What do you call the Law that says p/T = constant?
At school, I knew it as 'The Pressure Law', and I did idly wonder why Boyle's Law (pV = constant) and Charles' Law (V/T = constant) had been named after people but p/T = constant apparently hadn't. Later on, I worked in schools where it was known variously as 'Gay-Lussac's Law' or 'Amonton's Law' and teachers of each would look at me very oddly when I referred to it by different names. From reading around, I now know that it was discovered independently by different people at similar times, hence the confusion, and why some books chose to simply avoid the historical difficulty by not naming it after anyone. However, historians of science seem to have concluded that Amontons actually had priority of discovery, so I've now settled on calling it Amonton's Law.
Nationalism also probably played a part in this - Gay-Lussac was French and Amontons was Italian - rather in the way that Boyle's Law is usually known as Mariotte's Law in French-speaking countries.