Why would anyone want to bury a horse's head or skull under the floor of his or her house? Or more than one? Often quite a serious number? This is one of the questions arising from a splendid book issued by the Institute of Irish Studies at Queen's University Belfast, with authors from many sources and not only Ireland.

From Corrib to Cultra, a series of essays in folk-life, is in honour of Alan Gailey, who has retired as the second head of that great institution, the Ulster Folk and Transportation Museum at Cultra, Co Down.

It is a museum, of course, with a difference - most of it open-air, with, for example, a rural schoolhouse taken down and reassembled in toto there in Co Down. The cover picture is a handsome white-painted house, cobbled yard and handpump, all neat and tidy just as it was when it left Drumnahunshin, Co Armagh.

An article by Eurwyn William gives acknowledgement to the work of Sean O Suilleabhain, which linked the practice of burying horse skulls in churches with a view to improving their acoustics, to the same practice in many houses which were found to have been used for dancing and music-making.

But, according to the article, this was a secondary motive - rationalising a basic, primary notion of foundation sacrifice designed to keep the house safe from evil.

The author quotes Scandinavian reasoning that the skulls were buried under threshing floors to improve the echo and let the sound of solid threshing be heard by neighbours. Well, Alan Gailey added Northern Ireland examples to the lists.

A great number of such houses are from Wales. When a house in Wales was rebuilt in 1870, 40 horses' heads were taken from under the floor of what originally had been a hotel. A case for acoustic reasons?

All very mundane, but the writer of the article has his doubts, and quotes a woman under whose house five skulls came to light, that while she didn't believe in some of the superstitious theories about the real reason for these skulls "you never know what can happen, so we decided to rebury the skulls".

And who would fault her?

From Corrib to Cultra, £9.50 stg. Much more worth looking at, including an article on Francis Joseph Bigger: Donegal bothogs for summer transhumance, and other subjects. Why Corrib? Well, Gailey had a connection with that lake. Makes a good title too.