tube, with a sheet of water, the level of which is not more than from 25 to 30 feet below, it will fill itself by suction. In adding that, to avoid intermissions in the supply of water, Savery employed a third vessel, which filled with liquid, while the second was emptying, and reciprocally, that the second and third vessel were, one after the other, in communication with the boiler, by the assistance of a convenient system of tubes and cocks, I shall have noticed every thing essential in this engineer's machine. Solomon de Caus' apparatus has been found fault with, for only raising the water while hot. This reproach, it must be admitted, has some weight, in reference to economy, but it applies also, to a certain point, to Savery's engine. In this machine in fact, the steam proceeding from the boiler before acting upon the surface of the water of the second, or the third, vessel, is condensed in considerable quantities. Its elasticity does not become efficacious until after the water has acquired a high temperature: therefore when the water begins to rise, it is hot.* Robison said he had ascertained experimentally, that in employing steam as Savery did, at least ths is condensed, either by the sides of the second, or third, vessel, or by the water which they contain; even when the pressure is small. In an analogous machine, to avoid the enormous waste of steam, of which I have just spoken, Papin thought of interposing a piston or float, (flotteur.) This contrivance was not adopted, less, I think, on account of the difficulties in executing it, than on account of very serious defects inseparable from this kind of machine. To raise water to the inconsiderable height of 65 metres, (200 feet;) for example, Savery was obliged to raise the steam of his boiler to six atmospheres; hence, the continual derangements of the joints, hence, also, the melting of the cement, and even dangerous explosions. Moreover, in spite of the title of his work, the machines of this engineer served no useful purpose in the mines. They were only used to distribute water through various parts of the palaces, or of country seats, in parks or in gardens, wherever, in a word, the difference of level to surmount did not exceed some forty feet. With the assistance of the machine proposed by Papin, there is no height, on the contrary, to which water might not be carried, even in using a very low pressure of steam: for this purpose it is only necessary to give a sufficiently large diameter to the cylinder. To sum up, Savery tried to make use of the elastic power of steam, to * In fact, merely a thin stratum of hot water is formed by the condensation of the steam, and Savery's engine by no means raises hot water, as asserted by M. Arago; a very similar engine to Savery's, has recently been put up in one of the slaughter houses (abattoirs) of Paris to raise water! TRANS. † Mr. Robert Stuart believes that in introducing a float in the body of the cylinder, Papin's object was not to hinder the condensation of steam. (Seea Descriptive history, 21 edit. p. 52.) Papin nevertheless explains himself very clearly upon this subject, and we shall even see by the passage, which I find in page 26, of the work published in 1707, how forcibly this defect struck him: .. "I remark that the steam which passes into the pump to drive the water out of it, meets in the machine, (Savery's) cold water which condenses it, and makes it lose the greater part of its force. It is only after the water is heated that we can expel it ....; to heat the water in this way a great deal of steam must be consumed. It is necessary, therefore, frequently to replenish the boiler with fresh water, and it requires a great deal of time, and of wood to heat it again. Lut by means of our piston, (flotteur a deux fonds) the steam encounters always the same surface of metal, which soon acquires such great heat that the steam loses little or nothing of its force by the contact." 1 drive up water in a vertical tube; but Solomon de Caus had done it precisely in the same way, eighty-three years before. Savery filled the vessels in which the steam was afterwards to operate, by suction; but suction was not a new principle in 1698, since the " abhorrence of a vacuum” had been very anciently invented to explain it, and because we find elsewhere applications entirely similar to those of the English machinist, in the Raisons des forces mouvantes; suction at the most, added very little to the value of the machine, for it increased only by some thirty feet the height to which the liquid would have been raised without its aid. Savery, at length, caused the vacuum which produced the suction, by condensing the steam; here the method is important, but Papin had published it long before. The patent granted to Savery is dated 25th July, 1698; the trials of his machine before the Royal Society, took place in the month of June, 1699; the first edition of the Miner's Friend is dated in 1702, thus Papin's titles have a priority of three years, even if setting aside the Acts of Leipsic, we only go as far back as the Recueil, in which several memoirs of this machinist are found, for this work was published in 1695. What then is left to Savery? The honor of having first executed on rather a large scale, a steam draining machine, and if you please, that of having caused condensation by the affusion of cold water on the outside of the metallic vessel containing the steam. In describing for the first time this ingenious method of producing a vacuum, Papin, in fact, neglected to explain the different constructions easy to imagine, (these are his expressions) which may be employed to attain this end. During his experiments with a small cylinder, he contented himself, as we have seen with removing the fire. 1705. Newcomen, Cawley, and Savery.