I followed the info in the Thaumonomicon and added 4 Humanus (4 rotten flesh), 4 Motus (2 rubber balls), and 4 Spiritus (4 soul sands) and then threw in the hay bale... But nothing happened. What did I do wrong?
Did you do it fast enough? If you don't throw in the ingredients in quick succession, the aspects in the crucible start decomposing into their components, thus causing there to be missing aspects.