From 15th July 2013 onwards the term “Post and Telegraph” service will cease to exist in India. Instead it will be only Postal Service. Starting from 1855, Electrical Telegraph service had a glorious period in India. Getting a Telegram was no ordinary incident. The service was used for sending urgent information and before the arrival of Trunk call in 1960; it was the fastest mode to send information over long distance.
But when Electrical Telegraph leaves the stage with its head held high, few will remember that India too had an Optical or Visual Telegraph line, which extended over 400 miles from Calcutta to Chunar. Some information is available in the old Gazetteers of early 20th century and few books. In this article I will try to assimilate such information and reconstruct the line of events involving the advent of Optical Telegraph in India.
The Mystery Towers
If you are driving from the heritage town of Bengal – Bishnupur to Kolkata via Kamarpukur through the Arambagh Kamarpukur road, just before Goghat Bakultala you might have noticed on your far left an old Brick circular tower of around 100 foot in the middle of nowhere. It is quite different from the Brick Kiln towers or Rice Mill Towers which falls on your way in this route. You may have also seen as many as three such towers while on train from Bishnupur to Purulia. More near to Kolkata, one such tower exists on the middle of a busy city road at Andul – Khatirbazar, Howrah.
If you take an interest and drive to this tower for taking a closer look, you will find that the four storied tower looks nearing two centuries old. The structure has both side entrance and some of them still have a brick base. The towers are totally hollow from inside with huge windows on its each side on each tier, lined up just above the entrance. There are thin rims around the circumference just below the windows in each floor. In the interior you will find circular edges on the walls on each tier, indicating the presence of a floor or platform. Looking up you will see age old wooden planks hanging from the walls. There is no ceiling in most of the structures.
There are more similar looking towers in Bengal and Jharkhand. You will find them in Bankura, Purulia, Hazaribagh and even in the Steel City of Bokaro! The towers are generally of four storied ranging from eighty to 100 feet. There are two three storied towers too, where the second floor is larger than the four storied one. Finally there are two storied towers too, but these are essentially located on top of hills. More interestingly if you plot them in a map, you will find them more or less on a straight line.
The locals have fascinating stories about these towers. The most common is that they were watch towers used to alert attacks by ‘Bargis’, the Maratha Invaders who plundered Bengal for ten years (1741 – 1751). In Bengal the towers are referred as “Girje” and the bus stop near to them are referred as “Girjatola”. In Bankura and Jharkhand locals refer them as “Machan”.It may be relevant to mention here that at Parbbatichak, one local gentleman told us a story of a “magnet’ being dug up from the base of the tower by local thugs and getting away with it!!!
However, if you go into the old colonial aged documents of Bengal and relevant books, you will find that they were not watch towers built by any Indian rulers. These were optical Telegraph towers alias Semaphore Signaling towers built by the East India Company during the period of 1816 -1828, ages after the Bargi invasion. At that period, the only way of delivering messages were through runners or by horse riders.
Advent of Optical Telegraphy in France
To discuss about the Semaphore towers in India, we need to first travel back to the end of 18th century at France. There was a rush to find out effective solutions for a faster communication. It was in 1792 when a young lad named Claude Chappe and his four brothers came out with the first practical system of Optical Telegraphy through Semaphore Signaling.
Claude Chappe gave a demonstration of his device to the Legislative assembly on 22nd March 1792. Chappe named his system as “Tachygraphe”. The system was approved and finally the plans were bought by the Government in March 1793, when there was an outbreak of war between France and England. England was backed by its allied countries. It may be worth mentioning here that the word “Télégraphe” (Telegraph) was actually suggested by Miot de Melito of Ministry of War using the Greek words “Tele”(far) and “Grafein”(to write).
Chappe’s semaphore comprised of black movable wooden arms (indicators) on the each end of horizontal beam (regulators) fixed on a 33 feet wooden post. The position of the indicators indicated alphabetic letters. With counterweights (forks) on the arms, the Chappe system was controlled by only two handles which was simple and robust. Each of the two 2-metre-long arms showed seven positions, and the 4.6-metre-long cross bar connecting the two arms had four different angles, for a total of 196 symbols (7x7x4). However, night operation with lamps on the arms was a failure.
The wooden post was fixed on brick towers erected 10 miles apart. In the next tower another operator would read the semaphore signals through a telescope and retransmit the message to the following tower. Generally the towers had basic accommodation, kitchen and toilet facilities. The timing of the operators would mainly be in the daytime.
