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89 839.] THE CIVIL ENGINEER AND ARCHITECT’S JOURNAL. 8755lbs.; class second, 24881bs.; class third, 28871bS. ; class fourth, 2090lbs.” We ha*e examined those calculations but have not found one of them correct. Class 1. 8-1410 x 54 = 169.64, circumference of wheel, 14 2 x '7854 x 2=807-876, area of 2 pistons, 2x16 = 32 inches, length of double stroke, 307-876 X 64-7 = 19919-62896, force applied on the pistons, The same force of traction which is required to draw 100 tons up a rise of one in 180 would draw on the level 274 tons. IBS. lOOX^lbs. = 800lbs. friction at 81bs. per ton. . • 800 100x2240 12441bs. gravity of the 100 tons (reduced to lbs,) on a plane inclined in the ratio of-— 180 1*44 180 122X224o —Iyjj = 1491bs. gravity of the engine on thesame plane 149 =5-301, ratio of the velocity of wheel and piston, 19919-62896 5-301 . = 3757-71 lbs. power applied to make the engine advance. Class 2. 12 2 x "7854 x 2 = 226-195, area of 2 pistons, 226-195 X 64'7= 14634-816, force applied on the pistons, 3 1416x _ ra tio of the velocity of the wheel and piston, 2 x 16 = 2484lhs. power applied to make the engine advance. Class 3. 11 2 x "7854 x 2 = 190-0668, area of 2 pistons, 190 0668 x 64’7 = 12297-32196, force applied on the pistons, 3-1416 x 60 2 x 18 * ^ =2348lbs. power applied to make the eng ine advance :5'236, ratio of rhe velocity of wheel and piston, Class 4. II 2 X "7854 x 2 = 190 0668, area of 2 pistons, 190-0668 x 64'7 = 12297-32196, force applied on the pistons, 31416 x 60 2 x 16 = 5-890, ratio of the velocity of wheel and piston, 1__.)7 •!-1*6- _ 2087lbs. power applied to make the engine advance. 5-890 “ The gradients also, on the regulation of which so much depends, both in respect to the original cost and the ultimate value of the rail way to the country, have been carefully gone over by one of the com missioners, in conjunction with the engineer, and in conserpience several material alterations were made, which have much lessened the amount of the original estimate, without affecting; in an important manner, either the rapidity of intercourse or the commercial advantage.” •—Page 37, Railway Report. In the September number of our journal for 1838, we printed a list of sixty-five errors found in the gradients, and upon a more full examination there will be found at least from forty to sixty more ; this clearly shows that very little care or attention was bestowed by the commissioner and engineer who had examined and gone over the gradients; indeed, the very numerous errors found in the gradients are destructive to the character and accuracy of the Railway Report and Sections, although “ My Lords had full confidence, from the character of the gentlemen appointed to form the commission, that their inquiries would be con ducted in a satisfactory manner.” We consider an alteration in gradients from one in 330, to one in 180, as most important, both as to rapidity of intercourse, and also as to com mercial advantage, although the railway commissioners do not think so. The same force of traction which is required to draw 100 tons up a rise of one in 330, would draw on the level 195 tons. tons. lbs. lbs. 100 X 8 = 800 100 X2240 = 330 Engine 12 x2240 330 ~ 81 1560 Total resistance not including the friction of the engine. ^1560_ f 95tons ^ Total resistance not including the friction of the engine 2193 (T= 274 to-) This shows the difference between the rise of one in 330 and one in 180. The load, tender, and engine, taken at 100 tons, and running at the rate of 20 miles per hour on the level plane, will, on ascending a slope of one in 330, run only at a rate of 14.20 miles per hour, and ascending a slope of one in 180, will run at a rate of 11-43 miles per hour. An engine capable of evaporating 48 cubic feet of water per hour wil draw on the level plane 88-32 tons, at the rate of 20 miles per hour- up, 1 in 500 — 51-96 tons, ... 400 — 46-49 tons, ... 300 — 39-09 tons, ... 200 — 28-44 tons, ... 100 — 11-97 tons. ...... Woods on Railways. Page 578. Looking at the levels which the surface of Ireland presents, we differ entirely with the Irish Railway Commissioners, as to adopting 1 in 180 as the characteristic gradient for the main trunk lines proposed to be laid out through that country; and we object still more so to 1 in a 100 for the great main line of railway laid out from Dublin to Cork, which appears by the Railway Commissioners’ sections to be the characteristic gradient of that line, because an engine running up such a slope can only draw about one-eighth of the load that .it can on the level plane ; and running up 1 in 180 less than one third of the load it can draw on the horizontal plane. We are, therefore, thoroughly convinced that the Irish Railway Commissioners have notsufficiently studied this most important element in railway engineering ; 6r has their limited know ledge of such a subject precluded them from being able to comprehend the vital advantages arising from the adoption of good gradients, even although attended with some expense in cutting and embanking? In our journal for last September, we forcibly alluded to .the very great injustice of not giving railway communication to the centre of Ireland, and also to the fertile province of Connaught; we stated our reasons why that province ought to participate in railway intercom munication, as well as the other provinces of Ireland. In the same number of the journal we stated our reasons fully- against the line of railway projected by the commissioners from Dublin to Armagh, and we particularly observed that it ran parallel with the coast railway for nearly one hundred miles, and that it could not be possible that two such lines could exist, as one or other of tnem would be a total failure. Having with some attention sudied the commissioners’ inland lines of railway from Dublin to Armagh and Enniskillen, we think that those projects recommended by them are extremely injudiciously planned ; because, if an inland main trunk line was to be laid out. from Dublin to Armagh, with a branch line to Enniskillen, and were it. determined upon that the important trading town of Drogheda should be excluded from railway communication with the capital, then lines of railway might have been chosen which would have united Dublin to Armagh and Enniskillen, with a saving of twenty-six miles of railway, which would be a great advantage as regards economy, not only in the first construction of these lines, but also in the working of them afterwards. The system of main lines of railway, which have been proposed to be Carried into effect by the various companies through the south of Ireland, possess superior advantages in connecting the various large cities together, than those recommended by the Irish Railway Com missioners. The lines proposed by the companies TSfeih 1 * much more expensive, and laying open a wider, a more populous, and a richer extent of Ireland’s surface, with less mileage and better levels than the Irish railway commissioners’ main lines appear to do. This fact has been established by the calculations already given ; and by examining the Irish commissioners’ index map of the proposed railways, there is to be seen a small triangular portion of country lying between Cahir and Hollycross which is completely encompassed by railways, amount ing to more than 40 miles in length, and which cannot fail to strike every engineer, who will take the trouble to examine the proposed