Example.-On August 1, 1835, the comet had 5. 20m. of right ascension, 220 19m. of declination, N., 61° 9m. of meridian altitude, and its meridian passage was 20h. 11m. 31st day of July. The astronomical day begins when the sun is on the meridian, or just 12 o'clock; reckoning 20h. 11m. forward, will make out August 1, at 8h.11m. A. M.; consequently, the comet must have risen somewhere about midnight, and set somewhere about 4 o'clock afternoon, of the 31st day of July. Remarks. The present comet is supposed to be the same that appeared in the years 1005, 1080, 1155, 1230, 1304, 1380, 1456, 1531, 1607, 1682, and, as predicted by Halley from the equality of the intervals between these appearances and from calculation, again in 1758. The year 1005 being subtracted from the present year, leaves an interval of time equal to 830 years, during which time it must have accomplished 11 revolutions; therefore, 8301175, or 75 years for the mean revolution. For short periods of time the period of the comet lengthens; thus, from 1005 to 1835, the average period, as has been stated, amounts to 75 years, or, decimally, 75-454 years; while from 1080 to 1835, a period of 755, including 1) revolutions of the comet, the average period is 75 years. All its average rates of revolution are as under : 833.624 years ÷ 11 = 75·784 years mean average period of Halley's comet, or about 27,678 days. On or about the 1st of August the comet was about 250 millions of miles distant from the earth. About the 1st of September its distance will be within 125 millions of miles; it will rise about midnight in the N. E., and will then be visible till the dawn of day in the eastern heavens. On or about the 3rd of October, the comet will be only about 42 millions of miles from the earth, and will be seen entering the fore-foot of Ursa Major, or the Great Bear; this will be the period of its greatest brilliancy and magnitude. About the 8th of October it will approach nearest the earth, being within 28 millions of miles. The nearest approach of the comet to the earth will be between the 7th and 8th of October; but it will not reach its parhelion till the 17th of November, or about 40 days after its nearest approach to the earth, which is a matter of some regret; for had the comet been in its parhelion, and at its least distance from the earth, at the same time, a much more magnificent sight of cometary phenomena would have presented itself to our view. On the 17th of November it will be about entering the sign Gemini, and its distance from the earth will be about 90 millions of miles. The tail will then increase in brilliancy and magnitude. The comet will now rise earlier and earlier every suc ceeding evening; and its motion be very rapid. About the 20th of November, the comet will lose itself in the Sun's rays, and will be invisible till about the 27th of December, when it will again re appear at the distance of about 230 millions of miles. Once more it will approach the earth, and will remain visible till about either the 7th or 15th of February, when it will lose itself in the voids of space, near the largest star of Centauri, in right ascension 14°. 9'., and in declination 32°. 1'. south. Note. The same comet was in its perihelion about the 12th of March, 1759, and having reached the same point about the 17th of November, 1835, this shows the time which it has taken to enjoy itself in its last circuit round the Sun to be about 76 years, 8 months-a much greater length of time than it has hitherto employed. It may be inferred from the analysis given of its various periods, that its period is on the increase; but as the precise days of its entry into its perihelion, on each of its recorded appearances, has not been given, this cannot be positively determined. The comet was seen at Rome about six days ago; and it is reported to have been visible in England on Thursday evening, the 20th of August. Notices of the Appearance of the Comet. E. H. Observatory of the Collegio Romano, Rome, Aug. 6.-Yesterday, at about halfpast 7 (Roman time), Halley's comet was seen from here, at that part of the heavens calculated by Damoiseau. Its light was very faint, much resembling that of Biela's comet. It is near the star Zeta, in Taurus. Its right ascension we found to be 50. 26'.; and its north declension, 22o. 17'.- Algmeine Zeitung. Observatory, Kensington, Sunday Morning (23d Aug.) 4 o'clock.