To abftract the foregoing particulars, that is, to collect together the contents of the fame kind, next to reduce their fums to the ftandard thickness of a brick and a half, and then, having made the deductions, to collect the reduced fums, to obtain the whole in one fum, I proceed thus: I make only two columns for the whole contents, and two for the deductions of the fame thicknefs, viz. one column for the one-brick contents, and the other for the brick-and-half contents; and difpofe the fuperior denominations in one or both of thefe columns, by placing them down more than once; thus, the contents of 2 bricks thick, I fet down twice in the one-brick column; thofe of 2 bricks, I fet down once in the one-brick column, and once in the brickand-half column; thofe of 3 bricks, twice in the brick-and-half column; thofe of 3 bricks, once in the brick-and-half, and twice in the one-brick column; and thofe of four bricks, twice in the brick-and-half, and once in the one-brick column; and fo on, if there were higher denominations; and, laftly, for the contents of half a brick thick, I take the halves of them, and fet in the one-brick column. Then, having added up every column, I reduce the fums of the one-brick thick, to the brick-andhalf thickness; and add this reduced content to the brick-and-half fums, both in the folids and deductions; then, laftly, taking the one fum from the ether, for the whole content of the brick work, as follows.

Abftrat

Abstract of the Brick Work.

1 br. thick 1 brick thick 14 deduct 1 br. deduct

326 8 reduced cont. of the 4 quoins of the house 1612 3 the deductions

1933 11 fum

282 o vacuity of arch under the paffage, deduct

9)1656 11

184 yards to be added for workmanship only.

So that in the Bill we shall have

1691 yards 4 feet of brick-and-half
wall, work and materials at

£ s d

}

}-

The