Bernoulli, Drums and Tails

Bernoulli in Kochi(?)

The autumn of 1912. The big ocean liner ‘Olympic’ was cruising in the high seas when the much smaller ship ‘Hawke’ approached fast along a parallel trajectory. The two ships were a few hundred meters apart when something shocking happened: ‘Hawke’ suddenly veered from her path and seemingly drawn by an irresistible force, went straight at ‘Olympic’ and despite the best efforts of her crew to steer her away, rammed the liner. The damage to the ‘Olympic’ was severe. An enquiry held the captain of ‘Olympic’ responsible for the accident…. But the true reason lay in the real and very powerful attraction that can occur between ships at sea. It is but a fairly simple instance of the Bernoulli’s principle, an important basic result from fluid and gas dynamics….

Examples of Bernoulli-driven phenomena abound. Indeed, a fairly moderate water current of 1 meter/ sec can exert a potentially fatal pull of 30 kilogram weight on a man. A train running at a mere 50 km/hour can pull someone standing by the track with a force of 8 kilogram weight. But despite all the evidence, most people don’t seem to know nearly enough about this principle. So….

That was a slightly edited sample from Yakov Perelman’s ‘Physics for Entertainment’ (Malayalam version).

There is a lot of debate online and elsewhere about last week’s Fort Kochi boat collision that took 10 lives. But I saw no one pondering/approaching experts with this question: Did (a lack of proper awareness of) Bernoulli play a major role in this disaster? Was it all about the poor shape of the ferry that sank and the negligence of the crew?

Drums that Sing and Drums that Talk

S K Pottekkat’s short novel ‘Kabeena’ was where I first heard about the African ‘Drum Telegraph’ – use of drums to relay messages over very long distances. But the best description (known to me) of this unique technology is again due to old Yakov P (who also tells us that using drums for communication was not a uniquely African innovation; it was known to Polynesians and Central Americans):

In 1915, British archaeologist Hazelden was visiting the town of Ibada deep inside Nigeria. Throughout the day, he could hear drum beats from far and near keep up a persistent background noise. One morning, he saw some local Africans clustered in a heated and animated discussion. On enquiring, he was told: “A message arrived just now: Big ship carrying white people sank, many died”. Hazeldon did not take what he heard seriously but three days later, he was stunned to receive a cable on the sinking of the ‘Lusitania’. The Africans had heard the news right; and they had got it relayed down an immense chain of drummers stretching all the way to Cairo in Egypt from Ibada; moreover, the drummers belonged to different tribes who often spoke mutually unintelligible languages - and some of these tribes were even engaged in war with one another!

My reason for quoting Perelman on drums is as follows:

In the last post here, I put up a visual of an idakka player sculpture from Hampi and speculated a bit about the historical evolution of this much-loved Keralan drum. A few days back, I encountered, with some surprise, in a DK volume on musical instruments, the Japanese drum ‘tsuzumi’: “a small waisted drum; the player grips with one hand the cords that join the wide heads and squeezes or releases the cords to vary the note” (very like the Idakka, but smaller).

And right next to the tsuzumi was the picture of another cord-adjusted drum, this time from Africa: “The Kalengo from Nigeria is renowned for its ability to ‘talk’; the cords enable the drummer to raise and lower the note and the drum produces the sounds of a typically tonal African language (in tonal languages, the pitch at which it is uttered determines the meaning of a word)”.

And searching Wiki, one found the article: ‘Talking Drum’.

John F Carrington, in his 1949 book The Talking Drums of Africa explained how African drummers were able to communicate complex messages over vast distances. Using low tones referred to as male and higher female tones, the drummer communicates through the phrases and pauses, which can travel upwards of 4–5 miles. This process may take eight times longer than communicating a normal sentence but was effective for telling neighboring villages of possible attacks or ceremonies. He found that to each short word which was beaten on the drums was added an extra phrase, which would be redundant in speech but provided context to the core drum signal. For example, the message "Come back home" might be translated by the drummers as: "Make your feet come back the way they went, make your legs come back the way they went, plant your feet and your legs below, in the village which belongs to us"(**)

So, one could sum up: with adjustable drumheads, our idakka sings while its African cousin talks(***).

A Tale of Tails

Thanks to someone I have often mentioned here, I have known Sukumar Ray’s nonsense masterpiece ‘Abol Tabol’ for a very long time. Although my Bengali is too ill-equipped to enjoy Sukumar’s richly idiomatic and idiosyncratic verse, I have come to know one of his most distinguished creations fairly well - Sri. Hunkomukho Hyangla, he of the eternally grumpy disposition and blessed with a remarkable pair of identical tails. And just the other day, (thanks to Prof. C.S.Jayaram) I encountered the contemporary Italian artist Tullio Pericoli and a rather curious drawing of his showing a beaked Humpty-Dumpty like figure perched atop a big 'A'. Although curious affinities to Bosch, Bruegel and some other medieval surrealish (not surrealist, since surrealism, as a movement, is only about a century old) Masters were felt, I was most struck by the pair of tails the figure possesses. Here are both Herr Hunko and the unnamed Tullio apparition, placed side by side.



-----------------

(*) Wikipedia has quite a bit to say about the Olympic-Hawke collision but never mentions Bernoulli.

(**) In a vague sense, all that stuff reminds me of the curious language of ‘Tlon, Uqbar and Orbis Tertius’, a language with only impersonal verbs and no nouns and that expresses “Moon rose over the river” as “Upward behind the on-streaming, it mooned”

(***) Perelman also shows us the picture of a (curiously black-skinned) Fijian (Polynesian) 'drum communicator' in action. His instrument is a big object carved out of a log and it does not seem to have frequency adjusting cords and stuff. Perhaps this drum achieves tonal variations when struck at different spots - like the 'musical pillars' seen in several South Indian stone temples.