126 Transactions.—Miscellaneous. 
stone is not affected by the changes of the weather, and may, therefore, be 
taken as durable. 
Sandstone was deposited under water and hardened by pressure and 
drying, consequently it has a distinct natural bed. The stone is often of 
such a uniform colour and consistency that the lines of stratification are 
quite invisible, and as the stratum may not have retained its originally 
horizontal position, the mere inspection of a specimen in a museum or of a 
block in a quarry will not give the bed of the stone. It is, however, easily 
determined by the quarrymen, from the facility of working in a certain 
direction as compared with others. 
As a general rule, sandstones are hardest and most compact when 
found at the lower side of a thick stratum, or in the vicinity of basaltic 
dykes, or other volcanic rocks that may have disturbed them. The facilities 
for drainage afforded by the lie of the adjoining land has also considerable 
influence on the consistency of the softer sedimentary rocks. 
In building with stones from stratified rocks, it is absolutely necessary 
that they be laid on their natural bed. A disregard for this rule is the sole 
cause of decay in a large majority of cases where buildings have failed. 
When the stones are placed in an inclined position, they afford the greatest 
facility for absorbing moisture, and when vertical, the superincumbent 
weight has a tendency to split them. The latter evil is often greatly 
aggravated by a practice that exists among masons of working the beds 
slightly hollow, so as to ensure a neat joint. 
The appearance of some of our soft stone buildings fully bears out the 
above remarks, as to the necessity of laying stones on their natural bed ; 
some of them are smooth and solid after many years exposure, while others 
from the same quarry, and under exactly the same conditions, are in an 
advanced state of disintegration. This state of affairs could be prevented 
by simply marking the stones in the quarries where the lines of stratifica- 
tion are easily determined, and generally well known. Independent of the 
increased durability, it is advisable to lay all stones on their natural bed, 
for they are a fourth stronger in that position than in any other. 
Calcareous stones are less subject to decay from the mechanical action 
of the weather than sandstone, but more susceptible to chemical agencies. 
As the cementing material is always the same, the durability depends 
entirely upon the aggregates, and the proportions in which they are mixed. 
The compact and crystalline limestones are believed to be unstratified, 
consequently they are not liable to exfoliation, and may be used in any 
position ; but some of the softer kinds give indications of haying been 
deposited in horizontal layers, in which case it is necessary to build with 
the stone on its natural bed. Although limestone is generally more 
