Brass ferrules must be of best quality, bell-shaped, extra heavy cast-brass; not less than four inches long, and two and one-quarter inches, three and one-half inches, and four and one-half inches in diameter, and not less than the following weights:
Diameter two and one-fourth inches, weight one pound.
Diameter three and one-half inches, weight one pound twelve ounces.
Diameter four and one-half inches, weight two pounds eight ounces.
53 P.S. § 4642