ORIGIN AND FORMATION OF COAL.

New Zealander, Volume 5, Issue 414, 3 April 1850, Page 3

ORIGIN AND FORMATION OF COAL.

[As the endeavours now in progress to render the Coal which abounds in New Zealand available for the practical benefit of the Colony, have made Coal moie a theme of conversation than it formerly was, it may not be unacceptable, or without instruction to some of our younger readers, to copy the following interesting description of the origin and foimation of that mineral, which we find in a valuable work lately published in London, called " The Philosophy of Common Things."] The coal we use, to speak now ot its nature and vegetable origin, is a compound of carbon, bitumen, and earthy matter, in varying proportions. Anthracite, or stone coal, is destilute of bitumen. Lignite, or wood-coal, is not perfectly mineralized. Coal in which there is but little earthy mixture, and which contains a due proportion of bitumen, is the mo^t valuable : it cakes in burning, and leaves but a small residuum of ashes, which always consist of the earth contained in the coal. Our pit-coal is a pure mineral : it has the mineral substance, grain, and fiacture ; and, from inspection of the mineral itself, it would be thought to have an origin not in any respect diffeiing from that of other stony substances quarried out or the strata of the earth. More accurate enquiry and examination will, however, soon change this opinion, and conduct to the conclusion now generally received, that coal is of vegetable oiigin. The facts and considerations on which this opinion rests are various. In the fint place, we have in peat and lignite, examples of a process similar to that by which coal is supposed to have been formed, and ot the cbanga of vegetable matter into coal at different stages of its progress. Peat consists of vegetable matter, bitumenized by fermentation in places where it can be kept saturated with moisture, and where both the access of external air and the escape of the most volatile parts of the mass are effectually prevented. As the workmen penetrate deeper into the mass of peat, the portions they raise are more completely bitumenized, and the fluid or sludge, at which the ultimately an ive, is in the highest degree bitumenous ; and after being dried in shallow reservoiri, the solid mass that lemuim is found to burn most easily, and with the greatest fieiceness. But in ppat, though vegetable substance is bitumenized, it is not at all mineralized, because it Ins never been subjected to pressure, but is rather a spongy mass, somewhat more solid indeed in the lower portions than in those nearer the surface. Again, in. what is called lignite, or wood-coal, or sulurbrand, we have another form of vegetable sub6tanca become bitumenou«, and in different degrees mineral alio, without having lost the woody fibre, texture and lovm, in which it originally grew. Thero

