An awful lot of bottled water, fizzy or still, will have been consumed in the Christmas period by cautious or public spirited drivers. The bottling of mineral waters or spring waters, whichever is the correct term, is one of the phenomena of the last few decades. Long before we knew anything about groundwater and aquifers, long before slurry was spread widely over fields and chemical sprays stormed over so much of our agricultural land, people recognised good water from bad or run-of-the-mill water.

A quick look through the latest of those fascinating Ordnance Survey Memoirs of Ireland, published by the Institute of Irish Studies at Queen's University, Belfast, reminds us of the importance given centuries ago to special wells and waters. (The memoir was written in 1839; time employed "1,115 hours, equals 123 days.") This town, as you know, is on what is now called Belfast Lough until, probably, 1637, it was Carrickfergus Lough, before that Knockfergus. Anyway, throughout the 200 pages there are frequent references to rivers and wells, the latter often described as being of medicinal value.

We are told that near the eastern side of the town, in the bed of a stream is a mineral spring of nitrous taste and possessing a purgative property. During an epidemic of dysentry about the year 1741/2, these waters "made into a posset with milk were used with extreme success, and again in 1786 when a violent flux prevailed here, it was found to be very useful". Dr Rutty, in a work on the mineral waters of Ireland, particularly noticed and recommended these waters and gave an analysis. Even as the memoir was written, an arch over the well had fallen and the well almost destroyed.

And then there was a saline spring not far away "and in strength said to be very nearly equal to the Lymington and Harrowgate waters". A third well of "sulphureous chalybeate waters" was earlier of such repute that huge crowds, in summer, resorted to it, and tents for entertainment were pitched. When the report was written in 1839 "it is now almost covered up in mud".

Other parts of Ireland had and have, their special wells, but the "cure" - water taken internally and used externally - flourishes on a considerable scale in continental countries. (This is volume 37 in the series, £8.75 softback).