This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
The holes should be a foot deep and three feet across; they may be mostly made by the plough or by the spade, as each person finds handiest. For standards twelve to sixteen feet, and dwarfs ten feet apart, gives sufficient room for them to grow in ordinary soils. It will require 226 trees of the former, and 435 of the latter, at these distances for an acre. Two persons are required to set trees where there is any number, one to hold the tree upright; shake it gently up and down to settle the soil around the roots, and when the hole is half filled, to tramp it firm; the other to shovel in the earth, the fine top soil around the roots, the subsoil on the top; broken bones and ashes may be mixed in, but no manure should be allowed to come in con-tact with the roots; if it is used, place it on the surface, around the tree. If the roots are broken or bruised, trim them with a clean cut from the underside, and if the roots are not entire, prune the top so as to establish the balance in favor of the roots.