THERE is an old joke that it takes four men to drink a pint of Herefordshire cider - two to hold the man down and one to pour it down his throat.

In reality, the potent brew made on Herefordshire farms for centuries had a special place in the affections of the people. Cider was widely held to promote longevity and some children were baptised in it.

The true measure of the drink's popularity came in 1763 when the government of the day introduced a tax of four shillings on a barrel of cider or perry.

There was uproar - effigies of the Prime Minister, Lord Bute, were burnt in market squares.

The tax was levied for just a few years but it did great damage. Agriculture moved on as farmers turned their attention to the plough and orchards became neglected.

Enter Herefordshire-born Thomas Andrew Knight (1759-1838), for many years president of the (later Royal) Horticultural Society, the most distinguished horticulturalist of his age.

Knight, who spent much time among his family's orchards at Wormsley and Downton, sparked new interest in the county's traditional beverage.

In 1797 he published his Treatise on Cider describing each stage of production. This was followed in 1811 by his masterpiece Pomona Hereford-iensis describing locally grown varieties of cider apples and perry pears.

Stunning coloured engravings of the varieties by William Hooker, the top botanical artist of the day, made the reference book a work of art.

The book is now rare - a copy that has just come on the market through a county bookshop is being advertised globally for almost $10,000.

Meanwhile, cider and perry are enjoying a revival but old orchards remain vulnerable and traditional varieties of fruit in danger of being lost.

Enter a merry band of men and women known as the Marcher Apple Network, who are doing much to conserve this part of Herefordshire's heritage.

With their latest project they have turned to very modern means to enable a wider public to appreciate this heritage at the click of a mouse. They have put Knight's Pomona Herefordiensis and four other hard-to-obtain reference works on cider apples and perry pears on a CD.

It is a great companion to the network's first CD (released in 2005) of the Woolhope Club's Herefordshire Pomona of the 1880s, which depicted table fruit and some cider varieties.

Like the first CD, the illustrations on the second are a joy to behold. In the case of Hooker's evocative colour plates in Knight's Pomona it is because of their realism.

They show beauty up to a point but they also show scabby fruit, larvae-ravaged foliage and woolly aphid-clad twigs. In its day this was considered quite a departure from the norm - realism to a degree not previously dared in an expensive plate work.

Today, the images seem refreshingly down to earth, a unique reminder of the bounty of the Herefordshire countryside over many generations.

We can sip a cider to that.