earth sciences - geology, geography, ecology, weather

 

Navigation Instruments

The Compass

It was the discovery that lodestone could be used to magnetize small metal pins that would always point north that led the development of the compass.  That, in turn, led to a means of navigating ships on the high seas.  Dead Reckoning is a means of determining position by knowing your starting point, what direction you are traveling and the length of time traveled.  Columbus used it to navigate his ships across the Atlantic and discover America.

compass

compass keychain - compass key chain

metal compass

Black Plastic Compass/Thermometer Key Chain Quality Metal
Black Plastic Compass
1.5" face, housed in a black snap-lid plastic case with loop for chain attachment
  No. EP420-BK.  Only $2.95
Compass/Thermometer Key Chain
Two dial type indicators float in liquid filled chambers - direction and temperature.
  No. EP420-KC.  Only $4.95
Quality Metal Compass
Protective lid and needled stop lever to lock in the direction reading and protect the needle from bouncing during jarring activities.  
  No. EP420-MT.  Only $7.95

The Astrolabe

The compass requires that you know your starting point.  The Astrolabe doesn't.   Developed in the early 16th century, it is used to determine your position by the stars.  Used by the great explorers and even today it's very useful for astronomy, surveying and map-making.
astrolab to learn navigation Astrolabe Kit
This fascinating 7" x 6" is used to measure angle of sight.  Used extensively in making real scientific measurements of declination, altitude and azimuth of celestial bodies, to observe the  in order to motion of the earth, and to measure, slope, strike, dip, elevation of geological features.
  No. EP420-AL.  Only $12.95