AN IMPROVED METHOD OF PREPARING AND LAYING DIAMOND AND OTHER SLATES IN COVERING HOUSES AND OTHER BUILDINGS, AND OF' PREPARING SLATES FOR OTHER PURPOSES
Year: 1801

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BARKER:
CHIIFNEY, of the City of London, Gentleman, send greeting.
WHEREAS His most Excellent Majesty King George the Third did;"
by His Letters Patent under the Great Seal of the United Kingdom of
Great Britain and Ireland, bearing date at Westminster, tlie Second day of
May, in the forty-first year of His reign, give and grant unto me, the said
Barker Chifney, His especial licence, that I, the said Barker Chifney, during
the term of years therein mentioned, should and lawfully might make, use,
exercise, and vend, within England Wales, and the Town of Berwick-upon-'
Tweed, my Invention of "AN IMPROVED METHOD OF PREPARING AND LAYING
DIAMOND AND OTHER SLATES IN COVERING HOUSES AND OTHER BUILDINGS, AND OF'
PREPARING SLATES FOR OTHER PURPOSES;" in which said Letters Patent there is
contained a proviso, obliging me, the said Barker Chifney, by an instrument"
in writing under my hand and seal, to cause a particular description of the
nature of my said Invention, and in what manner the same is to be per-
formed, to be inrolled in His Majesty's High Court of Chancery within'
six calendar months after the date of the said recited Letters Patent, as in
and by the same (relation being thereunto had) may more fully and at large
appear.
NOW KNOW YE, that I, the said Barker Chifney, in compliance with the
provisoes and conditions in such Letters Patent contained, do hereby describe
the nature of my said Invention of an improved method of preparing and

page_text: Jaying diamond and other slates in covering houses and other buildings, and of
preparing slates for other purposes, in manner following, viz:-
Instead of splitting the slabs or parts of slabs to the thicknesses which it is
intended any kind of roofing or other slates, shall be of, as near as may be, and
then reducing them to their size or sizes by what is called a chopper, or iron
instrument commonly made use of in Carnarvonshire and elsewhere, or by any
other instrument or means whatsoever, I take the slabs as they come from the
quarry, and saw them by common or other machinery into square blocks, or
blocks of any rhombus, or other shape, of such sizes, or nearly so, as the dimen-
sions of roofs, their aspects or any other circumstances (according to the purposes
for which slates are intended) may make necessary or appear the fittest, and I
afterwards split them to greater or less thicknesses accordingly. In such saw'd
blocks the necessary holes may be drilled and the corners cut off (when it is
requisite); but I prefer and recommend, both for diamond and other roofing
slates, that the holes may be drilled and the corners cut off by common
machinery, after the saw'd blocks are split into such thicknesses as it is
intended the slates shall be of, by placing them in templates or frames so as
for the drills and saws to perform their operations with mathematical exactness,
or nearly so. It is particularly necessary that the slabs should be taken to the
mill to be sawed and then split, as soon as quarried, to prevent their parting
with their water or natural moisture before those operations; and in cases
where it cannot be done, I recommend immersing the slabs and also the saw'd
blocks (if they are to lie before splitting) in the water of the mill stream, in
some convenient pond, or in reservoirs constructed for the purpose, as other-
wise an adhesion of the particles will take place in a greater or less degree,
(in consequence of the evaporation of the water or natural moisture. of the
slate,) to the injury of the operations of sawing and splitting: It will fre-
quently happen that slabs will be got from the quarry with what are called
natural or self-edges, and of proper breadths to be made into roofing or other
slates, in which cases the slabs are to be sawed into their necessary lengths, and
afterwards split into their necessary thicknesses, as before described. What I
-mean-by-slabs, is, the pieces of slate rock as they are first got in or from the
quarry; and when such slabs, or pieces of slate rock, have assumed-some.regular
shape, or shapes by the operation of the saw or saws, I call them blocks or
saw'd blocks, indifferently. Sometimes the slabs will be too large to remove to
the mill or place of sawing, in which case it may be necessary to reduce them
by splitting or breaking to more convenient sizes for removal; but this is not
to be considered as a deviation from the principle here laid down.
In laying
diamond slates, I recommend that not less than one-sixth is allowed for

