GENTLEMEN :--In the February number or" the JOURNAL for 1882, I gave to your readers a paper upon a "New Theory of the Suspension System with Stiffening Truss." In that paper .[ advocated tile use of a. truss fixed horizontally at the ends and cpntinuous at the centre, and gave the mathematical discussion of such a truss, so far as I know, tbr the first time. Previous writers have a~umed that the curve of the cable for a partial loading remains unchanged, such a partial loading being distributed over the cable by means of the truss, and the cable therefore retaining its parabolic shape. This assumption I repudiated, and introducing instead of it the condition that the horizontal pull of the cable remains practically the same as if its form were unchanged, I applied tile received theory of flexure to this sy> tern, and as I think, completely solved the case. I need hardly say that no such structure as yet exists, to nty knowledge, as sucll a suspended truss, and I put forward the combination as a new one, which would be found stifl~r than any of the known tbrms of suspension, and which could by means of my fornmlm be coml)letely calculated.
I have just received a letter from C. B. Bender, C. E., member American Society of Civil Engineers, fi'om Englaud, enclosing a hectograph copy of a paper upon "Suspension Bridges of any I)esired l)egree of Stiffness," written by him May 28, 1881, upon which he claims priority for the theory. This paper I had never seen, and my solution was independently made; still it is but simple justice to Mr. Bender, and it is the object of this communi. cation to state to all interested, that so far as the .genera! method of solution is concerned, by tile application of the theory of flexure to tile suspension system in such a way as to avoid the incorrect assumption hitherto made, Mr. Bender's claim of priority is fully made out. As the entire originality of the discussion from a mathematical standpoint, lies in tl~is, such credit as there is in it belongs to him.
So far as my treatmentof the special ease supposed, i. e., ends horizontally fixed and centre continuous, is concerned, it still remains the only solution I know of, This solution is but a special case of Mr. i~ender's more general discussion, however, and one which he might easily have made had he chosen so ix) do. The special case to wllicll he di ~ apply his method, was that of a stiffening truss hin~ed at tl~e centre and ,supported at the ends. Our aetuM solutions, therefore, are widely diffbrent. This much As due to myself, as, owing to the fact that Mr. Bender is about to bring out a work which will contain Ills theory, and his undoubted claims to priority in the general mettled, as well as the similarity of much of the notation employed) I might otherwise be placed in an unenviable position.
Yours very truly,
~'E'i,V ]:;t'AVE~, CONN., November, I884.