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It is well known that this latter production itself, is a patchwork, priacipally from French and English authors, without any strict connexion, and certainly with no additional improvement. Mr. Farrar has, however, the merit of altering the awkward English dress which Gregory adopts, by changing the dot, or fluxional mark over the variable quantity, to d, the French mark for differential, to give his work, no doubt, an appearance of some uniformity, and clothe it in the more fashionable French costume.

Professor Olmsted of Yale, has taken, however, a more straight forward course. For the whole of his “Introduction to Natural Philosophy, vol i. Mechanics,” 1830-is taken verbatim from Bridge's Mechanics, published in 1814, for the use of the English East-India College, with the exception of two theorems taken from Newton's Principia, and placed in the front pages. In his explanation, however, of the character, i.e. id est, or that is, he ventures now and then to place the word theorum after it, in defiance of the compmon rules of grammar. For the rest, the figures, the words in italics, the examples, the whole, is a faithful copy, as far as Mr. Olmsted's work is carried. Even the sign , sufficiently formidable it is true, to our freshmen in college-a hasty mode of forming the letter r, the initial of radix or root, and when no member is placed in its claw or prong, it indicates, as is well known, the square root is illegitimately curtailed of ils usual privileges, in a variety of instances.* In the original, however, we presume these errors can only be typographical.

From such sources, therefore, we could expect to receive but a small portion of those rays of science, calculated to dispel any of the mists, which usually hover around these intricate inquiries, and which so often impede our progress.

We should now proceed to examine in order, the theory of the resistance of elastic fluids, such as air; its effects not only on the sails of ships, but on machinery in general, affording a subject for investigation extensive and important, as also its effects in rapid velocities on locomotive engines ; for the theory of these fluids, as we have already observed is extremely defective, and many of our preceding observations relative to nonelastic fluids would equally apply to this subject. It would be also within the scope of our review to examine the mode of arriving at the actual force, or actual resistance of fluids as well as the relative force, to which only we have hitherto had reference; but this article is already sufficiently long to prevent our

* See among other pages 33, 4, 5, 6, 8, of the original and corresponding pages 27, 8, 9, 30, of the copy.

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inflicting on our readers at present this further task of accompanying us in our observations on these abstruse researches. It is, however, remarkable, that in endeavouring to establish, or rather discover a principle, on which not only the theory of waves, that of sounds, and several other points of physical inquiry depends, as well as the resistance in question, Newton has fallen into an error that pervades the whole of his inquiries on these subjects. His followers, such as Emerson, Cavallo, Vince, and others have copied him faithfully, and it is amusing to read Biot's and even Laplace's reasons, no doubt, from not examining the formula, and from the great reverence for the ipse dixit of their master, why Newton's theorem for the velocity of sound gave less than experiments made it. It would, in fact, give even more than 1142 feet in a second, as experiments then made it, were it not for the error alluded to, which consists in bis assuming, that the volocity of a fluid issuing through an orifice in a vessel, was equal to that acquired by a body in falling half the height of the fluid, in place of the whole height; after having assumed that the velocity of sound is equal to that with which air of the usual density, rushes into a vacuum. On this principle as already remarked, viz. that the velocity is that due to the whole, and not to half the height of a fluid, depends the method of determining the actual force of any fluid against a body, its velocity or that of the fluid passing through it, being given ; for the force of the fluid on a plane is - estimated equal to the weight of a column of the fluid, having the surface for its base, and for its height the fall producing the velocity of the motion.

Notwithstanding our eagerness to arrive at the conclusion of this article, there is one observation of Dr. Lardner which merits some further notice, viz. that steam-engines have not been employed to any extent as yet on canals, so as fully to test their utility in these narrow channels, yet when we consider the rapi- . dity of the improvements, and the facility with which every difficulty that presents itself is obviated ;* if to this we add the recent improvements in locomotive engines, the application of the surplus steam, in passing it through the fire, which has been effected in one of Mr. Stevenson's engines, on the Manchester and Liverpool Rail-road ;t the producing a vacuum over the

* Mr. Blanchard of Massachusetts, bas, we understand, lately introduced several improvements, that may tend to obviate some of those difficulties.

+ Mr. Herschel, who is also an excellent chemist, in the Philadelphia Magazine, Feb. 1831, p. 375, has the following remark on the application of steam in this man: ner, which has, however, so well succeeded. - From one of the known ingredients of steam being a highly inflammable body, and the other that essential part of the air which supports combustion, it was imagined that this would have the effect of incrcasing the fire to tenfold fury, whereas it simply blew it out," &c. Dr. Cooper,

fire, as effected by Messrs. Braithwait & Erieson, in some of their engines, (see Mechanic's Magazine, 1830-1, passim) the passing the steam through tubes considerably heated; these, with the improvements in crank motion,* bid fair to produce a new era in practical mechanics.

We commenced with che intention of exbibiting also the comparative merits of rail-roads, and canal or river navigation, but we must, from the length to which this article has already extended, defer this important inquiry for some other occasion. We are satisfied, however, that each have many and peculiar advantages, and that it is in uniting these, that the greatest possible advantage, as far as depends on these means, can be attained.

President of the South-Carolina College, in one of his late experiments, has tested in a satisfactory manner, the utility of this application of steam. 'We would remark with regard to Mr. Herschel's anecdote and witty remark, that the cause of truth or science is not much advanced in this way. A little stock of these witty, but often trilling anecdotes, form in some cases, the whole apparatus of some respectable writers of our times, by means of which they decide the most weighty and important questions, in every department of human knowledge.

