These values of ${\displaystyle \mathrm {L} }$, are all, for the mortar when yielding in cohesion. When observed to yield in adhesion, the coefficient in each case becomes 0.1,${\displaystyle \mathrm {L} }$ for brickwork and 0.083,${\displaystyle \mathrm {L} }$ for limestone. The values given, are also all for ancient and fully indurated (except 5 and 9) mortar; where the latter is under twenty-five years laid, the value of ${\displaystyle \mathrm {L} }$ should be taken (quam prox.) at 3/5 ${\displaystyle \mathrm {L} }$ in the table.

Proceeding now to