Put all the larger stones at the bottom, but before throwing in any, tamp or pound the ground at the bottom of the trench until it is solid and hard, making a good bottom for the stones to rest on, and ensuring the walk from settling or sinking in spots. Where the big root and rocks are taken out, the holes must be filled up level, and tamped solid. Rake off the largest of the gravel, and let George wheel as much of it as he can, and dump it in the trench, while Nick or you wheel in the balance. Finish the top of the gravel off with smaller sized stones, and after you have filled in about five inches, throw water on the whole with the garden hose until quite wet, and then pound the gravel down until it is compact and firm. This bed forms a good foundation for the concrete which must be laid on it about four inches thick, and well tamped.

"After you have raked off the larger gravel, take a wire sieve, with meshes not larger than four to the inch, and sift the finer gravel out, to save for the top finish. Before filling in the concrete, strips of wood having straight edges on top must be nailed to the stakes on both sides of the walk, as I showed you on the blackboard in Fig. 1, marked A A. These strips must be placed at proper grade in their length, and level across from one to the other. A straight edge made of wood, and long enough to reach over the walk, and the strips as well, must be provided, and it may be notched out as I show at X, in Fig. 1. This straight edge is to be used in levelling off the top or finishing coat, by keeping both ends on the strips A A, and moving it along lengthwise of the walk. If the top of the walk is to be below the edges of the strips, you may notch the ends, as shown, to suit whatever depth may be required."

Fred told his father he thoroughly understood the process as far as explained, and the latter then left. By this time Nick and George—and, we might add, Jessie—had wheeled into the trench quite a lot of gravel, but for the want of a proper "tamper" they had to stop. So Fred cut two pieces off a fence post, each about a foot long, and with an auger or boring tool, made a hole in the centre of the end of each, about eight inches deep, into which he inserted a round wooden handle, about three feet long. These made excellent "tampers," not too heavy for George to use. Jessie, persuaded Fred to make her "just a little one," but he told her not to use it much or her hands would get sore and too stiff to practise her music.

The strips for the stakes were prepared, nailed on, and properly adjusted, and then it was time to commence the real work. Nick had nailed some boards on three pieces of scantling about six feet long, which made a good mixing table for the concrete. This was carried up near the top end of the walk, and placed where it would be handy. A pailful of cement was put on the board, next two pailfuls of nice clean sand, and then five pails of gravel that had no stones in it larger than would pass through a ring having a clear diameter of two inches. All this gravel, sand, and cement being in one heap on the board, Fred and Nick worked at it steadily for more than ten minutes, mixing it up until the sand and cement were thoroughly and evenly blended with the gravel. Fred then sprinkled the mixture with clean water from the hose, while Nick kept shovelling it over and over until the whole was damp, but not so much so that the cement and sand were washed from the gravel. The whole mass looked like a pile of dirty stones that had just been under a light shower.

"This," said Fred to Nick, "is a very important process, for if we make the stuff too wet, it will starve the concrete by washing away the cement, and if we leave it too dry the work will be rotten and crumble away."

Fred might also have added that the proper proportioning of the materials was as essential as the proper mixing, and in this case, where we are making it one of cement, two of sand, and five of gravel—all by measurement—we must adhere closely to the rule or the walk will be uneven in texture and colour.

The concrete being properly mixed, Fred and Nick began to shovel it into the trench, spread it to about four inches in thickness, and tamped it down until the top mass looked sloppy and muddy. While in this condition, a new lot of cement mixture was made, consisting of one part of cement and two parts of sand and the fine of the gravel that had been sifted. All were mixed thoroughly while dry, and afterward wet to the consistency of thick mortar. This was spread over the concrete to about one inch in thickness and levelled down by the notched straight edge until the proper thickness and level were obtained. The surface was then ready to smooth, or "float," as the workman calls it, which always gives to the top of the work a nice, even, level appearance, and makes it solid and firm. The "floating" is done with a tool made of wood, as shown in Fig. 7, and may be finished off with a plasterer's steel float, merely to give the surface a better finish.