15. What is the extreme length?
From the rear of the cascable to the face.
16. What is the bore of a piece?
It includes the part bored out, viz: the cylinder, the chamber (if there is one), and the conical or spherical surface connecting them.
17. What is understood by the calibre of a piece?
The diameter of the bore.
18. How do you ascertain the number of calibres in a piece?
Divide the length of the cylinder, in inches, by the number of inches in the calibre.
19. The number of calibres being known, how do you find the length of the cylinder?
Multiply the number of calibres by the calibre in inches.