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obtained from Avery's and the reciprocating, or Avery's and other rotary engines, to make up our minds respecting its real value; between four and five years, however, have elapsed since this engine was patented, and it has been at work at Syracuse, and various other places, during the whole of that time, so that those who have seen it, and who possess a competent knowledge of the subject, have had time enough to investigate it. Before the patent was obtained, we expressed to Mr. Avery, our general want of confidence in the real value of such engines, and our doubts respecting the importance of the improvements claimed; and we did not suppose that the career of the one in question would extend to two years, a length of life, greater than has usually fallen to the lot of rotary engines; it still lives, however, maugre our anticipations; and all the reports which we have received relating to it, tend to show that it has not yet exhibited the first symptoms of decline. Although we still adhere to the opinion, that upon a full comparison, the economy of a good reciprocating, will be greater than that of any rotary engine that has been, or will hereafter be, made, we most cheerfully confess that we have a much better opinion of Mr. Avery's, than we at first entertained; and, as to our wishes, they are that by the operation of this, and a hundred other contrivances, which we have esteemed of like value, we may be put entirely in the wrong; let the fact be well established, and we would be the first to make it public. Without putting in an undue claim to the suaviter in modo; we have sometimes thought that the tendency of onr animadversions upon patented inventions was to place us in the situation of "The best good-natured man, with the worst ill-natured muse ;" it must be recollected, however, that we stand between the claimants of exclusive privileges, and the public.

With respect to the amount of novelty necessary to security, as a founda. tion for a patent, we think that the fair test of this is the utility of the improvement; if it renders that valuable which was of little comparative worth, it is enough, although it be no more than the addition of a screw, or of a peg. The views which we have adopted upon this subject, may be found at large in Vol. 8, p. 411 of this Journal. The article is a borrowed one, and well worth perusal. "The main object of the patent law is the protection of original inventors in the enjoyment of whatever pecuniary advantages they may fairly derive from their useful inventions," and in attaining this end, it is not possible to test them by comparative weights, or to measure them by any established scale; absolute quantity, however small, is all that can be required.

Civil Engineering.

Report to the President and Managers of the West Philadelphia Rail Road Company, by H. R. CAMPBELL, Civil Engineer.

TO THE COMMITTEE ON PUBLICATIONS.

GENTLEMEN-I am directed by the President and Managers of the West Philadelphia Rail Road Company, to request the insertion in the Journal of the Franklin Institute, of the Report of their Engineer, accompanied by a map of the road.

This report contains some facts respecting the superiority of the Locomotive Engines made in this city. over those in use on the Columbia Rail Road which were imported from England, that are highly creditable to the

state of the arts in this country, and ought to be made known as extensively as possible. The work on the West Philadelphia Rail Road is in a forward state, and will be completed within the period contemplated.

Very respectfully, your obedient servant,

THOMAS FLETCHER.

To the President and Managers of the West Philadelphia Rail Road Company.

GENTLEMEN-I have the honor to report, that the line of the West Philadelphia Rail Road, has been located in conformity with instructions received from the Board. The ground over which it is traced is well adapted to the construction and grade of the road. The excavations and embankments are generally light, and by no means of an expensive character. But few small streams are crossed, and consequently but few culverts and bridges will be required, which will be built of stone in the most permanent and durable manner. In the location of the route particular care has been taken to avoid curves, and no curves have been made upon a less radius than four thousand feet.

The maximum rise of the graded surface of the road, is 46 feet per mile, which is only one foot per mile more than the maximum grade of the main line of the Columbia and Philadelphia Rail Road. A small portion of the line is level, and about one and a half miles are graded at 58 feet per mile. The average grade is 43% feet per mile, its length being 7 miles, and total rise 325 feet.

