IT'S amazing how many otherwise rational folk are superstitious.

They throw spilled salt over their shoulders, touch wood to avoid bad luck and refuse to walk under a ladder. Some pocket a rabbit's foot or tiny horseshoe in the hope of good fortune. And, in extreme cases, the deeply superstitious won't leave their homes on Friday the 13th of the month.

Yet, as explained by reader Mrs L. M. Feeney of Thatto Heath, an avid collector of unusual facts and figures, many of these superstitions are well grounded in ancient history.

Ever wondered, for instance, why old-fashioned window blinds often had small wooden acorn-shaped bobbins dangling at the end of their cords?

Mrs F has the answer. "The well-known precaution against misfortune - touching wood - can be traced to pagan worship of trees, a practice continuing well into the Christian era. It was believed that neither the oak nor its acorn, both sacred to the God of Thunder, could be struck by lightning".

For this reason, the acorn-style bobbins were put on blind cords... "thus protecting the house".

The ladder-dodging ritual has a more ghastly origin. "It probably has its roots in the barbaric practice of public executions", says Mrs F, "when the condemned prisoner had to ascend a ladder to the block or the noose. As a result, walking under a ladder became associated with the idea of bad luck".

And yet, avoiding walking under ladders makes sound commonsense. Who wants to risk the chance of being hit on the cranium with a workman's dropped hammer or a spilled pot of paint?

When you know the origins of some of the common superstitions it begins to make some sort of sense, says our Thatto Heath correspondent, who gives this scholarly summing up: "Superstition is a state of mind where rational faculties are paralysed by dread of the unknown. It's a belief in the absurd without any evidence to support it".

And she signs off with a swipe at modern attitudes: "I personally believe that money and education will never cure stupidity. You only have to see how some celebrities conduct themselves to know that's true!"

H ANYONE else got a peculiar superstition to tell us about?