Account of the Skerryvore lighthouse : $b with notes on the illumination of lighthousesStevenson, Alan
History
Account of the Skerryvore lighthouse : $b with notes on the illumination of lighthouses
Stevenson, Alan
Skerryvore Lighthouse (Hebrides, Scotland)
The next step is to raise the stone so that it may incline at about 30°
or 40° with the horizon; after which the mason, standing at the higher
side, commences to put on the _draughts_ or _guide-lines_ all round the
edge of the face which he has just _opened_. For that purpose he first
employs a pick of about 12 lb. weight, having a handle about 2 feet in
length (fig. No. 17), with which he dresses a band of about 3 inches
broad, taking care that this band or draught be straight and _out of
winding_. He then, with the pick, goes over the whole face between
the draughts, dressing off all the ridges which still remain between
the ruts which he had made while the stone was standing on edge, as
before noticed, so that the whole surface will present the appearance
of a pretty regularly _dabbed_ face. Having arrived at that stage, he
next proceeds to put on the _true draughts_ (as round the edges of the
stone, as in the case of the _guide-lines_), with the cast-steel chisel
or _punch_ (_a_, _a′_, fig. No. 18), and a small iron-mall of 3¹⁄₂ lb.
weight; and afterwards with the axe, he carefully _axes_ a band about
2¹⁄₂ inches broad, so as to be quite out of winding, and as straight as
possible all round. The dressing is then completed between those bands.
If the block be a broad one, the mason will probably be able to take
in only one half of the face at a time; and, in that case, the stone
must be let down at the high side, and the other one raised as high as
may be necessary to enable him to work to advantage. If the surface
thus dressed, which is in this case supposed to be the largest side, be
intended for the _bed_ of a stone, the knobs or high points between the
_pick-dabs_ are merely roughly dressed down with a blunt axe, so as to
be all as low as the axed lines or draughts round the extremities, and
thus to present no convexity on which the stone, when laid, could rock;
but if the surface should be meant for a fine _face_, the dressing
must be commenced with a bluntish axe, taking care that all the axe
marks be made quite across the stone, at right angles to the side
where the workman stands. The whole face having been once gone over in
that manner with a blunt axe, a sharper and well ground axe is next
used for crossing the first axing in such a manner that all the second
axe-marks may be inclined at an angle of 45°, or thereby, with the
first. The whole face having been thus brought to a smoother and more
uniform surface, the third and last axing follows; and then the mason
uses his shortest and lightest axe, which must, for that work, be well
ground and sharp. That axing must be done right across the block, or in
the same direction as the first axing had been done, and in that state
the surface of the stone may be supposed to be fine enough for most
kinds of work used in housebuilding or in public works; but for very
fine work, such as some sepulchral monuments, or for surfaces which are
Public-domain text, read in full here on John Shaqi.
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