Sidor som bilder

xire of saving the grass for a crop. Markets: 1 lean stock, higher since the late warm showerij and the prospect for a grass crop. Fat stock lower than at Michaelmas. Pigs in great abuna dance, and cows. Horses of good quality very dear. Straw has proved indifferent in quality, but more in quantity than was expected. Stock of wheat on hand universally considerable, oi barley and oats very great. · Vast quantities of pea, barley, and bean, meal have been consumed by live stock in course of the season. Oil-cake 15 guineas per M., Suffolk butter 84 s. per firkin. The country never manifested a more general state of prosperity.

Smithfield : Beer, 45. 4d. to 55. ?d. !Mutton, 4s. 6d, to 55. 2d.;-Lamb, 6s. to 75. 4d.

Veal, 6s. to 7s. 4d. ;-Pork, 4s. 8d. to 6s. 8d. ;-Bacon, 7s. to 78. 4d.-Irish dicto, 5s, 6d, to bs. 10d. ;-Fat, 3s 8d. ;-Skins, 20s, to 258.

Middlesex, April 25, 1811.

METEOROLOGICAL REPORT. Observations on the State of the Weather, from the 24th of March, 1811, to the 24th of April, 1811, inclusive, Four Nfiles N.N.W. St. Paul's. Barometer.

Tbermometer. Highest, 30:20. March 27. Wind S.E.

(Highest, 71° April 22,93, 94. Wind S.E Lowest, 28:80. April 19. S.W. Lowe st, 28° -- 10. On the oth in

( In the morning of stant the mercury

the 12th instant, the Greatest

Greatest ( 44 hun- stuod at 29 44, and

thermometer was at the Variation in " dreths of at the same bour

variation in 220 freezing point, aod at 24 hours. ) an inch. on the 7th it stood

24 hours. S

the same hour on the at 29.00.

13ch it was as high as

54. i The quantity of rain fallen since the last Report of it, is equalto nearly 2 inches in depth. The season has, indeed, been remarkably dry, and, the easterly winds being apparently set in, we may expect much more dry weather, with occasional showers only. The gardens require rain, but the season must be favourable for sowing the spring.corn, and also for the wbeat.

Snow fell on the 7th of the present month, but, on the three days prior to the present, we have had almost summer heat; the severe easterly wisid of this day has caused a variation of go in the thermometer, and to the feelings there is a still greater difference. There huve bren twchty very brilliant dars in the month : the average height of the thermometer for the month is 4895, and that of the barometer 29.54. The wind has blown chiefly from the easterly quarters. · Highgate, April 25, 1811.

TO CORRESPONDENTS. TF¢ hate received from MR. BAKEWALL, Mineralogical Surveyor, of Warwickcourt, an interesting Essay on the Application of the Principles of Mineralogical and Chemical Science to the Selciturn of the Stones for the various purposes of Architec. ture, which will uppeor in our next.

An interesting Memoir of Mr. Pave Sandler is also deferred, as well as some other approved articles.

Correspondents in general are informed that if their communications do not come free of posluge, they are returned to the Post- Orlice.

Other authenticated facts relatire to Sirumonium will be thankfully received.

Sonie. Irish Correspondents who compluin of difficulty in procuring this Mugazine, arc informed that it may be hud of ihe Dublin booksellers, or with more speed of the clorhs of the rouds, at the General Post-Office.

N.B. Numbers 74 and 83 of THE MONTHLY MAGAZINE being out of Print, anul wonlca lo complete Sets constantly in demand, Two SHILLINGS und SIX PENCE per (ory will be given for any of those Numbers which may be brought to No. 7, Now Bridge Sirect.

Chryne ITuik, Chelsea, April 28, 1811.

At page 312, line 4, for " sont provisions," read " such provisions."


No. 213.7"

JUNE 1, 1811.

[5 of VOL. 31.

As long as thore who write are ambitious of making Converts, and of giving their Opinions Maximum of • Influence and Celebrity, the mott extensively circulated Miscellany will repay with the greater Effect the

Curiosity of those who read either for Amusement or Infru&tion. - JOHNSON.

THE SUPPLEMENTARY NUMBER.. Hitherto our Supplementary Number has been partly occupied with imperfect critical

accounts of current English literature, confessedly and necessarily compiled from · those fallible, partial, and corrupt mediums, the periodical anonymous Reviews, uided by occasional originality; in future, howerer, it is proposed to substitute in a place of those wholesule criticisms, interesting charucteristic ertruets from the prin

cipal works published within the half yeur, arapted at once to gratify our reuders, .to qualify them to judge of every work for themselves, and to stimulate them to pur· chase those possessed of evident merit. The Supplement published on the first of

August, will be compiled on this plan; and, to assist our design, we shall feel ourselves obliged to authors and publishers, who will accommodate us with the loan of books publisheid between Michaelmas and Lady-duy last.