By 1794 communications towers within line-of-sight of each other allowed the French to send a signal from Paris to Lille – a distance of some 191 kilometres in bare five minutes. Later Napoleon used this system to his advantage. He even carried with him a portable semaphore system. At the end of Napoleonic era, there was 224 semaphore stations spread over 1112 miles in France.
The Term “Semaphore” however only came into existence only in 1801, when a former artillery officer named Depillon devised a signaling system which comprised of a mast with three arms which furnished upto 301 symbols for Ship to Shore communication. It was approved by the Ministry of Marine in France. Depillon termed his signaling system as Semaphore, which in Greek meant “Bear a sign”.
Advent of Optical Telegraphy in England
The English got information of Chappe’s Optical Telegraph system in 1794. Lord George Murray proposed a system of Visual Telegraphy for the Admirality in 1796. Rev, J. Gamble proposed a machine to be used, which was ignored.
Murray intentionally built a device for signaling which was based on shutter system. He wanted to create a system which did not resemble with Chappe as there were hostile relations between France and England. Murray built a large open wooden frame to which were fitted six boards (shutters) pivoted on a horizontal axis. The shutters were controlled by pulling on ropes from inside a specially designed building surmounted by large and heavy shutter system. The buildings were 10 meter high with the shutter system adding 5 metre. The buildings were perched on the top of hills. Till date they are known as Telegraph Hills. George Roebuck, latter added more variation and a message from London to Portsmouth took only 15 minutes.
However Murray and Roebuck’s system was abandoned in 1815, as after the conclusion of the Napoleonic wars they were no longer necessary. Modeled on the basis of the 3 arm French Semaphore made by earlier mentioned Frenchman C. Depillon, Sir Home Riggs Popham devised a signaling system which consisted of single fixed vertical 30 foot pole, with two movable 8 foot arms.
Claude Chappe had always mentioned that poles and wooden post had a better visibility than shutter. It took Englishmen 20 years to understand that Popham’s model was much more visible than those of the Murray semaphore.
In 1822 Popham’s design was revised by Colonel (later General) Charles William Pasley. The new system still had two movable arms, but this time each arm could be set in one of eight positions, producing 8×8 or 64 code combinations, and of course resembling the Depillon system even closer.
Pasley’s telegraph was used to reconstruct the line from London to Portsmouth, which had been abandoned in 1816. London to Portsmouth Line was operational from 1822 until 1847. However due to rising cost of tower erection and lack of skilled operators, no further semaphore telegraph lines were being constructed.
Optical Telegraphy in India
When it was decided to rebuilt the Optical Telegraph line in England, the British had started their thought process on building up a similar chain of Semaphore based Telegraph Towers in their colonies, especially in India.
During the nineteenth century, mail was delivered in India solely by mail-runners. With a Javelin in one hand and the sack full of letters, they ran through tough terrains to deliver message. In the night they had to carry kerosene lanterns to show the way.
In 1813, it was suggested to start Visual or Optical telegraph system in India. The task was not easy as the terrain and the people were still not very familiar and favorable for the British. However, to rule a vast country like India, it was necessary to send message at a fast pace. Optical telegraph system involving sending Semaphore Signals through towers seemed the only solution. The system was intended to start experimentally only for military purpose.
Several lines were proposed based on the city of Calcutta which even included telegraph line between Calcutta and Bombay. The first such line on which survey was to be done was that between Calcutta and Chunar. Sir George Everest was given the charge on 21st October 1817 to survey a distance of around 400 miles between Calcutta and Chunar. He was assisted by Lieutenant Fergusson of Ramgarh Battalion.
Everest received information near Sherghati that he has been appointed as chief assistant to Colonel Lambton, the Superindent of Great Trigonometrical Survey of India. However Everest decided to complete his survey and then only return to Hyderabad to join Lambton. He completed his survey till Chunar and started his return journey on 16th October 1818. The line of towers were to be built through Howrah, Hooghly, Bankura, Purulia, Chas, Chandankiari, Gumia, Hazaribagh, Katkamsarai, Kanhachatti (Near Chatra), Sherghati, Dhangain pass into Gaya and finally to Chunar. This was through the Old Benaras road or the Military Road, which ceases to exist after the advent of G.T. Road.