From its juncture with the Columbia Rail Road, a short distance below the Buck Tavern, the route is nearly straight to the Market Street Permanent Bridge over the Schuylkill River, and more direct than the main line of the Columbia Rail Road. By its completion a new outlet will be opened to the travel and transportation of the Columbia Rail Road, and the inclined plane at Belmont will be avoided. The distance from the city of Philadelphia to the head of the inclined plane is about 4 miles; the nearest point to which locomotive engines can approach the city. By the West Philadelphia Rail Road, locomotives can carry their trains to the line of the city proper, at Market Street Permanent Bridge, and to the tide water of the Schuylkill opposite the city.

Trains of cars by this route, propelled by locomotive engines, will gain one hour in advance of those which pass over the inclined plane, by the main route of the Columbia Rail Road. This circumstance is alone a sufficient inducement to divert the travel and a large portion of the transportation from that Rail Road. Statements have been made in the public papers, since the commencement of the West Philadelphia Rail Road, that the construction of a line was contemplated by the Canal Commissioners of the State, by which the inclined plane is to be avoided, without exceeding a grade of 25 feet per mile, and an increased distance of two miles It is due to the stockholders of the West Philadelphia Rail Road and to the public, to state, that no such route exists, and that the name of the engineer, given as authority upon which the statement was made, was used without his permission or consent.

The importance of avoiding inclined planes upon roads constructed for the accommodation of passengers traveling, is beginning to be justly appreciated. By reference to the recent report of the Baltimore and Ohio Rail Road Company, it will be found, that measures have been taken by

them, to abandon those parts of their road upon which inclined planes have been constructed, and to construct new lines upon which locomotive engines can ascend without the aid of stationary power. By experiments made on the Columbia Rail Road with locomotive engines, the question has been settled, that 45 feet per mile, is an inclination upon which that species of power can be applied with more advantage than any other. The fact, that the original design was abandoned, of adopting stationary engine power on the Rainhill and Sutton inclined planes of 55 feet per mile, on the Liverpool and Manchester Rail Road, in England, to the more advantageous use of locomotive engines, might also be adduced as evidence, that even steeper grades, may be safely adopted.

The locomotive engines on the Columbia Rail Road, which were manufactured by Mr. Baldwin, of Philadelphia, carry trains of 20 and 24 cars, containing each three tons of merchandise, up 45 feet grades at 10 to 12 miles per hour; while engines of English constructure, from the works of Robert Stephenson, Esq. the celebrated engineer, carry upon the same road only 14 cars, at the same rate of speed. This great difference is produced by the superior arrangement and mechanical application of power to Mr. Baldwin's engine, and not from any difference in the weight and adhesive power of the respective machines.

It has been clearly ascertained that Mr. Baldwin's engines, under all circumstances, are able to generate more steam than is adequate to overcome the adhesion of the wheels upon the surface of the rails, while those of English construction are unable to keep up a sufficient supply. These facts are mentioned as evidence of the progressive improvements in the science and construction of locomotive engines, and of the perfection to which their manufacture has arrived in our own country. The durability of these engines, and the amount of annual repairs, are not less striking than the result of their effective force.

Enough, it is presumed, has been said to prove conclusively, the superiority of the route of the West Philadelphia Rail Road, over that portion of the Columbia Rail Road which it is destined to rival. With regard to the comparative distance of the two lines, the former is about half a mile shorter than the latter, from the intersection of Broad and Market Streets. The whole cost of the West Philadelphia Rail Road, including a double track of edge rails, laid on foundations of locust timber, will be $250,000. work is all under contract and rapidly progressing to completion.

The

The grading will be finished by the 1st of May, 1836, and the rails will be laid ready for travel by the 1st of August following. Contracts have been made for iron edge rails, of a pattern similar to those of the Camden and Amboy Rail Road, to weigh 60 lbs. per lineal yard, and also for all the materials necessary to complete the work, which are to be delivered in all the month of April next. The Board have every reason to be satisfied with the progress of the work under the respective contracts. The prices are generally fair, and no obstacles exist to the completion of the road within the time specified in the contracts. H. R. CAMPBELL, Engineer of the West Philadelphia Rail Road,

Philadelphia, October 15, 1835.

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