How Helmholtz liked being brought chemists' notes and other such principles! (8)
I believe the answer is:
elements
'principles' is the definition.
(I have seen 'First principles ' mean 'elements' so perhaps 'principles' could also mean 'elements')
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for elements that I've seen before include "Basic principles of the weather" , "fire and water, say" , "Fire, air, earth, water" , "Components or weather conditions" , "Atmospheric forces like wind and rain" .)