is an extensive deposit of this substance at Bovey Tiacey, in Devonshire, whence it, has received in this country the warns of Bovey coal. Here is found a much moie recent deposit than the proper tuincial coal seams ; it is thought, indred, to be more recent than even the chalk. It consists, besides, of certain trees, which (Tow to greater mass and solidity, and in which the woody fibre is far more fiim and lasting than the o;Lcr plants of which the true coal is supposed to be composed. Here then is a substance found in strata I alternately with beds of clay, which is at once wood and coal. There is the grain, fibre, and form of wood, bur. it is bitiunenous in a high degcee, and diff-rant portions of it are in different degrees mineralized. — i Some m-e soft and will bend as a piece of board ; others are brittle, and have the weight, substance and fracture of a mineral. As, thereto. c, we have vegetable matter thus accessible in its progress to bitumemzation and miueialization, the two great characteiistics of cual, a i presumption arises, that coal itself has arrived at its most complete attainment of these propeities from the 6ame origin, by a more lengthened and complete subjection to the sume process. A second consideration which exceedingly confirms the probability arising out of the former, that coal is of vegetable origin, is that traces of vegetable remains are most abundant in immediate connection with seams of the most perfect coal. In perfect coal itself they, of course, are not found, because, when the process of forming coal ib complete, nothing can be discerned but a unifoira mineral mass of carbon and bitumen. But coal is universally deposited in seams of no very great thickness, alternating with beds of indurated clay, shale, and similar substances. Now in these are iound the stems, the leaves, the fragments of plants ; and these in such positions and sometimes so partially converted into coal as to leave no loom to doubt that the entire mass of coal is (O.nposcd of vast quantities of similar plants, of which these poor remnants alone escaped, to boar witness tithe existence und fate of those luxuriant foicits in which they once flourished. Another striking proof of this kind will avnil more than lengthened general descriptions. When a seam of coal ia mined, the turface ot slmle, or other subatance, on which it rested, is called the floor, and the under surface of the str«uum of shale, which rested on it, is denominated the roof. Now, it will sometimes occur, when the coal is removtd, that the roof will exhibit, tiared on it with inot>t beautiful and delicate accuracy, the lews, the stems, the iorms of various plants ; the substance of the clayey stratum ofcen funning a light ground on which the plants are traced in shining black. Now, this appearance reveals the history of the cjal formation. A mass of vegetation, either by growth or transport, occupied tha spnee now fiiled with peifeet coal, while that mass or at least the upper Burface of it, retained uninjured its vegetable form and structure : the mas*, now forming thu stratum ie^tin!£ upon it, was deposited most probably by gentle, gradual deposition Horn turbid waters, aivl received on its under surfare the tracing of every line and fibre of the piauls on which it pressed. These afterwards fermented, blackened, and hardened into coal ; and by colouring the traced impression on the incumbent stratum, made visible what otherwise might have remained the imperceptible mosaic of the roof under which the miner plies his laborious and htuardOUB task. Coal is. now indeed univarsally allowed by geo To»T o» gists and chemists to be a vegetable substance. It is found in beds, varying in thickness, in ninny paitaof England and Wales. A clay ironstone from which a large portion of the iron used in this country is obtained, ia usually associated with it— a circumstance of gieat itupoitance, because the presence of coal upon tlie spot greatly facilitates the process of smelting. It is often observable that strata of ironstone, coal, and lime, are found to be alternate : so that on the same spot may be obtained the ore of the metal, and the fuel and the flume to fuse it. "Few persons are aware," says Dr. Buckland, "of the remote and wonderful events in the economy of our planet, and of the complicated applications of human industry and science, which are involved in the production of the coal that supplies with fuel the metropolis of Englaid, The most eaily Etnge to whic'i we can carry bick its ou^in, wus ajaor.g the suiamps and forests of the primeval earth, where it flourished in the form of gigantic trees. From their native bed these were torn away by the storms and inundations oi a hut and humid climate, and transported into some adjacent lake, or estuary, or sea ; here they floated on the waters until they sank, saturated, to the bottom, and, being buried in the detritus of adjacent lands, bscame tiansferred to a new estate amung- the members of the mineral kingdom. A long inteimcnt followed, during which a course of chemical changes, and new combinations of their vegetable elements, have converted them to the mineial condition of coal. By the elevating force of subterrauean fi es, these beds of coal have been uplift d from beneath the waters to a new position in the hills and mountains, where they are accessible to the industry of man." This information is not only deduced from the com* position of coal, but from the situations in which the beds are found. The vegetable matter of which it is formed must have been deposited in a horizontal position ; but, by the agency of some most violeut causes, the beds have been upheaved, and instead of being buried at a considerable depth under a long series of rocks, it is found on the surface. In all these phenomena we trace the hand of a wise and benevolent Creator, who so directed the influence of his Ilia physical agents as to secure the comfort and happiness of His intelligent creature man. If we now proceed to some explanation of the circumstances under which these vegetable masses are supposed to have been deposited, and then conyertecl into coal, we shall in our progress find opportunity to obviate the two great difficulties with which the doctdne of the vegetable origin of coal is encumbered — One is, the vast quantities of this mineral, which it is difficult to conceive could ever hare been supplied by vegetation, the more especially when the great compression to which vegetable substance 3 must have been subjected to reduce them into the dense, compact, form of coal, be consideicd. And the second, tlie entire, perfect change plants must have undergone, hefoie they could be conveited into the compact substance of mineral coal. Nothing of ihe. plant seems, to the senses, left. The plant is gone, a stonj occupies its p ace, and we a-e required to believe th.it what is now the stone was once the plant. Wnnilcifal operations must no doubt have attended b)lh the production of the vtge'abie origin of coal and its conversion into that substince. Here \va ure tciu&poited into far remote geologicul eras, and have to contemplate t! c primeval slate of our planet by su:h glimmering lights as reveal to us its then co dition, and the operations of which it was then the scinj. The coal formatioi s are the most recent of the transition rocks, and complete th.it series of g. ological formations. Let it be considered that the primary, granitic rocks from the substratum of the earth's crust, us far as known to us. What may lie beneath thtra is to us unknown and matter of meie conj cure. This primary group consists of unstratificd, crystalline rocks, the granites, gnei'B, and mica slates. I-; Hum, or

