Porter Poinier

“ But without insisting on the improbability of this supposition, we have only to recollect that from the results of actual and decisive experiments, made for the express purpose of ascertaining that fact, the capacity for heat of the metal of which great guns are cast is not sensibly changed by being reduced to the form of metallic chips in the operation of boring cannon; and there does not seem to be any reason to think that it can be much changed, if it be changed at all, in being reduced to much smaller pieces by means of a borer that is less sharp. ”

“ Is there any such thing as an igneous fluid? Is there anything that can with propriety be called caloric?
"We have seen that a very considerable quantity of heat may be excited in the friction of two metallic surfaces, and given off in a constant stream or flux in all directions without interruption or intermission, and without any signs of diminution or exhaustion.
"Whence came the heat which was continually given off in this manner in the foregoing experiments? Was it furnished by the small particles of metal, detached from the larger solid masses, on their being rubbed together? ”

“ It is hardly necessary to add that anything which any insulated body, or system of bodies, can continue to furnish without limitation, cannot possibly be a material substance; and it appears to me to be extremely difficult, if not quite impossible, to form any distinct idea of anything capable of being excited and communicated in the manner the heat was excited and communicated in these experiments, except it be motion. ”

“ From this quotation we see, then, that Rumford, with a sagacity indeed consummate, had seized upon the most notable circumstance presented by these experiments, against the materiality of heat. Italicizing the word inexhaustible—a far more significant proceeding than the use of any acids would have been—he showed most incontestably that, to still further reconcile the doctrine of caloric with experience, it would be necessary to admit the creation of it—a substance—in the production of heat by friction. ”

“ Since the increase of temperature consequent on friction cannot arise from the diminution of capacity or oxidation of the acting bodies, the only remaining supposition is, that it arises from an absolute quantity of heat added to them, which heat must be attracted from the bodies in contact. Then friction must induce some change in bodies enabling them to attract heat from the bodies in contact. ”

“ With the reformation of philosophy does our historical sketch then properly begin, and, moreover, with Lord Bacon as its founder; for, in illustrating the proper method of establishing a philosophical doctrine, he forever identified himself with the dynamic theory, by showing that the most comprehensive explanations were afforded by considering heat to be an intestine motion of the constituent particles of a body. ”

“ The total quantity of heat generated may be estimated with some considerable degree of precision as follows:
"As the machinery used in this experiment could easily be carried round by the force of one horse (though, to render the work lighter, two horses were actually employed in doing it) , these computations show further how large a quantity of heat might be produced, by proper mechanical contrivance, merely by the strength of a horse, without either fire, light, combustion, or chemical decomposition; and, in a case of necessity, the heat thus produced might be used in cooking victuals. ”

“ The explanations which it gave of the mechanical excitation of heat were not so plausible, however; certain phenomena appearing utterly incongruous with the idea of an unalterable material supply of heat-substance, and its continued production of friction a phenomenon which has been since said to have furnished the key to the whole science of thermo-dynamics—serving eventually to completely overturn it. In explaining such phenomena, therefore, those who still chose the material hypothesis were compelled to overlook some very significant objections ”

“ The material hypothesis was, therefore, the prevailing one, when about the year 1797 Count Rumford, [11] while engaged in superintending the construction of cannon at the military arsenal at Munich, became impressed by the considerable generation of heat accompanying their boring. And as he thought upon the explanation of the phenomenon consistent with the then prevailing ideas as to the intimate nature of heat, it seemed to him impossible that an apparently unlimited supply of any substance could be separated from so inconsiderable a quantity of borings. ”

“ In short, although the laws which govern the relations of molar energy to heat are in the abstract positively known, yet in endeavoring to trace the distribution and precise condition of energy when it becomes absorbed within a body, or vice versa, the mode and minutest detail of its transformation into gross mechanical effect, the most consistent theories have heretofore depended on the hypothesis that actual or real heat is a condition of molecular kinetic energy, and that the various latent heats are due to potentialities of molecular arrangement. ”

“ In this, the friction cylinder was made to rotate in a water-tight box, which, being filled with water, completely submerged all the heat producing parts. Here, therefore, the only supply of caloric, if any, lay in the water, which itself was to be heated by the friction; for had any caloric been abstracted by the heated water from the ambient air, there would have necessarily been a flow of heat from a cool body to a warmer, which every one admitted to be contrary to experience. ”