* The improvements made by Professor Wallace, of the South-Carolina College, who first pointed out the use of two or more pitmen, or connecting rods, in place of one, which saves most of the power lost by the use of the crank, which is fully threefourths of the original, as theoretically proved, and tested by the experiments mude with the Cornwall engines. For this invention he some time ago secured a patent. It is, bowever, more than probable, that as his avocations will not permit him to attend to its application in person, he will derive but little advantage from this important improvement. From an article published in the National Intelligencer, Sept. 21, 1831, where Professor Wallace is spoken of in terms of respect not only as to talents, but as to his invention, and where it is stated that some persons are al. ready endeavouring to claim for themselves the substance of this invention, by petty changes made, as they imagine, in the mode of applying the principle of the two or more pitmen, and thus infringing on his patent, particularly a Mr. Tibbets. It is proper to observe, that whenever more than one pitman, or connecting rod, is applied, to remedy the loss of power, any and every such application is an infringement of his patent right; this being its essential principle. We may on some future occasion enter into a full discussion of the objections and observations of the writer in the Intelligencer. They are certainly erroneous. Experiment alone, however, can now satisfactory decide this matter; and 30 or 40 dollars expense would be sufficient to make the trial in almost any of our steam-engines. Professor Wallace, we have no doubt, would furnish any further particulars in making the experiment to any one who should desire it; and in applying the pitman either vertically or horisontally.

vol. VIII.--No. 15.

ART. VI.-A Year in Spain. By a young American. 2 vols.

12mo. second edition. New-York. 1830.

This very pleasant and instructive book, is understood to be written by Lieutenant Slidall of the United States Navy. With the laudable design of acquiring a thorough knowledge of the language, and of seeing and knowing a country now almost as little travelled as Egypt or Mongolia ; he pushed on into the heart of the kingdom, penetrated the villages and ventured into the very by-ways and wastes, undismayed by bad roads, ill contrived stage-coaches, uncomfortable inns, or the daily danger of being robbed and murdered. Never did a traveller appear to possess a more happy temperament for getting on with the world, and especially for conciliating favour among a people celebrated for their hauteur and deep rooted prejudice in favour of their national manners and customs. He mingled with the groups round the fires of the village inns, chatted and joked with the conducteurs, his guides, and chance acquaintances, eat unhesitatingly in the same dish, and to suit the good subjects of his Catholic Majesty, crossed himself devoutly as often as occasion required. A traveller of this character is precisely the one to give us a fair account; for his urbanity is generally repaid by an attention and politeness from the inhabitants of the country that puts him in a good mood to view things with an impartial eye.

Spain exhibits little change on the present day from the description of Townsend, Bourgoanne, Dihon or Swinburne; but this, with us, is, in fact, one of the attractions of the work before us. Our wonder is constantly excited in beholding, amidst the general and rapid progress of most of Europe, the stationary character of a kingdom from three sides of which can be daily seen every flag of the civilized world. Perhaps we are even wrong in using the word stationary, where the slight advances of a few sea-ports cannot counterbalance the progressive wide spread decadence of the rest of a realm. Not to revert to the golden days of the Spanish monarchy, in vain shall we at present look abroad for the wealth, the splendour, tbe comparative general comfort that has been made familiar to us by the Bachelor of Salamanca and Gil Blas, fiction to be bure, but whose perfect verisimility has always been admitted, both as to the manners and the countries they describe.

On entering the Spanish territory, our travellers trunks were examined to discover any infidel or revolutionary works, especially those of Marmontel, Rousseau, Voltaire, and the

modern metaphysicians and economists. This salutary caution had become the more necessary, as, recently, a large package of books composed of the “ Social Compact," and Llorente's “ History of the Inquisition,” backed with the pious title of “Lives of the Saints," had safely crossed the loyal and orthordox boundaries of the Peninsular. The transition from the two neighbouring kingdoms is striking.

“ In the public offices, police, military, in fact, in every thing which relates to the general service, the traveller will, however, notice a most decided change, in passing from France into Spain. On the French side, he finds snug buildings to shelter the custom-officers-men who would repel a bribe with indignation; cleanliness and uniformity in the dress of the employé's; and gens-d'armes well accoutred and well mounted, patroling the country in pursuit of robbers, and enabling the citizen to pursue his avocations in security. On the Spanish side how different! Miserable looking aduaneros crawl forth, with paper cigars in their mouths, in old cocked hats of oil cloth, and rolled in tattered cloaks, from beneath mud hovels, which seem to be only waiting for their escape that they may tumble down. They make a show of examining you, ask for something for cigars, and if you give them a peseta, they say that all is well, and you go by unmolested. Here there is no law but that of the strongest, and every man is seen carrying a gun to protect his person and property.” vol. i. p. 25.

The first place of importance our traveller arrives at is Barcelona, where he gives us a picture of Spanish comfort, and of the cattle that in a great measure cause it.

“Our fonda was situated, as we have already seen, upon the Rambla, an immense highway through the city, the chief thoroughfare and promenade of Barcelona. Being of modern construction, we found large and commodious apartments. But to one accustomed to the conveniences and luxury of a French bedchamber, which constitutes indeed the chief excellence of their inns, my present room was but dreary and desolate. Besides the tile floor and white-washed walls and ceiling, there were a few chairs, a table, and no mirror ; on one side a comfortless bed, hidden by curtains in an alcove; on the other a large window with folding sashes and grated balcony. It overlooked an open field, which had no trees, but was covered with ruins and rubbish. The place had formerly been the site of the convent and spacious garden of a Capuchia fraternity. The property had been sold during the late period of the constitution, and the buyers were proposing to build houses, and to render it productive, when the royalist insurrection, which the despoiled clergy had stirred up, aided by French armies, brought about the counter-revolution. Those who had paid for the land were dispossessed with little ceremony, and the materials which they had been collecting to erect stores and dwellings, were now fastened upon by the returning fugitives, to renew the demolished combi

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