This section is from the book "The Gardener V2", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
Seeing how well these succeed as standards, especially in the more southern counties, it is scarcely advisable to generally devote much wall-space to them. Where, however, space is plentiful, or where they do not succeed in the open, they will most probably be found profitable on south and west, and, in favourable localities, even north and east walls. The most appreciated are the different Gages, and these require warm positions to properly ripen their fruit. Green Gage, M'Laughlin's Gage, Purple Gage, and Transparent Gage are all deserving of a place on either west or south walls; and the same may be said of Oullin's Golden, Jefferson, Washington, Guthrie's Late Green, and Reine Claude de Bavay - all being good dessert varieties. In this district, and in other southern gardens, I have found Washington, Kirke's, Jefferson, Oullin's Golden, Coe's Golden Drop, Reine Claude de Bavay, and Ickworth Imperatrice of dessert varieties; and Orleans, Magnum Bonum, Victoria, Pond's Seedling, Early Rivers, Goliath, and Prince of Wales - cooking varieties - succeed admirably on walls of east and north-east aspects.
We have several dessert varieties on a wall here with a north-west aspect, and although they crop fairly well, the quality is generally inferior.