In these articles, the content of a roof is found by multiplying the length of the ridge by the girth over from eaves, to eaves; making allowance in this girth for the double row of slates at the bottom, or for how much one row of slates is laid over another. When the roof is of a true pilch, that is, forming a right angle at top, then the breadth of the building with its half added, is the girth over both sides. In angles formed in a roof, running from the ridge to the eaves, when the angle bends inwards, it is called a valley; but when outwards, it is called a hip. It is not usual to make deductions for chimney-shafts, sky-lights or other openings.

3 inch Cover.

2 inch Cover.

6izes of Slates.

No. of Slates to the Square or 100 Feet.

No. of slates to the square or 100 Feet.

24

by

16

86

84

24

by

14

98

934

2»

by

12

114

109

22

by

1 4

108

102 ¼

22

by

12

126

120

22

by

10

152

144

20

by

14

129

114¼

20

by

12

143

133¼

20

by

11

l 46

145½

20

by

10

169 ¼

160

1-

by

12

160

150

3 inch Cover.

2 inch Cover.

Sizes of Slates.

No. of Slates to the Square or 100 Feet.

No. of slates to the square

18

by

11

174¼

163½

18

by

10

192

180

18

by

9

213

200

16

by

12

184

1714

16

by

10

2214

205 ¾

16

by

9

246

128½

16

by

8

277

257

14

by

10

262

240

14

by

9

293

2664

1 1

by

8

327

300

1 1

by

7

374

848

"Each slate in 3 Inches bond or cover. The rule for measuring Slating is, to add one foot for all hips and Valley. No deduction ii made for Lutheran windows, skylights or chimney, except they ore of unusual size i then one half is deducted," plasterers', pavers', and painters' work. 137

Imported Slates

Names of Slates.

Sizes.

Number of Superficial Feet each M of 1200 will cover.

Weight of each M of 1200 Slates.

Inches

[Inches.

Duchesses, ..............

24

In

12

1100

60

cwt.

Marchionesses, . . .

22

"

12

1000

55

"

Countesses, ...............

20

"

10

750

40

"

Viscountesses, . . .

18

"

10

666 2-3

36

"

Ladies, .................

16

"

10

583 1-3

31

"

do..............

16

"

8

466 2-3

25

"

do.............

14

"

8

400

22

"

do........

12

"

8

333 1-3

18 1-2

"

Plantations ............

14

"

12

600

33

"

do......

13

"

10

458 1-3

25

"

do ..............

12

"

10

416 2-3

23

"

Doubles, ..............

13

"

7

320 5-6

17 1-2

"

do. small, . . .

11

"

7

262 1-2

14 1-2

"

School Slates for

5 ft. by 2 1-2 ft

Blackboards, . . . .

5 feet by 3 feet.