Newspapers / The Harbinger (Chapel Hill, … / Dec. 12, 1833, edition 1 / Page 1
Part of The Harbinger (Chapel Hill, N.C.) / About this page
This page has errors
The date, title, or page description is wrong
This page has harmful content
This page contains sensitive or offensive material
VOL. I. tXNIVERSITY OF NORTH-CAKOL1NA, CHAPEL HTLLvl THURSDAY, DECEMBER 121831. I NO,i f 6. PUBLISHED WEEKLY Under the supervision of tTi6 'of the University. Professors Terms Three Dollars jpr annum, payable yearly fj in atlance, or ' aur uouars 11 payment oe delayed six months after the commencement of each1 subscription . year. , Advertisements (which are limited to ,four co- i lumns,") inserted at the customary rates publisher, at Chapel Hill, Orange County, North Carolina. Internal Improvement. I DESCRIPTION OF THE LlVERPOOL AND MANCHESTER RAILWAY. There is so little in scenery thr-fs inte resting on the turnpike road fronij Liverpool to Manchester, that a formal description of the way between the two towns may ap- pear to be rather an unpromising! undertak ing. The travell jr along the Railway, how ever, will speedily admit that there is little I similitude between the two routes the whole Character, structure, and appearance- of the Raihray hei . altogether diflerenjl from the ireneral aspect of the turnpike toad. Instead i of d unifonn, 11 t. and uninteresting country, , the line ol naiiway is uiversiueu jconnnuai oy by hill and dale, offered to the contempla tion of the' traveller in a sort of inverse pre sentment, the passenger by this new line of roite having td.traverse the deepest recesses, j where the natural surface of the ground is I th highest, and being mounted on the lof- tiest ridgest and highest embankinent, rid r inET above the tops of the trees, hand over- looking the surrounding country! where the I natural surface of the ground is te lowest,--ih peculiarity and this' variety being occu sio'ieJ by that essential requisite in a well- co jstructed Railway1 a levied h:ne impo ! sinrthe necessity of cutting through the high ' land'and embanking, across thej low; tfi'us, in effect, presenting to ihe traveller all the j variety of mountain and ravine in pleasing i succession, whilst in reality he is n ovfpg al most n a level plane, and while the natural, face of the countrv scarcelv ex libits even I hose slight undulations which are necessary i to relieve it from lameness and insipidity. ! To accomplish a complete survey of the Railway, we should commence our journey ' of observation at the Liverpool end, in the Company's yard, at Wapping. Here the "lower entrance of the great Tunnel is acces- ; pible through an open cutting, 83 feet de6p and 46 wide, being space for four lines of Railway, with pillars between ihe linqsto supp-in me ucauis unu iitiuriiig ui iiie vuiii- nv s warehouses,-which are thrown across' his excavation, and under which ihe wagons pass to be loaded or uiscnarged tnrougn hathchways or trap doors communicaing 'with the stores above; wagons loaded with coal or lime passing underneath the ware houses to the open wharves at the Whap ping end of the station. 1 ' .. lnceeding along the. Tunnel, thejUiic of soiah-east, Railway curves to the right, or till it reaches the bottom of the incline! plane which is a perfectly, straight line. 1980 yards in length, with a uniform rise of three-quar- ters of an inch to a yardi The Railway Xroni WanDinir to the commencement of the. in- clined plane is level; the whole rise there- Jijre, from Wapping to the Tunn el mouth at Edffe-hill. is '13' feet,: .The Tunnel is 22 feet wide and 1G feet high, jhe sides being j perpendicular' for 'five i feet in heightsur ;munted by a semicircular arch of feet auius; tne total lengm is xou yarns. n is cut" through various strata of. red rock, blue shade and clay, but principally through rock of every degree of hardness', from the softest sand-stone to the most compact free-stone, which the axe or "the chisel wi etiltv penetrate. It frequently iecessary, irj the progress of the work, to rake an artificial vault of masonry, which ; las been effected by brick arch-work in those laces where , ihe natural rock could not be trusted to support the superincumbent mass. 