GEOSPATIAL-INTELLIGENCE AGENCY, National (2004). "Handbook of Magnetic Compass Adjustment" (PDF). Archived from the original (PDF) on 2019-05-09 . Retrieved 2019-05-09. The M-73 Liquid Prismatic Compass is a robust, precision instrument of predominantly brass construction, designed to withstand the most arduous climatic conditions. Kearny, Cresson H., Jungle Snafus... And Remedies, Oregon Institute Press (1996), ISBN 1-884067-10-7, pp. 164–170: In 1989, one U.S. Army jungle infantry instructor reported that about 20% of the issue lensatic compasses in his company used in a single jungle exercise in Panama were ruined within three weeks by rain and humidity. Many modern compasses incorporate a baseplate and protractor tool, and are referred to variously as " orienteering", "baseplate", "map compass" or "protractor" designs. This type of compass uses a separate magnetized needle inside a rotating capsule, an orienting "box" or gate for aligning the needle with magnetic north, a transparent base containing map orienting lines, and a bezel (outer dial) marked in degrees or other units of angular measurement. [17] The capsule is mounted in a transparent baseplate containing a direction-of-travel (DOT) indicator for use in taking bearings directly from a map. [17] Cammenga air filled lensatic compass

Apart from navigational compasses, other specialty compasses have also been designed to accommodate specific uses. These include: The elegant blued steel needle is also engraved with 'N' & 'S' gold letters for clarity, and sits under a glass crystal which is free of any damage.William Simms inherited his fathers jewellery business in the early 1800s which was soon converted to the manufacture of scientific instruments. Some compass models come with a whistle, which can turn out to be a life savior when you find yourself in an emergency. A whistle is a survival tool that will alert fellow hikers to your predicament when you need help. In 1826, Simms joined with Edward Troughton to form the famous partnership of Troughton & Simms, dating this compass to the early 19th century.

Originally, many compasses were marked only as to the direction of magnetic north, or to the four cardinal points (north, south, east, west). Later, these were divided, in China into 24, and in Europe into 32 equally spaced points around the compass card. For a table of the thirty-two points, see compass points. Set in a mahogany case, with an attractive paper sunburst dial, divided into 90 degree quadrants and displaying 32 cardinal and inter-cardinal points, it's in very good condition with a glass crystal retained by a brass bezel, and a shapely blued steel needle engraved 'N' & 'S' in gold letters. The Suunto A-10 is a simple compass that won’t eat into your budget. It is easy to use and would make the perfect first compass for an inexperienced hiker. It comes with useful features such as a declination scale, bezel, and ruler. The compass has been constructed using scratch-resistant plastic to enhance durability. When you go looking for a field compass, you might have to decide whether you want a digital or analog model. On the one hand, digital compasses are battery-powered and need to be recharged, every once in a while, to remain useful.Not only is this Glauser MK 4 a rare compass, but it's also in excellent condition and comes complete with its leather case & most of the original service kit. The Francis Barker range of liquid filled prismatic compasses are among the finest professional compasses ever made, and are currently in use by many military forces around the world including NATO.

Gies, Frances and Gies, Joseph (1994) Cathedral, Forge, and Waterwheel: Technology and Invention in the Middle Age, New York: HarperCollins, ISBN 0-06-016590-1Made by the celebrated Manchester optician John Benjamin Dancer, son of Josiah Dancer whose business he inherited in 1835, Dancer was a scientific instrument maker who lived from 1812 to 1887 and was renowned for his many contributions to the field of optics, barometers and microscopy.

The MK VI is less common and unusual to find in relatively good condition, particularly with its centre paper label completely intact, although the anti slip ring appears to be a later replacement. It is accompanied by a leather case which is in good condition with all stitching intact and has the letters "E.V.B" impressed on one side, and on the other side is written "J R Richardson R.M" in faint pen, which would have been a previous owner, possibly in the Royal Marines. A clinometer is paramount, depending on where you plan to hike. It makes it easier to gauge the slope and determine the nature of the trail you’re about to face. If you’re hiking during winter, it might alert you to the possibility of an avalanche and help you avoid the risk. All lensatic military compasses are the same when it comes to parts and features, so your choices will be a bit limited. Your deciding factors when purchasing one are likely to be its quality, finish or appearance, and budget. This means you’ll either have to carry a portable charger or bring along a few extra batteries. On the other hand, analog compasses don’t require an external source of power. Waters would go on to release notable publications including 'The War in South Africa', ' Secret and confidential : the experiences of a military attaché', and 'Russia Then & Now'.Position the lens holder: The lens should be moved to the rearmost position, forming a 90-degree angle from the base. Lane, Frederic C. (1963). "The Economic Meaning of the Invention of the Compass". The American Historical Review. 68 (3): 605–617 [615]. doi: 10.2307/1847032. JSTOR 1847032. Always make sure that the orienting arrow is pointing to grid north (the top of the map) rather than grid south (the bottom of the map) – even if you are walking south – the orienting arrow still needs to point north.