24G 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[AuorsT, 



and k the co-efficient of contraction : we obtain — 



Q = k\ I ydx. 



And when for \ its value found above is substituted, it follows, that 



(H) Q = k^{ig)J'ydx^{n + j). 



If the orifice be situated iu the bottom of the reservoir, and be 

 horizontal, \ = /\/(l^H), we obtain 



(I) (i = ky'{igl{)J'ydx. 

 (To le continued.J 



THE PUBLIC WORKS OF ENGLAND. 

 No. II. — Caledonian Canal. 



The whole progress of the Caledonian Canal is so entirely illus- 

 trative of the conduct of public works in this country, that a de- 

 tailed account of it would not be undesirable. 



The act for the purpose, which passed on the 27th December, 

 1803, granted to the government the sum of 20,000/. for the un- 

 dertaking. The engineering and conduct of the canal was en- 

 trusted to Telford, but the commissioners appointed another emi- 

 nent engineer — Mr. Jessop — to survey the line and calculate the 

 cost. The estimate of these gentlemen for the whole work was 

 IT+jOOO/., exclusive of the price of land, which expense, they sup- 

 posed, would not be considerable — many proprietors having offered 

 their land gratuitously, and the general value of land in the 

 country through which the canal passed not being great. The 

 expense for the first year was calculated at 75,000/. Before the 

 close of the year docks on both seas were in a considerable state 

 of forwardness; they were set out at 400 yards in length and 70 in 

 breadth; 400 bolls of oatmeal (56,000 lb.) were lodged in store- 

 houses, and delivered to the workmen at prime cost; 150 persons 

 were set to work, besides persons making and repairing utensils — 

 a number in those days thought very great, thougli a railway en- 

 gineer would smile at it. The average wages to the workmen was 

 ISd. a-day. Fir was cut down on the spot or in the neighbour- 

 hood, costing from lOd. to 14rf. the cubic foot — imported timber 

 would have been twice as dear, and answered no better. Thus the 

 preparatory arrangements were begun with much forethought and 

 economy. 



The salary of the engineer, Mr. Telford, was at the rate of 

 three guineas per diem, including travelling expenses, with some 

 allowances for the expenses of one or two lengthened journeys. 

 This sum would make Mr. Brunei stare. The salaries of the 

 superintendents were fixed at from 50 to 150 guineas per annum. 

 The valuation of the land was about 15,000/. 



Great apprehensions were entertained that the nature of the 

 soil would interpose insuperable diflBculties. Mr. Jessop's report, 

 in the actual state of geological knowledge, is curious. "It seems 

 (he states) probable that in some early age of the world the im- 

 mense chasm, almost two-thirds of which is still occupied by 

 water, has been nearly (why did I not say quite) open from sea to 

 sea, and that the land which now separates the locks has been 

 formed from the decay of the adjoining mountains. This decay is 

 very apparent in Ben Nevis, which is evidently a part only of a 

 much greater mountain which seems to have included the present 

 one and two adjoining mountains of lesser height. Impressed 

 with this idea, I was very apprehensive, after the iirst trials of the 

 ground at Inverness, that many other parts would be found similar 

 to it. Tliat greatest part of the land there being composed of 

 gravel and sand, is so open that the water in the pits sunk and 

 rose with the tide. Fortunately, a place has been discovered where 

 a foundation on clay may be got at by surrounding the pit with a 

 cofferdam." It was found generally that the gravel and sand had 

 a sufficient admixture of earth to exclude water. 



The width of tlie locks was calculated at 38 feet, length in the 

 chamber 152 feet: 23 locks were provided for, at an estimate of 

 171,327/., and as many bi-idges, at an approximate estimate of 

 34,000/. The common cutting of the canal was estimated at 

 142,000/., the depth being 20 feet, with a bottom of 50 feet— a 

 slope of IS inches to a foot, and 90 feet width at tlie surface. The 

 remainder of the estimate was for deepening rivers, cofferdams, 

 aqueducts, culverts, with a sum of 12,000/. fur steam-engines. 