Pimlico, May 8, 1811.

[ocr errors]

· ORIGINAL COMMUNICATIONS. For the Monthly Magazine. is owing to the want of mineralogical On the upplication of MINERALOGICAL science in the selection of the materials,

and CHEMICAL SCIENCE to the SELEC- by which they were sentenced to perish TION of STONE, for the purposes of at an early date. None of thein will DURABLE ARCHITECTURE.

rival in duration the temples of antia THE remains of ancient architecture, quity, and remain two thousand years,

1 which prove the greatness and or more, after the ruin of the state, splendour of states and governments the august monuments of its former that have long since ceased to exist, greatness. This may with certainty be whilst they iinpress the mind with a me- predicted from the perishable nature of lancholy conviction of the mutability of the stones of which they are built; they empire, excite also a kind of religious ve. are rapidly decaying, and require conneration for the editices which have en slant renovation and repair, dured, amidst such great and various Perhaps the following remarks on the changes in human affairs, and have seen selection of materials, for the construction a long series of successive generations of public buildings, may not be undea perish from the earth. When we com- serving attention at this time, when two pare these monuments of antiquity with new bridges are to be built from London the proudest structures of modern tiines, and its vicinity, to the southern side of we are forced to acknowledge the su: the Thames. The most important quality perior skill, or science, with which the in stone, for purposes of architecture, inaterials of the foriner were selected. is durability, or the property of resisting Many of the most splendid works of our, the action of moisture, change of temcelebrated architects, are hastening to perature, vegetation, air, and light. It is decay, in), what may be justly called, the also required, that the materials of very infancy of their existence, if com bridges, and many public works, should Dared with the date of public buildings be capable of resisting the effects of via which remain in Italy, in Greece, i bration and impulse. The most careless Egypt, and the East. This is remarkn observer can scarcely have avoided 10ably the case with the three bridges of ticing, that many kinds of stone decay Loudon, Westininster, and Blackfriars; much sooner than others. It is not only the foundations of which speedily and in stones of different kinds, that the visibly began to perish in the very lite power of resisting decav is variable; even time of their founders. Tre destruction in stones of the same kind, and brought of ancient architecture has been chiefly from the same place, a considerable dif. occasioned by the ravages of wars, and ference in this respect is found to exist; the desolating hands of superstitious bar., but the principles on which the proper barians; the decay of modern buildings, seleccion of building-stone should be MONTHLY Mac. No, 213,


made, has been little understood or at. The best kind of Portland stone is ill tended co. During a few months' re. suited to resist the decomposing effects sidence in the metropolis, I was induced, of water, the two former of these magby the nature of my mineralogical pura nificent bridges, constructed at so much suits, to pay some attention to the dif. expence, are perishable monuments of ferent stones of which the pavements the neglect of mineralogical science. and public edifices are constructed. On In stones of the aryillaceous genus, walking into the court of Somerset- more striking instances of rapid decay house, after some weeks of dry weather, occur. I have seen stones of this kind, I was particularly struck with the ap- in their native beds, or quarries, some pearance of the columns on the left 'hundred feet under the surface of the band, facing the west. The stones, in earth, so extremely hard, that they rea three columns, were 'some of them en. sisted the point of the pick-axe, and could tirely coated with soot, when the stones only be removed by blasting with gun. above and below were perfectly white. powder; yet, when the same stone was In other parts, a white stone was be. exposed to the air for a few months, it tween two black ones, and the division became soft and shivered into sinal! of colour as distinct as if the one had pieces. The cause of this sudden debeen painted white and the other black. cay, I shall afterwards explain. It rarels These stones were all equally exposed, happens that builders or architects have and the variation of colour could not be any acquaintance with mineralogical and explained by their situation. At first chemical science, to enable them to anI conceived, that this difference of ticipate the changes which will be effected Golour inight be occasioned by some sub. in the materials they select, by the action stance entering into the composition of of the agents to which they are to be exthe black stone, that had a chemical posed. The loss and disappointment affinity for ammonia, which is contained which this ignorance has occasioned ia® jn soot; but, on examining some of the the construction of inany public works, is stones that were within my reach, I found well known.-A remarkable instance of that those which were covered with soot, this kind lately took place at Paris. A had a hard, smooth, surface, and the gentleman was walking with an eminent white stones were evidently decaying. Inineralogist in one of the newly-erected The particles on which the soot" had public edifices; they were pleased with fixed, were faken off, and had laid bare the appearance of soinė large columns in the natural colour of the stone, as per the interior; when the latter had exa. fectly as if they had been recently scraped mined them more closely, he predicted, with a chissel. In other parts of the from the nature of the stones, that they building, I observed the visible decom. would perish in less than three years, position of the stone, by moisture, par- About ten months after, the gentleinan ticularly in the upper part of the alto happened to pass the same place, and relievo figures.