'The height from the roof of the Tunnel up wards to the open surface of the ground, va lies from o feet to 70, the greatest mass of juperatraium being in the vicinity of, Hope street 'and Crabtreeuane. The whole length of this vast cavern is now furnished with gas-lights, and the sides and roof are white- Isashedi'tn give better effect to the lillumi- ration. The different colours appearance ,of the varying strata through uhich the Tunnel passes are thus hidden worn view, and the attention is no longer at faded to those faults or slips j in the solid t ck which indicate that the whole mass has pen rent 'asunder by one or more of those terrible convulsions of nature, of which the faces are so frequently visible, )but of which further record remains. The -geologist Kill be disappointed, in traversing the sub terranean vault,, to find the natural varieties I' C&nverted by lime-water into one' uniform n(i artificial appearance; but he principle f utility is paramount in a coi lmercial.tin Cfrtaking. : At the upper or eastern end of the Tunn- JiJ, the traveller emerges into a spacious and tjjtle area, 40 feet below the surface of the f pound, cut out of the solid rock, and sur- '- aounted on every side by walls and battle ments. From this area there returns a small tmncl, 200 yards in length. 15 feet wide, f1 . !cfl n,Sh parallel with tfie large one; tit inch ing upwards fn the opposite direc tion, and terminating fn the Company's pre! rises in Crown street, at the upper and'eas tern boundary of Liverpool; being the pi A cipal station for the Railway coaches, and the depot for coals for the supply of the higher districts of the town. j Proceetling eastward from the. two Tun nels, the, road passes through a Moorish archw ay, at present unfinished, which i to connect the two Engine-houses, ami will form the grand entrance to the Liverpool station. The structure is fro'D a spirited design of i Mr. Foster's. The traveller now finds himself on the open road, to Manches ter, and has an opprtunity of contemplating the peculiar features., of a well-construCtetii Railway, the line in this place bing per fectly level; the slight curve which was un avoidable beautifully set out; the road-way clean,. dry, and free from obstructions; and the rails firmly fixed on massive blocks of stone. Crossing Wavertree lane, the; Rail way descends fer5J miles at ihe rate of four feet in the mile, a declivity so slight and uni form as not 'o be 'perceived., ry the eye, but still sufficient to give a mechanical advaniage and facility of motion to a. load passing in that direction. The road a little beyond Wa vertree lane is carried through a deep marie cutting, under several massive stpne arch ways, thrown across the excavatinn to form ihe requisite ; communications beiween the roads and farms on the opposite sides of the Railway. Beyond the marie cutting js the great rork excavation through jQlive Mount, about half a mile to the north of the village mf JWavertre. Here , the 'traveller passes through a deep and narrow ravine, TO feet below the surface of the ground, lit tle more space being opened out than suffi cient for two trams of carnages to pa.-s eaci other; and the road winding gently round towards the south-east, the prospect is boun. (led by the perpendicular rock on either side, w ith the blue vault above, relieved at .-. ... ... 'i jnte.rvals bv a bndg i high over head, con Ti l . . mi ' i nerjiuig me opposite precipices. l lie, sines of the rock exhibit already the green surface of ,vegetation, and present' altogether 'far jnore oi me picturesque in ineir appearance man niigiii oe expecien irom so recent an excavation. At j night, when the natural gloom of the place is farther ,deepe'nM;."''the scene, from ihe bridges above will readily hie imagined to be novel and striking. The light of the moon illuminating about half the depth, and casting a darker shade oh the area below -the general silence interrupted at intervals by a noise like distant thunder ' presently a train'of carriages led on by an -Engine of fire and steam, with her lamps like two furnaces; -throwing their light on ward m dazzling signal of their approac.H- with the strength and spe -d of a'warliorse the Engine move? forward with its glorious cavalcade of merchandise from all countries and, passengers of all nations. But the! spec taele.is transient as striking; in a inoment the" pageant is gone the meteor is passed, the,, flaring of the lamps is only seen in the distance, and the observer, .looking down from the battlement above, perceives that all again is still, .and dark, and 'solitary. . Emerging from the Olive Mount cutting', yon approach the great Roby embankment formed ot the materials dug out of the exca vation we have described, lhis embank ment j stretches across the.jvallev for" about two. miles, varying in height- from 15!to 45 feet, and in breadth at ihe base from' 60 to 135 feet.