Where 1 Ton Tin= 2,240 Lbs, @ £/$4.86 1849: the UK Price for Refined Tin (1 Lbs) was £0.0377, or $ 0.1833 1849: the UK Price for Common Tin (1 Lbs) was £0.0352, or $ 0.1709 1849: the LOW UK Price for Common Tin (1 Lbs) = £0.033, or $ 0.1606 1849: the LOW DUTCH Price for Common Tin (1 Lbs) = £0.0299, or $ 0.1454
The Cost of Exporting Silver to Russia was 3.75%, but the overall profit (at the prevailing par) was 4.08%. The cost of shipping Platinum from Russia certainly entailed a similar cost, but with the same kind of offset arbitrage possible.