associated with them, are found no organic remaii whatever, vegetable or animal, nor any traces of tl existence of oiganiscd forms during 1 the deposition < these rocks, or while they alone continued to form tl cisutor suiface of the globe. By some potent irn sistil)le forces acting fiom beneath, these solid massi were disrupted, fractured, and made to pr< sent a uneven surface of alternate elevation and deprcssioi Upon them were then deposited what geologists ten the transition series, consisting chiefly of lhe old re sandstone, various blntes, and the old earbotiifcioi limestone. It is in connexion with this series of rod that the earliest traces of organised existence in 01 planet are found ; but these remains are of tlie mo 1 simple and and the lowest orders, both of aui,ual an vegetable life. It was while these transition form; tions constituted the surface of the crust of the cue tl that the vast accumuJatioMs of vegetable substanci now converted iuto coal, were pioduced and dene sited. Now, it may be thought the mere play of fancy t attempt a description of the primeval globe in a peim so remote, of which we teem equally destitute of recor or means of information. Yet this k- not ultogethe fhe case. Indications of the then state of the woil have been traced, by able and sagacious observers, i the facts connected with that period, which leinain t this day accessible to observation and nseriivh. I the basin or trough-shaped hollows, in which it i evident that coal was originally deposited evidence i found that our globe had, at that early period, beei subjected to the disturbing foices which produce< mountains and valleys, with their accompanytn streams, marshes, and estuaries. In the tribes o plants, of which remains are obtained from the coa formation', proof is obtained of the genenil prevalenc of a hot »nd humid climate over the whole "lobe : be cause in every latitude where coal is found, the asso ciated plants are surh as now flourish only in tropica regions. Fiom the amazing quantity of vegetable cr.attei thus produced, and the great proportion of carbor contained in the coal into which it li3S been chpneed it is inforr d that the atmosphere was then liighlj charged with carbonic ga», which being abstracted bj the rapid growth of immense tracts of vegetation, the air became gradually more fitted for the respiiation o! land animals. The alternating beds of shaie and clay universally occmring with the stiata of coal, seem nls to prove that our planet was then liable to tiernen-loui periodical lams and inundations, as could not indeed be otherwise when a high temperature and a widj watery surface prevailed together, and that vast floods of water flowed from the elevated portions of the globe charged with earthy matter, which was deposited in the lotver regions wheie the waters spread, and then course became less rapid and tumultuous. These conditions being supposed, as of ther correctness nnd reality there is, to say the least, a vorj high probability, it needs no great exercise of the imaginative faculty to picture to ourselves the scene amidst which our beds of coal had their vegetable origin. In the low marshy tracts of the ancient globs there flourished wild fields of tropical sedge, reeds, cane«, gigantic ferns, equisefae, and other plants of a simple structure, such us requiie for their production great heat and moisture. Finding nil the conditions necesiary for their rapid and luxuriant growth, a high temperature, abundant moisture, and a plentiful supply of carbon from the atmosphere, they attained a luxuriance and magnitude which even the present productions of tropical regions will not equal, though they may assist our conceptions. While these wide tracts of marsh vegetation were fl -wishing in rampant growth torrents of rain fell in high and remote districts, and washing away with them, by the violence of their full und motion, the soil of extensive regions, the turbid flood rollrd on towards the ocean. By the time it reached the wide hollows of the coal basins, it spread, and its turbulence and rapidity diminished. The reedy, sedgy vegetation, not rooted up and swept away, was | swayed down and flattened by the mass of w-iters passing, probably slowly, over it, and loading, pressing it down by the mud plentifully deposited on the mass. The buried plants became the mtferiel of a s°ain of | coal — the incumbent mud of ci bed of clay or shale.