-: Here the traveller finds himsell affected by sensations 'the very- reverse of what he felt a few minutes before.' Mounted i above the tops of the ,trees, he loqks around him over a wide expanse of country, in the full enjoyment of the fresh breeze, froi whatever quarter it may blou This vast embankment strikingly exhibits how much may be accomplished when our efforts are concentiated on one grand object. There is a' feeling of satisfaction by no means common-place, in thus overcoming obsta clcs and surmounting difficulties, in making the high places low and the; rough' places plain, and advancing in one straight and di rect course to tne end in vie - ; wtuie tne pleasure afforded by the contemplation' of this "great.; work is farther enhanced, when considered in contrast with ordinary land eve? ry-day impressions. A-y- T. j After passing the Roby embankment, you cross : the-Huy ton turnpike road, leaving II uy ton Church and village on the left hand, and proceed in a slightly curved direction to the bottom of the in line plane at Whiston, between seven and .eight miles from the Company's station .in Liverpool. This plane rises in the ratio of three-eighths of an inch in a yard, or'l in 96. It is a mile and a half long in one straight line, and the inclination (being so slight) would scarcely attract ob servation, did not a decrease in the speed of the ; carriage indicate that an . important change had taken place in the level of the way. At the top of the Vhiston inclined plane there iva portion of the road (nearly two miles in length) on the exact level. About half a mile from the top of the incli ned plane, the. turnpike toad from Liverpool to Manchestericrosses the line of the Rail way'at an acute angle of 34 degrees, and is carried' over lhe Railway by a substantial stone bridge, of very curious arid beautiful construction, being built on the diagonal or skew principle, each stone being cut to a particular angle io fit into a particular. place,! the span of the 'arch, measured at the face, being 54 feet, while the width of the Rail way underneath, measured from wall to wall, is only 80 feet each face of the arch ex- tending diagonally 45 ft. beyond the-squaie. Rainhil) bridge is nine miles from ti e Comr panyNs yard" in Wapping, and it was under- heath and on each of this bridge that the experiments took place with the Locomotive Engines which ; contended for the! premiuni of 500 in October 1829.- .J I , t f Passing over, the summit level at Rainhill, we come to the r5uttonirichned plaue, ivhich descentls jin the opposi te direction; and is si milar in extent and inclination io the Whis ton plane, the top level being jb2 feet above the basej of each plane. Par Moss is the next object of attention, the road way across the principal part of it being! formed by the -deposliei: lnlS tena J ;chfp'rL k ) dug out of the Suttnn incline(fj)7ane. This Moss is about 20 feet deep, artuhe materjial forming the Railway, as it wai deposited, sank to the bottom, and noWjfornis an em bankment in reality 26 feet high, tho' only four or, five feet appears above the surface of t ie Moss. The borderk of this waste are in a state of increasing cultivaiiohl, ; and the carrying or the Rail" ay. across ihis Mss will hasten the enclosure of the whole area. Leaviug Par Moss, wc sooii approach fhe great valley of the tSankey about half w;ay beiween Liveipool and Manchester, withfits Canal at the bottom, and its flats or bargf s in full sail passinor to and froV between the River Mersey, nea WarringtonJ: and the great Coal districts near St.? Ijelen's. 0k r this valley and Canal, and ot er the topmasts and high peutvs of the barges, the Railva is carried along a agnificen't viaducij of nine arches,, each 50 feet spaa, built princi pally of brick, with stone facings', j,he heighl from the lop ;f the parapets io the wateit n the Canabt ing 70 fee , aiul! the width j.f the R ihvay between the parapets 25 feet. The approach to this -reat structure is along a stupendous.' emhanko ent, formed princi pally of clay, dug out from the hi .h lands on the