India has a variety of Landscape. Especially from Bankura onward there are many hillocks, some of which are smaller version of mountain. Also the climate is entirely different from Europe. The British had to think of improvising their methods of building Semaphore Towers. For Manbhum (Now Purulia) and Bihar (Part of it now Jharkhand), they built up two storied towers above the Hills. The Semaphore essentially needed to be black, so that it could be visible against the sky.
The main operating station would be of course at Fort William at Calcutta. A 100 feet tower was built in 1824 to provide vantage point for providing Semaphore Signaling to ships passing by. Much later in 1881, the Calcutta Commissioner installed a huge Ball on it as a time piece for shipping. It would be raised at 12:55 hours and lowered at 13:00 hours daily to indicate the correct time. From then it is known as the Ball tower.
This tower still exits inside Fort William premises and you can see it clearly rising tall amongst the tress on your left, while getting down the second Hooghly Bridge while entering Kolkata. It is difficult to shoot it from the bus; I have to try again for a couple of times to get a perfect shot. Meanwhile my dear friend Ayan Mallick presented me with a sketch of the same, which I am sharing here.
Description of the Indian Semaphore towers
As mentioned earlier the masonry towers had two doors facing each other. On the same line of the doors, there were two windows on each floor of the towers. The doors were of the same shapes and size with one or two exceptions (displayed in photographs above). Both the windows and doors had proper frames. Remaining of window frames exists as well as edges on the wall on the ground floor entrance where a door clamp might have existed. I found circular holes in all floors, generally two in each floor. In some occasions there are four such holes too. I take these to be ventilators. Some of the window frames still exists at towers of Babudih, Aararah and Chhatna.
Inside the tower there are square holes in the walls of each floor from which you can see wooden beams hanging. In the most of the towers, there is not much remaining of the wooden planks. However in Andul and Dilakash most the wooden beams are more or less intact. If the planks at Andul are closely observed, one will find that the spaces between them are not equal. Comparing this with the structures of two ceilings, which I found intact at Parbbatichak and Satanpur Hills, I felt there may be an entry point in this area in each floor for the people to climb up.
I did not find any sign or the remains of any staircase. It may be safely assumed that ladders were used to climb up the floors. The walls were plastered both inside and outside. Many portions of the plasters exist. The most interesting is the tower inside the jungle of Tantipukur near Bishnupur. Here a huge hole has been dug almost till the internal foundation of the tower. It made me remember the fascinating but rather baseless magnet story (!) which I heard at Parbbatichak. Also the tower at Ramsagar has an interesting shape as lighting fell on it. It has cracked from inside and dense undergrowth inside prevented me from going to its interiors.Many of the towers still retained the base.Specially the Base of the Goghat Tower will give a clear idea about its structure. Thank God that there were no relic hunters in that area.
From the construction of the ceilings and the deep circular insertion at each wall, I felt that each floor was made using Surki, Clay and Lime with support of wooden beams below it. As mentioned earlier there was a square entry point in each floor. This is evident from the ceiling entrance of the two storied tower on Satanpur Hills at Dhanbad. The ceiling of Parbbatichak tower also indicates this.
An Interesting information may be mentioned here. At Satanpur, I found one tower each on the top of each of two hillocks. This is surprising as the towers were supposed to be built at least 20 km apart. However I discovered one of the towers to be a crude replica of the first, the bricks looking rather new. Locals informed it was only around 70 years old.
On the ceiling of Parbbatichak tower, one can observe in the centre of the ceiling an inserting gap from where the main mast of the semaphore was being fixed. There are interesting gaps in the ceilings, both in Parbbatichak and Satanpur Hill towers. I believe this is where clamps may have been inserted to attach the semaphores to the floor of the ceiling.
Besides this I noticed that in all towers on both side of the top floor outer walls, there are three long rectangular insertions. These insertion looks like channels dug on the wall. The middle channel is straight, while the other two are at exact opposite angular position. In many towers they are clearly visible.
There are square holes just below these insertions. At towers of Dilakash and Babudih wooden pegs can be seen still protruding out of these square holes. There are three such holes on each side of the walls just below each insertion. It seemed the ropes were tied to the wooden pegs and placed through these channels to tie up the semaphore. The channels prevented the rope from swaying in the wind and getting torn in the process.
Some of my viewers after reading the blog have suggested that there may be wooden planks instead of ropes. They have opined that the middle channel is quite wide for fixing a rope and I may also try out a digitized version of how it would have looked if there have been wooden planks. I am putting up here a rather amateurishly done digitized version with wooden planks just to give an idea.
