1) The other component of gunpowder after charcoal and saltpetre is sulphur. In 1862 this is still mined by hand. The Confederacy is awash with the stuff, there are a few small mines and it was widely imported before the ACW for cotton processing. I want to know where the Union got it from and how much they imported. Does anyone know?
There was overseas purchase:
'Later in 1862, E.I. du Pont de Nemours and Company was again secretly commissioned by the armed forces to undertake the purchase of saltpeter and also sulphur. This time the firm bought through regular trade channels, which it considered less disturbing to the market.' (Harold B. Hancock, Norman B. Wilkinson, '"The Devil to Pay!": Saltpeter and the Trent Affair', Civil War History, Volume 10, Number 1, March 1964 p.31.)
The footnote to this statement cites three letters, all written in August (Du Pont Co. to J. A. Dahlgren, Aug. 2, 1862; Asst. Secy, of War Peter H. Watson to Du Pont Co., Aug. 4, 1862; Dahlgren to Du Pont Co., Aug. 12, 1862).
2) How much gunpowder and saltpetre was in California in 1861?
My guess is that the supply in California for mining purposes would be sufficient that the scant weapons in the state could be considered to be well supplied. There simply aren't many guns in California so we would not expect the supply to be run down fast.
3) Someone suggested that kerosene would be in short supply in Britain if the Union stopped exporting it and that this would cause Britain to reconsider its position. It is my understanding that 1861 was only just after the peak of whaling, that they were already producing coal oil in Scotland, British cities have been lit by gas for decades and that the Baku fields were already open with the Russians refining oil. So I think this is a non-issue for the British. Does anyone else have a view or information?
The statistics of the foreign and domestic commerce of the United States note a sudden
increase in exports in petroleum from the US to Britain from 1861 (low) to 1862 (high) and 1863 (higher) - seen on p.43. This is noted to have partially replaced the cotton trade.
Based on this my opinion is that if the Union does not export kerosene etc. then the British wouldn't really notice the shortfall
as such because their consumption would simply remain flat or not change much (instead of undergoing the historical large increase).
In 1861 the export of petroleum products from the US to Britain was about 140,000 gallons, worth about $8,000.