borders of the valley. Looking over the battlements, there' is a Sne view down the valley to the south 'Wiwiclij spire ri sing in i he distance, and below you, the lit tle stream ol the Sankc'y running parallel with the Canal; whilst the masts and sails of the v ssels, seen at intervals in'the land scape is ho longer visible, present a vivid specimen iif inland navigation. Immediately below you, the barges, as they approach the bridge,1 escape from view for ja few nunutes, till, having sailed under your feet, they he- ctm agdiif visible on the Ofposue side of the viaduct.'' " .j y , '--y: . ' , On leaving the Sankcv, we speedily ap prdach the tow n tf Newton, or ! ratherMhe hortmgh; j for this ancient arid loyal place send ds two representatives to Parliament, lin the auspices of Colonel Leghj M. P. ' A der the auspices "of Colonel Lechj M. P. f A few h mndred yards to the south ol the town Railway crosses a narrow valley by a the R shoit hut! hltv embankment, anj a hand- sonye bridge of f.-ur arclies each 40 feef span.,, Under the eastern arch ol. the turn pike roadj passes froio Newton' to Warring ton, and beneath another arch tlows a stream which turns an eld corn mill, iminediatjely below: the bridge. Adjacent als .-, is situate 'one of those antique ;-ma'nsionsbuiltp in the ancieni oaronicai siy ies, w nose ..w uue, rior,: vvi:h black oak crossings, -and pointed gables, harmonizes weli with the rude see nerv around. j I I A few miles beyond Newton is the geat ir . JL : c . . i : .v. . onr rt-enyon excavation, imm-wiucu ouuui- ovn,!, 000 cubic yards of clay ahdlsand have beu dug out, i part being; carried; to " form -;t line of embankment to the east arid w est the cutting, and the remainder, deposited le vf Ns spoil banks, may.be Reaped up, like Pjibn u)on Ossa, towering over tire .adjacent nnd. Near' the end of this cutting, the Kenyon ind Leigh Junction. Railvvay'ioins the Liverpool and Manchester line by two branches, point ing to the! two respectively.! ThisjRailjv ay- joins the Bolton and L"eigh1t-e, and thus forms the connecting link between Bolufn; Liverpool, ,' and Manchester, rrom tjit Keny)n excavations the transition is easy to the'Broselv embankment,; formed of the material f dug Mut of j the cutting, as before deicribed Moving onward, we. pass orer Buirv lane anl the small River less, Jor Glazebrook, being arrived the borders jof .1 ' . m ". nni',l'l ; 1L . i.: : tnft i;nai-iioss. tins oarre i vtuie cuiujj ses an area of about. twrelve squares miles,; varyi' in depth frdm 10 to 26 feeUf thei whole mass being ot so spongy and sott a texture that cattle cannot walk over it; jl'hei bottom is composed of clay arid .sand, and it is hot an uninteresting, if not a very profita-i ble speculation, to carry our 'ideas that remote period when ihe sea over thebasin of this huge fungus.' oacK tot ffujwf Ther. are thev who profess, by examining the- ve getable fibre of the Moss, to calculate its' age: as the fortune:teller will cast your na tivity by the furrows in your hand. I JNo. doubt this vegetable matter is. still increas ing. The flower and the leaf of the heather still. bud, grow to maturity, and fall; and the proces'3'of r Jecomposition amalgamates; the new and the old fibre;: but what is thus de posited ha been, previously1 extracted from the Moss, save what has been supplied ; from the hydrogen and other .gases absorbed and combined jin this great labratory. At a very moderate calculation Chat Moss comprises sixty millions of tons I of vegetable matter; and we shall leave to philosophers to calcu- i 1 1 . t . i i Vit iate m now many centuries una weigntcouiu be dr ewn j from the: clouds' and : the air. - Northward of the Moss, in the distance, i Ttldsley Church, odd of the modern Parlia- ' :' i ii eastern boundary.; conspicuous on a gentle ' eminence to, the left, ; is VVorsley Hall, ti. sea4 of R. If. Bradshaw, Esq. M. P. so well known as Trustee j U)i the Duke of Bridge- pater's Canal. . A, ' A'.A ' ? ' !i- -y ';", Bey q;d ('hat Moss we traverse the Bar ton embankment, crossing the low la ds f r about a mile between the Moss and the jWorsley Canal, over which the Railway is carried by a neat stone bridge. At this sp. t it i evident you are' approaching a 'manu ifacturing district. On the banks of the Ca nal a great cotton factory rears its talllsidesy w i th its h un dr ed wind o ws, and- the fly-w heel LAisjtp,m'firigi iig ptrrumg its continuous, and uniform revolution, as. if fiymbJUcaLL'JL that eternal round of labour and care, of a bundant toil! and scanty remuneration, of strained exertion and insufficient repose, which, through day a. id night, through, see s time and harvest, -through years of civiliza tion and ages! of barbarism, have been the Condition and tenure on which the. existence of so j large it :i portion of mankind has de pended. A -A.