A Little Abney, on the level. Srsly.
(1) The abney level or clinometer, invented in the 19th century, is named after Captain William Abney of the School of Engineering in Chatham, England.
It is a hand-held instrument used by trail builders for measuring the angle of inclination of trails.
It consists of a telescope, an adjustable tubular spirit level, and a vertical scale readable in degrees.
The Winnipeg Free Press of Saturday, July 27, 1946 reported that Frank Jaeger of 352 Montrose Avenue, East Kildonan, received instruction from Lieutenant G. Duncan, a cadet instructor, in the operation of an abney level to measure the height of trees.
In case you wanted to know.
(2) The angle sextant.
When the angle of the dangle is expectant in the sextant and the light of the moon is about to make you swoon, then grab yer Abney Level and take off like a devil, my good man, faster than a snail, and try avoiding hail.
Etc.
(3) The Abner Level is an instrument similar to but cruder than the abney level.
The Abner Level is of course named after Al Capp's famous comic strip character Li'l Abner, who was known for both his naivete and virtue, i.e., uncomplicated operation and reliability, which is how the Abner Level is known.
It is sometimes even referred to as the "Honest Abner".
Much larger than the pocketable abney level, the Abner Level was nevertheless designed to be dead simple, so much so that any idiot at all could operate one.
It consists of a life-size model of Li'l Abner carved of rot-resistant wood, and is used to measure trail slope, the depth of holes and other obstructions, and as a measure of length, being exactly six feet (1.83 m) long from the soles of its boots to the top of its painted-on hair.
Its front-to-back thickness is precisely one "foo" (0.30 m), which makes it useful as a measure of both trail depth and wetness factors.
When the Abner Level is lying horizontally, then 0.12 abners or less of standing water is considered "wettish" to "mucky", 0.25 abners indicates an inconvenience, 0.50 abners defines "very messy" conditions, and 0.75 or more abners is rated as "glopulous" or even downright dangerous, depending on whether there is current and what could be living in the stuff.