A military dictionary

by William Duane

2. The diameter of the excavation,

3. The line of least resistance,

4. The charge.

Problem. I.

Given the nature of the soil, the diameter of the excavation, and the line of least resistance, to find the charge.

Rules.

1. To the square of the diameter of the excavation, add the square of double the line of least resistance, and reserve the said sum.

2. Multiply the square root of the reserved sum by double the line of least resistance, and subtract the product from the same sum.

3. Multiply half the remainder by the line of least resistance, and 1.57 times the product, will give the solidity of the excavation.

4. The charge will then be determined from the nature of the soil, as in the following example.