waywiser

noun

1. An instrument for measuring distance travelled, such as an odometer, pedometer, perambulator, etc.

   “I went to see Colonel Blount, who showed me the application of the "Waywiser" to a coach, exactly measuring the miles and showing them by an index as we went along.”

   “The Emperor Rudolphus II had a curious waywiser or odometer which is attributed to Schissler.”

   “Therefore, Elector Augustus did all he could to promote the development of mechanical waywisers that would be able to do this work automatically.”

2. An instrument for determining direction (and possibly other aspects of one's travel as well).

   “Not being accustomed to this cruciform movement, I was not able, by the waywiser, to determine the real direction of the balloon, and on this account M. Robertson suffered to escape a considerable quantity of gas; on which we again fell till the barometer stood at 29 inches, about 50 minutes past seven.”

   “THE Waywiser is an instrument whereby a man may steer himself where there is no path, or underground, in a mine; or find his way if he have lost it.”

   “The purpose of the waywiser was to enable a navigator to keep a track of a ship's location by measuring and recording the speed and direction of its journey.”

3. (figuratively)A guide; A means of determining the direction in which to proceed.

   “We have not sought to make a treatise, but only to set up a waywiser or signpost to show the road the law is taking .”

   “In previous volumes we have often given a few words of help to the prospective reader, intended as a sort of waywiser to guide him through those pages not always possible to lighten by some memorable illustration .”

   “This is the research question. This is the waywiser.”