observed the stones of these colurnns were This edifice, like most of the modern shivering so rapidly, that workmen were buildings in the metropolis, is constructed then engaged in replacing them; which of Portland-stone; a peculiar kind of had become necessary to secure the lime-stone, which I shall afterwards more roof. In forming the tunnel of the Huda particularly notice. It is evident, how. dersfield canal, which is three miles in ever, that this stone which is considered length, the workmen in one part had to of the same kind, and comes from the cut through a bed of stone of considera same place, varies much in its property able extent, so hard that they were of durability.

obliged to remove it by blasting. It apo When the same stone is constantly peared so compact and firm, that it was exposed to the action of water, the dif. thought unnecessary to wall and arch the ference in its qualities of resisting decay passage; but, in a few months after the is more apparent, as is evident from an access of air to it, it shivered and sell in; inspection of London, Blackfriars, and and the removal and repair occasioned Westminster, bridges, at low water.* much delay and expense. It was a dark

compact argillaceous stone, containing The stones of Westminster bridge ap.

oxyd of iron, and resembling some kinds pear to have been selected with more know.

of basalt; but its shistose or slaty jedge, as they are much less decayed than structure was soon apparent, and it those of Blackfriars; the architect wu i became as soft as the bituminous shale Franchman,

which accompanies coal. Some kinds of

stone stone become harder, by exposure to the basalts, which are extremely compact, atinosphere. An inquiry into the causes ponderous, and hard, striking fire with of decay in different kinds of stone, steel, contain more than 25 per cent. of and also in stones considered of the iron, and are soon decomposed at the same kind, may not be undeserving the surface, when exposed :o the atmosphere. attention of the public.

In general, specific gravity, where it does To ascertain these causes with pre- not arise from the absorption of water, cision, it will be necessary to attend, first and the presence of iron, or other nee to the external character of stones, and tallic earths, may be considered as a the qualities and proportions of the quality indicating excellence for purposes carths of which they are composed; and, of architecture. No stones, except those secondly, to the decomposing or disin. which contain the earth of stroutian, or tegrating effects of the agents to which barytes, weigh three times as heavy as they are to be exposed.

an equal bulk of water, unless they are The four earths which form the prin combined with some metallic substance, cipal part of all building-stones are which is generally iron. The specific siiex, or the earth of flint, clay, lime, gravity of few stones, except foreign mare and magnesia. The substances which bles, exceeds 2.80, unless some iron be sometimes enter into their composition, present. and alter their quality, are oxyd of iron, The quality of the three earths, silex. water, and carbonic acid : the other clay, and lime, is essentially distinct; earths, or metals, are generally in too but there are scarcely any stones that sinall quantities to deserve the attention can be employed in architecture, in of the architect. The qualities which which they are not more or less combined these four earths communicate I shall together; communicating their character afterwards state. The most important ex- according to the proportion in which they ternal characteristics of stone for building combine. Hardness is a distinctive are, coinpactness of texture, hardness, character of stones, into which silex degrees of frangibility, and specific gra- enters in a very large proportion. Silex vity. Compact texture, or closeness of being insoluble in water, and all the grain, is always an advantage in stones acids, except one of rare occurrence, of the same kind; for it is evident, that a silicious stones are, of all others, the porous stone will be more exposed to most durable, and best suited for the the action of air, or moisture, than a foundation of bridges, piers, and docks. denser one of the same kind: but com- Silicious stones are frequently com. pactness of texture is no test of excel. pounds, containing two, three, or more, Jence in stones of different kinds, for substances, united together in a granular chalk is frequently inore compact than or crystallized form. many kinds of durable sand-stone. Hard- Granite is composed of quartz, felspar, ness is also an important character in and mica. The quartz contains more comparing varieties of the same species than ninety parts of silex, the felspar of stone, but it will not serve as a test sixty, and the mica, which is generally of durability in stones of a different ge. in the smallest proportion, about forty. nus, on account of the different effects The grains, or crystals, though distinct, which different agents have upon them. are as firmly imbedded and united to The hardness of natural or artificial sub- each other, as if they had been inelted stances is no direct proof of their together, Granite is not only extremely strength; glass, which is harder than hard, but is also very infrangible, reiron, is more frangible than soft lime. sisting the effects of violent percussion, stone. In compound stones, which have Some kinds of porphyry, which contain a crystallized texture, we frequently find crystals of felspar, imbedded in a silicious the parts extremely hard, but the adhe- base, are as hard, and still less frangible sion of the parts to each other very than granite. Many of the edge-stones slight, as in some kinds of sand-stone. of the foot pavements in London, are of