 By the time a single year had passed, the usual fate attended 



these estimates. It was found that the locks would be too small, 

 as frigates of 44 guns might be required to pass — the length was 

 extended to 185 feet and the breadth to 43, with an addition to 

 the estimate of 122,624/. Then side locks were required for small 

 vessels, to save the wear and tear of the large locks; these were 

 further estimated at 75,200/. Iron railways were constructed for 

 the purpose of conveying stone from the quarries opened in the 

 vicinity of the canal — one of them 11,000 yards, a great length in 

 tliose days for such a purpose. The number of labourers was in- 

 creased from 150 to 900. The greatest difficulty was encountered 

 in the erection of the sea locks, in the construction of which a 

 good deal of ingenuity was exhibited. 



In addition to the increase of other estimates, the salaries, as 

 usual, were increased. Two resident inspectors were appointed, 

 and several other officer.s, at allowances of upwards of 200/. yearly 

 each. Far more trouble and expense than was anticipated oc- 

 curred in the valuation of land, which the proprietors did not 

 seem disposed to part with gratuitously, nor at other than a high 

 value. 



A great improvement on the usual practice of canals was intro- 

 duced at the very commencement of the undertaking in the con- 

 struction of the bridges. On the Forth and Clyde Canal wooden 

 drawbridges had been used at first, raised by chains and timber 

 framings; as these wore out, cast-iron bridges were substituted, 

 raised hy a wheel and pinion; but the Caledonian bridges were of 

 iron, on the swivel principle, which had been already used in the 

 London Docks. One of the most important works in the early 

 stage of the canal was the altering the course of the rivers Ness 

 and Oich. The beds of both of these rivers were required for the 

 canal. The embanking necessary was very extensive. 



In 1820 the first steamboat was constructed for the canal by Mr. 

 Henry Bell, the introducer of steam navigation into England, and 

 the person who established the well-known steamboats on the Forth 

 and Clyde. 



On the 23rd of October, 1822, the canal was opened from sea to 

 sea with very great ceremony. The principal landlords along the 

 land fired salutes and gave entertainments on the occasion, and 

 the papers of the day describe the affair as one of great magnifi- 

 cence. The passage back, from west to east, was made in 13 

 hours. The depth of water was then only 12 feet, but dredging- 

 machines were in active operation for the purpose of deepening 

 the canal to 20 feet. 



The entire term, from the commencement to the opening of the 

 canal, was 19 years. It was begun in October, 1803, and opened, 

 as we said, in October, 1822. The expenses to this time were 

 921,373/. — of this no less than 47,886/. was paid for land which 

 was to have been granted gratuitously; 612,770/. was paid for 

 labour and did vast good to the country. The steam machinery, 

 estimated at 10,000/., only cost 5,596/., but the whole machinery 

 cost upwards of 121,408/. The cost of management for the whole 

 time averaged under 1,500/. per annum. On the whole, and by 

 comparison with modern undertakings, this great enterprise was 

 conducted with extreme economy and great ability. At times 

 the persons employed on the canal ai one time amounted to above 

 9,000. 



In the first year of the opening 307 vessels entered the canal, of 

 which 37 passed from sea to sea. This was tlien considered a fa- 

 vourable account. The tolls fixed were a farthing a ton per mile, 

 with an increase upon very short voyages. 



From May 1822, to May 1824, 278 vessels passed through the 

 canal, but the expenses of maintaining the canal were considerable. 

 Nearly 200 workmen were employed on the works, and the tonnage 

 duty was consequently doubled. The canal dues, previous to the 

 increase, from the year qiioted above, amounted to 1,555/. Not- 

 withstanding the increase the profits of the canal were small — 

 more workmen were obliged to be employed. The increased ton- 

 nage drove the shipmasters to the circuitous passage of the Pent- 

 land Frith, though even now the duty on the whole passage was 

 but 2.5. Id. per ton. One of the reasons for increasing the duty 

 was the complaint of the proprietors of the Forth and Clyde Canal, 

 who complained that tlie Caledonian, constructed at the public 

 expense, entered into an unfair competition with them by low 

 terms. 



Since that time no efforts have been able to make it a profitable 

 one, though the Caledonian Canal, taking the circumstances of 

 the time in whiili it was constructed into consideration, is a work 

 of whicli tlie nation may be justly proud. 



The mounds, wliich guard the entrance of the canal at the 

 Beauley Fritli, were advanced from the high-water mark to 4 

 fathoms deep of water; at the end is the sea lock. These im- 

 mense works are 400 yards long, and took four years to construct. 



