I learnt about this spice mixture from Kumud Shah's Quick After-Work Indian Vegetarian Cookbook. According to her, it is used in fairly large quantities to flavour and thicken curries.
Makes about 1 tbsp
1. If using the whole spices, roast them over a low heat in a dry frying pan (ie, no oil) until they start to smell nice. Remove from the heat and grind together.
2. If using ready-ground spices, just mix them together.
Kake's (Vegan) Cookery Site - http://www.earth.li/~kake/cookery/
This page added some time in 1997 - comments and questions to Kake L Pugh (firstname.lastname@example.org).