A prismatic compass is a common navigation and surveying instrument which was used extensively by the Forests Commission The compass most commonly used to run a traverse line. The compass calculates bearings of lines with respect to magnetic needle. A magnetic deviation correction was needed to convert the reading to a true bearing The compass could also determine angles between the traverse and waypoints (such as hilltop features). Commonly used for navigation. Largely replaced by modern GPS technology.Ex Army WW2 prismatic compass with leather case and strap. Rugged design and made of metal the internal compass plate floats on oil to help it stabilise The user lines up the direction of travel with the hair sightline in the fliptop cover and readings are taken through the viewfinder prism (hence the name).forest measurement, surveying, forests commission victoria (fcv)

Prismatic Compass Brass case with floating faceMK IX No.6442 Made in Australia 1941

Representative of a piece of military equipment used in both world wars.Military type prismatic compass with hinged lid and rotating glass face with luminus markings allowing the instrument to be used for night navigation. Black metal construction.compass, military

After years of precursory surveying, debate and proposals the most ambitious civil engineering project of the day, the Overland Telegraph Line, began construction in September 1870. Superintendent of Telegraphs, Sir Charles Todd led the construction through “terra incognita,” guided by the precursory surveys of John McDowall Stuart and technologies such as his prismatic surveying compass. The unknown and hostile landscape claimed the lives of several men and scores of transport animals in the dogged pursuit of telegraphic connection to the rest of the world. Completed in August 1872, the Line connected Australia to the world via telegraph wires running 3,200 kilometres from Port Augusta in South Australia, to Darwin, then connecting via submarine cable to Java and beyond. The “earth [had been] girdled with a magic chain” according to the then Governor of New South Wales, Sir Hercules Robinson. How does it work? For use in surveying, the sight vane and prism are turned up on their hinge and the instrument is held horizontally either in the palm of one's hand or on a tripod. Two small discs of red and green glass attached to the prism can be flipped down over the sight line to reduce glare. The objective is to bring the subject into the sightline created by the prism, aligning with the thread of the sight-vane until the subject is bisected evenly. Once aligned, the division on the card may be read through the prism. This reading provides the magnetic azimuth, used for calculating the bearings of distant landmarks. Circular instrument mounted in a brass case with glass window and brass lid. The compass card face four black compass points printed on mint green paper; on the underside the magnetic needle would be affixed, all held in place by a brass knob at the centre. The arched labels of "Sawtell" and "Adelaide" and the Prince of Wales feathers appear to have been affixed with adhesive which has since yellowed in the areas of application on the compass card. The compass face is printed with numbers, every 10 degrees from 10 - 360, printed in reverse indicating this compass would have once held a mirror at the sighting bracket. On one side of the brass case is a brass hinged sighting-prism, possibly of ebonite. The sighting-prism is mounted in a hinged brass bracket on one edge of the brass case. It has two flip-type filter glasses (red and green) and folds down into a retracted travelling position. A hinged brass bracket on the opposite edge would have held the sighting bracket - carrying the sighting vane and mirror - which is now missing or removed. Under the hinge is a lever, possibly related to the movement of the bracket. Underneath the brass case is an indented circle with screw threads, possibly for attachment to a tripod, and indistinguishable marks scratched into the surface.Etched on to the centre of the lid, "Sawtell ADELAIDE / No 792." Affixed to the paper compass face, possibly from separate pieces of paper, "SAWTELL / ADELAIDE" with the Prince of Wales Feathers above "SAWTELL". Underneath on remains of white tape in red: "159."surveying, compass, charles todd, overland telegraph line, telegraph

Round Compass of Alloy Material. Fold out cap with clear glass viewer. The inner top has has numerical markings 1-36. The actual compass movement also has many numerical markings & EWNS, Around the side direction indicators. Screw on attachment on side.Inscription on base,- Compass Prismatic Liquid. MK III (Aust) No 8668 - J.W.H./V. Other markings as listed in Physical Description.

Type Mark 3 black plated prismatic compass, standard issue to Army personnel during the Vietnam Conflict. Circular circumferential scale, silver with black writing, graduated from 0-64 representing hundreds of MILS. Refer item 00002 and 00002.2There is an identifying number on the rear of the compass: 333739(top)and MK.3 AUST/2 (bottom)vietnam, compass, prismatic, conflict