-Having cautiously examined that portion of the heavens between 4 hours, 50 min. and 6 hours, 30 min. of right ascension, and 30 and 24°. north declension, I found in the field of the telescope, at 1h. 11m., sidereal time, a round, well-defined nebulous body, hitherto undiscovered, extremely faint, and perhaps about 2m. of space in diameter.-James South, Times, 24th August. Ditto, Monday Morning, 4 A.M.-The nebulous body is Halley's comet. At 23h. 55m. and 47s., sidereal time, this morning, its right ascension was about 5h. 43m. and 8s.; whilst its northern declination was 23°. 49m. 43s.-James South. Ibid. Rectory, Hayes, Kent.—Seen here by Dr. Hussey on the nights of Saturday and Sunday (22d and 23d of August), who, in a note to the Times, says :-" The approximate place is right ascension 5h. 42m. 30s., declination north 23°. 45m. 20s.; is very large, and in an achromatic telescope of 6.5 inches aperture, it is the faintest object the eye can distinguish."-Mr. Lubbock states, in a note to the same journal, "That the place assigned to the comet in the ephemeris published in the Nautical Almanac for 1835, Aug. 23, is 5h. 42m. 56s. right ascension; declination, 25o. 21m. 1s. A closer agreement could not have been hoped for." 66 Sir, I have read an extract from an American paper, in your last Number, p. 384, giving an account of the trial of the Lexington steamer. I do not quite understand the construction of her deck; and should be glad to receive further information by a sketch in your Magazine. Neither do I comprehend how she could move at the rate of 20 miles an hour, seeing the greatest velocity of her paddlewheels is but 19.7064 per hour. Perhaps your printer made the error, in stating the diameter of the wheel at 24 feet; surely it should have been 34 or 42 feet: it is in vain to expect an engine with a stroke of 11 feet to make more than 23 per minute; indeed, this speed for the piston is greater by far than is usual in England; so that the speed of the vessel must be attained by increasing the diameter of the wheel. Under this idea, I do hope your cor respondent will write for a more detailed account of the Lexington and her engines, for at present she looks a "trifle slanting-dicular." At the saine time, I am ready to acquit your correspondent of any personal intention of misleading your readers. 1 am, Sir, Norwich, August 22, 1835. W. THOROLD. 66 Sir,-Having read in your valuable journal for August 15th, an account of the fastest boat in the world," I was induced to look minutely into the description given; and upon comparing the diameter of the wheel with the number of strokes mentioned, I find that the speed of the boat (which is stated to be twenty miles per hour) is two miles an hour faster than the motion of the periphery of the wheel! Now, Mr Editor, I take upon myself to say, that no steamer in this country has approached within some miles, the speed of the diameter of the wheels. The "Diamond," "City of Canterbury," and "Star," now running in the Thames, are no doubt the three fastest boats in Europe; the speed of these boats, is as near as possible, thirteen geographical miles per hour, during which time the periphery of the paddle-wheels moved seventeen miles, travelling four miles per hour faster than the vessel. Now in the description of the "fastest boats in the world," the diameter of the wheel is given at twenty-four feet, and the speed twenty-one to twenty-three strokes per minute; I have taken the mean of twenty-two strokes per minute; this gives, for the speed of the wheels, eighteen miles per hour, and deducting four miles, as is the case with the three boats before mentioned, will leave fourteen miles per hour; but I will not allow the Americans even this speed, for two reasons; first, it will be observed, that I have founded my previous observations upon three of the fastest, as well, perhaps, as the best boats in this country, both as regards engines and construction, which is the reason that the speed of these boats approaches so near the speed of the wheels; for if the average of thirty boats on the Thames be taken, we shall find that the wheels are often going fifteen miles an hour, while the boats are going only ten miles. Again, the lumber, which is used in American boats, and called steam engines, can never be compared with the engines as now manufactured by our first-rate makers, either for lightness, safety, or effective force. Taking all these facts into consideration-facts which are well known to scientific men in this country -I think we may allow the American boats a speed approaching thirteen miles an hour, and not more; and this speed is not produced by the eleven-feet stroke or the arched deck and beams, but from the simple fact of her enormous length, as compared with her beams. Vessels of this class may do very well for the large rivers of America, but never would do for sea service, or for the rivers of this country. 