— The process wou'd be oftcn v repeafcd. The clay became the soil of a fre^h giowth of plants, to be again [ in irq turn submerged, atid covered with soil for the production of another harvest of vegetation. In all coal formations these conditions are observed. They are all formed in hollows—they all consist of numerous alternating beds of coal and slate, or clay, of varied thickness, fiom the fraction of on inch to several fee. It is not pretended that this description of the mode of the deposition of beds of coal will accord with every fact ond appearance observed in these wonderful formations. There must have been many cauie9 to produce, in diflVrent localities, variations of what might be, nevertheless, general operations and results. Tho pmpose of the writer has been attained, it what bns besn advanced Ins proved sufficient to give au idea, probably coirect, of the general circumstances and mode under which coal beds had their vegetable origin. The vast masses of vegetation thus bu led, were, saturated with water, and highly charged with carbon. It is also supposed that from s'ime source they were impregnated with sulphuiic acid, which would greatly promote their becorn n^ bimmenized. It is probable, a'so, that considerable heat was present, partly eco'ved tiom the covered and decaying plants themselves— partly from the ciu>tof the globe, whuh at that period had probably n higher temperatuic than now; nnd party from the greater warmth of the atmosphere and climate. Thus buiied, saturated aud heated, the mius fermented and became bitumenous. Mechanical pressure constantly increasing, compressed the substance into thfc hardened, mineral 6tate in which vre find it. Tin? caus s now adduced seem adequate to account both for the immense quantities of vegetation needed to foim the coal strata, and also for the peifect transmutation of the vegetable into the minernl substance. In regard to quantity and muss of plants, let it be remembered, coal fields or basins, are found covering six eight, or twelve hundred square miles. Of um.-su the marshy forest or jungle, whose bui if d vegetation now fotms the coal, was co-extensive wiih lhe present bed of coal. But from what is now witnessed in many p-trts of the world, of extensive tracts of marsh or forest, we may conceive without surprise, in the primeval, uninhabited, state of the globe, to which our present inquiries have reference, of marshy jungles me hundred and filty mi!es in length, and bix iv breadth. And in icspect to the thickness of the separate seams of coal, in some instances as it would seem, rejo'ning to several feet, the dense and lofty mass of hnunaiit plants, produced by the concuirence of every c»Us>e that could stimulate and fone their growth, might be quite adequate for their production. The change, indeed, in substance is complete and surprising. But hoie we are under some illusion from our scnbO', which cai dfceern no re semblance or analogy between the materials forming a p ait nnd thi.se constituting coal. The reuearches of the chemist teach U 3 that lhe ultimate pait'cles of bodies the most diverse in sensible appearance and proper.ies are often identical in nature, though varied in proportion and combination. The same material may exist in a g&i, Oi a^ u lock. Now, cqal consists, of carbon and bitu«

