Nobody told me there would be math!

CaptHenway

A thread in the coin forum about how bullion was counted made me think about working in the melting and refining department of the Mint in the 19th century.

Imagine you have one bar that is 243.68 ounces of 0.887 gold and 0.072 silver and the rest copper and another bar that is 138.94 ounces of 0.914 gold and 0.045 silver and the rest copper and half a dozen more completely random bars like that. Imagine trying to calculate what you would need to bring the entire mess to an even 0.900 fine!

I assume it was simpler to melt it all together (after checking the total weight), assay the mix while keeping it hot, and then add pure gold or pure copper or whatever to adjust the fineness.

All without a calculator!

djm

.887 or 0.914 Close enough for Government Work. Nobody's gonna know the difference

Timbuk3

Sounds about right to me !!!!

ricko

That was back when they taught 'arithmetic' in schools.... no calculators, flash cards and long division.... Cheers, RickO

mvs7

Brutal, but not horrible if they always used the same calculations in the same order. It would become somewhat rote over time. (1) convert percentages into amounts; (2) group by metal and add; (3) etc.

Jinx86

Where do they get those numbers from? Assaying back them was done with fire assays. Once the bar was poured samples were taken, inquarted with silver, wrapped in lead, then melted in an oven. the sample then placed in nitric acid/distilled waller mix. The silver would part in the solution and the gold remain. The sample then melted, was pure gold. From that they would determine the pure silver/gold/base metal content.

I skipped a few steps in there to help it read better.

All that mess can be skipped if you can afford an XRF. Although the fire assay would be a hair more accurate. My last lot I shipped out I figured 148.778ozt Gold came back as 148.765ozt. So I was close enough without the fire assay.

Here is an image of me dropping silver from a solution I poured from some gold I was refining. Total lot weighed just over 24.5ozt so should net 6.15 ozt gold. The gold was from scrap karat jewelry the silver was from a previous project. Ill use this silver over and over again.

1630Boston

Interesting lab you have there @Jinx86

Jinx86

@1630Boston
Thanks, its works, but I take claim to it as Im the only one in the building who knows how any of it works.