Rail-Roads. \\Q 



divisions branched off" in different directions in search of new 

 theatres for their enterprise. Some proceeded down the river 

 to the Passo del Norte, some to the mines of Chihuahua and 

 Durango, in the province of New Biscay; some to Sinera and 

 Sinatoa, on the Gulf of California; and some, seekino- new 

 lines of communication with the Pacific, .had undertaken to 

 descend the western slope of our continent through the unex- 

 plored regions of the Multnomah and Buenaventura. The 

 fruit of this enterjirise, for the present year, amounted to one 

 hundred and ninety thousand dollars in gold and silver bullion, 

 and coin, and precious furs ; a sum considerable in itself in 

 the commerce of an infant state, but chiefly deservino- a 

 statesman's notice, as an earnest of what might be expected 

 from a regulated and protected trade. The principal article 

 given in exchange is that of which we have the greatest abun- 

 dance, and which has the peculiar advantage of makino- the 

 circuit of the Union before it departs from the territories of 

 the Republic — cotton, which grows in the south, is manufac- 

 tured in tlie north, and exported from the west. 



KAIL-ROADS. 



On a well made road a horse will draw a load of one ton, 

 in a cart weighing 7 cwt. at the rate of two miles an hour — 

 (Leslie's Elements, p. 253). The whole strength of the horse 

 is exerted in overcoming the friction. On such a road, there- 

 fore, a force of traction of 100 pounds moves a weight of 

 3,000 pounds, or the friction is l-30th part of the load (the 

 cart included). 



On a rail-way of the best construction it has been shown in 

 a former paper, that a horse travelling at the same rate of 

 two miles an hour draws 15 tons, including the vehicles. In 

 this case then a power of traction of 100 pounds moves a 

 weight of 33,600 pounds ; the friction of course is l-336th part 

 — or in round numbers l-300th part of the load. 



On a canal, a horse travelling at two miles an hour draws 

 30 tons in a boat weighing probably 15 tons*. Reducing the 

 ton to 2,000 pounds for the sake of round numbers, as in the 

 last calculation, we find here that a power of traction of 100 

 pounds moves a mass of 90,000 pounds — or the resistance 

 which the water opposes to the motion of the vessel is equal to 

 1-yoOth part of" the load or entire weight. At sea, where the 

 water-way is of unlimited breadtii, the resistance is probably 

 one-thir(I less ; but as a compensation ibr this, when steam- 



• Bouts in sonic cases carry only 1.5 or iiO tons, in others 3.5 fas the ■ 

 coal boats on the [ 'nioii Canal); hut in the one case they travel (juicker,|and 

 'n oiliei-> slower, lluin the rate nientioneil. 



power 



