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REPORT ON MR. C. W. WILLIAMS'S PATENT FURNACE, AS APPLIED TO MARINE BOILERS. BY JOSIAH PARKES, ESQ., C. E. To the Directors of the City of Dublin Steam Company.

Gentlemen,-Having been called upon by you, professionally, to examine the construction, management, and effect of Mr. Williams's Patent Furnace, as applied to marine steam-boilers, and to report thereon, I have to state the following results.

The experiments were conducted, during several days, on a boiler 15 feet in length, having a grate of 2 feet broad by 3 feet 9 inches long, the length of flue traversed by the heat being 40 feet from the grate to the foot of the funnel, and presenting a heated surface of about 300 square feet. This flue was surrounded on all sides by a water space in the usual way of marine boilers, and the boiler truly represented a section of those which commonly form the generating apparatus of a large steamer.

In order to obtain the value of Mr. Williams's method of inflaming the gases passing over from the fire, I first ascertained the weight of water which this boiler was capable of generating into steam under the ordinary working circumstances; that is, when no air was admitted except through the grate from the ashpit. The fire was carefully managed, and as much coal burnt off the grate during the day as the full draught of the funnel was capable of effecting. A continuous steam of smoke issued from the funnel, which varied only in its depth of black colour according to the quantity of gas and soot passing off unconsumed.

On the following day the boiler was worked on Mr. Williams's principle, no other change having been made than the opening of the air passages which communicate with the gaseous matter beyond the bridge. The results, from the commencement to the termination of this second experiment, were of a highly interesting and satisfactory nature. Scarcely a trace of smoke was visible at the summit of the funnel, except at the instant of firing or poking the fire. On inspecting the flues through the various sight-holes pierced for that purpose, and by which I was

Some notice of the Association transactions referred to by Mr. Williams will be found in a subsequent part of our present Number. Edit.

enabled to see every part of the interior, the gases were found to be converted into perfectly bright flame, and there was no deposit of carbonaceous matter. The evaporative power of the boiler was considerably increased, arising in part from the increased draught produced by the ignition of the gases, and in part from the heat occasioned by their more perfect combustion. A difference of 47 per

cent. resulted in the weight of water vaporized, per pound of coal, in favour of Mr. Williams's process.

This large increase in evaporative economy and power, obtained from the mere ignition of the gases, might surprise persons unacquainted with the structure of marine boilers; but it is readily accounted for. The flues of such boilers are altogether immersed in water, and, if combustion be not complete, become rapidly coated over with soot and tar, (which was the case in the first day's experiment,) and these substances impede, to a great extent, the transmission of heat through the metal. At no one period, during the working of the boiler on the common plan, was I able to discern, through the sight-holes, a ray of light in the flues: a densely black current of gas and smoke occupied them. On the second day, the flues were constantly filled and traversed by brilliant flame, or clear transparent heated gaseous products of combustion, and the thermometer, at the foot of the funnel, indicated a temperature in these escaping products more than double that marked on the first day. This is, necessarily, so much waste heat; but, unfortunately, the space assigned to boilers in steam-boats will not frequently permit so extended a surface to be exposed to imbibe the heat and transmit it to the water as is requisite to obtain the greatest economy in the use of fuel.

During the above-named and other experiments, I made numerous essays of the effect produced by shutting off the admission of air to the gases behind the bridge, after the visible inflammable gases, such as carburetted hydrogen, had ceased to come over, and when the fuel on the grate was clear and incandescent. In such cases, I always found the entire stoppage of air to be followed by diminished heat in the flues and by diminished evaporation; for, at these times, carbonic oxide continued to be evolved—a gas which, though colourless, was convertible, by a due mixture of the atmospheric air, into flame, possessing evidently a high intensity of heat and producing much useful effect. The ca- · lorific value of this gas is lost when the air is excluded, although its non-combustion is not attended with the production of visible smoke.