- ' ; l j From the Barton embankment we soon afrive at E cles, four miles from Manches-' ler, leaving to the right the vicarage and pa rish church rof that village. Between this placej and Mane ester the Railway passes at ;no great distance frdni several country seats! arid villas, whose rich lawn and flonrishii g plantations afford an agreeable variety, af ter the great Sand hills at Kenyon Or the , wiile waste Of Chat Moss. ; ; The immediate approach to Manchester, bv the.Rail way; is through a portion of Sal- ford, as lit.tleiriteres'ting as can well be iina- gineu. Uver-th. Kiver Irwell me Kaiiway is carried yeryi handsome, stone bridge,1 and then over a series ot arches, into .the Company's station in Water street and Li verpool road, Manchester; fro in which the trav eller whose object is. pleasure rather than business, will pr? bdbly make his way, with out loss of time, to the more genialj attrac tions! of the Albion Hotel, or Ne w Bridge u a ter Arms. .1 Booth's IV. IV Report. A Mathematics. -..('; coi tiik HarbB'c.u. .; . ;. -j . . ( Solution to quest. XXX'Ii. by Ned NurascuH. i p! ABC 'represent the horizontal plane; B the point vbprf the wheel touches it; DUB Hj:diameler jierjiendiculat to the plane, and EPH parallel to it. Let the. radius '..11 be taken to express the . weight of tho, birow :..! the direction iri whili the ariiis are to be elevated, and resolve it into perpendicular forces G I, I H . Now G il is the only part of he force! GH which, is employed in pushing the barrow hbrizohtally, and'is the Isame as though it were collected at the point I and employed in fuming the wheel round; but this .effect is, by mt cha nicsGl.lH'a maXil)y hypothesis, .-. it is well known that GllH and the angle of elevation 4 5 degrees, i f r - I J r . w. w. r: Solution to quest. XXXIV. by Moses ElboV- It is well known that if the two sides of a trjarigle represent the quantities and directions of two forces, the base will representfa force equivalent to both; therefore thereire given two sides of a plane: triangle and arj angle oppo site to one of them to determine the other side,' a ques tion which would iecommerid . to the notice of the 'sophs.- . .: -;''.!: ; I ' w. w, it. A general solution by Zero. Let P, S and & repre sent the forces, A the angle which P make with S, and x the angle the sine force makes, with Q.; thert, art. 24, VenturoTi's Mechinicsl S squared P squared--2P.Q,. cos. squared, anqi ;lji ! Q. Ij lA- -t i;7'. . kin A sin x; , hence S squared . " I j- ' A I S J , (Q, cos A) squared- (P sin A ) squared . . sin .A squared ; - ',.-! : A i ' P squared-f-2F. Q, cos ar-f-U. squared, from which by an obvious reduction cos i , " ' - j :P ! ':Ay -. A' HA cos A .. .A r, ;.' ! h I ij,. sin A squared . : V ' Q-squared ) ;r a ; i-i!y--:a:j:-, (Psin A) sq$ Cor. I." If 'U; then cos x( sin A squared-J-cost A squared cos 2A; .r xm2A and S 2P cos A. : ! II. lfcts jri; then a cos Ai: sin Ai f ZC f24.4. -AZB is bise ted :(2cor. 4.3) :NZH HZC (13.n and the arc NHliC. Again, be cause the-arc A Fiarc FB (4.3), CF bisects the verti cal angle A CB, but by construction CGsC B, .. .. CF is rjennndicular to BG and Tll FCABG, because each ii the suculemenf ofrCiB, . arc HCAM NHAFFT. ' AGi? E. DJ A' " - ! ji- S ilution to same by Uncle Ben. In the triangle A ZB, since the diameter 1 IF is drawn at right angles to AB, lit bisects it (4.3) ;. AZZB andAZE BZE. But NZZC when A'-ZB (24.4), hence NC is bisected at nght angles- and JHHU (4.3;. Also the alternate angles FC1 and CFH being equal the ares which they subtend are equal (6. 3.) Again, the triangles MG A and BGi. are similar (6.4Y lor; the vertical angles MUil andjts are equal, and the sides about the equal angles are proportional (24.4) iMAGMGACG13; but (2cr. 4.3) the angles at V are right angles as well as UOF (b.3) .