men, which is itself a compound of caibon and hydrogen. Coal, then, is chuily composed of carbon and hydrogen, so also arc phmU it is not then tint the ultimate particles and elements which compose coal find plants arc wid.ly d (Ffient— for they iiiie nearly identical— it is onl) that the two substaices me in foidi and sensible qualities qnle diveis\ In (limits caihon and hydrogen fie connected with orj>amY ition, life, pruce'iil forrm, sweet odoui", and he.iulirul colouis. — In co.tl, ct'ibon and hydrogen ure seen in mass, inert, mim'iul, condensed. Hut thry arc the same ultimate niuttos still. And what is our world, iv all Us wondeis and beauties, hut an incPbsant, vnned, infmili' nenc of changes anil trunsfoi muttons, in which a lew dimple and ultimate elementu aie mado to puss out of oue combinntioi) ont\ form into another, n a manner which we cannot tiace without wonder mid aJmiution which at once delight and ovtrwhelm our fjuillies?

The dismissed Magisthatts and Lord Clarendon. — A great deal of comment hHsbeeu called foithby the summary dismissal of the Earl of Uodrn and the Messrs licet s from the Commission of tlie Peace, the siippoiteis of Government applauding that step an an net of firmness and good po'i<y, whilst the opposition journals denounce it as a capucious, uncalled-for, and insulting e.\erche of anthoiity. In the present stale of excited feelling on nil matters of Irish administtation, it is difficult if not impossible to arrive at an impartial decision; and in the present case the time has not come, nor are the documents before us, to pronounce a final veidirt. Loid U irendon has thininv more light on the ultair by wilting, 01 rather cnusing to be written, n lettn to the- Lord Chancellor ol Lcland, explaining the reasons why he adopted the extraordinary proceeding in question. Lord Roden has also addressed a letter to the Chancellor, in reply to tbe notification of his being superseded; but the Noble Earl enters into no formal defence of his conduct, merely asserting that he acted on the occasion lefmrcd to in strict conformity with his duties as a Magistrate, and intimating hit intention to take another opportunity of expressing his opinions at greater length. The cvi» dence, therefore, is to a considerable degree ex paite ; but with all the advantages of ampler explanation, it does not appear to us that Lord Clarendon has succeeded in convincing the public that hii sudden dismissal of three tespectablc Mngietiatcs was not a precipitate and arbitrary stretch of power — ,1 step which ought to fiave been delayed till clearer proofs of n;uilt were established. The whole met us of thr-C'isc rest on a single point, ate Orange procesbions Ic^al or illegal ? There was a recent act of P.uliament proclaiming them down, and had it been in force there was an end to all doubt on the matter. But that Act has expired, and the presumption is, the law resumes its former course, Smb. was the opinion of the Orange leaders on the 12th of July; and their opinion was strengthened by the facts that last year a Bimilar procession look place without the (lightest hint about itsunhiwfulness, and this year no objection was made to the legality of the procession by any of the Queen's officers, civil or mils tory, that weie present on the spot at the time. Ihey remonstrated against it, and advised to take a different route on its return, but that was to avoul collision with the armed llibbonroen that lay in ambush to attack them. It is true die liish Attorney-General declared the procession to be illegal, but that was after the bloody day nt Dolly's Biae had occiured. Had the opinion been givn before, in all probability the conflict would have been prevented, for though the Orange leaders refused to listen to the remonstiunce of the two stipendiary Magistrates, Messrs Fitzmauiice and Talmteau, who endeavoured to persuade them not to march through the Pass, there can be little doubt such an au- I thoritative declaration of the law would have had the effect of making it respected. This was not done, so that thelegality of the pi ocession was practically acknowledged both by Lord Clarendon and the AttorneyGeneral. If it was illegal, why were not steps taken to prevent its assembling, and why weie band* of armed Ribbonmen allowed to lie in ambus.li for a whole day without molestation, when it was well known to the police nnd die military that they meditated bloodshed? Had the Magistrates, v/ho predicted the collision, swept the Pass of its Romanist banditti, they could have better prevailed with the Orangemen to foiego their procession. But these precautions were not taken, and for no other reason, we can imagine, except that the Government anthorities did not chooie to irritate their Roman Catholic nupporters. The Orangemen, in their proceßsion of 1848, avoided an occasion of bloodshed, by changing their route and notmarc'-ing through the Pass where their armed opponents way-laid them; and we think they were to blame this year for not adopting the samo coui6e. No doubt it would have given another triumph to the Roman Catholics* but that is a trifle compared with the pretext which th<=tr obstinancy or their " courage" afforded the Government to insult and degrade their leaderß. The Ribbonmen conspirators have again had a triumph, and the price paid for it is the degradation of three Pi otcgaiit Magistrates. The Clearance System in Ireland.— Eight years ago, there were in Ireland, 310,375 " holdings" of from 1 to 5 acres each, and 252 778 holdings of fioni 5 to 15 acres, while the holdings of 15 acres and upwards were only 128,061, lei 8 than one-fifth of th (5 total number. In 1817, according to the returns prepued by Captain L^rcom, nnd presented lo the House ol Lords by the Muiquis Lnnadowne, ju3t before the close f f last sessions, there had then taken place a dcaense in the smallest clabs of holdings of 171,334, while upon the next class there was an increase o/ If. 756 ; and upon the larger holdings, of 193,473. 'Hi is augmentation in the holdings must have been effected it the cost of a conoiderable change of bands, as well as by means of a change of system ; nor can it be explained, without supposing either a greatly increased width of land to havo been brought under cultivation, or an extensive abandonment of agriculture for pastoral occupation. In 1841, the 691, 1 14 holdings might embrace, upon a rough calculation, a total of some six millions and a half of acres ; but in 1847, the 730,000 holdings must have comprised not enucb less than ton millions of acres.

