Chumbak Mani, described in Brihad Vaimanika Sastra by Maharshi Bhardwaja around 4000 BCE, was ancient land mine detector, which emits electrical signals to find hidden arsenal inside ground, while flying or moving above.
Bharadwaj, was father of Garga and Drona (Guru of Pandavas and Kauravas in Mahabharat). He lived for many years and was also contemporary of Emperor Bharata (he was son of Dushyanta and ancestor of Pandavas and Kauravas. On his name, India was called Bharat-Varsh).
Bharadwaja is one of the Saptaṛṣis (Seven Great Sages or Rishis) in the present Manvantara; with others being Atri, Vasiṣṭha, Viswamitra, Gautama, Jamadagni, Kaśyapa.
Chanakya, who lived around 1600 BCE, mentioned Bharadwaja Maharshi in one of his works about politics and economics, Kautilya Arthashastra.
Bharadwaja is also credited with many instruments such as Dhvanta Pramapaka Yantra : Spectromer.
Chumbak Mani, the ancient land mine detector, was made of two electrodes and a liquid (to propel it as a fuel or to charge it).
It emits electrical signals, which detect any material which is hidden underground while the airplane is on its flight.
Chumbak Mani, mentioned in sutra No 47-50 of Vaimanika Sastra, is made by mixing equal amounts(10g each) of the following ingredients, and then firing in the furnace at desired
temperature Fe3O4 , sand, borax, ivory, pippali, mercury, parvan ( mixture of equal amount of K2CO3 and KCL) copper, ranjik (shinguraf), sonamakhi, gridhanik, sauri, Buffalo’s nail, VishwaKapal (buffalo’s head).
These materials are to be washed several times with water and dried at 40oC. These were to be then grinded in a grinding machine for 24 hours. These mixtures were to be taken in recrystalised alumina crucible
and heated in the furnace. Temperature was to be raised slowly to 1250oC. When on the top of the molten liquid bluish flame type started appearing, the entire material was poured into a flat container and allowed to cool down.
It is very necessary to heat the sample till the dancing of blue type flames appear on the top of the liquid in crucible. This is mentioned as NETRAMILAN.
Finally the liquid was to be poured into a flat plate for cooling. After cooling two phases were visible and could be separated easily. One part has shining dotes. This part was magnetic. Other part was non magnetic. About 25% of material was magnetic and this part has been referred in the book as Cumbakmani, because it glows like Mani (Jewel).
Such a flux technology was known to ancient seers.
Vaimanika Sastra was recompiled by Swami Brhammuni Parivarjak around 1860 CE.
It mentions various types of aeroplanes and types of food pilot has to take, while flying them.
3 Professors working on Nanotechnology at Chemistry Department, IIT Bombay, Mumbai could replicate Chumbak Mani from available texts.