It is worth noting that at the time most of these parts were cast, few foundries had the ability to determine the exact composition of their castings. Most used known scrap with some virgin metals to produce their melts and relied on experience to get their charge formulae correct. This worked fairly well for the unsophisticated alloys of the day.

Typical foundry practice would involve breaking an attached specimen bar which a highly experienced old hand would then ‘read’. The old hand would assess the color and texture of the fracture surface in sunlight to determine acceptability of the metal grade. Lead was the most difficult to assess, since it tends to segregate by gravity and the lead content of the specimen bar might not correlate well with the actual lead content of the castings. This explains the higher variability of lead than the other elements.

The elements other than copper, tin, lead, and zinc are residuals picked up from scrap and ore contamination. Sophisticated refining steps to remove these residuals were not implemented until well after World War I, and adoption of extra refining was concentrated on more demanding copper based alloys.