The Beauty and Use of Irish Buildine; Stones, 169 



case of a museum. Despite its delicacies of form and mould- 

 ing, it must, like the Forth Bridge or the steamers of the Irish 

 Mail, earn its crown and glory by weathering out the worst of 

 seasons. As I^ongfellow Avrote in his Michael Angelo, 



" Painting and sculpture are but images, 



Architecture, 



Existing in itself, and not in seeming 

 A something it is not, surpasses them 

 As substance shadow." 



The old cathedral-builders of England, before the days of 

 railwaj^s and long sea-carriage, were rather limited in their 

 choice of materials, and, when once they had hit upon a good 

 stone, the}^ went on confidently using it. They were thus 

 guided in most cases by experience ; in others, as at Chester, 

 their lack of geological knowledge led them into serious error. 

 Now-a-days, when in our cities public and private bodies vie 

 with one another in the costliness and handsomeness of their 

 offices, a number of stones are being introduced, and a novelty 

 is likel}' to be well received if its beauties — in all senses — can 

 be demonstrated to the purchaser's satisfaction. 



In books published for the guidance of architects and builders 

 there is usually very scant}^ reference to the real mineral 

 characters that determine the external beauty or the utilit}' of 

 a stone. Too few '' practical " workers in the stone-trade have 

 ever been shown how to determine the nature of the cement- 

 ing material of a sandstone, with a view to learning something 

 of its durability, or how to distinguish granite from dolerite, 

 or even from rocks that are rich in olivine, and therefore liable 

 to decay. The simple chemistry and the structural details of 

 building-stones should be familiar to all who have an interest 

 in their sale or in their purchase ; old-fashioned analyses and 

 inexact rock-names would not then be quoted, as they are 

 too often now, to give a show of scientific respectabilit}^ to 

 circulars intended for the trade. 



The constituent minerals of a rock, the materials that bind 

 them together, and the extent to which they have been affect- 

 ed by decomposition, are best seen in a thin section viewed 

 with a polarising microscope. Such sections are now com- 

 monly prepared and utilised by geologists ; is it too much to 

 hope that one person at least in ever}^ great builder's 3^ard may 

 some day be able to examine critically bj^ such means the 

 materials upon which his business-reputation may depend ? 