-. Hu an MB are parallel (4.2) and CGB C AM AC H, con sequently in the triangles ACM AHC, the sidei AC is cominoii, 'CA M AC H, and ar therefore equilateral (?. . arcs which thev subtend are equa i;MAAHl, they HCMA and the (3.3). f OL E. D. jThis is a very ingenious solution, and we hope pur correspondent wui try nis sou on me suDsequcni; prop ositions; .' :r ..--'! .-T AA&- A ' ). A Po. I. by Zero. CD is perpendicular to HP,. l U me arc M ti o r cr rr on anu am 'W- IIC. y : :": .' : r IIF. The AClihalf the supplement of the ! vertical angle ACB. ; ;); ; ' . IV. If R lie the centre ot the circ inscribing circle; then the angle CZBCRB. For ZAZB, .-. CZB 2ZAB (6 2)s( RB ( 5.3). Hence a circle will pass through the points C, Z, R, B, (cor; 6.3). j vj , r Quest. XLIX. A person rows from A to! B 10 miles and back again fromB to A in five hours, the ti Je flow ing uniformly in the same direction the whole time; and he j finds tbat he can irow 8 miles with the tide in the sarne time that he can row 3 miles againstit. Requir- d the velocity of thei tide supposing it to communicate prilestroy a velocity fqual to its own f . duest. L- by Zeroi The whole surface of a right cylinder is six times jthe area of the base, Required the ratio of the altitude to the diameter of the base, h I Quest. LI. by Zero. Four agents A, B, C :.nd D ean jointly produce a given effect in 10 hours.'. A's agency alone would produce it in ub-nours, but with the assis tance of E the difficulty, can be surmounted in the san ie tioie that it would take' B. C and D together: B can ac complish the same object as soon as G anid D united, j meutui edifices? n-f. as We-approach; the: Solution to quest. XXXVI1IJ by Diory Sweep stakes. Since CT is purallel to HFHFCKC f and arc HCarc FT. I Because AZB (4.1), ZN rl A and' r in the Kr' ii. jc as B and E: Fow Ion" wi!! it take for their joint and setarate produ.-..-." of' thiseffect?i i - ! , ! . ' i 1 Quest LII. Prop. 7. The rectangle ED, El is eqhal to the sum of the sides, OC. y- i We had. prepared the above when we received a com itiunitrttionifroni ''badiah Ganjer?bahk containing so lution to questions 38 and 39. They tare concisely and perspicubuslv demonstrated and shall aptx-ajr m our next. . ': ;-!"; J - '! '' '-' r - I -'d . , Continuation of our tirlicle on Soyvn. f Let us'now exairrine how the.air is ipodifzecl in dif ferent parts ofthe wave; nd, ferthiJ pjurjipse,!, ;! hs.- imdgine planes parallel to the jiiston, which divide tho column of air into lamina, or thin slices, such as abed. edef, Ac, having all the same thickness; it is rnbiblc inat m. each lamina all thei .molecules of air from I ho ajyJatje centre of Ihe tube, underWtbeuniiJuidi. -1 1 .ncations, ior &u are smiuany circuiuranced. i ricrc-i i " i I - - f - : i i ., ' ' lore, to understand what has happened to thcN whole mass of ajr which composes the wave, jit is sufficient to know what has happened to a molecule of each lamina. Now since the air which was included within ;Pp umL Ail kas been compressed in its totality, and reduced so as Io. occupy only the space SsAA it necessarily fol- lows tnat the molecules in each lamina have cxtxrienc- ed two effects; lt,t, they have' become compresd; 2d,. they have received a certain inpulsivt 'ctQx't) i. e. a celerity which removes them irom the centre of tho shock or of the piston which moved them. I r; it II evident that, in the whole length of the wave, 1 thei diherenj laminse cannot ; e in the same state: tho last laniina,! for example, that which touches JA, Uae only received a very small velocity and a I verv slight compression, because the 'motion has bn.y justtauened! there; the lirst lamina, that which touched Ssj lias a!; ready regained , its stale ol, rest, snke we 'are con bidering ;ttie phenonena "at the iiibtant in- wnkh thb piston was j stopped; and as the lamir.a has ho loi.gcf! , anV velocity, it has lor that reason no comprtwi-ion; it has already communicated all it 'possessed. 