332 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[September, 



products which arise from such towns, ami are injurious to buildings, 

 are not to be found. 



The chemical action of the atmosphere produces a change iu the 

 entire matter of the limestones, and in the cementing substance of the 

 sandstones, according to the amount of surface exposed to it. The 

 mechanical action due to atmosplieric causes, occasions either a re- 

 moval or a disrui)tion of the exposed particles ; the former bv means 

 of powerful winds and driving rains, and the latter by the congelation 

 of water forced into or absorbed by the external portions of the stone. 

 These effects are reciprocal, chemical action rendering the stone liable 

 to be more easily affected by mechanical action, which latter, by con- 

 stantly presenting new surfaces, accelerates the disintegrating effects 

 of the former. 



Buildings in this climate are generally fomul to suffer the greatest 

 amount of decomposition on their southern, south-western, and western 

 fronts, arising, doubtless, from the prevalence of winds and rains from 

 those quarterns ; hence it is desirable that stones of great durability 

 should at least be employed in fronts with such aspects. 



Buildings situated in the country appear to possess a great advan- 

 tage over those iu pop\ilous and smoky towns, owing to lichens, with 

 which they almost invariably become covered in sucli situations, and 

 wdiich, when firmly established over their entire surface, seem to 

 exercise a protective influence against the ordinary causes of the 

 decomposition of the stone upon which they grow. 



As an instance of the difference in degree of durability in the same 

 material, subject to the effects of the atmosphere in town or country, 

 we may notice tlie several frustra of coluuuis and other blocks of stone 

 which were qirarried at the time of the erection of St. Paul's Cathe- 

 ilral in Loudon, and are now lying in the Island of Portland, near the 

 quarries from whence they were obtained. These blocks are inva- 

 riably found to be covered with lichens, and although they have been 

 exposed to all the vicissitudes of a marine atmosphere for more than 

 150 years, they still exhibit, beneath the lichens, their original form, 

 even to the marks of the chisel employed upon them, whilst the stone 

 which was taken from the same quarries (selected no doubt with equal 

 if not greater care than the blocks alluded to), and placed in the Ca- 

 thedral itself, is, in those parts which are exposed to the south and 

 south-west winds, found in many instances to be fast mouldering 

 away. 



Colour is of more importance in the selection of a stone for a build- 

 ing to be situated in a populous and smoky town than for one to be 

 placed in an open country, where all edifices usually become covered, 

 as above stated, with lichens ; for although in such towns those fronts 

 which are not exposed to the prevailing winds and rains will soon 

 become blackened, the remainder of the building will constantly 

 exhibit a tint depending upon the natural colour of the material em- 

 ployed. 



Before we proceed to adduce a few examples of the present con- 

 dition of the various buildings that we have examined, we would wish 

 to observe, that tliose wdiich are highjy decorated, such as the churches 

 of the Norman and pointed styles of architecture, afford a more severe 

 test of the durability of any given stone, all other circumstances being 

 equal, than the more simple and less decorated buildings, such as the 

 castles of the fourteenth and fifteenth centuries, inasmuch as the ma- 

 terial employed in the former class of buildings is worked into more 

 disadvantageous forms than in the latter, as regards exposure to the 

 effects of the weather ; and we would further observe, that buildings 

 in a state of ruin, from being deprived of their ordinary protection of 

 roofing, glazing of windows, &c., constitute an equally severe test of 

 the durability of the stone employed in them. 



As examples of the degree of durability of various building stones 

 in particular localities, the following may be enumerated. Of the 

 sandstone buildings wliich we examined we may notice the remains of 

 Ecclestone Abbey, of the thirteenth century, near Barnard Castle, 

 constructed of a stone closely resembling that of the Stenton Quarry, 

 in the vicinity, as exhibiting the mouldings and other decorations, 

 even to the dug's tooth ornament, in excellent condition. The circular 

 keep of Barnard Castle, apparently also built of the same material, is 

 in fine presei-yation. Tintern Abbey may also be noticed as a sand- 

 stone edifice that has to a considerable extent resisted decomposition ; 

 for, although it is decayed in some parts, it is nearly |ierfect in others. 

 Some portions of Whitby Abbey are likewise in a perfect state, whilst 

 others are fast yielding to the effects of the atmosphere. The older 

 portions of Ripon Cathedral, constnxcted of sandstone, are in a fair 

 state of preservation. Rivaulx Abbey is another good example of an 

 ancient sandstone building iu a fair condition. The Norman keep of 

 Richmond Castle, in Yorkshire, affords an instance of a moderately 

 hard sandstone, which has well resisted decouq)osition. 



As examples of sandstone buildings of more recent date, in a good 

 state of preservation, we may mention Hardwicke Hall, Haddon Hall, 



and all the buildings of Cragleith stone in Edinburgh and its \icinity. 