* The draining machine known to artisans by the name of Newcomen's engine, or, the atmospheric engine, was the first which rendered any essential service to art. I will observe indeed, that in a great many places where coal is not dear, it is still in use, and that it has not been found profitable to replace it. This machine, finally, excepting some details in its construction, which I shall notice farther on, is none other than the machine proposed in 1690, and 1695, by Papin, and which he tried on a small scale. In both, we remark, in fact, a vertical metallic cylinder closed at the bottom, open at the top, and having a well adjusted piston intend. ed to work through its whole length. In both, the ascending motion of the piston works by the effect of a counter-poise, when the steam can come freely into the lower part of the pump and fill it. In the English machine, as well as in Papin's, as soon as the piston reaches the end of its ascending course, the steam which has forced it there is condensed, and in this way a vacuum is made in the space through which it has just passed, and the atmosphere forces it then to descend. Papin announced that this condensation must be effected by cold; and it is by cold that Newcomen, Cawley, and Savery, also get rid of the steam which would counter-balance the atmospheric pressure. Among many different constructions which may * Thomas Newcomen and John Cawley, both lived in the town of Dartmouth, in Devonshire. The first was an iron monger or a black smith, for he is mentioned as exercising both of these trades in the English biographies; the latter was a glazier. Newcomen was a man of some education, and was in correspondence with Hooke, Secretary to the Royal Society, and one of the most ingenious Savants of whoun England may boast. We are ignorant whether the two associates took an equal part in the various experiments which led to the construction of the first large atmospheric engine. be imagined for this purpose, (this is the expression contained in the Recueil de pièces, p. 53,) the English machinists have adopted one, much preferable in a large machine, to that which Papin himself used in the experiments made with his little model. In the place of removing the fire as Papin did, Newcomen, Cawley, and Savery, caused an abundant quantity of cold water to flow into the annular space comprised between the outside of the cylinder and a second cylinder rather larger in size, which enveloped it. The cooling communicated itself in this way gradually to the whole thickness of the metal, and soon reached the steam itself. Papin's machine, thus modified as to the mode of cooling the aqueous vapor, excited the attention of proprietors of mines in the highest degree, and appeared, from the beginning, to furnish an unhoped for solution of the problem of which the fruitless attempts of Savery had particularly shown the difficulty. Newcomen, and Cawley, solicited a patent. Savery objected that he was already in possession of an exclusive privilege with regard to the means of producing a vacuum by condensing the steam. To avoid all dispute, the patent was taken out in the name, and for the advantage of the three competitors, who in this way attributed to themselves, in the plan borrowed from Papin, the two first the idea of the steam engine with a piston, and the third that of condensation.* At the commencement of the 18th century, the art of constructing large and perfect cylinders, and the art of fitting to them movable pistons, which close them hermetically, had made very little progress. Thus, in the machine made in 1705, to prevent the steam from escaping through the interstices comprised between the surface of the cylinder and the piston the upper surface of this piston was continually covered by a layer of water which penetrated into, and filled all the hollows. One day while a machine of this description was in operation under the eye of the constructors, they saw, with extreme surprise, the piston descend several times in succession much more rapidly than usual. This rapidity appeared the more strange to them, as the refrigeration produced by the current of cold water which descended along the outside surface of the body of the cylinder, had so far been rather slow in producing the condensation of the steam on the inside. Upon verifying the fact, it was proved that on this occasion, the phenomenon was attributable to an entirely different cause: the piston having accidentally a small hole in it, the cold water which covered it, passed into the inside of the cylinder itself, in a jet, across the stream, cooled it, and consequently condensed it faster. From this period, atmospheric engines were provided with an opening like the mouth of a watering pot; from this proceeded a shower of cold water, which spread in the interior of the cylinder, and there condensed the steam at the moment in which the piston was about to descend. The exterior * In the arts, as in the sciences, the last comer is supposed to be acquainted with the labors of those who preceded him. All denial in this respect is without value. The publication of the memoirs written by Papin upon the atmospheric engine, being much anterior to the patents granted to Savery and Newcomen, I shall have no motive for investigating whether the English