299
certain localities where again others are only found, it becomes necessary, in orderthat all may be equally well served, that an interchange of these commodities shouldtake place, so that the whole country may participate equally in the enjoyment anduse of those things which would otherwise be confined to only certain districts.Thus, we may have in one part of a country huge forests, stocked with various kinds oftimber; in another, extensive tracts of fertile land, capable, if properly cultivated, ofyielding supplies of corn and other produce, sufficient for the support of a densely-populated country; in a third, mineral treasures, coal and iron, or the more preciousmetals; in another, stone, well adapted for the construction of houses, and for otherbuilding purposes: and yet, with all these latent treasures dispersed throughout thecountry, of what avail would they be, unless the means were possessed of conveyingthem to every part of the land, and thus distributing to all what would otherwise beenjoyed but by a few ?
It is not, however, only for the purposes of its own internal trade that good meansof communication are required; they become even more necessary, to insure anextensive commerce with foreign countries, to enable the peculiar produce of theseveral districts to be brought together to those parts of the coast which have beeneither naturally or artificially formed into ports, and then again to distribute toevery part of the country the goods brought in exchange from foreign lands, com-prising frequently the necessaries as well as the luxuries of human life.
And further, good means of internal communication are essential for the properdefence of a country (whether island or continental) against either the attacks offoreign aggressors or civil tumults, rendering a much smaller standing army neces-sary for this purpose than would otherwise be required.
Such being the case, it will not be a matter of surprise that, from the earliestperiods, and in all nations having any pretensions to civilization, the establishmentand improvement of the means of internal communication has always been regardedas a consideration of primary importance ; and one which has engaged the highesttalents of the Military or Civil Engineer , the result of whose exertions, devoted to theaccomplishment of this object, has been the perfection of common roads, railways,and canals.
It is not necessary to enter into the comparative merits or advantages of theseseveral means of communication, in order to establish the importance and necessity ofcommon roads. For although, under certain circumstances, it might be questionablewhich of the three would be the best adapted for serving the tract of countrythrough which it was to pass, there are an innumerable number of cases in whichonly the common road could be advantageously employed. Railways and navigablerivers or canals may be regarded as the arteries of traffic; while common roads aresimply the veins or smaller ramifications through which the means of conveyancearc carried into every nook and corner of the land. It would be quite impracticableso to intersect any country with canals or railways as to obviate the necessity ofcommon roads, or to make the former universally supersede the latter.
The formation of a perfect general system of railway communication necessitatesthe construction of several new common roads, in order that towns situated at somedistance from the nearest line of railway may fully participate in the benefits to bederived from it.
Before entering into practical details on the construction of such roads, it will bedesirable to explain the manner in which a person should proceed in exploring atract of country for the purpose of determining the best course for a road, and theprinciples which should guide him in his final selection of the same.
Let us suppose that it is desired to form a road between two distant towns, a and n,