Book II. CANALS. 551 



ment, has secured to himself, and will it should seem (from a comparison of the great 

 features, and minutiae of execution in this the first canal, with most others in this country, 

 even of the latest construction,) long continue to hold that rank among the English en- 

 gineers, to which Riquet seems entitled among foreigners. 



3532. Since the duke of BHclgewaters time the extension of canals in the British isles 

 has been rapid. A number of scientific engineers have arisen, of whom we need only 

 mention Smeaton, Rennie, and Telford, and point to the Caledonian canal. 



Sect. II. Of discovering the most eligible Rout for a Line of Canal. 



3533. The first object when the idea of a canal is determined on by a few landed pro- 

 prietors, is the choice of a skilful and experienced engineer. Such an artist should 

 undoubtedly possess a considerable degree of mathematical knowledge. Calculations, 

 of which some are of the most abstruse and laborious kind, will frequently occur ; and 

 he should, therefore, be well acquainted with the principles on which all calculations 

 are founded, and by which they are to be rightly applied in practice. An engineer 

 should also have studied the elements of most or all of the sciences immediately con- 

 nected with his profession ; and he should particularly excel in an acquaintance with 

 the various branches of mechanics, both theoretical and practical. His knowledge 

 should comprehend whatever has been written or done by other engineers, and he should 

 have information in every department of his office, from an accurate examination of the 

 most considerable works that have been executed in all the various circumstances that 

 are likely to occur. It is necessary that he should be a ready and correct, if not a 

 finished, draughtsman. He should also be conversant with the general principles of 

 trade and commerce; with the various operations and improvements in agriculture; 

 with the interests and connection of the difierent owners and occupiers of land, houses, 

 mills, &c. ; and with all the general laws and decisions of courts, pertaining to the ob- 

 jects connected with his profession. By an extensive acquaintance with the disposition, 

 inclination, and thickness of the various strata of patter which compose the soil or 

 land of the British islands, he will be able to avoid many errors incident to those who 

 are destitute of this knowledge. As the last, though not the least, of these qualifica- 

 tions of an engineer, which we shall enumerate, he should be a man of strict inte^ 

 grity. 



3534. A proper engineer being fij:ed upon, the adventurers should not tie him down too 

 closely, by restrictions as to time, but allow him leisure to consider, digest, and revise 

 again and again, the different projects and ways, which will naturally in most instances 

 present themselves to him in an extensive and thorough investigation, The engineer 

 should be allowed to choose and employ the most competent assistants, and to call in 

 and occasionally to consult the opinions of eminent or practical men, as land-surveyors, 

 agents of the neighboring landed property, the principal and most expert commercial 

 men of the district and who are best acquainted with its trade and wants, any eminent 

 miners, &c. &c. ; and such men the engineer should be authorised liberally, and at once 

 to remunerate for their -services and intelligence. Previous to the beginning of any 

 minute survey or system of levelling, the engineer ought to visit personally, and endea- 

 vour to make a just estimate, and preserve memorandums of all the objects within the 

 district under consideration ; as of the trade and importance of all the towns likely to be 

 affected by the undertaking ; of all mines of coal, iron, &c. ; quarries of limestone, free- 

 stone, slate, &c. ; or the situation where such can be found ; of all the manufactories of 

 heavy and cumbrous goods, and other extensive works ; and generally of every thing 

 likely to furnish tonnage for a canal. The most eligible rout for a canal being settled 

 in the engineer's mind, he will then proceed to make a rough calculation of the quantity 

 of goods of each different kind which may be expected to pass upon the line in a given 

 time; he will also examine all the canals and rivers which the proposed canal is to con 

 nect with, and ascertain the widths and depths thereof, the sizes of their locks, and of 

 the vessels usually navigating them. 



3535. The dimensions, number, and kind of locks or inclined planes, length of levels, 

 &c. may now be determined on, and how far railways or branch canals or roads may be 

 connected with the main line. Many engineers, and especially Fulton, have warmly 

 advocated the formation of small canals. On this subject. Chapman, a most judicious 

 artist observes, *< that the system of small canals is particularly eligible in all countries 

 where limestone, coal, iron ore, lead, and other ponderous articles, not liable to damage 

 from being wet, or likely to be stolen, are the objects chiefly to be attended to; and 

 where the declivity of the country runs transversely to the course of the canal, which will 

 generally be the case along the side of mountains, at an elevation above the regular 

 ground at their feet. In those situations, the great falls or inclined planes may be made 

 at the forks of rivers, so that the upper. levels may branch, up both the vales, and thus 

 give the most extended communication. A situation suited for those canals will often 



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