According to quantity required, so you vary the amount of split peas. If you have stock at hand use that; if not, water will do, but, of course, the stock improves the soup. Put the split peas on in cold water, throw in onions, carrots, turnips, celery - small quantity, as too much will spoil it - also green mint, if obtainable (if not, dried mint will do), and any ham or bacon bones or trimmings. Let all gently boil for about three hours, or until the peas are soft, pass all through a tammy, and season with a little curry-powder, pepper, salt, sugar, and a very little vinegar. Care must be exercised in the use of curry-powder and sugar. I cannot give you the exact quantities; practical knowledge teaches this, and it is according to the quantity of soup required.