The consequences of regulating and vary

ing the quantity of air admitted, so as to suit the varying state of the furnace as regards the quantity of gas given off, also occupied my close attention, and are important for you to know. It is quite certain, that, in order to effect the perfect combustion of all the combustible gases produced in a furnace, a large demand for air (distinct from the air entering the grate) always exists; also, that, by entirely excluding air from behind the bridge, smoke is produced in certain states, and the heat is diminished in all states of the fire. Thus, with correctly assigned proportions once ascertained, no attention is required, on the part of the fireman, in regulating the admission of air; for, though it is certain that by a nice adjustment of air to the various gases the effect would be increased, such attention is inconvenient and practically unnecessary, since, in all states of the fire, under the circumstances of rapid combustion practised in marine boilers, air is constantly required for those gases. The experiments were quite satisfactory on this head, that, to a certain and not inconsiderable extent, the quantity of air entering the diffusion bridge adjusts itself to the demands of the gas coming over; and this it is which renders the regulation of the air by the fireman unnecessary, just as the quantity of air requisite for perfect combustion in the Argand Lamp adjusts itself, within all practical limits, to the quantity of gas at any time in action, according to the desired length of flame. On looking through the sight-holes, it was manifest that, as a stream of either carburetted hydrogen or carbonic oxide gas was at all times generated and passing over, so there was necessarily and at all times a corresponding demand for air, and, when supplied, a continuous stream of visible flame, the minimum length of which was from 10 to 12 feet beyond the bridge.

There yet remains one other point of some moment to advert to. An inspection of the whole process of combustion, and of the absorption of heat, so completely afforded by the sight-holes, offers convincing evidence that the temperature, or intensity of the heat developed in different portions of the first or fire flue, is very uniform. The inflammation of a current of gas is a continuous, not a momentary, process; nor is it confined to any one spot. It would be difficult to assign the place of maximum temperature when large quantities of gas are coming over, as it necessarily varies with the nature and bulk of the gases evolved, as does also the length of flame produced; which, in these experiments, sometimes extended through 40 feet and entered the funnel; whilst, at other times, the flame did not exceed 12 feet in length. So far as brilliancy of light can be

considered as an index of intensity of heat, every observer of the process will be satisfied that the most luminous aspect of the flame exists at the distance of many feet from the place where the air is admitted, and not until after a perfect incorporation of the air and gases has been effected. These remarks may, possibly, serve to dissipate an idea which has long been nourished and is even still propagated by inexperienced persons, viz., that the inflammation of gas under a boiler after it quits the fire-place (not before) is injurious to the metal, or, as they suppose, tends to burn the boiler. How such an effect can be produced, while the vessel contains water and is in clean condition, has not yet been attempted, rationally, to be explained. It is well known that an approximate equilibrium of temperature obtains with wonderful rapidity amongst all aëriform fluids where motion or communication is unimpeded; and, in the case of the flues of steam boilers, the motion of the particles of heated matter, as well as the absorption of heat, is far too rapid for the determination, to any particular spot, of an intensity of heat likely to be prejudicial when the vessel is clean and a proper circulation of the water is provided for. An ocular inspection of the combustion of coals in boiler furnaces cannot fail to satisfy the most sceptical person that a far more uniform temperature exists in the fireplace and flues, when using Mr. Williams's, than in the common process.

I have alluded to the great waste of heat escaping through the funnels of marine boilers, when pressed, as they frequently are, from contracted dimensions, to afford the greatest possible quantity of steam in a given time. A great corrective of this waste seems likely to result from the introduction into the flues of Mr. Williams's conducting pins, trials of which, to some extent, have proved satisfactory. As this, however, is a subject distinct from combustion, and as Mr. Williams is arranging the means of submitting the invention to exact investigation in marine boilers, I propose to make it the subject of another report.

I enclose the details of the present experiments, and remain,

Gentlemen, your obedient servant, JOSIAH PArkes. Westminster, 7, Great College-street, May 30, 1842.

METHOD OF IMITATING MAPLE AND OTHER FANCY WOODS.