Great specific gravity, or weight, is a porphyry, which appears to he of a very proof of excellence in stones of the same durable kind, and might probably be kind, unless it arise from a combination used to great advantage in forming the seith water, or the presence of iron, which foundation and base of the arches of the is a circumstance deserving great atten. two new bridges, to be erected over the rion; as iron, when in combination with Thames. Granite is found chiefly on the stories, is acted upon by air and water, western side of our island; there is, how. which occasions their decay. Some ever, a range of low granite mountains,

at Charnword forest, in Leicestershire. of Nottingham is built; and the red-sand The granite is chiefly used for paving in rock of Cheshire. The former may be the neighbourhood; it is small-grained, considered more properly as indurated or what some mineralogists would call, gravel, intermixed with rounded quartz secondary granite; and others sunite as it pebbles; but, though it is too loose to be contains small crystals of hornblende. applied to purposes of architecture, it Its specific gravity I found 2.77. It is ex. may be excavated to a considerable extremely hard, and is worked by blasting. tent, without the necessity of supporting If it can be raised in blocks of sufficient the sides and root. Tie granite of magnitude, it might be employed with Charnwood forest, and the loose sand. great advantage in constructing the foun- rock of Nottingham, are not more than dation of the new bridges; as it is only twenty miles distant, but they may be one hundred miles distant from London, considered as forming the two extre. fron, whence there is direct carriage by milies of the scale of aggregate silicious water. It is, I believe, the most durable stones, from the very hardest to the stone that can be found in any great softest kind. Argill, or clay, is never quantity at the same distance from the found pure in any kind of building.stone. metropolis. At the same place is pro. It is soft, smooth, and unctuous to the cured another stone, resting upon the touch, and will absorb more then 21 granite; it is a species of greenstone, and times its own weight of water; and, as hornblende porphyry, containing small Mr. Kirwan has observed, it coinmu. crystals of felspar, in a basis chic ily of vicates, in some degree, these properties hornblende. The workinen informed me, to stones, if it is combined in a proportion it is broken with more difhculty than of from 20 to 30 per cent. In a greater granite; it is not so hard, but is very inte proportion it destroys the qualities of frangible. Its specific gravity I found silicious stones. Many argillaceous stones 9.88. It contains some oxyd of iron, contain a considerable quantity of iron, like other stones of this species, which not perfectly oxydated. When exposed to may perhaps render it improper to be the atmosphere, they speedily decay. It used, where it can be acted upon by is in stones of the argillaceous kind, that water; but it has every appearance of the greatest caution and mineralogical being a very durable stone, and might knowledge are required, in the sclection deserve the attention of builders, where for purposes of durable architecture. I great strength of materials is required. have seen a billock at the mouth of a Iu silicious sand-stoncs, the coarseness lead-mine, supporting a luxuriant veor fineness of the grains is of less in- getation, which a respectable miner in. portance than the substance in which formed ine he had twenty years before they are imbedded. Those which have a blasted from a compact bed of toadbasis of ferroginous clay, are sost' and stone, or basalt, that resisted the pickperishable; but when the basis itself is axe, and no soil had been since thrown of a silicious kind, the stones are almost upon it. An instance of this kind was equally durable with granite. The upper the occasion of an action at the last York strata of many of the highest bills in assizes, betwcen the proprietors of the Yorkshire and Derbyshire, are of this Barnsley canal, and the engineer. On kind, which Mr. W hitshurst calls a mille the part of the proprietors it was constone grit. It is of a finer-grained stone, tended, that the hill through which he of the same kind that Kirkstall Abbey, had to cut a tunnel, was a soft marble. near Leeds, is built. Though the Abbey On the part of Mr. Pinkerton it was is a ruin, the stones which remain are stated, that, though the part exposed was little decayed. After the lapse of six now soft, it was, when first opened, a hundred years, they preserve their an- very bard and compact rock, extremely gular sharpness, and the impression of expensive and difficult to work; and the the chissel, as fresh as if they had been truih of this statemcot he offered to recently worked. There is a quarry of, prove, by perforating any part of the this stone in the neighbourhood; and I hill where the stone had not before been have observed soine of the stones in the laid bare 10 the action of the atmosphere. London docks, are of a similar kind.. The argillaccous sand-stone which acSome silicious sand-stones appear to be companies or lies over coal, is used for of alluvial formation, and have their parts buildings in coal countries, as in some so imperfectly cemented, that they are parts of the West Riding of Yorkshire: unfit for the purposes of architecture; of but it is not suited for public buildings this kind are the rocks on which she town or works intended to be durable. Stones


« FöregåendeFortsätt »