ARTIFICIAL STONE MANUFACTURE. 871 
worked into the finest and most elaborate decorative examples of art. 
But so far as the style of agricultural buildings is involved, a sufficiency 
of ornamental work can be easily effected, at comparatively no increase 
of expense — certainly at a less increase than it is at present done by 
manual labour. 
Apart from improved mechanical means now at the command of 
builders, it has often occurred to us, when examining old Pictish masonry, 
that improvements could be made in the breaking and laying of the stones 
in the wall. The kind of stones used in the old fortified strongholds or 
castles and buildings to which we more especially refer, is chiefly 
sandstone. Few of them are larger than what one person could hand to 
another, and so shapeless in form and irregular in size, as to resemble 
very closely the rubbish of a quarry, broken-off in forming and dressing 
the large blocks for hewn work ; and the position of the largest of them 
is as often lengthways as vertically, instead of being placed in the 
mould or box lying on their flat sides, and more frequently in the cen- 
tre of the wall, than on the outside, as seen over doors and windows, 
and in places where the wall had been broken down by artillery, under 
a lengthened siege, which it at one time sustained. Towards the outside 
and inside of the wall, however, thin, small fragments are more in a flat 
or edge position tranversely. Some say the stones were first placed in 
the box or mould, and the finely tempered mortar then poured in ; 
others, that the mortar was first poured in, and then the stones sunk in 
the semi-fluid mass ; but we could never reconcile the actual posi- 
tion of the stone, so far as visible to the eye exclusively, to either of 
these two plans ; for they evidently indicated rather that both processes 
had been carried on alternately at the same time — i. e. y sometimes the one 
and sometimes the other, in accordance with certain definite rules based 
upon the peculiar shape and size of the stones. We know from experi- 
ence that the success of forming a good concrete foundation for a wall, 
or in fixing gate-posts, and the like, depends, in a great measure, nearly 
as much upon expedition, as upon the quality of the gravel and mortar ; 
and we aver that this rule of quick action entered largely into the theory 
of Pictish masonry, and that it must still be the rule of action in any 
successful attempt to make concrete walls, whatever may be their 
dimensions. 
There was another peculiarity in the experimental lesson which the 
masonry of the old Pictish castle taught us in early life, relative to the 
durable quality of the stone. With few exceptions, the stones for exampls 
had been carefully selected, but here and there the end of a sand- 
stone had given way to the weather, the mortar around it remaining 
hard and weatherproof to the hand of time. This further shows the 
reason why the Pictish mason put the smooth straight head of a large 
stone as often into the interior of his wall as to the outside, and 
why in putting the stones into the mould he studied the bonding of 
