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III. — Experimental Researches into the Laws of Certain Hydrodynamical Pheno- 

 mena that accompany the Motion of Floating Bodies, and have not previously 

 been reduced into confm^mity with the known Laws of the Resistance of Fluids. 

 By John Scott Russell, Esq. M. A., F. R. S. Ed. 



Read 3d April 1837. 

 INTRODUCTION. 



In the summer of 1834, I was led to examine with considerable interest some 

 of the phenomena of fluids, from the cu-cumstancc of having been consulted upon 

 the means of improving a system of navigation to be conducted at unusually high 

 velocities. Being well aware, however, of the very imperfect state of that part 

 of Theoretical Hydrodynamics which relates to the Resistance of Fluids to the 

 Motion of Floating Bodies, and that there had been found in its application to the 

 solution of practical questions, discrepancies so wide between the predicted re- 

 sults and the observed phenomena, as to render the principles of the theory ex- 

 ceedingly false guides, when followed as maxims of art, I felt it impossible to 

 recommend conscientiously any mode of procedure founded on defective prin- 

 ciples, and I therefore determined to undertake a series of investigations concern- 

 ing the laws of the resistance of fluids, and the means of applying them to the 

 formation of rules for the arts of practical navigation and naval architecture. In 

 this investigation, I have now been engaged during the leisure of two summers, 

 and I am still continuing to prosecute the investigation. 



The following papers contain the experiments of the two summers 1834 and 

 1835, with the resolution of certain anomalous phenomena, and the illustration 

 and application of certain laws that have been developed. The experiments were 

 conducted on a very large scale, and the forms given to the floating bodies were 

 analogous to those which are most highly approved in the practical construction 

 of ships, as well as those of certain theoretical solids. The vessels used were 

 from 31 to 75 feet in length. Accurate Chronometers and Dynamometers of various 

 descriptions used by a number of highly educated and scientific assistant obser- 

 vers, render the experiments worthy of great confidence. In 1834 the power 

 used to overcome the resistance was the force of horses directly applied to the 

 vessels ; but although out of a multitude of experiments, some were obtained that 

 were distinguished by uniformity in the application of the force, yet in general 



