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years of exj3osure to a climate and atmosphere similar to 
those which the building stones of Manchester are exposed 
to, without the stone is of a pure silica, or nearly so. In 
all stones which are subject to chemical decomposition, these 
experiments will not surely guide us. 
Old buildings in country places remote from the smoke and 
gases of large towns are often adduced in evidence of the 
strength and durability of a stone to be employed in a manu- 
facturing town. However well the dolomite of Bolsover 
Moor might endure the climate and atmosphere of Southwell, 
in Notts, as it is seen in the Minster there, or the triassic 
sandstone of Furness might endure in the Abbey of that 
name, each seven or eight centuries, still it w’ould be 
unreasonable to expect that either of those stones could 
resist the action of the moist climate of Manchester, and 
the atmosphere of a city in which about forty thousand tons 
of sulphur are annually burnt in the coal consumed in it, to 
say nothing of the gases given off by the numerous chemical 
manufactories and the exhalations from half a million of 
human beings. 
On examining the buildings of Manchester, we find that 
the stone employed is chiefly from the middle and lower coal 
measures, the only instances of triassic or new red sandstones 
having been used are, as I have been informed, the Portico 
and St. Peter’s Church, from the Oughtrington quarry, near 
Lymm, and the beautiful church lately built by Mr. Crowther 
at Moss Side, which is from Hollington, near Ashbourn. 
The Cathedral was built from the sandstones of Smedley 
and Collyhurst, two rocks belonging to the upper part of the 
middle coal field. These stones are both soft, and contain a 
large amount of clay and peroxide of iron. As you proceed 
further down into the middle coal field, you find the sand- 
stones containing less iron in a state of peroxide and con- 
siderably smaller proportions of clay, still the stones are not 
suitable for outside work, as they contain protoxide of iron 