I have not been able to find any schematic internal diagram of these towers. But after visiting 14 such towers spread over Bengal and Bihar I have made a sketch of the interiors as well as the exteriors. I am sharing first the Interior sketch.
Which Semaphore to Use ?
There were several options for the type of Semaphore to be used in India, keeping in mind its climatic conditions. The English gave a serious thought to the construction of Semaphore as can be understood from the following excerpts taken from ‘Description of the universal telegraph for day and night signals’ By Sir Charles William Pasley.
Palsey writes “A friend acquainted with effects of climate in India has recommended, that in that country, no Iron shall be used in the construction, and no wood , excepting the post, which may be of teak and the nocturnal indicator rod, and brace, which may be of bamboo. The panels of the arms and of the day indicator, to be of light copper plate. All the other parts to be of brass, or of bronze.”
Pasley further added:
“If Telegraphs were introduced into British India, or into any other of our foreign possessions, a number of military phrases and sentences, and a great number of local word and phrases would require to be introduced, which are not found in Sir Home Pophom’s Book.”
In the book “The Worldwide History of Telecommunication” by Anton. A. Huurdeman, it is mentioned that Kolkata to Chunar line had as many as 45 semaphore stations erected between them. Initially it had a semaphore system using four 1.2 m to 1.8 m Balls pioneered by one William Boyce.
There were several others inventors approaching with their system on Semaphore Invention to be used by East India Company. Among them was one Colonel Macdonald who had developed several Semaphore Telegraph systems including one Twelve board Telegraph system. He even came out with a Dictionary of Telegraph.
However his plan was rejected by The Telegraph Committee on October 26th, 1818 who commented that Macdonald’s Semaphore was extremely large instrument , too complicated in design and liable to be affected by the heat and moisture of the country. Government wanted a full proof instrument, less affected by Indian weather and easily adapted by Indian troops.
The person who drafted the letter to Colonel Macdonald representing The Telegraph Committee was the secretary of the committee, Captain G. Swiney. Swiney was an enthusiast too in this matter and he came out soon with his own Shutter Semaphore Telegraph design
On 1822, the ball system Telegraph was replaced by a system closely resembling to Swiney which had four 6 ft squares. The Semaphore line was planned to be extended to Nagpur from Chunar. I have no idea how that Semaphore system looked like. So I have designed an Indian Semaphore tower with Swiney’s Semaphore on it.
Although the Pasley Semaphore was doing great guns at England, the British Government opined that in Indian Climatic conditions six foot square will be more visible than a long wooden post with arms
Location of the existing Semaphore Towers in India
The Towers at Hooghly however took some time to be built. In the book “A brief history of the Hugli District” by Lieutenant Colonel D.G. Crawford, it is mentioned that in 1821 Lieutenant Weston was at work, building the towers required for the purpose in Hughli district. He was succeeded in 1825 by Captain Playfair, who appears to have finished the towers.” There were 6 total towers in Howrah and Hooghly. They were located in Mohiari ( Khatirbazar at Andul), Baragachia, Dilakhas (9 km from Sitapur), Haiathpur (9 miles north-east of Khanakul), Mubarakpur (at Parbbatichak on Bandar Road)and at Nabasan (Goghat). The towers of Baragachia and Haiathpur have crumbled down, while the rest still exist. I have already shared the photograph of Goghat Tower. Now I am sharing the photographs of rest three towers of Hooghly and Howrah
Further down towards Bankura, there are still five towers existing at Tantipukur jungle, Ramsagar, Salghata at Onda, Chhatna and Arrarah Village near Jhantipahari. There were two more, one of which was in Bankura town itself. Though it has collapsed long ago, still the area where it stood is known as “Machantala” at Bankura!
At Purulia, I have been able to locate only one two storied tower atop Joychandi Hill near Adra. At Jharkhand near Chandankiari, there is a four storied tower at the village of Babudih. Other hill towers which I have been able to locate are atop Satanpur Hill at Bokaro, Silwar Hill of Hazaribagh, Unknown Hillock at Pabra village near Hazaribagh and atop a high hill infested with many trees located somewhere between Kotkamsari and Itkora . I have only personally visited the Satanpur hills. Rest have been visited and photographed by my friends at Jharkhand. There are supposed to be two more hill towers at Jharkhand near Chatra and Gumia, which I am yet to locate.
Such Towers were built in the style of “Martello Towers” or simply “Martellos”, which were small defensive forts built on Hilltop in England during 19th century.
