Researches, critical and experimental, on the capillary circulation / by Bennet Dowler.

  • Bennet Dowler
Date:
1849
Catalogue details

Licence: Public Domain Mark

Credit: Researches, critical and experimental, on the capillary circulation / by Bennet Dowler. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    The Italian [>hil(>si)[)liers, nearly two ceiiUiries; ago, (ocjk flie k^atl in research and discovery in the phenomenology of motion, comprehending the greatprinciples oi equilibrium, statics, dynamics, and hydrodynamics. The Italian^ and, sul)se(pient]y the French governments, expended the public treasure liberally in at?emnts to ascertain and lix the laws of motion, particularly the movements of fluids, constituting ihe science of hydrodynamics. (Jurious readers, who will examine the two hundred large quartos containing the traiisactions of the Academy of sciences at Paris, for nearly two centuries, will find many, if not satisfactory papers on these topics. The following remarks by the learned and candid Mr. Whewell, will doubtlessly prove as acceptable to the reader, as they are pertinent to the general physical aspect of this subject, and the more so, as physical, or at least chemical force, is, at the present time, trenching upon animal dynamics. The mode of solving the problems relating to the motion of fluids, has been, to introduce certain other hypotheses, often acknowledged to be ialse, and almost always in some measure arbitrary, to assist in determining and obtaining the solution.—In most cases, the solutions of problems of hydrodynamics are not satisfactorily con- firmed by the results of observation.—The assumptions of the math- ematician here do not represent the conditions of nature ; the rules of theory, therefore, are not a good standard to which we may refer the aberrations of particular cases; and the laws which we obtain from experiment are imperfectly illustrated by o ^?7'o?'i calculation. The case of this department of knowledge, hydrodynamics, is very peculiar ; we have reached the highest point of the science,—the laws of extreme simplicity and generality from which the phenomena flow ; we cannot doubt that the ultimate principles which we have obtained are true ones, and those which really apply to the facts ; and yet we are far from being able to apply the principles to explain or find out the lacts. In order to do this, wo want, in addition to what we have, true and useful principles, intermediate belween the highest and the lowest;—between the extreme and almost barren generality of the laws of motion, and the endless varieties and inextricable complexity of fluid motions in special cases. The reason of this peculiarity in the science of hydrodynamics appears to be, that its general principles were not discovered with reference to the science itself, but by extension from the sister science of the mechanics of solids : If w^e had lived in a world in which there were no solid bodies, we should probably not yet have discovered the laws of motion: if we had lived in a world in which there were no fluids, we should have no idea how insuflicient a complete possession of the laws of motion may be, to give us a true knowledge of particular results. The same formula expresses the general condition of statics and that of the dynamics. The tendency to generalisation vihich is thus introd- uced by analysis, makes mathematicians unwilling to acknowledge a plurality of mechanical principles; and in the most recent analytical treatises on the subject, all the doctrines are deduced trom the single law of inertia. * Stevinus, in 158G, developed the principles of equilibrium and thereby * Hist. Ind. Sci. i. 114 to 121.