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INTRODUCTION.

Experiments on the friction or resistanceof carriages moved on Rail-roads. TheseExperiments, being varied both withrespect to weight and velocity, it istrusted, will be found useful, especially,as the want of the necessary data isjustly acknowledged. They were multi-plied until no doubt could be entertainedof their accuracy; and the details aregiven with every minuteness, that thereader may be able to judge of thedependance which may be placed uponthem.

Some ambiguity having arisen, respect-ing the law of resistance of carriagesmoved at different velocities upon Rail-roads, I have attempted, by a compre-hensive and minute illustration, assistedby diagrams, to define the proper ratio,which I have derived from Experi-