3G0 



drives with the rubble foundation, in order to compare them with 

 those having Telford foundations, and they have been found to com- 

 pare favorably with them. The road gutters have been constructed 

 almost exclusively of stone blocks similar to Belgian blocks, and laid 

 upon a bed of sand one foot deep. They are much less expensive 

 than the brick gutters, will be equally as durable, and will be much 

 more easily repaired. There is but one serious objection to them, 

 and that is that a large amount of surface water is lost by passing 

 between the blocks, and thus into the ground. At this time this is 

 immaterial, as there is an abundant supply of pure water for the lake 

 with its present area, but when the lake is completed it will be ad- 

 visable to save all of the surface water possible, in order to keep it 

 supplied ; but the probabilities are that the fine silt worked from the 

 roads will, before that time, so effectually close up the crevices be- 

 tween the stones that almost no water will be lost. Should it be 

 found that too much water is lost, a very simple, cheap and effective 

 remedy will be to cover the surface of the block gutters with a light 

 layer of tar concrete. This will make a gutter that will be imper- 

 vious to water, and thus equally as effective as brick gutters. 



Several additional experiments on tar concrete drives have been 

 made. The specimen of drive laid by the Scrimshaw Patent Con- 

 crete Company, in the fall of 1867, has steadily improved since its 

 construction. During the year it has had no repairs, and no expense 

 has been put upon it except to sweep off the dust and mud brought 

 upon it by carriages from the adjacent gravel roads. It is at the 

 present time in perfect order. From experiments which I have 

 made, I have been convinced that there is no difficulty to be antici- 

 pated in making repairs either from the breaking up or wearing out 

 of the concrete material. If, from the unequal settlement of the 

 ground, or any other causes, the concrete should crack, a section of 

 it can be removed, and new material put in its place, without mate- 

 rial injury to the drive surface ; and when the surface has worn un- 

 even, as it will in time, by constant use, a new surface can be laid 

 upon the old, and the adhesion is so complete that no tendency to 

 crack is exhibited. 



Samples of the Scharf patent concrete pavement have been laid. 

 This promises well, and if it withstands the action of the frosts, it 

 will also make a good road surface. 



Later in the season a sample of the Haider patent concrete pave- 

 ment was laid on the drive. This also promises well, but time and 

 the elements must decide the merits of this or of the Scharf pave- 

 ment. The sample of Fisk concrete laid in 18G7 was almost entirely 



