00000-00---off-0hdl--00-0----0-10-0---0---0direct-10---4-------0-1l--11-en-50---20-about---00-0-1-00-0--4----0-0-11-10-0utfZz-8-00&a=d&cl=CL2.14.6&d=HASH5653c08b1d2b731918158f.3.3.3
How to Use an Abney : http://forest.mtu.edu/pcforestry/resources/studentprojects/StephenJesse/mapping_files/Page483.htm

Technical Details

Product Details

Package Dimensions
Width : 3.54 inch
Height : 1.77 inch
Length : 6.3 inch

Shipping Weight: 0 ounce (View shipping rates and policies)

ASIN : B01NCHO4NS

Product Description

Circle Diameter : 30mm
Measuring Range Angle : +90°~0~-90° (Min. Grad.1°)
Incline : +45~0°35''; 1:1~1:100
Vernier Graduation : 10''
Plate Vial : 20''/2mm
Instrument Size : 130mm(5-1/4'')×56mm×29mm