machine is, or is not a copy: according to rule, it is a copy since it is like Papin's machine, and because it followed it. But we krow moreover, in this particular instance, that Newcomen was acquainted with the plans of our countryman! It results, in fact, from various notes found among Hooke's papers, that the Dartmouth artist had consulted this famous Savant before beginning his experiments, and then, in the confidence of intimacy it was really the French engine which he wanted to construct. (See Robison A System, &c. vol. 11, p. 58.) cooling was in this way suppressed, and the strokes much quicker. This important improvement, like many others which might be cited, was the result of a fortunate accident. I regret very much not being able here to point out which of the three associates it was whose inventive mind saw directly, in the unexpected event of which I have given an account, the principle of an improvement which is still found in the engines of the present time; but tradition gives us no information upon this subject. [TO BE CONTINUED.] Notices of the advancement of Mineralogy in 1837, from Berzelius (Continued from Vol. XXIV, page 367.) In the former report p. 206, I mentioned two of the new minerals analysed by Thomson, one of which was said to consist of 2 (CaO + CO2) + (Ba 0+C02) and the other of one atom of sulphate, and two atoms of carbonate of baryta. Johnston* repeating the analysis, found the former (Ca 0+ C 02) + (Ba 0+C02) and the latter Ba 0+C 02 or a simple carbonate of baryta. Thomsont again repeated the analysis of the former, and although this formula differs from his first, yet it varies from that of Johnston, being represented by the formula (Mn0 + CO2) + (4 CaO + CO2) + (4 Ba 0+ CO2), or one part carbonate of manganese with four parts each of the carbonates of lime and baryta. The identity of its crystaline form with that formerly given for the same compound, favors the results of Johnston. It will be interesting to see how many of the results of Thomson's analyses presented in my last report, will stand the test of the experiments of other chemists! Sheppard examined a protophosphate of cerium (Edwardsite) which occurs in Gneiss, in Norwich, Connecticut. It forms crystals, with an oblique rhombic prism as its radical; the small prisms generally present pyramidal terminations. It is hyacinth red; gives a white streak; is translucent-transparent; sp. gr. 4.2-4.6. It is found in crystals from of an inch in breadth. Before the blow pipe it becomes pearl-gray with a yellowish tint, and fuses on the edges to a transparent glass. Analysis gave: The proportion of phosphoric acid to oxide of cerium is represented by (Ce 0)3 + (P2 05). Copper-mica from Goslar was examined by Borchers. It is a pale, sometimes gold-yellow, artificial mineral product of a metallic splendent lustre, in the form of very thin, micaceous, six sided tables, occurring in an inferior kind of copper, called by the workmen mica-copper, and remains after dissolving the copper in nitric acid. This peculiar product consists of: * L. & E. Phil. Mag. X, 373. † Journal für Pract. Chem. XII, 185. Poggend. Annal. XLI, 335. The oxides of copper and nickel together, appear to contain four times as much oxygen as that of antimony. Damur* analyzed a vanadiate of lead, the locality of which was unknown. It sits on quartz, forming brownish-yellow warts, which are dark green on their fractured surface, but yield a pale yellow powder. It contains: Apjohnt analyzed a mineral from Africa, which occurs in snow-white fibres with silky lustre, about 6 inches in length, and ascertained its composition to be (Mg 0 + S03) + (Al2O3 + S309). It is therefore an alum, in which the potassa is replaced by protoxide of manganese. Von Holger has undertaken to enrich the science of mineralogy with an entirely distinct branch, of which no one would previously have dreamed, viz. with a "Pathology of the mineral kingdom." In order to have a Pathology, minerals should also possess vitality. "No one," says V. Holger, "now views minerals as lifeless bodies, in contradistinction to living, organic beings, but it is believed that they possess life like the latter, although it is of a different kind. They must then exert vital energy, &c." He proceeds from this introduction to the Diseases of minerals, which constitute mineral Pathology, and attempts to show that they may be diseased in regard to their composition, their form and their origin. What was said by a philosopher about 2000 years ago still holds good, that nothing is so absurd, but it may at some day be asserted and maintained by the learned ! The present number closes the extracts from Berzelius' Report, for the year 1837, and should it be deemed of sufficient interest to the readers of the Journal, the committee will endeavor to introduce similar notices from the Report of 1838, which is at present in the course of publication in Germany. Civil Engineering. On the Mensuration of Excavation and Embankment, upon Canals, Roads, and Rail Roads. By ELLWOOD MORRIS, Civil Engineer. On directing the attention to Public Works, one is immediately struck with the vastness of the amount of money expended in Excavation, Embankment and Masonry: forming on the Roads and Rail Roads, usually the chief, and on the canals nearly the only items of outlay. We have the authority of the Chev. de Gerstner, that the 3000 miles of railway this year * Journ. für Pract. Chemie. XI, 134. † Annal. der Pharmacie, XXII, 272. ‡ Zeitschrift für Physik von Baumgärtner & Ritter, v. Holger, V. 159. |