1 t n thq contrary the laminae which are towaids the middle of the wave haive at the same time the greatest compress : s uioft and the most eelerityJ There is therelore a certain- I. order ni thji various modifications ol'the'ddlereiit lami nae', both as! respects th velocity of the molecules i.i tio air' and their compression, 'i his order depend on thei incn:asing And decreasing velocities through which th 4)istou passed in iieirig transferred troijij I'p to jbs. I ' -V can represent, ! by a figure which addresses' the eye, all the Imgtions' which characterize a wae Iroi.. its . origin to its termination; ior this purpose, it is sulhcient to j erect on 'the line SA, . which expresses1 iu Icrth;. perpendiculars which represent the -degree 'of C4iu;pres sioti ot the corresponding lamina? the extremiti 8 of these perpendiculars wiii form a line whose curvature or bin uosites ' pwIH' accurately represent th ofurr in which the compressions ,oi "the successive lamina1. suc cccd one another. At S the heijiht ofthe ierit:ndicu-. lar will bernothing because the compression i nothing, j it will be the same at A; at X the height of the perpeii- diciular will be for example, XA, at V it wUl jbe Y 1 at M it will be MJ1, &c. s that the curve of oom res- siohs SilA n.ght be a srniu ircumferencc of a circle. Bhit we perceive that, on this length SA, wcj can trace a muititudejof i continuous - urves passing through the points S and , and even one of tiiese curves Irfing given, we can alwa) s give the piston such a motion in its passage troiin. ijp to Ss that it may exeke a wave . whose successive compressions should lc rt presenti'd by this curve When there are mny sinuosities in thfr , curve of compressions we say that the corresponding , U...dulation U an indented vate. , 1 f' Attcr having analysed the various modifications which the ' piston taay impress on the column of all whilst j ; passing froni Pp to Ss in the interval of-one 'nrcond, , we; may endeavor to ascertain what will lake place io ; the succeeding, intervals,'' the piston always continuing -to stop at Ss. The air momently" compressed from bsto -AA cannot'remain in this state; for the tube! being ; n , at iTpit follows that after a certain tisuc,! the excess of jtir must egress, and the whole column return to a. state i s &! ' ' ' i . i '. ' j ., of rest'. Now, it is demonstrated, in mechanics, ti:at compression and velocity are communicated, successive- ' lv in the following manner: in the first instant ol the 'second second the velocity passes to the right of Aj4, in vades a first lamina, and at the same time tbp la nana which touches the piston returns to a state of rest; in the second thstant a second" lamina on the jright of A A is invade.!, kiid a second lamina inlront of the piston sinks to resir in the third instant the motion - reaches the 3j lamina in front ;of A A, and a state of rcstnaches the third lamina iri advance of the piston, &r; so that at the end of the second second, the air is in a state of v rest from S !to A, and is in a state of. agitation from A to B the length AB is equal to SAand morccver tho cwnpressions and velocities from- A to B jarej exactly what they werjp from S to A, Tkus, the undulation advances and is conveyed, in some measure .unkfornily, by preserving its length and all its characterful tho end of the tjiird second it Would be at BCj at the end . ofthe fourtk at"CD, &c. I" ! ' . '- The wave which we have just described, lin w Inch all its lamina are compressed and all the veIociU-s.tnt-rrudsive is called si condensed ware, ot sometimes cor- denstng wave. !-. ft ' l t :! f : - ' : i- 1 - i I But it Is esy to sec that the invcise1 phenotnelia are ping at the left of thet piston I'p wlulst it U developing at the left oi thet piston I'p transferred to Ss. - In facf a greater pacc has been preseni ed to the column of air, the first lumina rushes after "the piston hj- being rarijied, the second rushes after the first and takes its pbee, &e. '&c; and after the first second, when the pistan'stops at.S the rarefaction w perceived as far as a. Jl' waie which rpJnlts from it is called a rarifxd icare, or rtlirr rati fyfng vave; its length w cxat tiyUhe same as that ofthe condensed wave which is produced before the piston, the1 rarefactions are nothing at Ss and at a a, and, in all the lamina;, the velocities are appulsirc, i. e. directed to wards the centre of tho shock. . 1 . The rarificd wavc is al propagated, succrssivc) thrbuwh the Whole extent ofthe column of air, preseri. in every where the same length and the same succes sion of veloeitijs and rarefactions. j . These considerations shew us,"now, the principles cat which the phAioncnon of heiring rest?, for' if wc ija.- i 1$ ! I . ! 1 'I ij i i
The Harbinger (Chapel Hill, N.C.)
Standardized title groups preceding, succeeding, and alternate titles together.
Dec. 12, 1833, edition 1
1
Click "Submit" to request a review of this page. NCDHC staff will check .
0 / 75