Detect Danger

One of the potions of detection, made with 2 drs. of bull's blood and 2 drs. of powdered black opal. It tells the drinker whether danger lurks anywhere in a 100x100x100 ft. area and roughly where, though not what kind of danger it is.

Potions grant temporary magical or spell-like powers, normally for 40 + 1-20 minutes. The base is a pint of clear water with a dram each of powdered gold, silver and copper and a carat each of any seven powdered gems (an alchemist may use 2 drs. of Rare Earths instead of the gems). It takes a week in a small cauldron or alembic over a furnace, with a 90% chance of success plus 1% per level (99% at most), and a 1% chance of mishap while it ferments between the 2nd and 7th days. Potions sell for at least 400 G.P. Herbs with similar properties may stand in for scarce animal parts, but only if the base is doubled, and the chance of success drops by 25%.