66 As I find in your last number, another American has been giving his countrymen a fillip, by endeavouring to explain more clearly than your former correspondent has done, why this boat has attained this wonderful speed," but which explanation only shews the manner in which she is trussed longitudinally; perhaps he will now have the goodness to explain, why in America steam ships go faster than their wheels, while in all other countries they gene. rally go from one third to one fourth slower. I am, Mr. Editor, NOTES AND NOTICES. Dear and Bad-It is stated by Colquhoun, that "the chief consumption of oysters, crabs, lobsters, pickled salmon, &c., when first in season, is by the lowest classes of the people. The middle ranks, and those immediately under them, abstain generally from such indulgences, until the prices are moderate.' ." This abstinence of the middle classes may be also ascribed to their better information; knowing that when provisions are highest in price, they are the worst in quality.-History of the Middle and Working Classes, Second Edition. The Great Western Railway.-The Lords' Committee, after an inquiry of forty-six days, have come to a decision in favour of the Bill for this railway. There was a majority of twelve in favour of the undertaking. Such was the interest excited, that more than seventy of their lordships attended the Committee and voted. "A Jurat" informs us, that the new Pier, Gravesend," presents the rare spectacle of a pub lic work of great difficulty executed within the architect's estimate." We are glad, but not sur prised, to hear it. The architect is Mr. Tierney Clarke, who built the Hammersmith Suspension Bridge, which also was erected for some 2001, or 3001. less than the estimated cost. We invite the attention of Mr. Barstow, and of Americans in general, to the letters in our present Number of Mr. Thorold and Fanqui, respecting the "Fastest Vessel in the World." R. M. M. has been misinformed. When engravings are necessary for the illustration of articles of "public interest," it is not our practice (whatever may be the practice of others) to charge the authors with the expense of them. We are at all times very willing to be at such expense; and the more extensively this is known, shall be the better pleased. W.'s valuable paper on Indigo, in our next. Communications received from Mr. MilbourneT. C. Mr. Davy-A Subscriber and AdmirerP. A. M.-T—§ H—d- Alongshoreman - Steam Serpent-Major Longbow -A Young Apprentice (who will find at the next P. O. a letter addressed to him). LIST OF NEW PATENTS, GRANTED BETWEEN THE 22D OF JUNE, AND 22D OF JULY, 1835. Henry Bernard Chaussenot, of Leicester-square, civil engineer, for an improved construction of the lamps or apparatus used for burning gas for producing a better combustion of the gas. July 28; six months to specify. Spole Rosenborgh Anderson, of Cornhill, Esq., for improvements in hand and power looms. July 28; six months to specify. Robert and Alfred Charlton, of Manchester, ca. lende ers and finishers, for certain improvements in the machinery used for stiffening and finishing woven or manufactured goods. July 28; six months to specify. William Crofts, of New Radfor, county of Nottingham, machine-maker, for certain improvements in certain machinery for making figured or ornamented bobbin net, or which is commonly called ornamented bobbin net lace, and which improve ments are in part in extension of part of the im provements for which Letters Patent were granted to him on the 23rd day of December, 1834. July 30; six months to specify. William Mason, of Brecknock-terrace, Camden town, county of Middlesex, engineer, for improvements in the manufacture of fire arms and artillery. August 6; six months to specify. William Mason, of Brecknock-terrace, Camdentown, county of Middlesex, engineer, for improvements in t'e manufacture of steam-engine cylinders, pistons, bearings, pumps, and cocks. August 6; six months to specify. Samuel Faulkner, of Manchester, cotton-spinner, for