SIR, I beg to send you a description of a method invented by me of improving the appearance of most common woods, as plane, birch, and the like, so that they

may be employed in veneering and beautifying the most costly cabinet work, &c. The wood is first sawn into sheets or slips of about one-eighth of an inch in thickness; this done, they must be pressed between two warm metal plates, having corresponding grooves cast on the surface, resembling waves (and fitting accurately when placed together); the sheets of wood must be kept between them until they have properly set and become firm, when they may be taken out, and, after the inequalities have been planed off and made smooth, the texture and appearance will be precisely that observed in the finest and most beautifully figured maple; the richness of the latter arising entirely from the form and disposition of the fibres.

If a strong pressure be at command, the sheets of plane-tree may be made very considerably thicker previous to undergoing the process just described, so that they may be afterwards sawn into two or three separate veneers, instead of one only being produced,

Your obedient servant,
T. W. NAYLOR.

Newcastle-upon-Tyne.

PRACTICAL GLEANINGS FROM THE TRANSACTIONS OF THE MANCHESTER MEETING OF THE BRITISH ASSOCIATION. JUNE, 1842.

[The following notices are chiefly derived from Reports of the Meeting which have appeared in the Manchester Guardian, and which, for their great extent and general accuracy, do much honour to the provincial press. When taken from other sources, these sources will be found also duly acknowledged.]

MAGNETIC AND METEOROLOGICAL

OBSERVATIONS.

Sir John Herschell made a report on the great system of magnetic and meteorological co-operation, which, three or four years ago, was commenced by the British government, at the instance of the British Association, and which is by far the greatest combined scientific operation the world has ever yet witnessed. After noticing the vast increase and extension of the surveys and observations, the report referred to the Antarctic expedition, taking it up where the report of last year left it, at Hobart Town, in 1840. Captain Ross observed the November term [for observations] in 1840, at the Auckland Islands. Though (according to observations which had lately reached England) Captain Ross was still to the east of the greatest intensity, the intensities observed by him in those regions exceeded by 24 the minimum of the observations made by him near St.

The Ad

Helena, on his outward passage. miralty (who had rendered every service to these inquiries) had placed under the care of Col. Sabine the observations made on board each ship by Mr. Fox's instrument, the results of which were most satisfactory, as regarded the observations at sea; for out of 647 observations of this kind made between London and the Cape, on board the Erebus and Terror, one only had been declared doubtful; while the observations taken by both ships exhibited a steady accordance, that could not be accidental, and might well be called beautiful. It would appear, that the line of least intensity in successive meridians is travelling rapidly northward. The terms of November, 1840, had been kept (by Captain Ross) at the Auckland Islands; those of May and June, 1841, at Van Diemen's Land; those of July, at Sydney; later terms had been kept in New Zealand; and the November terms in the Bay of Islands; and, from a letter from Captain Ross, dated 22nd November, 1841, it ap peared that the expedition was to sail the day following, to resume the investigation; and it was his intention to traverse the isodynamical oval, which was supposed to be in latitude 60 south, commencing in longitude 10° and latitude 52° 53′ south; and it was his intention to pursue the frozen barrier wherever it was accessible; the working out of which intention might of course involve another winter, spent within the Antarctic zone. Should it be otherwise, we might expect ere long to hear of his arrival at the Falkland Islands; but, in the other alternative, another year would elapse without any further tidings of the expedition. As to British and foreign observatories, the British and Indian stations, except that at Aden, had long been in full activity. The Russian government had been pre-eminent in the aid given, supported by Mr. Cankrien, minister of finance, as well as aided by the funds placed at the disposal of the parties conducting these observations by Prince Menzikoff. Amongst other things noticed were the re-erection of an observatory at Tiflis; the erection of a new one at Moscow, under the care of Count Strogonoff, curator of the university of that city. These operations, conducted by every European power, had occupied much time; the original term granted by our own government and the East India Company expired in the current year, just when the arrangements were completed over a great portion of the world, and the fruits were beginning to be gathered in. Accordingly, application was made to government by the president and council of the Royal Society, for their continuation for another period of three years, to terminate

