Sunday 13 October 2019

Antiquity s&t objects of historical importance


Antiquity s&t objects of historical importance
One of the major events to commemorate the India - UK year of Culture was the historic exhibition “Illuminating India 5000 years of Science and Innovation” that was displayed at the Science Museum London. Our Honourable Prime Minister, Shri Narendra Modi ji, paid a visit to this exhibition recently. Nehru Science Centre had the honour to be the Nodal Agency for this exhibition and 6 antiquity objects of historical significance were sent from India for this exhibition besides 8 other non antiquity objects. These objects have now come back to India and they will be displayed for public viewing at the Nehru Science Centre just for three days from 11th May, the National Technology Day to the 13th May 2018.
A brief write up on each of the antiquity objects is given below. The Mid Day has covered in today’s paper.
CARY'S GREAT THEODOLITE
Cary’s Theodolite, an instrument that measures the angles between distant points using a moveable telescope, was the most advanced theodolite in use anywhere in the world, which was produced in the year 1830. This remarkable surveying instrument was extensively used by Lambton and Sir George Everest for the monumental Survey of the Indian subcontinent in the 19th century. This great trigonometrical survey, by triangulation method, is now etched in the annals of history as the Great Trigonometric Survey of India. This also provided the first accurate measurement of the arc of longitude -the curvature of the earth from pole to pole.
This survey helped in calculating not only the exact size of the Earth but also the height of the world's tallest mountain, the Everest, named after Sir George Everest. This theodolite, even today, is still in working condition. The boundary of India that we are most familiar with and see in the India map, was mapped by this very theodolite. In the early 1800s, the British, then ruling India, set out to make a precise map of Indian continent. With the help of this theodolite and Ramsdens’s 100ft chain, the basic surveying tool of that time, the herculean task of survey of India was completed. It took 70 long years to complete the task.
Currently this precious theodolite is under the possession and custody of the Indian Institute of Survey and Mapping, Survey of India, Hyderabad, Telangana, India
COMPENSATION BAR
The Compensation Bar is a Precision Measuring Instrument that uses the principle of thermal expansion. This very bar was used for the Great Trigonometric Survey of India in 1800's by the Surveyor general of India George Everest. It was developed by Thomas Colby the superintendent of Irish survey between 1926 to 1928. The Compensation bar that works on the principle of difference of expansion rates of metals is a precision measuring equipment made up of two equal bars, one of iron and one of brass, each being 10 feet long. The bars are firmly clamped at the middle with brass members so that they do not move. At each end of both the bars an aperture is worked out to admit a conical pivot, and the two pivots, one is the brass and the other the iron bar, are adjusted to a flat iron tongue. The bars are supported by brass rollers and enclosed in deal boxes, from which only the Tongues project. There is a Glass encased spirit level fixed at the centre, in between the two bars. The metal clamps at the centre that keep the bars fixed along the central portion and allow expansion only towards the end.
Currently this precious object is located at the Indian Institute of Survey and Mapping, Survey of India, Hyderabad, Telangana, India.
COMPOUND LEVER CRESCOGRAPH
This is a very delicate and precision instrument, which was fabricated under J C Bose's supervision by goldsmiths and silversmiths who were adept at precision work. This unique instrument was invented and used by Acharya J C Bose to measure plant growth. The instrument uses a series of clockwork gears and a carbon coated glass plate to record the movement of the tip of a plant (or its roots) at magnifications of up to 10,000. Marks are made on the plate at intervals of a few seconds, demonstrating how the rate of growth varies under varying stimuli. Bose experimented with temperature, chemicals, gases, and electricity. It is a two-tier instrument and currently a plant sample is still preserved in the system.
It is constructed with multiple materials including painted iron, brass, glass (for the plate, tubes and beaker), silk thread, wood and carbon that coat the glass plate. Additionally, an old Plant fragment and a glass beaker with Cotton are also seen with the instrument.
Presently it is not in working condition The Instrument is kept at the Acharya Bhavan (now called the Science Heritage Museum) in Kolkata and is placed inside a glass box (without a base) on a wooden stool.
OSCILATING PLATE PHYTOGRAPH
This instrument too was invented and used by Acharya J C Bose in his quest to prove that plants respond to environmental factors. The Phytograph, could amplify the oscillation of leaves for instance under different environmental conditions to record effects on them. Bose published his findings in 1906.
This Instrument is presently kept at the Acharya Bhavan (now called the Science Heritage Museum) in Kolkata. It is a precision instrument with various delicate mechanical parts which are believed to have been fabricated under Bose's supervision by goldsmiths and silversmiths who were adept at precision work.
RAMAN SPECTROMETER
It was made around 1928 or few years earlier. The functioning of this path breaking instrument was first published in the renowned international magazine, Nature, 121, 3053,711(1928). It has 6 different components, namely the Mercury Vapor Lamp, Collimating Lens, the Sample holder, the Collecting lens, the Violet Filter. The first 5 components have been mounted on a new wooden base and the Spectrometer is separate. The Sample holder and the Violet Filter are new. Today the position of the Violet Filter is yet under discussion.
There is an additional tapered glass tube with a blackened end which has been displayed with the instrument and features in a historic photography. The Raman Spectrometer is not in working condition now as the inner contraptions of the spectrometer are missing. It was originally used to identify materials that display Raman Scattering. Sir, C V Raman got the Nobel Prize for the discovery of an effect named after him in the year 1930, using this very instrument. This scattering today is known as Raman effect. Today the spectrometer is in the custody of IACS. (Indian Association for the Cultivation of Science)
RAMSDEN'S 100 FEET CHAIN
Like the theodolite it was also a basic surveying tool. The length of each link is 3.43 feet and Width – 1 feet, Depth: 0.65 feet. The chain is made up of steel. The brass plates help the folded chain to be held in place. like an enormous ruler the chain was used to measure the distance between two points. It was used to measure the distance while surveying India in the year 1830. It was invented by the British mathematician and surveyor Jesse Ramsdens. Its length was 100-feet. It 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. It requires lengthy calibration to correct the expansion and contraction it goes through due to change in temperature. moreover, it stretches with use.
Currently this object is preserved at the Indian Institute of Survey and Mapping, Survey of India, Hyderabad, Telangana, India

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