Page images
PDF
EPUB

demanded an immediate explanation from the council of regency, threatening to fire upon the town, if a single Frenchman entered the city. At this dangerous crisis, amidst the confusion and fears of the inhabitants, Rumford assumed the command of the Bavarian forces, agreeably to the orders of the Elector, and immediately the confusion yielded to order, and tranquillity was established. He peremptorily refused to comply with the demand of the Austrian general, and his firmness and presence of mind silenced and awed both armies. Neither the French nor Austrians entered Munich, and the city escaped the evils, which awaited it.

The noble conduct, displayed by Count Rumford in his excellent defence of Munich, did not pass unnoticed by its grateful inhabitants.

He received again the most unequivocal testimonies of their attachment to his person, and all classes of people united in acknowledging him the saviour of the capital, and many presents were made to him by the nobility and the most respectable citizens.

On the Elector's return he did not long wait for an opportunity of showing the high esteem, in which he held the Count, and, uniting in the general expression of the inhabitants in his praise, placed him at the head of the department of the general police of Bavaria. In this employment, though less brilliant, than military exploits, the result of his services was lasting and highly useful.

While at Munich at this time, he made many important experiments on philosophical subjects, and, having the superintendence of casting and boring cannon for the Elector, and aided by the assistance and encouragement of his generous patron, he prosecuted his favorite inquiries concerning the cause, nature, and operation of heat.

However industrious and useful were his labors, they were not sufficient to screen him from the shafts, which jealousy and envy occasionally aimed at him. His health was again impaired, and his Serene Highness, wishing to confer on him an honorable testimony of his acknowledgments, appointed him envoy extraordinary and minister plenipotentiary at the Vol. II. No. 3

L1

Court of St. James. But the rules of the English Court alallowing no subject to be accredited, as the minister of a foreign country, the Count, after his return in 1798, resided in London, as a private person.

He left Bavaria to go to England in 1798, and it was supposed he had bid adieu to that country forever. About this time he received a formal and official invitation from the

government of the United States, through our embassador at London, to revisit his native land, where an honorable establishment was provided for him, To this flattering invitation, attended with the highest assurance of esteem, he returned an answer, in which he declared with the warmest sentiments of gratitude, “that engagements, rendered sacred and inviola“ ble by great obligations, did not permit him to dispose of “ himself in such a manner, as to be able to accept of the offer, “ which was made to him.". In this answer, however desirous we may be to see him in America, there is not the least tincture of enmity. But those, who are acquainted with his works, and" can duly appreciate the value of the connexion, which existed between him and his munificent patron, the Elector of Bavaria, cannot attribute his refusal to an improper motive.

The Count's sixth essay, which commences the second volume,“ on the management of fire and the economy of fu“el,” deserves a more particular notice, than can be assigned it in a biographical sketch. It will be found to contain some of the most useful and practical philosophical principles, applicable to the common affairs of life, which any subject can afford ; and, when it is considered how many wants and comforts of mankind depend on the operation of that subtle and illusory agent, heat, the numerous details and experiments, which are found in this essay, cannot but be highly interesting. No possible use, to which fire can be applied, seems to have escaped the author's scrutinizing mind.

But its

application to cookery and warming rooms has been his chief study. With respect to the former the kitchen of the house of industry at Munich, of the military academy, of the military mess house, of the farm house, and those, belonging to the Inn in the English garden, of the hospitals of La Pieta and La Miserecordia at Verona, of one, fitted up, as a mode el, in the house of Sir John Sinclair, Bart. in London, of the foundling hospital at London, of the military kitchen for the camp, and several others in different parts of Europe are sufficient to show the ingenuity and usefulness as well, as the success of his plans of reform.

In warming the habitations of men by common fires, by steam, and by smoke, though this application of the two last is quite novel, he has made the heat, produced in the combustion of fuel, pass through the several offices of cooking, boiling water, and warming rooms in such a manner, as scarcely a particle of heat is lost. He fitted a boiler at one end of one of the working halls to the house of industry in Dublin, by which steam, in conjunction with smoke, was made to warm the room, and in one of the churches of that city steam alone was made use of, which completely answered his expectations. He also formed a plan of the same kind for heating the superb new building, destined for the meeting of the Irish house of commons.