Hardcovered book, half leather bound with marbled paper. Formerly book number 4040 from the Ballaarat East Public Library. Contents include: new pit-saw, self-moving carriage (car), Lord Worcestor's steam engine, extinction of fires, Cameron's Soda Water Apparatus, Newton's Lectures on Astronomy, coining at the Royal Mint, mechanical geometry, lifting ships by steam, voltaic-mechanic agent, steam navigation, portable hand-mill, Brown's pneumatic engine, Bell's invention for saving lives from shipwreck, triple pump, cycloidal chuck, potato-washer, sand clock, Galvanic electricity, perpetual motion, Hadley's Quadrent, Wollaston's Night-Bolt, rope bridges, boring machinery, locomotive steam-engines, new London Bridge, naval architecture, steam and water wheel, Spencer's Patent Forge, boat with wings, ivory profile portraits, Jenning's Gas burner, Ramage's Telescope, washing machine, tallow lamp, iron masts, self regulating pendulum, prismatic compass, simple blowpipe. Includes image of Henry Brougham, and many drawings of inventions.non-fictioncar, newton, fire, shipwreck, bell, naval architecture, locomotive, ballaarat east public library, ballarat east public library, ballarat east library, henry brougham, potassium, meridian lines, pit saw, self moving carriage, lord worcestor, steam engine, cameron s, soda water, astronomy, royal mint, mechanical geometry, lifting ships by steam, voltaic mechanic agent, steam navigation, hand mill, brown s pneumatic engine, triple pump, cycloidal chuck, potato washer, sand clock, galvanic electricity, perpetual motion, hadley s quadrent, wollaston s night bolt, rope bridges, boring machinery, steam engines, new london bridge, steam and water wheel, spencer s patent forge, boat with wings, ivory profile portraits, jenning s gas burner, ramage s telescope, washing machine, tallow lamp, iron masts, self regulating pendulum, prismatic compass, simple blowpipe, bookplate

Handheld oil filled compass possibly of German military origin. Labelled 'Bezard Kompass'. Complete with leather pouch.Bezard Kompasscompass, prismatic

This type of kit was used by the Regiment for vehicular cross country navigation. The crew commander would stand in front of the vehicle with a prismatic compass and guide the driver to align the vehicle on the back bearing of the required direction of travel. The discs were set for time of day and the required bearing and the driver would watch the compass and steer so that the shadow of the gnome was on the arrow. The compass would be re-set about every half hour to adjust for rotation of the Earth. In featureless country navigation was by dead reckoning by direction travelled by compass and distance travelled from the vehicle odometer. Armoured vehicles are now equipped with GPS navigation aids rendering the sun compass obsolete Type of equipment used by the Regiment on exercisesMetal construction. One fixed and one rotatable aluminium disc with a vertical steel gnome at the centre. The lower disc is marked with bearings in mils, the upper with time of day. There is a rotatable aluminium arrow under the 2 discs. A 33 mm dia spirit level is fixed to the top disc.On spirit level "GENERAL #847"daytime use only, navigation aid

The engraving possibly relates to William Piercy Austin No 618. Enlisted 17.8.14 in 5th Batt Machine Gun Sect age 22 years 3 months. Embarked for Egypt 21.10.14 then for Gallipoli and the landing. promoted to L/Cpl 9.5.15, hospital 1.9.15 with Dysentry and then Debility. Transfer to 57th Batt 24.5.16, embark for France 21.6.16, detached to 5th Div MG School, hospital 5.7.16 with Scabies, return to duty 21.7.16, posted on strength of 15th MG Coy 4.11.16, Promoted to Sgt 4.1.17, detached to 58th Batt, promoted to Lieut 29.1.17 and transfers to 60th Batt, hospital 19.2.17 with Trench Feet, while in England recovering hospital with Abcess, rejoin unit in the field, 8.8.17, transfer to 5th MG Batt 30.5.18, discharged from the AIF 21.6.19..1) Compass, Magnetic Prismatic. Serial No 97299 .2) Povat, leather, belt mounted .1) Engraved “15th MGC AIF Lt W. P. AUSTIN”compass, leather case, military

Diver's underwater compass used by British Royal Navy clearance divers during World War ll. Originally issued to ex-RN demolition diver (frogman), PO Leslie Wade, service number RJX 162991 of the Landing Craft Obstacle Clearance Unit (LCOCU), 1939 to 1945. Wade participated in the 'Operation Overlord' D Day landing at 'Juno' Beach, Normandy, France on the 6th June, 1944, in the early hours of the morning prior to the Canadian Army task force landing. Wade was with the LCOCU team tasked with clearing anti landing craft obstacles which were destroyed by placing explosive demolition charges. note: at some stage during the day Wade was wounded by enemy mortar fire and successfully evacuated to England for treatment. This compass is a large round prismatic type compass in a substantial watertight housing designed to be worn on the lower arm (wrist area). There is a thick leather two piece strap for attaching to the arm. The compass is presumably oil filled with a rotating disc marked with the numerals 2 to 34 in mirror image characters. The compass reading is viewed through a prismatic lens attached over the fixed heading marker.The rotating disc is marked with the usual compass markings of "N, E, S, W". The disc is marked in five degree divisions with mirror image numerals indicating the "2nd to 34th" major divisions. The circular bezel surrounding the compass viewing glass is stamped "Patt 251, No 177D"compass, frogman, diver, underwater

Prismatic compas.equipment, ww2, army