jReviews — Frof. Hull on Building Stones, etc. 35 



cording to their geological distribution and mineral character, and 

 their application in ancient and modern structures illustrated. 



The study of the more solid building materials is of considerable 

 interest and importance, either in regard to their applications,, or iu 

 relation to their origin. Under the former head may be considered, 

 1st, The proximity of the source and nature of the material ; 2nd, 

 Durability ; 3rd, Tint or colour ; 4:th, Change of colour by exposure 

 or weathering; 5th, Capability of absorbing water; 6th, Eesisting 

 weight or crushing power. All these are points which more or less 

 influence the selection. Thus the contrast of the cities of London 

 and Manchester with those of Paris and Edinburgh, or why the 

 former are chiefly of brick and the latter of stone, are examples of 

 the proximity of certain geological conditions in both cases. The 

 abundance of brick-earth and tile-clays are a marked feature in the 

 vicinity of London, and have therefore influenced the street archi- 

 tecture, whilst, as Prof. Hull remarks, "the presence of the Carbonifer- 

 ous sandstones in the immediate vicinity of Edinburgh and Glasgow 

 have greatly contributed to the substantial character of the dwelling- 

 houses, as well as of the public buildings, of these cities, — a character 

 which strikes the eye of a visitor on arriving from the great brick- 

 formed cities of England." So, again, the Tertiary limestone of 

 Paris has a pale yellowish tinge, admirably adapted for street archi- 

 tecture under a smokeless sky ; and no one can fail to observe how 

 much of the beauty of the noble public buildings, and scarcely less 

 noble ranges of houses, in the principal streets of this queen of 

 cities, is due to the chaste purity of the stone, and its capability of 

 being employed either in massive structures, or in those of a more 

 ornate character. 



On the other hand, the public buildings of Oxford are a marked 

 instance of durability and decay in the materials employed ; thus, 

 the Headington limestone, obtained within the immediate vicinity of 

 Oxford, and of which nearly the whole of the churches, colleges, 

 and other public buildings, have been built within the last three 

 centuries, are in a deplorable state of decay, so as in some instances 

 to have caused all traces of architectural decoration to disappear ; 

 whilst the ancient parts of the Cathedral, Merton College Chapel, 

 New College Cloisters, of the 12th, 13th, and 14:th centuries, 

 respectively, built of the shelly Oolite, belonging to the lower part 

 of the Great Oolite, from Tainton, fifteen miles distant, and Burford, 

 are generally in a good state of preservation. 



Geologically considered, the building stones of our large cities are 

 also instructive, as they afford examples of the different origin of 

 rock masses ; thus the granites and porphyries are igneous rocks, the 

 slates and statuary marbles are metamorphic, the limestones are 

 chemical and organic, the cement stones are in part concretionary, 

 and the bricks and tiles are artificially metamorphosed clays and 

 loam, either of marine, drift, or freshwater origin. 



As before stated, the work is chiefly devoted to the stony materials 

 for architecture, and these are clearly and scientifically arranged by 

 Prof. Hull in thirteen parts, the first of which comprises a general 



