!) 



e 



THE GENESEE FAEMEE. 



^^J^ 



and save the load, Avhicli may be adjusted again as soon as the dangerous point is passed. 

 This principle also shows the reason why it is safer to place only light bundles of 

 merchandize on the top of a stage coach, while all heavier articles are down near tlie 

 wheels. When it becomes necessary to build very large loads of hay, straw, wool, or 

 other light substances, the "reach," or the long connecting bar of the wagon, must be 

 made longer, so as to increase the length of the load. For, by doubling the length, 



two tons may be piled upon the wagon with as much 

 security from oversetting as one ton on a short wagon. 

 Where, however, a high load cannot be avoided, 

 great care must be taken to have it ev^enly placed. If, for 

 instance, the load of hay represented by fig. 4, be skill- 

 fully built, the line of direction will fall equally distant 

 within each wheel. But a slight misplacement, as in 

 fig. 5, will so alter this line as to render it dangerous to 

 drive except on a very even road. 

 It is familiar to every one, that a body resting upon a broad base is more difiicult to 

 overset than when the base is narrow. For instance, the square block, fig. 6, and 

 pyramid, fig. 7, are less easily thrown over, than the tall and 

 narrow block of equal weight, fig. 8. Because, in turning the 

 square block over its lower edge, the center of gravity must be 

 lifted up considerably, in the curve shown by the dotted line ; 

 but with the tall narrow block, this curve being almost on a 

 level, very little lifting is required. 



Wheel-carriages owe their comparative ease of draught t';> 



the fact that the center of gravity in the load is moved forward, 



by the rolling of the wheels, on a level, or parallel with the 



surfiice of the road. Each wheel supports its part of the load 



at the hub. Hence, on a level road, the line of direction falls 



Fig. 7. Fig. 8. precisely where the wheels rest on the ground ; but if the road 



ascend or descend, it falls elsewhere ; hence the reason that it will run by its own 



weight down a slope. Whenever a stone or other obstruction occurs in a road, it 



becomes requisite to raise the center of 

 gravity by the force of the team so as to 

 throw the wheel over it, as shown by fig. 9. 

 One of the reasons thus becomes very plain 

 why a large wheel will nm more easily on 

 a rough road than a smaller one, the larger 

 one mounting any stone or obstruction 

 without lifting the load so much out of a 

 level, as shown by the dotted lines in the 

 annexed figures, (figs. 9 and 1 0.) Another 

 reason is, the large wheel does not sink 

 into the smaller cavities in the road. 

 When a load is carried on the shoulder, it should be so placed that \he line of direc- 

 tion may pass directly through the shoulder or back down to the 

 feet, fig. 11. An inexperienced person will sometimes place a 

 bag of grain as shown in fig. 12. The line falling outside hi^ 

 feet, he is compelled to draw downwards with great force on 

 the other end of the bag. A man who carries a heavy pole on 

 tiH^S^ his shoulder should see that the center is directly over his shoul- 

 Fio. 12. der, otherwise he will be compelled to bear down upon the lighter 

 end, and thus add in an equal degree to the weight upon his shoulder. 