“ The proposition that the entire energy existing in the universe is a magnitude as definite and unchangeable as the quantity of matter which it contains, is now considered one of the most fundamental and far-reaching in natural philosophy. ”

“ Premising that the temperature of a body could not be increased unless either its "capacity" were diminished from some cause, or heat were added to it from still other bodies in contact, and observing a production of heat to be consequent on friction or percussion, he enumerated the following as including all possible explanations of the phenomenon consistent with the assumption of caloric:
First, the production by the friction of a specific diminution in the "capacity" of the body, whereby caloric would be disengaged, and thus made sensible. ”

“ Experience has not as yet encountered any phenomena at variance with these fundamental laws; which furthermore agree with the strictest requirements of intuitive science, and illustrate, respectively, the axioms that nothing is by natural means creatable from nothing, and that things are equal to the same thing only which are equal to each other. ”

“ In a memoir published in Liebig's Annalen, for May, 1842, entitled "Bemerkungen über die Kräfte der neubelebten Natur," he undertook to answer the questions: "What are we to understand by force? and how are different forces related to each other?" Toward the latter part of the disquisition he entered upon the subject of the mutual convertibility of heat and mechanical energy, considering the generation of heat by the shock or gradual stopping of a falling body, by friction, and by compression ”

“ Five experiments upon the thermal effect thus attending the expansion of atmospheric air showed a mean increase in the temperature of the water of 0.0074°, while the correction to be applied amounted to 0.0068, leaving a difference quite within the limits of observation by this method. Joule, therefore, concluded that "no change of temperature occurs when air is allowed to expand in such a manner as not to develop mechanical power." ”

“ But no circumstances can be imagined in which this method of procuring heat would not be disadvantageous; for more heat might be obtained by using the fodder necessary for the support of a horse as fuel. ”

“ The quantity of heat excited and accumulated in this experiment was very considerable; for, not only the water in the box, but also the box itself (which weighed 1514 pounds) , and the hollow metallic cylinder, and that part of the iron bar which, being situated within the cavity of the box, was immersed in the water, were heated 150° Fahr., namely, from 60° (which was the temperature of the water and of the machinery at the beginning of the experiment) to 210°, the heat of boiling water at Munich. ”

“ The experimental evidence possessed as to the fact appears for the most part in the invariability of the ratio of any dynamic magnitude of a definite kind which disappears to that of another kind which is thereby produced, and the numerical value of which, for a particular transformation, depends only on the relative magnitude of the characteristic units as compared by the same standard system of dynamic units. ”

“ But very few among the countless suppositions which we might thus succeed in raking up, however curious or predictive in themselves, would have the slightest bearing on our present subject. Developed only to the extent demanded by the superiority of the scholastic mind, they would be found in general mere arbitrary, whimsical assertions ”

“ This borer was securely held in place against the bottom of the cylinder, and kept from turning by an iron bar, m; and thus disposed for the experiment the apparatus is represented in Fig. 2.
In Rumford's first determination the borer was forced against the bottom with a pressure of about 10,000 pounds, and the cylinder was rotated at the rate of thirty-two turns in a minute, by the labor of two horses. To prevent also as far as possible any loss of heat by radiation, the exposed parts were protected by thick coverings of flannel. ”

“ Taking the casting of a brass cannon, solid and rough as it came from the foundery, and with the cylindrical mass of metal a (Fig. 1) , called the verlorner Kopf, still adhering to the muzzle, Rumford caused to he turned upon the superfluous end a smaller cylinder, b (Fig. 2) ,
Fig. ”

“ Nicholson's Journal, vol. xxvi., p. 30. ↑ Published in the Edinburgh Philosophical Journal, x., p. 280. ↑ Published in the Edinburgh Journal of Science, iii., p. 276, 1825. ↑ A particular instance of this supposition will be seen in our account of Carnot's engine. ↑ Entitled "Études sur l’Influence des Chemins de Fer," p. 378, et seq. Paris, 1838. ↑ The method indicated, with the data then at his command, for steam, gave 650 kilogrammetres as the mechanical value of an increase of temperature of 1° Cent, in one kilogramme of water. ”