This section is from the book "The Gardener V1", 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.
For real comfort no garden is complete without good walks; but what constitutes a good walk is not so well understood. Well, then, a good walk should be firm, smooth, dry, and of an agreeable colour. To make a dry walk many people go to a vast amount of trouble, especially in draining, making foundations, etc. This is all time and material thrown away, for if we only look to the asphalt we find that a very small quantity of material, properly applied, will make a firm and smooth pathway. Of course the general drainage is indispensable; but if that be usually dry there is no further need, as is practised by some, for a drain under each walk. The fact is, the whole secret of a perfectly dry walk is not a dry foundation, but it is an impervious surface, which will enable you to get rid of the water at the sides, and without it percolating into the walk at all. Hence all walks and roads should be waterproof, and when they are so, a comparatively small portion of material only will be necessary to form them. Nothing is more common in going into a garden in course of formation than to find the walks excavated to the depth of 1 foot at the least, with a drain at the bottom.
This will be filled with stone, broken to various sizes, and finally be surfaced with a 3 or 4 inch layer of finely-sifted gravel. If all this material has to be purchased, broken, and put in its place, the cost per yard is something considerable; and at the last you have not a dry walk nor a firm one, for the rain sinks into it, and when the frost breaks the surface, gravel is just so much mud. To remedy this we have for many years past abandoned that system of walk-making altogether; and now we can not only produce a good path, but a cheap one at the same time. Given the plot upon which you intend to form the walk or walks; first put in your levels, that each shall fall gradually to a given point, and then, placing your line, dig the ground over one spade deep, level it perfectly from end to end, and make it as firm as possible, not only by treading it with the feet, but also by ramming it with a cast-iron rammer. When the first edging is done and made as smooth and level as a billiard-table, take a straight-edge, and with a plumb-bob or spirit-level, level across to the other side of the walk, and then proceed to make it up in the same manner.
The lining out of the walks, especially if they are curved, is a matter of great nicety, and one upon which the beauty of a walk in a great measure depends. Hence the curves must be perfectly easy and regular, and the two sides of a walk must correspond to the greatest nicety. This accomplished, proceed to lay down the verge or edging; and, be it turf, or box, or tile, the same nicety must be observed in making the two sides uniform and perfectly level. The excavation need not be more than 4 inches deep, rounding up, if the walk is 6 feet wide, 1 inch from the sides to the centre. Make the bottom quite firm and even, and then it will be ready to receive the material of the walk. The best is stone broken to the size of a walnut; but when that is expensive or difficult to procure, clinkers from the furnace, brickbats, cinders, or any hard material may be substituted, or all may be mixed together. Of course it is important that the material be broken to a regular size, and that it be free from soft dirt. Sufficient rough material being provided, select a firm piece of ground, and divide into heaps of six barrow-loads, and in the centre of each leave a hole to receive a barrow-load of fresh lime. The lime should be of the best hydraulic quality, and should be fresh from the kiln.
All being in readiness, cover the lime over with the rough material, and then pour six to ten gallons of water upon it. This will cause it to slake into fine powder, and then with more water it may be mixed like mortar into concrete, and immediately be laid down and levelled regularly, 3 1/2 inches thick - retaining the necessary rise from the sides to the centre. Smooth the surface with the back of a spade and make it perfectly level. In three or four hours, according to the "quickness " of the lime, the concrete will be getting firm, and then the fine gravel must be put on 1/2 inch in thickness, be trodden firm, made quite level, and then rolled, and the edges of the walk, or any where where the roller cannot get, must be rammed quite firm. After the first soaking rain, when the surface-gravel is washed clean, follow again with the heavy roller and rammer, and you will have a walk as firm as a pavement, perfectly impervious to moisture, and not to be injured by either rain or frost. Of course provision must be made to carry the surface-water away; but if the subsoil be light, then we have found an inch crowbar driven into the side of the walk to a yard in depth where the water accumulates sufficient to secure a quick riddance of the water, and perfect dryness.
Walks made in this manner twenty years ago are as firm, dry, and smooth as the day they were put down, and will remain so for many years to come. Recently we have made several thousand yards of walks with nothing but cinder, concrete, and a facing of gravel, and these came very cheap. One specialty in these walks must be observed, and that is, to take care that there be no lumps of lime in the concrete, as a piece the size of a walnut, on becoming slaked, would make a sad patch in the walk, which could only be mended by taking the patch out bodily and replacing it with fresh concrete, not an easy matter to do without its showing. "Walks of this kind rarely become troubled with weeds or greenness, and if they do, a sprinkling with sulphate of copper (blue vitriol), in the proportion of 1 lb. to six gallons of water, will destroy every vestige of vegetation, and improve the appearance of the walk at the same time. After saying this much, it is scarcely necessary to add that vitriol will destroy vegetation of all kinds, and therefore be careful not to allow it to extend to or beyond the verges of the walks. - Field.