in 1835; and at the same time it was officially stated, on the part of the Russian government, that the observatories in that empire should be kept up as long as the British ones, Baron Brunow stating, that this extension was the shortest adequate to obtain results to repay the outlay. The British government gave an unhesitating assent to the continuation of the present scheme for three additional years. For this new period the past had been an excellent preparation; all improvements that experience could suggest would be adopted; hourly instead of two-hourly observations would be made, and hourly magnetic corrections might henceforward be accurately determined and confidently applied. But the past had not been merely a season of preparation; it had afforded demonstrations of the ubiquity of those singular disturbances called magnetic storms, which could not otherwise have been obtained,-data, which afforded numerous proofs in support of the truth of the Gaussian theory. As to magnetic surveys, in South Africa, Lieutenant Clarke, R. A. had joined the observatory at the Cape, as assistant to Captain Wilmot; and it was proposed that the survey should comprehend, in addition to the colony, as extended a portion of the earth's surface, from the observatory, as circumstances would permit. The Admiralty had instructed the admiral on the station to permit the sea portion of the survey to be carried into execution, so far as it was not prejudicial to the service, in her Majesty's vessels, and these surveys would include the coast on each side the Cape; and then we should be better able to judge of the expediency of completing the survey by an expedition into the interior. The Geographical Society had furnished a notice of a great lake in the interior of Africa, the existence of which was ascertained, but which had never been visited by Europeans. In North America, Lieutenant Lefroy had been appointed to the principal observatory at Toronto; he was now in England preparing instruments, and would proceed thither in a few weeks, to assist Lieut. Younghusband, in the observations conducted on the excellent system of Mr. Riddell. The Hudson's Bay Company had liberally undertaken to furnish conveyances in the years 1833-4 and 1835, to extend the surveys to the Pacific Ocean, and they also made an offer of passages on board their annual ships to England; and this would enable them to include in this magnetic survey Hudson's Bay and Straits. In the United States, Professor Bache (of Philadelphia), during the last summer, had completed the survey of Pennsylvania commenced in the previous year, including three series of observations-the

declination, inclination, and survey. These and numerous other observations and surveys in the States would connect the northern British survey with the determinations of Captain Barnett, of the Thunder, in the Gulf of Mexico. As to observations at sea, by the use of Mr. Fox's instrument the inclination and dip of the magnetic intensity might be measured with a precision quite as great as requisite for every possible use to which observations at sea could be turned, for the purpose of tracing out the isodynamic and other magnetic curves in portions of the globe covered by water. To extend and facilitate the use of this valuable instrument, the set of instructions drawn up by Colonel Sabine had been printed by order of the admiralty, as a general circular, with some statements of the mode of using it practised on board the Erebus and Terror; and the hope was expressed, that this method would be followed, not only in exploratory voyages, but by ships pursuing ordinary tracks, so as to furnish data for complete magnetic seacharts. For these important observations, as well as the declination, it was necessary to eliminate the quantity of ship's iron-an evil increasing from the greater quantity now used. After noticing the observations of Captain Belcher, of the Sulphur, on more than twenty islands in the Pacific seas, which had arrived in England, and would be published, and the important results deduced from M. Erman's magnetic journey in Siberia, the report noticed the subject of magnetic disturbances, respecting which Gauss remarked, that one of the results of this British enterprise was that the existence and extension of these disturbances over the whole of the globe had been ascertained. As a physical fact, this was indeed a result of the first magnitude; and considering all the circumstances, how it was modified by distance and locality, was eminently calculated to lead to theoretical truths. It distinguished what was local from what was general, and traced individual shocks from observatory to observatory, and station to station, till they were so far enfeebled as to be confounded and masked by the growing influence of other shocks nearer the principal point of observation. The report recommended smaller bars than those now in use, as more easily affected by sudden shocks. It was now considered advisable to collect from all sources to which we had access, accounts of the remarkable disturbances beginning with 1840 and 1841, arranging them in chronological order, and publishing them in volumes by themselves; and the first volume would be published in the course of this summer. The great disturbance of the 12th of September 1841, which was observed at Greenwich, and was immediately