page_text: the lap, as in Figure 1; which is the form of a common diamond slate;
Fig. 2 is the form of a diamond caves slate, which should always be made
thicker and stronger than others to bear the pressure of a ladder, or any other
necessary erection against the eaves; a, a, Figs. 1 and 2, are the screw holes.
Fig. 3 represents a number of slates laid on a roof, the head of each screw
catching and securing the side slates and passing through the under ones.
The screws should be rimer-headed, to cut their way in the side slates, so as
to allow the upper or covering slates to lie close to those under them. Nails
inay be used, but ought not, the difference of expence being inconsiderable..
The heads of the screws or nails should be secured with cement or putty, and
the under side of the roof, whether laid on laths or rafters, should be pointed
securely with a. composition of lime, sand, and Parker's Roman or other water
terras, mixed in such proportions as the quality of the different materials may
make necessary. In laying diamond slates I. do not pretend to claim any other:
improvement than what arises out of the exactness of the workmanship, from
the preparation of the slates, from the rimer-headed screws, and from the
security arising from pointing with composition.
The duchess, countess, and lady slates of Carnarvonshire, and the rag slates
of Carnarvonshire and other places, are commonly laid with or hung on oak laths,
by wooden pegs or iron pins put through à hole made near the top of the slate,
by which, the wind acting under the lower edge of the slates, they have nothing
to resist its force except. the weiglit of the covering slates; whereas, in case:
the bleak and exposed situation of a house or building require great, sécurity
to resist the winds, I drill or make four holes in each slate by common or
other machinery, if duchess, countess, or lady slates; or if the slates, are all of:
any other regular size, whetlier larger or smaller, as in Fig 4, where b, b,.
represent the upper holes about, half an inch from the top, and a. quarter of
the width of the slate from each side edge; C,.C, the lower holes, three quarters;
of an inch more than half the length of the slate from the bottom, and a
quarter of the width of the slate from each sideedge; the upper holes b, b,
are to be large, and the lower ones are to be nearly the size of the screws or
nails, and countersunk. Other proportions for the distances of the holes from
top and bottom may, however, be used; but for rag slates, and for duchess,
countess, and lady slates, or any other slates of the same lengths in common
situations, I drill or make two countersunk holes nearly the size of the screws
or nails by common or other machinery, as d, d, Fig 5, about one inch more
than half the length of the slates from the bottom, and about one inch from
the side edges, although greater or less distance from the bottom may be
adopted, and greater or less distance from the side edges; Fig. 6 represents part

page_text: of a roof laid with slates, having four holes in each; and Fig. 7 represents part
of a roof laid with slates having two holes in each, where it may be observed,
that the top edge of every slate bears on the lath above, which it is fastened
with screws or nails, a matter of the first consideration. Houses and buildings
covered with duchess, countess, lady, rag, or any other sort of slates in the
ways herein pointed out, should have the. heads of the screws or nails secured
with cement or putty, and the insides of the roofs should be pointed securely
with composition, in the same manner as diamond slated roofs; common
mortar may be used in pointing and securing roofs laid with slates after any of
these methods; but I by no means approve it, for, by drifting rains and snows,
or by the attraction of vapours, it frequently becomes so charged with moisture;
that by the expansion which takes place in sudden frosts, it is not unusual. for.
the mortar to. crack, and sometimes to fall off, by which water gets through
the roof and injures the rafters and the ceiling.
In witness, I, the said Barker Chifney, have hereunto set my hand and
seal, this Thirtieth day of October, in the year of our Lord One
thousand eight hundred and one.
BARKER CHIFNEY, (L.S.)
AND BE IT REMEMBERED, that on the Thirtieth day of October, in
the forty-second year of the reign of His Majesty King George the Third,.
the said Barker Chifney came before our said Lord the King in His Chancery,
and acknowledged the instrument aforesaid, and all and every thing therein
contained and. specified, in form above written: And also the instrument:
aforesaid was stamped according to the tenor of the several Statutes made in
the sixth year of the reign of the late King and Queen William and Mary of
England, and so forth, and in the seventeenth, twenty-third, and thirty-seventh
years of the reign of His present Majesty King George the Third..
Inrolled the Thirtieth day of October, in the year of our Lord One
thousand eight hundred and one.