The seventh essay relates to "the propagation of heat in « fluids." This is diversified by so many experiments and

* His plan is to confine the steam in the boiler so, that it is made to pass off by a leaden tube through the halls or rooms, in the same manner the smoke is conducted from common stoves. Care should be taken, that, instead of placing the tube or funnel horizontally, it pass through the apartment inclined, that by this means the steam, as it condenses in its passage, may run back at the bottom of the tube to the boiler. This useful contrivance may casily be applied to halls, near any great kitchen, in a manner, that would neither increase the quantity of fuel, nor make any additional trouble in the process of cooking. By this scheme, it is conceived, the commcns hall at Harvard University can be heated, the hall being immediately above the kitchen ; and by a little improvement in the cooking apparatus the quantity of fuel might be considerably diminished, and even this decrease of expense be converted to an increase of the comfort of those, who breakfast and dine in commons. Even in the humble habitations, provided for the poor through out the New England towns, arrangements of this kind would be found advantageous.

such just observations on the general economy of the universe, with all the various and beautiful changes of seasons and climates, that the mind is unwarily lead to sublime contemplation. In these, as in all his philosophical researches, he makes the most accurate experiments, faithfully relates them, makes his own reflexions, and leaves his readers to draw such conclusions, as facts will justify, without wishing them to adopt any particular theory.

The object of his enghth essay, “ on the propagation of “ heat in various substances,” is principally to investigate the causes of the warmth of natural and artificial cloathing.

Count Rumford's ninth essay, which closes the second volume, is an inquiry concerning the source of the heat, “ excited by friction.” With such a patron and assistant, as the Elector, he could easily command whatevever might aid him in his useful studies. Pursuing his official occupation of superintending the ordnance, and boring cannon at Munich, the process suggested to him many important hints relative to this subject.

An idea, that heat is caused by friction, has been entertained by many philosophers, while some have given it a different origin. But Rumford's experiments place the question in a clear light. By confining the end of a cannon, while boring, in a box filled with water, so that the operation was performed below the surface of the fluid, the heat, generated by the friction, communicated itself to the water, and, by measuring the temperature of the water at regular periods, he determined the quantity of heat, produced in the experiment, The event, as may easily be supposed, afforde 1 him much satisfaction, and quite astonished the bystanders, who witnessed it. While the machinery was moving, the degree of heat, which the water acquired by the friction between the borer and the cannon during two hours and thirty minutes, was sufficient to make the water boil.

While upon this subject, we shall insert the substance of a « mémoire sur la chaleur, par M. le comte de Rumford, lu à la * séance publique de l'institut national, le 6 messidor an. 12," though not communicated to the public, till June 1804 in the “ Gazette Nationale."

He has in this memoir, read before the national institute of France, of which he is a member, endeavored, with great success, to reconcile the different opinions among philosophers, some of whom consider heat, as a substance, and others, a vibratory movement of the component particles of bodies. The Count has adopted the hypothesis of vibratory movement, and concludes from his own researches, that this is alone sufficient to account for all the phenomena of heat.

The French philosophers, perceiving the difficulties, which arose from the ambiguity of chemical language, adopted the word, calorique, to express heat, whether considered as matter, or the movement of its particles ; and this term will suit all opinions, leaving the question yet undecided, what is heat, and what are the certain invariable laws of its operation?

To ascertain how extremely active this principle is, and to expose its most secret works, he contrived an instrument, very simple indeed, which he called a Thermoscope. It consists of a glass tube about 28 inches long, with the interior diameter half a line. The two extremities, ending in very thin glass bulbs of about one inch and a half diameter, are bent so, as to form right angles with the remaining part of the tube, and leaving the horizontal or middle part sixteen inches long. In this instrument is inclosed a small quantity of colored spirits of wine, and wholly defended from any communication with the external air. While it is used, the two arms are placed perpendicular, and when any warm or cold body is presented to cither bulb, the other being secured from its effects by proper covering, the operation on the spirits of wine is designated by graduations on the horizontal tube.

“ La sensibilité de cet instrument est si grande que, lors “ qu'il se trouve à la température de 15° à 16° du thermom “ etre de Réaumur, la chaleur rayonnante de la main, quand "elle est présentée à une de ses boules, à la distance de trois "pieds, suffit pour faire avancer la bulle d'esprit de sin de

« PreviousContinue »