an improvement in the construction of a machine for carding cotton and other fibrous substances. August 6; two months to specify. John Cooper Douglas, of Great Ormond-street, county of Middle-ex, esq., for certain improvements in ventilating subterraneous and other places, and in constructing an apparatus or apparatu-es in which combustion is carried on, and al-o in a ply ing certain fluids to various useful purposes, and in constructing an apparatus or vessel for the ap propriation of such fluids. August 10; six months to specity. Edward Jones, of Birmingham, builder and brickmaker, for certain improvements in machinery for moulding bricks, ti es, and other articles made of brick earth. August 10; six months to specify. Samuel Wilson Nicholl, of Elham, near Canterbury, gent eman, for certain improvements in rendering condensing steam-engines portable and applicable as a means of general transport on rail and other roads. August 10; six months to specify. Luke Hebert, of Paternoster-row, London, civil engineer, for certain improvements in flour mills. August 10; six months to specify. William Evatt Wright, of Regent-street, Westminster, gentleman, for an improved box for holding coals. August 12; six months to spec fy. John Day, of York-terrace, Peckham, gentleman, for an improved wheel for carriages of different descriptions. August 14; six months to specify. Richard Sheppard, of Newport Pagnell, carpenter and builder, for improvements in ti es for covering of roofs. August 17; two months to specity. Thomas Rock Shute, of Watford, silk throwster, for improvements in spinning and doubling organzine silk. August 17; six months to specify. Frederick Bowman, of Great Alie-street, county of Middlesex, sugar-refiner, for an improvement in the process of renewing the virtues of animal charcoal when exhausted or impai ed, being a communication from a foreigner residing abroad. August 17; six months to specify. Henry Phillips, of Exeter, chemist, for certain improvements i purify ng gas for the purpose of illumination. August 17; six months to specify.. William Banks, of Spring-hill Terrace, near Birmingham, minufacturer, for a certain improvement in machinery pens and presses for ruling and pressing paper. August 17; two months to -pecify. Henry Pinkus, late of Pennsylvania, in the United States of America, but now of 76, Oxfordstreet, Middlesex, gentleman, for improvements in inland transit; which improvements are applicable to, and may be combined with, an improved method of, or combination method and apparatus for communicating an | Transmitting, or extending motive power by means whereof carriages or waggons may be propelled on railways or roads, and vessels may be propelled n canals, for which improved methods, &c., Letters Patent were granted to the said Henry Pinkus, dated the 1st day of March, 1834. August 17; six months to specify. Elijah Galloway, of Wellington-terrace, Water100-road, county of Surrey, for certain improveme: ts in paddle-wheels for propelling vessels. August 18, six months to specity. William Johnson, of the Horsley Iron-Works, county of Stafford, gentleman, for a certain improvement or certain improvements in the construc tion of boots and shoes. August 22; six months to specify. William Lucy, of Birmingham, miller, for certain improvements in steam-engines. August 24; six months to specify. Theodor Schwartz, technologist, formerly of Stockholm, but now of Bradford-street, Birming ham, for a practical application or practical a, plications of known principles to produce mechanical power. August 24; six months to specify. Charles Appleby, of Sheffield, merchant, for cer tain improvements in m nufacturing tiles. August 25; six mo..ths to specify. John Lane Higgins, of Oxford-street, Middlesex, Esq., for certain improvements in the construction of and in working vessels for navigation. August 26; six months to specify. Patents taken out with economy and despatch; Specifications prepared or revised; Ca. veats entered; and generally every Branch of Patent Business promptly transacted. Drawings of Machinery also executed by skilful assistants, on the shortest notice. LONDON: Published by J. CUNNINGHAM. at the Mechanics' Magazine Office, No. 6, Peterbo rough-court, between 135 and 136, Fleet-street. Agent for the American Edition, Mr. O. RICH, 12, Red Lion-square. Sold by G. G. BENNIS, 55, Rue Neuve, Saint Augustin, Paris. CUNNINGHAM and SALMON, Printers, Fleet-street. |