Uttarakhand News

Check out 3 historic survey instruments being sent from Dehradun to London museum!

The historical survey equipment that measured the height of Mount Everest for the first time will travel to London from Dehradun to be at display at British Museum. An exhibition titled ‘India’s Achievements’ will be held at British Museum in the month of September this year. A large portion of historical survey equipment that will be sent to London belong to Dehradun-based Survey of India. These instruments will be brought back to India once the exhibition ends.

3 Instruments that will be sent to London exhibition

Great Theodolite: This survey instrument weighs half a ton and requires 12 workers to move it from one place to another. Apart from determining the height of My Everest, this Theodolite also played a major role in the pioneering Trigonometric Survey of India (1818-1921).

The Great Theodolite survey instrument at display.  (Image Source)

Ramsden 100-foot chain: Invented by the British mathematician and surveyor Jesse Ramsden, the 100-foot chain was first brought to India by General William Lambton from England. The chain weighs 20 kilograms and had 40 steel bars 2.5 feet in length fitted with double hinged joints to allow for easy folding and portability.

The Ramsden chain weighs 20 kilograms and had 40 steel bars 2.5 feet in length fitted with double hinged joints. (Image Source)

Colby Compensation Bar: Built by Thomas Fredrick Colby, this compensation bar was used by Sir George Everest after rejecting Ramsden chain for surveying. Two bars, each ten feet long – made of iron and brass – are joined at the center but allowed to expand and contract freely depending on changes in temperature.

Colby compensation bar was used by Sir George Everest after rejecting Ramsden chain for surveying. (Image Source)

Apart from these three survey instruments, spectrometer used by eminent scientist CV Raman, historical telegram cable laid from Diamond Harbor to Kolkata as well as more than 200 other instruments and documents will be sent to London for display.

Inputs from Hindustan

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