Friday, August 17, 2012

Cyclic Memories - 6

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Sunday, February 22, 2009


Every dog his Day!

It's raining dogs here today!

Pet dog, Lap dog
Bull dog, Watch dog
Hot dog
Top dog
Better rear a Slumdog!


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Quite a few dogs squeezed in there!

But in 1967, our best UG Teacher in EE at IIT KGP, Prof BRR, told me one day:

"Your cycle has a dog, you know!"

That had me frisking my Webster; and how MANY dogs were there under that single item: "dog"! 

God!

After my catastrophic fall from my tricycle at 4, I stood in awe of all such pedaled vehicles.

In 1953, our seaside Village, Muthukur, had no bicycles. The entire village was an oval with the main road as the major axis less than a mile long. The highlights of the Village were the High School, Police Station, Dispensary, and the Post Office. And all were walking distance from one another. Most of the students of our School were from nearby villages and they walked in droves happily singing songs and gossiping and frolicking.

In 1955, when I was in Class IX, a young teacher, Harihara Sarma, joined the School fresh from his College; smart and friendly. My Father, the HM, was kind to him (these brahmins stick together) and permitted him to stay in his Village, Ipur, 5 miles away and commute (which was against the prevailing rules). So, he bought a brand new Raleigh Cycle with a bicycle-pump fitted to it; and he used to ride it to our school everyday dressed in impeccable white shirt and pants. He soon became our hero.

With wide-eyed admiration I used to watch him cycle down the main-road tingling his bell. Two things struck me as strange that never happened with my tricycle. 

First, he would pedal furiously for a while and then stop pedaling...but the bike wouldn't stop...it went on and on and on till the end of the road as if it were an eagle in the sky that flew without flapping his wings.

Second, he would often reverse-pedal while the bike is on the run. It would make a naughty whirring sound but never back-track...so unlike my tricycle...that was due to the dog that BRR talked about later.

Both these features mystified me no end.

When I got promoted to Class XI, which was my school-leaving year, I used to beg Harihar-sir whenever he used to visit our home, to put up his cycle on stand and let me sit on the floor and pedal it furiously with my hands and also reverse-hand-pedal to my heart's content. And he used to oblige because I was but a child of 13 and just about 4 feet tall.

Much later, at IIT KGP, BRR asked me to watch another curious thing about our running cycle-wheels...the optical pattern generated by the spokes. And as I did so he asked:

"You teach EM, no? What does the pattern look like?"  

And I got him there:

"Dipole field?"

BRR was great...as I said the other day, he was the one who asked me to run to Thackers and buy the only copy left of Jerome K Jerome's Three Men in a Boat. As it happens, that half-century-old book is still with me, and I must have read it a handful of times, and consult it often for my blogs...all the books I mention are available full-text online, but, as I said the other day, nothing beats a book since each has its own nostalgic aroma around it.

Coming to that dipole-pattern of the running cycle wheel, it took me a long while to realize that it is a Dynamic Moire' Pattern.

Talking of Moire' Patterns, I recall one more fascinating thing that I daily used to watch while walking on the Road in front of Gate # 5 at IIT KGP from the Gate to the end of the road. After crossing the Tata Steel Stadium, there are about half a dozen Y-shaped 3-storied B Type Qrs. Their front balconies had walls with tiles removed in a regular array to allow for breeze to stream through. Two of these striated walls were at an acute angle. 

On my evening walks, when the balconies were well-lit by bulbs, as I proceeded, the holes in the walls used to go in and out of step rapidly and generate a Dynamic Moire' Pattern of regular huge ghost-holes passing in succession. That was a truly great spectacle!

People over the decades tried fiddling with the basic design of the pushbike, like changing the wheel diameter ratio, the sizes of the sprockets that are connected by the chain giving various 'amplification factors', and the shape of the frame...but in vain. The pushbike resisted all such tinkering and stayed the same almost like that figure of Eve designed by God.

Hats off to the anonymous inventor of this blessed machine!



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