Parallel to this a Semaphore Line existed between Calcutta and Barrackpore, which was an army Cantonment. The Semaphore tower here is of three storied, which exists inside the Flagstaff Bungalow residence. You can view this tower from The Mangal Pandey Ghat at Barrackpore. To get inside the Flagstaff Bungalow premises, however you need to get permission from the Raj Bhawan, Kolkata.
The rising cost of maintaining a Semaphore line
Maintaining such a huge semaphore line was however becoming costly. A monthly expense of Rs 3,500 was being incurred in maintaining the Calcutta Chunar line. Building more towers needed more fund. Already in England itself Semaphore lines were not being extended. Besides the Shutter system was getting obsolete as the moveable arm Semaphore similar to the Pasley model was more acceptable model worldwide for its simplicity, durability and being user friendly. I believe getting a skilled operator who would sit whole day on the top of a tower in a hot humid day with eye on the telescope was becoming difficult too.
Finally the Calcutta to Chunar line was abandoned as a failure project on 1828. The fine masonry towers were abandoned. Many were broken down too.
Calcutta to Kedgree Semaphore Line
Later in 1831-1833, a semaphore line was made with 13 telegraph stations between Calcutta Exchange and Kedegree ( Khejuri). At Kedegree the Semaphore was used from the lighthouse of Cowcally (Kaukhali, a village near Khejuri). The other 12 stations were at were at Coverdale’s Tree/ Bluf (Kedgree), Mud Point, Middle Point, Lower Middle Point, Diamond Harbour House, Hooghly Point, Old Fultah Point, Lower Point, Royapore Reach, Moyapur Magazine, Powder Mills and Budge Budge Road.
In this line, two armed Semaphore adapting the Popham – Pasley system was used. It was mainly an initiative by the mercantile body of Calcutta which would help in receiving communication in town regarding the arrival of vessels within signal distance from the extremely southerly station (Kaukhali light house) within a few minutes. One Mr. Conolly was instrumental for the completion of the project.Total amount of Rs 25000 was spent by the Government in building these semaphore stations.
These towers were all severally damaged and some totally destroyed by the hurricane of 1847. The light house of Kaukhally still exists, but the village is not easily accessible. In many of these points three armed Tidal semaphores are still used to indicate the rise of the tide in the Hugli River. Although they have less significance as the whole system is computerized at present.
It may be noted here that such type of Pole Semaphore signalling were later adopted for using in Railways.
Enter Electrical Telegraph of O’Shaughnessy
The fate of optical telegraph in India was sealed when like many others experimenting on electrical Telegraph, Dr William Brooke O’Shaughnessy a 24-year-old assistant surgeon with the East India Company laid up successfully an experimental telegraph line near Shibpur Botanical Garden in the year 1839. He used bamboo for building Telegraph Posts and sent signals over a wire coated in gutta-percha (natural latex available in India), which served as insulation and enabled the wire to be placed under water. His principal assistant Shib Chandra Nandy was in charge of overseeing the actual laying of the cable.
That was only two years after Samuel F.B. Morse built his famous demonstration system in the United States. But O’Shaughnessy was unaware of Morse’s work. When the British were aware of the progress the Americans were having with electric telegraphy over cable, O’Shaughnessy’s was asked to start afresh.
Backed by Lord Dalhousie, O’Shaughnessy resulted in transmitting the first telegraph message live through electrical signals between Calcutta and Diamond Harbour, a distance of about 50 km, on November 5, 1850. This line was later extended upto Khejuri (then Kedgeree).
First Indian Telegraph Office was established in 1852, connecting Khejuri with Calcutta. Lord Dalhousie reported to Court of Directors on April 23, 1852 – “We have the honour to transmit the accompanying report from the Government of Bengal, announcing the completion, by Dr. W. B. O’Shaughnessy of the line of electric Telegraph from Calcutta to Kedgeree”.
Dalhousie authorized O’Shaughnessy to build a full trans-India telegraph. O’Shaughnessy finished it three years later and the service was opened for the general public in February 1855. The first Telegraph Act for India was the British Parliament’s Act XXXIV of 1854. When a public telegram service begun in 1855, the charge was fixed at one rupee for each sixteen words (including the address) for every 400 miles of transmission.
Later in 1857 during Sepoy Mutiny, Electrical Telegraph played a major role in saving the British from the revolting soldiers.
