508 



MONTHLY JOURNAL OF AGRICULTURE. 



lessens its advantajres to the agricultural popu- 

 lation ; since the vehicles which are adapted to 

 travel on a railroad cannot be used on the com- 

 mon roads leading to them, nor in the ordinary 

 labors of the farm ; while on all other improved 

 roads the same w^agons, horses and men em- 

 ployed at one season in cultivating the g-round, 

 can also be profitably employed, in their other- 

 wise idle moments, in conveying the produce 

 to a market. For these reasons, even if a rail- 

 road came to every man's door, he could more 

 economically use a good common road ; but 



The great fault in laying out our common roads, according to Prof. Gillespie, 



is our passion for straightness, to the forgetfulness of every other requisite. He 



maintains that 



since, on the contrary, the expense of the con- 

 struction of railroads must always restrict them 

 to important lines of communication (where, in- 

 deed, their value can scarcely be estimated too 

 highly) in every other situation, the greatest 

 good of the •greatest number, and the most uni- 

 versal benefits with the fewest accompanying 

 evils will be most effectually secured, by im- 

 proving (in accordance with the principles to 

 be presently set forth) the people's highways — 

 the common roads of the country. 



escape a hill a hundred feet high, it would be 

 proper for the road to make such a circuit as 

 would increase its length two thou.«and feett 

 The mathematical axiom that " a straight line 

 is the shortest distance between two points," is 

 thus seen to be practically untrue in road mak- 

 ing, and less appropriate than the paradoxical 

 proverb that " The longest way round is the 

 shortest way home." 



The gently-curving road, besides its substan- 

 tial advantages, is also much more pleasant to 

 the traveler upon it ; for he is not fatigued by 

 the tedious prospect of a long straight stretch 

 of road to be traversed, and is met at each 

 curve by a conslantlj' varied view. 



It cannot be too strongly impressed upon a 

 road-maker, that straightness is not the highest 

 characteristic of a good road. As says Cole- 

 ridge : 



" Straight forward goes 

 The lightning's flash, and straight the fearful path 

 Of the cannon-ball." 

 But in striking contrast he adds: 



" The ROAD the human being travels. 

 That on which blessing comes and goes, doth CoUow 

 The river's course, the valley's playful ■winding's, 

 Curves round the cornfield and the hills of vine8."J 

 The passion for straightness is the great fault 

 in the location of most roads in tliis countrj', 

 which too often remind us how 

 " The King of France, with forty thousand men. 



Marched «^) a /ti'/?, and then — marched dvtrn again," 

 so generally do they clamber over hills which 

 they could so much more easily have gone 

 around ; as if their makers, like Marshal Wade, 

 had " formed the heroic determination of jiursu- 

 ing straight lines, and of defyine; nature and 

 wheel-carriages both, at one valiant cflbrt of 

 courage and of science." 



One reason of this is that the houses of the 

 first settlers were usually placed on hill tops, (to 

 escape the poi.«onous miasmata of the undrained 

 swamps, and to detect the approach of the hos- 

 tile savages,) and that the first roa<i8 necessarily 

 ran fmi.i house to house. Our error consists in 

 continuing to follow these primitive roads with 

 our great thoroughfares. These original paths 

 were also traversed oidy by men, and therefore 

 very properly followed the shortest though 

 steepest route. Tracks for pack-horses came 

 next, and a considerable degree of steepness is 

 admissible in them also. Wheeled carriages 

 were llnally introduced and brought into use 

 upon the same tracks, though too steep for true 

 economy of labor with them — the standard of 

 I slojie being very ditlercnt for foot, horse, and 



* Sganzin, p. 89. 



t This proportion depends on the degice of friction assumed, a subject to be investigated in a following 

 section. J The riccolomini, i. 4 



(10-8) 



Straightness sliould always he sacrificed to 

 obtain a level, or to make the road less steep. 

 This is one of the most important principles of 

 road making, and it is the one most often vio- 

 lated. 



A straight road over an uneven and hilly 

 country may, at first view, when merely seen 

 on the map, be pronounced to be a bad road ; 

 for the straightness must have been obtained 

 either by submitting to steep slopes in as- 

 cending the hills and descending into the val- 

 leys, or these natural obstacles must have been 

 overcome by incurring a great and unnecessary 

 expense in making deep cuttings and fillings. 



A good road should wind around these hills, 

 instead of running over them, and this it may 

 often do without at all increasing its length. 

 For if a hemisphere (such as half a bullet) be 

 placed so as to rest upon its plain base, the 

 halves of great circles which join two opposite 

 points of this base are all equal, whether they 

 pass horizontally or vertically. Or let an egg 

 be laid upon a table, and it will be seen that if 

 a level line be traced upon it from one end to 

 the other, it will be no longer than the line 

 traced between the same point.s, but passing 

 over the top. Precisely so may the curving 

 road around a hill be often no longer than the 

 straight one over it ; for the latter road is straight 

 only with reference to the vertical plane which 

 passes through it, and is curved with reference 

 to a horizontal plane ; while the foi-mcr level 

 road, though curved as to the vertical plane, is 

 straight as to a horizontal one. Both lines thus 

 curve, and we call the latter oi^g straight in 

 preference, only because its vertical curvature 

 is less apparent to our eyes. 



The difference in length between a straight 

 road and one which is slightly curved is very 

 small. If a road between two places ten miles 

 apart were made to curve so that the eye could 

 nowhere see farther than a quarter of a mile of 

 it at once, its length wotild exceed that of a per- 

 fectly straight road between the same ])oints by 

 only about one hundred and fifty yards.* 



But even if the level and curved road were 

 very much longer than the straight and steep 

 one, it would almost always be better to adopt 

 it; for on it a horse could safely and rapidly 

 draw his full load, while on the other he could 

 carry oidy part of his load up the hill, and must 

 diminish his speed in d('.'<ccnding it. As a gen- 

 eral rule, the horizontal length of a road may 

 be advantageously increased, to avoid an ascent, 

 by at least twenty times the perpendicular 

 hight which is to be thus saved : that is, to 



