Elements of experimental and natural philosophy : being a familiar and easy introduction to the study of the physical sciences; embracing animal mechanics, pneumatics, hydrostatics, hydraulics, acoustics, optics, caloric, electricity, voltaism, and magnetism / by Jabez Hogg.

  • Hogg, Jabez, 1817-1899.
Date:
1861
Catalogue details

Licence: Public Domain Mark

Credit: Elements of experimental and natural philosophy : being a familiar and easy introduction to the study of the physical sciences; embracing animal mechanics, pneumatics, hydrostatics, hydraulics, acoustics, optics, caloric, electricity, voltaism, and magnetism / by Jabez Hogg. Source: Wellcome Collection.

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    at the beginning, and the amount of the materials at the end of this process be the same, then we have always the same amount of work, of mechanical work, or its equivalent, done dming this process. ]N'either more nor less work can be done by the process. Commonly, no mechanical work in the ordinary sense is done by chemical force, but usually it produces only heat; hence the amount of heat produced by any chemical process must be independent of the way in which that chemical pro- cess goes on.- The way may be determined by the wiU of the experimenter as he likes. We see, therefore, MTitcs Professor Hclmholtz, that the energy of every force in nature can be measured by the same measure, by foot-pounds, and that the energy of the whole system of bodies which are not under the influence of any exterior body must be constant; that it cannot be lessened or increased by any change, Now the whole universe repre- sents such a system of bodies endowed with different sorts of forces and of energy, and therefore we conclude from such facts that the amount of working power, or the amount of energy on the whole system of the universe, must remain the same, quite steady and unalterable, whatever changes may go oji in the universe. Again, in the words of Professor Thomson, We can now look on space as fidl. We know that light is propagated nice sound, through pressure and motion. We know that there is no substance of caloric—that inscrutably minute motions cause the expansion which the tliermometer marks, and stimulates our sensations of heat—^that fire is not laid up in coal more than in a Ley den jar: there is potential fire in each. If electric force depends on a residual surface action, a resultant of an inner tension, experienced by the insulating medium, we can conceive that electricity itself is to be under- stood, as not an accident, but an essence of matter. What- ever electricity is, it seems quite certain that electricity in