Khejuri was devasted in a hurricane on 1864. The town never recovered. The ruined post office of Khejuri still exists inside a jungle near the sea at Khejuri, five km from the Kaukhali village lighthouse. Both are not easy accessible. I am sharing here a photograph of Khejuri Post office taken by Arindam Bhowmik many years ago.
Many will fondly remember electric telegraph because of its immense role in public service. However the optical telegraph line was a major effort in India by the East India Company, keeping in mind the unfavorable conditions they had to work in. Though it never was used for public service and was intended mainly for military usage, it gave George Everest the required experience, which he used later in conducting the Great Trigonometrical Survey.
Although the Towers used in Great Trigonometrical Survey(GTS) looked completely different from The Semaphore towers, yet some of the later structures were used successfully for the Survey. It may be worth mentioning that the towers of Parbbatichak and Goghat were used at GTS towers.
Rebuilding of Semaphore Towers and Tourism Prospects
Some semaphore towers at Europe have been rebuilt and people can actually visit these structures, which are functional like the old days. Chatley Heath Semaphore Tower in England, Gharghur Semaphore tower at Malta and a Semaphore tower at Nalbach based on Chappe’s system at Germany are some examples.
There was a model of Semaphore Signaling at The Birla Museum at Kolkata. However, the communication department has been shut down long ago so the model is no more in display.
Could we hope of rebuilding some of the semaphore towers at Bengal and Bihar, so that our present and future generations can know about the Semaphore Telegraph line built long ago by the British as a first effort for a faster communication system? This can be an added tourist attraction too. Otherwise these historical towers will get forgotten in deep jungles and fields. Eventually they will crumble like the others.
I will be on the hunt of more existing towers and more information on them, which I will share in blog too.
Special Thanks :
1. Rangan Datta, for accompanying me to most of my semaphore tower hunting ventures and participation in tower related discussions
2. Arabinda Singha Roy for helping in locating some of the semaphore towers
3.Banani Bhattacharya for providing me with some of the gazzeteers relating to optical telegraphy in India
4.Google Maps for helping me to pinpoint locations of most of the semaphore towers
1.Communications: An International History of the Formative Years by By Russell W. Burns. (Chapter 2 : Semaphore Signaling)
2. The Worldwide History of Telecommunications by Anton A. Huurdeman (Chapter 4 : Evolution of The Telecommunications)
3.History of Telegraphy By Ken Beauchamp
(Chapter 1 : Things Mechanical)
4.Description of the universal telegraph for day and night signals By Sir Charles William Pasley
5.The Great Arc: The Dramatic Tale of How India was Mapped and Everest was Named by John Keay
6.Everest : The Man and the Mountain by J.R. Smith
7.Groundbreaking Scientific Experiments, Inventions, and Discoveries of the 18th Century By Jonathan Shectman (Page 172 -173)
8.Science, Technology, Imperialism, and War , edited by Jyoti Bhusan Das Gupta
(Chapter 5 : Technology whats is it ? BY Saroj Ghose
Subsection IV : Profile of Colonial Technologists)
9. A brief history of the Hooghly district by Lieutenant Colonel . D.G.Crawford.
10.Bihar and Orissa District Gazetteers : Hazaribagh
By E. Lister, CLE. Indian Civil Services
11.Bihar – The Heart of India by Sir John Houlton
12.History of the British Colonies: Possessions in Asia By Robert Montgomery Martin
13.Bengal District Gazetteers by L.S.S. O’Malley
14.Conquerors of Time: Exploration and Invention in the Age of Daring By Trevor Fishlock
15.Journal of the Asiatic Society, Part U : July to December, 1844
16.Gazetteer of Manbhum by Coupland, 1911
17.The Good old days of Honourable John Company By W.H. Carey(1907)
18.The Asiatic Journal, Volume 6, September to December , 1831
19.The Asiatic Journal, Volume 3, September to December, 1830
20.The Asiatic Journal, Volume 10. January to April, 1833
21. The Asiatic journal, Volume 27, January to June 1829
23.L’inventeur des sémaphores côtiers : Charles Depillon 1768-1805 by François Cabane
24.Connecting the Nineteenth-Century World: The Telegraph and Globalization By Roland Wenzlhuemer
25. Science, Technology, Imperialism, and War edited by Jyoti Bhusan Das Gupta
26. Sea – Seek Ebook Sailing guide / Guide nautique
Bay of Bengal Indian Ocean February 2013
27. Bankura Jekar Purakirti by Amiya Bandopadhyay