FARMERS^ REGISTER— BOAT BRIDGES FOR RML ROADS, &c. 



185 



onward. 'J'hat another priacipal road will be Jrom 

 this new city on the Cape ot" Florida, into the 

 great valley at" the Mississippi. This Strings me 

 back to the thoughts which put me upon this essay, 

 the errors likely to be made in the location of rail 

 roads. I jjcrccive some are designed to communi- 

 cate only between one inland water navigation 

 and another. These may prosper long enough to 

 refund their cost; but the day is not distant when 

 they will have comparatively -little value. 



Finally, as jour journal is likely to be exten- 

 sively jjreserved lor lliture reading and reference, 

 and as I am an old man, and shall hardly trouble 

 you many times more, I ask of you the I'urther 

 tavor to record a lew prophecies. 



First, fresh water navigation,, including that of 

 the Mississippi and all its tributaries, will be dis- 

 continued, probaljly within twenty years. 



Secondly, New Orleans, and all cities in un- 

 healthy situations, will greatly decline, and new 

 cities and towns spring up in more healthlul and 

 advantageous situations, and that the • queen of 

 these will be somewhere at apohitnot yet thought 

 of in the great valley. 



And thirdly, that either Boston or Halifax is 

 destined to take the sceptre Irom the highly fiivor- 

 ed city of theMsland.. 



And to conclude, again I would most respect- 

 fially hint to the men of Boston (and for this I 

 hope they will remember my children) two thhigs 

 — first, to spare no pains, nor grudge any capital 

 either in the location or construction of their west- 

 ward and southward rail roads; and secondly, to 

 turn their attention to European steam packets on 

 a large scale.. I beg pardon: Boston folks need 

 no hint from me on their own affairs. .' ' 



c. o. 



Deep Creek, Sept. 5, 1833. 



BOAT BRIDGES FOR RAIL ROAnS. 



From a Camden (S. C.) paper. 



Much apprehension is entertanied, as to the 

 ditpculfy of passing the Santee or Waferee, for 

 the want of a bridge. If the reader will refer to 

 the Journal of the Franklin Institute for June, 

 1S32, he will see the matter scientifically discussed 

 and illustrated. We add a letter from a traveller 

 who speaks of it in a familiar manner. . 



Boat Bridges. 



Extract of a letter from a gentleman wlio has recentl}^ 



travelled in Gerniany . 



" The. boat bridges on the Rhine appeared to 

 me, to be as capable of taking as gr€iat a load as 

 the Columbia bridge.* The Diligences in that 

 country, weigh, about 300.0 lbs. without a load, 

 and carry Irom twenty to thirty passengers; and, 

 on the top much merchandize, &C. . They could 

 easily take all the cars I have ever seen on- the 

 Charleston Rail Road, with all their loatl. 



" The Rhine at Cologne is very much such a 

 river as the Santee. It overflovvs in the same 

 way. At Cologne, high walls confine it. Just 

 above Cologne, the mountains begin. At Mentz, 

 the low grounds between the mountains on each 

 side ot the river commence — and so it continues 

 till you get to Basle in Switzerland. 



* For the information of strano-eis, it is well to ob- 

 serve that this bridge is built on the shoals, and that it 

 has a foundation of the very best kind. 



"These boat bridges are in various places, viz: 

 Cologne, Bonne, Coblentz, Mentz, Worms, Spi- 

 res, .Manlieim, Strasburg, &c. I have oiten 

 thought such bridges, would ■ admirably suit our 

 state. 



"Seven, eight or twelve boats are anchored in 

 tlie stream, and the anchors are secured with piles 

 of stone. The boat has a considerable (query 

 chain) cable attached to the anchor, so as to rise 

 and fall with the Mreshet. Uprights are framed 

 upon these boats, and bridges thrown across them 

 — each boat answering for a pier. A swinging 

 platform is fixed on the shore — this is connected 

 with the main bridge, by a lalling bridge, (a draw 

 bridge,) lilted up by ropes fixed on the principle 

 of the crane. In this ;way the crossing is made 

 to accommodate the rises and falls of the river. 

 Places are also made to lift up the draws or bridge, 

 to let the vessels jjass up and down tlie "river." 



RO An MAKING. 



From tlin National Intclligpiieer. 

 Replies to questions hy Mr. John Davis, dated 27th 

 Nov. 1822, front. JIagerstown. 



Line of the road. — This branch belongs to the 

 engineer, and no general directions can be given 

 respecting it; ^. . ° 



; Surface or bed of the road. — The bed of a road 

 is the soil of the country, after being made smooth, 

 and as level as circumstances, will admit. 



The great object of road making, is to preserve 

 this bed Irom wet, which assails it both from be- 

 low, and from above; the, under water is. to be 

 kept off by sitle drains, that shall always keep the 

 water of the soil some inches below the level of 

 the bed, at every season of the year, and should 

 the line be so level and low as that no sufficient 

 fall can be got to bring I he water of the soil below 

 the bed of tlie road, in such case, the bed must be 

 raised above the. level of the water. 



This principle of preserving the bed or a road 

 from lying in water, is founded on the reason that 

 if a road be laid in water, the sub-soil is kept soft, 

 and the road will surely be .pressed into it by heavy 

 carriages — and in winter the frost affects that wet 

 soil so as to lift up the whole mass — by which it is 

 loosened, and on a thaw is broken to pieces.. 

 These reasons have been ibund sufficient to induce 

 the abandonment of the former practice of digging 

 a trench, into 'which the road was placed, "^and 

 which ensured the bed of the road being wet at al- 

 most all seasons of the year. 



The wet from above is to be kept from the bed 

 by the matei-'ials (or as we term it the metal) of 

 the road, broken of stone, of angular form, skilfully 

 and careiully.laid on, forming a body so compact 

 as to be an eflectual cover or roof to prevent water 

 from penetrating from above. 



Having secured the bed or natural soil of the 

 country fi-om wet, it is of itself sufficiendy strong 

 to cany any weight; there is, therefore, no ne- 

 cessity tor the bottom or foundation, as it is called, 

 of large stones, which, if they were not injurious, 

 are objectionable, on account of the useless ex- 

 pense; but this bottom is ])ositively injurious, inas- 

 much as it is constantly shaken by heavy car- 

 riages, which keeps the upper strafimi always 

 loose and open to receive rain water. 