 Of sandstone edifices in an advanced state of decomjiosition we may 

 enumerate Durham Cathedral, the churches at Newcastle-u])on-Tyne, 

 Carlisle Cathedral, Kirstall Abbey, and Fountains Abbey. The sand- 

 stone churches of Derby are also extremely decomposed ; and the 

 church of .St. Peter's at Shaftesbury is in sucli a state of decay, that 

 some portions of the building are only prevented from falling by means 

 of iron tie-:. 



As an example of an edifice constructed of a calciferous variety of 

 sandstone, we may notice Tisbiny Church, whicli is in unequal con- 

 dition, the mouldings and other enrichnients being in a perfect state, 

 whilst the ashler, apparently selected with less care, is fast moulder- 

 ing away. 



The choir of Southwell Church, of the twelfth century, may be 

 mentioned as affording an instance of a magnesio-calciferous sand- 

 stone, resembling that of Mansfield, generally in good condition, after 

 long exposiu'c to the iiifiuences of the atmosjihere. 



Of buildings constructed of magnesian linu'stone we may mention 

 the Norman portions of Southwell Church, built of stone similar to 

 that of Bolsover, and which are throughout in a perfect state, the 

 mouldings and carved enrichments being as sharp as when first exe- 

 cuted. The Keep of Konmgsburgh Castle, built of a magnesian lime- 

 stone from the vicinity, is also in a perfect state, though the joints of 

 the masonry are open in consequence of the decomposition and disap- 

 pearance of the mortar formerly within them. The Church at Hem- 

 mingborough, of the fifteenth century, constructed of a material resem- 

 bling the stone from Huddlestone, does not exhibit any appearance of 

 decay. Tickhill Church, of the fifteenth century, built of a similar 

 material, is in a fair state of preservation. Huddlestone Hall, of the 

 sixteenth century, constructed of the stone of the immediate vicinity, 

 is also in good condition. Roche Abbey, of the thirteenth century, in 

 which stone from the immediate neighbourhood has been employed, 

 exhibits generally a fair state of preservation, although some portions 

 have yielded to the effects of the atmosphere. 



As examples of magnesian limestone buildings in a more advanced 

 state of decay, we may notice the churches at York, and a large por- 

 tion of the Minster ; Howden Church, Doncaster old Church, and others 

 in that part of the country, many of which are so much decomposed 

 that the mouldings, carvings, and other architectural decorations, are 

 often entirely effaced. 



We may here remark that, as far as our observations extend, in 

 proportion as the stone employed in magnesian limestone buildings is 

 crystalline, so does it appear to have resisted the decomposing effects 

 of the atmosjihere ; a conclusion in accordance with the opinion of 

 Professor Daniell, who has stated to us that from the results of expe- 

 riments he is of opinion that " the nearer the magnesian limestones 

 approach to equivalent proportions of carbonate of lime and carbonate 

 of magnesia, the more crystalline and better they are in every respect." 



Of buildings constructed of oolitic and other limestones we may no- 

 tice the Church of Byland Abbey, of the twelfth century, especially 

 the west front, built of stone from the immediate vicinity, as being in 

 an almost perfect state of preservation. Sandysfoot Castle, near Wey- 

 mouth, constructed of Portland oolite in the time of Henry the Eighth, 

 is an example of that material in excellent condition; a few decom- 

 ])Osed stones used in the interior, and which are exceptions to this 

 fact, being from another oolite in the innnediate vicinity of the castle. 

 Bow and Arrow Castle, and the neighbouring ruins of a church of the 

 fourteenth century, in the island of Portland, also afford instances of 

 the Portland oolite in perfect condition. The new Church in the 

 island, built in 170G of a variety of the Portland stone termed roach, 

 is in an excellent state throughout, even to the preservaition of the 

 marks of the chisel. 



Many buildings constructed of a material similar to the oolite of 

 Ancaster, such as Newark and Grantham Churches, and other editices 

 in various parts of Lincolnshire, have scarcely yielded to the effects of 

 atmospheric influences. Windrush Church, built of an oolite from the 

 neighbouring quarry, is in excellent condition; whilst the Abbey 

 Church of Bath, constructed of the oolite in the vicinity of that city, 

 has suffered nmch from decomposition ; as is also the case with the 

 Cathedral, St. Nicholas and St. Michael's Churches, in Gloucester, 

 erected of a stone from the oolitic rocks of the neighbourhood. 



The churches of Stamford, Ketton, Colley Weston, Kettering, and 

 other places in that part of the country, attest the durability of the 

 shelly oolite termed Barnack Rag, with' the exception of those i>or- 

 tions' of some of them for which the stone has been ill selected. The 

 excellent cundition of those parts which remain of Glastonbury Abbey 

 show the value of a shelly limestone similar to that of Doulting; whilst 

 the stone employed in Wells Cathedral, api)arently of the same kind, 

 and not selected with equal care, is iu parts decomposed. The Man- 

 sion, the Church, and the remains of the Abbey at Montacote, as also 