made the subject of a circular from the astronomer-royal to his brother observers, was also observed at Toronto, the Cape of Good Hope, Cape Drummond, and Travancore. The reports from all these stations arrived in time to be inserted in the volume for 1841; and surely it might be regarded as a remarkable fact, that this phenomenon was seized upon by our observers in Europe, Asia, Africa, and America, reduced to determination, and printed in three weeks after the arrival of the observations in England. The returns from the different stations, showed, that these disturbances were general; that, though the movements individually might not be, and in fact, were not always, simultaneous, the observations on the same day never failed to exhibit unusual discordances at all the stations, and were generally characterized by the diminution more or less of the horizontal intensity, prevailing more or less for several hours every where, and the movement of the north end of the needle towards the west. Besides the colonial observatories, these phenomena were watched with great attention at the observatories of Prague, and Munich. The report next noticed the new magnetic instruments and modes of observation. We can only enumerate the former, viz.—the transportable magnetometer, Dr. Lloyd's induction inclinometer, Weber's inductive inclinometer, and another method proposed by Dr. Lamont. The report next enumerated the publication of various magnetic observations, and descriptions of observatories during the year. The only expense incurred by the Association, during the year, was 101. 88. 10d. for observatory registers; and the committee prayed a further grant. [A grant of 891. 118. was afterwards voted.]

STANDARD WEIGHTS AND MEASURES.

The Rev. Dr. Peacock, dean of Ely, after stating that the Imperial Standards of Weights and Measures, (the yard, the pound, the gallon, and several of their multiples,) had been lost in the fire which destroyed the two houses of parliament, mentioned, that a commission of which he was a member, had been appointed to report on the best means of restoring these standards. The standard pound weight was Troy weight (5,780 grains,) though the pound avoirdupois (7,000 grains) was used throughout the country, in the proportion, perhaps, of 10,000 to one of Troy. The commission recommended the standard pound to be the representative of the avoirdupois, and not (as before) of the Troy pound; that, hereafter, the use of the Troy pound should be abolished, except for a very limited number of transactions, and 'hat the avoirdupois pound should be con

sidered as the standard pound of Great Britain. They recommended that measures of capacity should be determined by measures of weight,-by far the most convenient method, inasmuch as weighing was a much more accurate operation, than, for instance, the formation of a perfect cube. The commission also ventured to recommend strongly some alterations in the coinage, and the systems of weights and measures, arising out of a more extensive introduction of the decimal scale. The nearly unanimous determination of the commission was, that any attempt to interfere materially with the primary units of the coinage, weights, and measures, in ordinary use, would produce such confusion and bad consequences in the ordinary transactions of life, that they would adhere strictly to all those primary units, viz. the pound sterling of our coinage; the yard in the measure of length (and also the foot, for there were two primary units in this measure;) the acre, in the measure of areas; the gallon, in the measure of capacity; and the imperial pound, in the measure of weight. As the coinage must necessarily be the basis of any changes leading to the more extended adoption of a decimal scale,-Taking the pound sterling as the primary unit, they proposed to introduce a coin of the value of 28. (one-tenth of the pound ;) another, either silver or copper, of one-tenth of 28. (or 2d. and a fraction) which might be called a cent (the hundredth of a pound) and the thousandth part of the pound sterling, or nearly the value of our farthing, (of which there are 960 in the pound,) which new coin it was proposed to call a millit (from thousandth.) The difference in the value of the copper coinage was less important, as it was merely a representative coinage, and had not an approximating intrinsic value like the gold and silver coinage. For the proposed coin of 28. various names had been suggested, as Victorine, rupee, and florin; it being not much different from the value of some of the rupees of the East Indies, or the florin of the Continent. Under this new decimal scale, the shilling would be retained, and also the sixpence, (but the latter under another name, more representative of its value.) For the half-crown would be substituted the 28. or Victorine. The very rev. gentleman dwelt at some length on the advantages of this change, in the extensive money transactions and accounts of bankers and merchants; in the Bank of England, for instance, where a thousand clerks were employed, where it would greatly facilitate the operations of calculation and book-keeping. Thus discarding millets (for bankers now excluded the subdivisions of a penny in their accounts,) the sum of 171. 3 Victorines, 7 cents would be represented at once by 17:37 ; only

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