. American highways; a popular account of their conditions, and of the means by which they may be bettered . is service need generally to be madeof peculiar strength, arranged to break up the firmestearth which can be moved at rll by such instruments. Itis likely that in time steam-power will be used for thisservice, being applied either by means of cables or bytraction engines. An engine of this description mighteasily be devised which would serve, when laden with wateror stone, as a road-roller. No considerable task of grading can advantageously beundertaken without the use of the wheeled sc
. American highways; a popular account of their conditions, and of the means by which they may be bettered . is service need generally to be madeof peculiar strength, arranged to break up the firmestearth which can be moved at rll by such instruments. Itis likely that in time steam-power will be used for thisservice, being applied either by means of cables or bytraction engines. An engine of this description mighteasily be devised which would serve, when laden with wateror stone, as a road-roller. No considerable task of grading can advantageously beundertaken without the use of the wheeled scraper, a con-trivance by which earth lifted into a scoop by the use ofthe ordinary sliding scraper can be elevated from theground, so that it is no longer dragged over the surface,but is borne on wheels. With earth broken up by the plowor by dynamite, excavation can be done by means of thisinstrument at a small portion of the cost incurred in theslower method of pick and shovel. USE OF EXPLOSIVES When the cuts are to be made in what is ordinarilytermed hard-pan, , very firm clay or other material of. MACHINES USED IN KOAD-MAKING 193 the same consistency, too compact to admit of being brokenup by the plow, the use of small charges of dynamite isexceedingly helpful in cheapening the expense of the this explosive should be applied in half-pound car-tridges in drilled holes considerably longer than the the conditions admit, these charges should be placed afew feet back from a working face of the cut, at intervals,and with a depth below the surface which experience withthe particular ground may indicate as most suitable 5 thefiring being done by a small electrical battery such as isobtained at a small cost from merchants who furnish con-tractors supplies. This method of exploding the dynamiteinsures the simultaneous action of all the charges; more-over, it diminishes the danger arising from the use of suchpowder. It is hardly necessary to say that dynamite
Size: 1427px × 1751px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1896
