(This is the annotated version of my new column for The Hindu Business Line’s magazine BLink, published on April 4, 2014. The image is a depiction of the Konark Sun temple from James Fergusson’s 1847 text Ancient Architecture in Hindoostan. )
That the Sun Temple of Konark once contained a giant lodestone magnet, which held the entire edifice together by its force — is a story often told. And in the telling, this tale becomes taller, whence idols in the sanctum sanctorum begin to levitate, and the temple’s magnetic field is said to disorient the mariner’s compass on any ship passing in the Bay of Bengal. Or imagine, the holy magnet pulling out all the iron nails of a Chinese wooden ship causing it to fall apart. Some have even tried to explain the infamous Indian rope trick using various magnetic contrivances.
Another tall story, both incredible and uncertain, attributed to an American general named Benjamin Alvord in a letter to the poet Longfellow (circa 1842), is about a magnetic plant: “There has been discovered in the forests of India a strange plant (philotacea electrica) which possesses, to a very high degree, astonishing magnetic power. The hand which breaks a leaf from it receives immediately a shock equal to that which is produced by the conductor of an induction coil. At a distance of six metres a magnetic needle is affected by it, and it will be quite deranged if brought near. The energy of this singular influence varies with the hours of the day. All powerful about two o’clock in the afternoon, it is absolutely annulled during the night. At times of storm its intensity augments to striking proportions. While it rains the plant seems to succumb: it bends its head during a thunder-shower and remains without force or virtue even if one should shelter it with an umbrella. No shock is felt at that time in breaking the leaves, and the needle is unaffected by it. One never by any chance sees a bird or insect alight on this electric plant; an instinct seems to warn them that in so doing they would find sudden death. It is also important that where it grows none of the magnetic metals are found, neither iron, nor cobalt, nor nickel — an undeniable proof that the electric force belongs exclusively to the plant. Light and heat, phosphorescence, magnetism, electricity, how many mysteries and botanical problems does this wondrous Indian plant conceal within its leaf and flower!”
Apart from a few scattered references, the history of magnetism in India prior to the British Raj is poorly documented, much to the chagrin of science historians. That Indian sailors were already using the magnetic compass had been noted by Vasco Da Gama (circa 1497). A few decades later, while sailing near Goa and Bombay, the Portuguese naval officer João de Castro discovered magnetic declinations in his compass caused by nearby ferrous rocks. Even Sawai Jai Singh II, the astronomer-king of Jaipur — although his artistic sundials are singular — seems to have had little interest in magnetism.
The first major character in magnetism from India appears to be Jagadish Chandra Bose in the late 19th century, by whose time the relationship between electricity and magnetism had been firmly established. And for some reason Bose began to investigate the electrical and magnetic signals in plants through his invention, the magnetic crescograph. There is no public record, but one wonders whether Bose knew of that mysterious Indian plant mentioned by Alvord, the philotacea electrica. His early biographer Philip Geddes does mention a similar American “compass plant” (silphium laciniatum) in the book The Life & Work Of Sir Jagadis C Bose (1920).
More importantly, Geddes describes Bose’s spectacular experiments with radio waves: “Bose himself had as early as 1895, in a public lecture in Calcutta, demonstrated the ability of electric rays to travel from the lecture-room, and through an intervening room and passage, to a third room 75 feet away from the radiator, thus passing through three solid walls on the way, as well as the body of the chairman (who happened to be the Lieutenant-Governor). The receiver at this distance still had energy enough to make a contact, which set a bell ringing, discharged a pistol, and exploded a miniature mine.”
This ability to transmit signals through space would soon evolve with better engineering into sophisticated radar systems in the build-up to World War II, and radar — in as much as it was being used for the purpose of sea and air navigation, was really an advanced avatar of the magnetic compass. Both the radio and the compass were for Bose, ways of seeing “invisible light”, they were his prosthetic Third Eye — for visible light and radio waves were different slices of the same electromagnetic spectrum.
Bose’s vision is both romantic and eloquent, he writes: “From amongst the innumerable octaves of light, there is only one octave, with power to excite the human eye. In reality, we stand, in the midst of a luminous ocean, almost blind! The little that we can see is nothing, compared to the vastness of that which we cannot. But it may be said that out of the very imperfection of his senses, man has been able, in science, to build for himself a raft of thought by which to make daring adventure on the great seas of the unknown.”
- The Life & Work Of Sir Jagadis C Bose (1920) by Geddes
- João de Castro, the Portuguese officer and scientist is notable in this regard:”..the comments made by João de Castro are the most important record of values of magnetic declination in the Atlantic and Indian oceans, in the sixteenth century, and useful for the study of terrestrial magnetism. He made 43 determination of magnetic declination through rigorous measurements of geomagnetic declination over the entire circum-Africa route. The instrument used by him was the Bussola de Variacão, also developed by Felipe Guillen a decade earlier in Seville. João de Castro undertook many observations and can in a way be considered as one of the discoverers of crustal magnetism. He discovered spatial variations of Declination in that Bay of Bombay (near Baçaim), which he attributed to the disturbing effects of underwater rock masses (this is near where the large basaltic and rather strongly magnetized Deccan traps outcrop). In the 1890s, G. Hellman, quoted by Chapman and Bartels (1940), considered Castro to be the most important representative of scientific maritime investigations of the time, and the method he tested was universally introduced on ships and was used until the end of the sixteenth century."
- On The Compass Plant by Benjamin Alvord
- Silphium Laciniatum, the compass plant: Wikipedia
- Gautam Pemmaraju asked if there were some ancient sources for magnetism and I found this from Magnetism In Medicine: A Handbook by Nowak & Andra: