Weighing Machines

Aravind Adiga, in The White Tiger, describes the weighing machines that are a common sight on Indian railway platforms – the ones where you insert a coin and lights flash and wheels whir and there is an almighty clanking and then, in something of an anti-climax, the six-foot tall machine spews out a little cardboard chit with a picture of an actress and your weight in kilograms. Adiga claims:

Two kinds of people use these machines: the children of the rich, or the fully grown adults of the poorer class, who remain all their lives children.

The generalization is more catchy than accurate. These machines are used by many, many people outside of Adiga’s two categories. And sometimes, they are even used for purposes other than weighing oneself.

When we were interning in Bombay in the summer of 2008, Lahiri returned to our hostel one afternoon with a thick bunch of cardboard chits in his hands and a manic glint in his eyes. I pressed him for the story, for I knew there had to be one (there always is when Lahiri is involved).

With many an expletive and animated gesture, Lahiri told his tale. It turned out that he had wanted to weigh a suitcase. The weighing machine at Grant Road station struck him as ideal for the purpose, and he accordingly directed his footsteps thither. It was but the work of a moment to hoist the suitcase onto the platform and insert a one-rupee coin into the slot. After the usual spectacle of flashing lights and whirring wheels, it spat out the ticket: 16 kg.

It was then that Lahiri made his big mistake. Wanting to be sure, he inserted another coin. Lights, wheels, ticket: 3 kg.

In a deranged frenzy, he fed in coin after coin into the machine, and each time he got a different figure. When he finally ran out of one-rupee coins, he had accumulated at least twenty tickets ranging from 2.5 to 17 kg.

Lahiri wanted to use the arithmetic mean to estimate the suitcase’s real weight, but there were a couple of outliers at the lower end of the range, so I suggested that we eliminate them using Chauvenet’s criterion before computing the mean.

So, to Adiga’s two categories, we may add a third: Obsessive-compulsive interns who want to weigh a suitcase, and have way too much small change.