STONE TILES. 483 
Collyweston Slates. 
These slates have been worked for upwards of 350 years at Collyweston 
and Easton near Stamford, Duddington, Medbourn, Kirby, and Dene 
Park, near Rockingham. 
Prof. Judd has remarked that the Collyweston Slates have been dag 
over a considerable area, old pits being traceable from Wothorpe near 
Stamford to the western side of Collyweston, a distance of more than 
three miles. He has given the following full account of the method of 
working, &c., to which I have added a few notes. " The valuable fissile 
character of the beds is merely a local accident ; and in some directions 
the bed of stone has been followed and found to become non-fissile and 
in consequence worthless for roofing purposes. There is only a single 
bed of stone (the lowest limestone of the series) which is used for making 
roofing-slates. This varies greatly in thickness, being often not more 
than 6 inches thick, but sometimes swelling out to 18 inches, and in rare 
cases to 3 feet ; while, not unfrequently, the bed is altogether absent and 
its place represented by sand [or sandstone]. Rounded mammillated 
surfaces, like the " pot-lids " of Stonesfield, abound in these beds." 
"The slates are worked either in open quarries or by drifts (locally 
called "fox-holes") carried for a great distance under ground, in which 
the men work by the light of candles. The upper beds of rock are 
removed by means of blasting, but the slate-rock itself cannot be thus 
worked, for though the blocks of slate-rock when so removed appear to 
be quite uninjured, yet, when weathered, they are found to be completely 
shivered and consequently rapidly fall into fragments. The slate-rock is 
therefore entirely quarried by means of wedges and picks, which, on 
account of the confined spaces in which they have to be used, are made 
single sided. The quarrying of the rock is facilitated by the very 
marked jointing of the beds, a set of master-joints traversing the rocks 
with a strike 40 W. of N. (magnetic), while another set of joints, less 
pronounced, intersect the beds nearly at right angles." 
" During the spring of the year the water in the pits rises so rapidly 
that it is impossible to get the slates out. The slates are usually dug 
during about six or eight weeks in December and January. The blocks 
of stone are laid out on the grass, preferably in a horizontal position. It 
is necessary that the water of the quarry shall not evaporate before the 
blocks are frosted, and they are constantly kept watered, if necessary, 
until as late as March. The weather most favourable to the production 
of the slates is a rapid succession of sharp frosts and thaws. If the blocks 
are once allowed to become dry they lose their fissile qualities, and are 
said to be " stocked." Such blocks are broken up for road-metal, for 
which they afford a very good material. The limestone beds above the 
slate-rock are burnt for lime." 
After the blocks are split, the slates are stacked on edge in circular 
piles or heaps. Subsequently they are shaped, and again stacked on edge 
according to size. 
"The slates are cleaved at any time after they are frosted. Three 
kinds of tools are used by the Collyweston slaters. The ' cliving hammer,' 
a heavy hammer with broad chisel-edge for splitting up the frosted blocks. 
The 'batting hammer ' or ' dressing-hammer,' a lighter tool for trimming 
the surfaces of the slates and chipping them to the required form and 
size. The ' bill and helve,' the former consisting of an old file sharpened 
and inserted into the latter in a very primitive manner. This tool is 
used. for making the holes in the slates for the passage of the wooden pegs, 
by means of which the slates are fastened to the rafters of the roof. 
These .holes are made by resting the slate on the batting hammer and 
cutting the hole with the bill." 
" The slates are sold by the ' thousand,' which is a stack usually con- 
taining about 700 slates of various sizes, the larger ones being usually 
placed on the outside of the stack. The slates when sold on the spot 
fetch from 23s. to 45s. per thousand. Many of the Collyweston slaters 
except contracts for slating, and go to various parts of England for the 
purpose of executing their contracts." 
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