Sextants are navigating instruments extensively used on ships before the invention of GPS (Global Positioning System). The word sextant refers to the actual arch of the frame, which occupies one sixth of a circle. Through the viewing scope two images can be seen with the half -silvered split mirror. The upper image is of the sun & the lower one of the horizon. The arm is moved to zero, which is the starting position. It is then moved until the sun sighted through the mirror half of the glass was brought down to touch the horizon. The angle of elevation could be read from the scale. Then calculations are done with log tables, which enables one to calculate longitude & latitude. |
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Our range of surveying instruments were first invented in England following the dissolution of the monasteries by Henry V111 in 1539,the new owners favoured by the king needed to have their land demarcated. Levelling is the art of finding a line parallel to the horizon at one or more stations, to discover how much one plane is higher than another. This is essential when cutting canals & other forms of building. Allowance has to be made for the curvature of the earth during construction. Theodolites were first invented in the mid-16th century. They are regarded as the most important of the surveying instruments, because they can measure at the same time horizontal angles between two points and their angle of elevation. |
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With the help of a compass navigation on a ship is possible. A bearing of visible objects can be taken to fix a ship's position on a sea chart. The needle of a compass is magnetised by stroking it with a soft magnetic iron ore, known as lodestone. The needles of all our compasses are set on a pivot & always settle in the direction of north. |
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Our range of telescopes is all `Refractors` which were popular during the 17th & 18th century. This means the telescopes have 2-3 lens inside the brass pipes & an objective lens at the opposite end to the eyepiece. The lenses are all positive, so the resulting image is upright. The handheld & pocket telescopes are small & compact having shorter sections of tube nestled into each other |
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All telephones shown are fully functional as normal telephones & fully compatible with modern telephone systems all over the world. They are sold with the USA style telephone jack. If the telephone is used outside the UK, an adapter can be attached for the instrument to function in the relevant country. If used in the UK we will attach an adapter so the instrument can be plugged into the wall socket. |
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The sundial was first invented in the 15th century. They were very common throughout the 17th & 18th century because all mechanical clocks required a sundial to check that it was keeping correct time. Anyone who possessed a watch was very likely to also own a pocket sundial. Since every town & locality has its own time people required a sundial or clock to tell the time. By the 1850`s this all changed because the railways needed to keep the same time all throughout a journey. So they adopted Greenwich as the standard time. After which the sundial ceased to be of any practical importance and remained merely as a decorative object. |
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All key rings are miniature versions of larger pieces. They make excellent inexpensive gifts for children. |
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This is range of different items that do not fit into any of the above categories. |
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