Thr Toweu.— ln conarquence of communications from the Duke of Wellington, High Constable of ihe Tower, respecting the sanitary state of the fortress, the Commissioners of Woods and Forests is«ued instructions on Tuesday for the immediate demolition of all tli« buildings known as the Old Mint, situate on «fae rast, fronting St. Katherine's Docks. This has hitherto been the quarters occupied !>> the non commissioned officeis and privates, and is the most unhealthy part of tlio fortress, and is no longer necessary, the new Barracks built upon the site of (he Armoury, destroyed by fire in 1841, being ready for occupation. The new officera' quarters arc rapidly approaching completion. The Tower is being thoroughly drained. It io also proposed to bore aa Artesian well for the supply of the garrison.

Awothkr Anv.i,A.mo and Hbloise. — The corroipondcnt of the Times at Home gives the pnnicalars o c

1 a roraanfic story, which has excited great public sympathy. Some ten or fifteen years ago there lived in the town of Viterbo, about 30 miles from Rome, on the road to Florence, a young man and a beautiful girl, who were teiidctly attached, and who desired to marry. The friends on both sides opposed the union|; and nftcr all hope was exti' guished, and the impob. eibility of aijain meeting proved, a s< cond edition of Ahelaid and Hcloue actually took place. The lover bucawp a pi jest and .1 monk, and the beloved rctiied into a Nunnery and took the veil. It would appear that the piicst found menus oi visiting the nun, and that «evewil interviews took phce, which occasioned much scimdul in the respective establishments and in the neighbourhood. The bi&hop of the diocese interfered ; orders were given which would »eparate lor ever the imprudent pair; but a last meeting, in spite of every difficulty, was managed j uud, on the morning after, the nun was discovered dead, evidently poisoned, in her cell J— and the friar was not to be found, nor could any trace of his flight be procured. "Whether the nun pniioned herself in despair, on being patted from her lover, or whether the friar administered to her the dose, is a question still legally undetermined ; but the flight of the latter was considered to be evidence against him, and as he was not present to defend himself, (he people of Viterbo imagined he was guilty, and so the mutter was lost sight of, and nenrly forgotten. The friar went to the United States, after having viiited Malta and Gieat Britain, and in the course of time abjured the Roman Catholic doctiine and embraced the Protestant faith. He became a member or agent of the Missionary Society; and when the late Republic flourished at Home, the Pere Aclulle returned to this part of the world, and with the zeal of a convert laboured in his vocation as a distributor of Bibles and an expnuuder of Protestant doctiincs. He had full liberty of speech and action under M. Mazzini ; but when the Republic expired beneath the fire of French artillery, things look an other turn, and one of the first acts of the restored government was the arrest of the missionary and his incarceration in the Church prison. A double accusation weighed against him — first, the death of the nun at Viterbo, and secondly the ecclesiastical crime of being a recusant piiest. With regard to the one, it is proper to lay that no evidence exists against him. With respect to the other, the ca»e ii not denied, and the only question to consider is, whether it be just and right that in these days a man who has changed his icligioii from conviction, being a priest, is subjected to the ciirninal jutisdiction of the Chuicb. Mr. Frreburn, representing a Piotpstnnt country, ha?, without instructions from the Foreign Office, taken the matter up, and used whatever influence he possesses in favour of the accused, representing that no man should be punished for conscience sake, and that (he Protestant community of England would rise as one man to protect a person whose conversion they believed to be sinceie. As our consular agent has not the ear of the Court at the Quiunal, his remonstrances were unheeded. Nor were those of the French ambassador of much more influence. The utmost they could do was to procure the removal of the accused liom the prison of the Church to that of the Cattle of St. Angelo. English sympathies are naturally engaged in favour of a convert to their religion, and a zealous member of the Missionary Society; though, at the same time, it is admitted that the gentleman alluded to is a Iloman subject— a priest of the Roman Catholic Church— once a priest, e\er a priest; and that a criminal charge, however unjust it be, weighs against him.

Royal Gift.— A magnificent box-oak bracelet was presented to her Majesty on hrr late tiiit to the Irish metropolis. The several links of the bracelet, which are joined by loops of WickW gold, compose the name of "Victoria," and the clasp is an Irish harp. The bracelet ii enclosed in a beautiful inlaid case of arbutus wood, also indigenous to the mountains of Killarney.