I want to know the answer to the following question:
What was made visible at a partial vacuum of 10 Pa?
All the background I'm provided with is that "Thereafter, research into the partial vacuum lapsed until 1850 when August Toepler invented the Toepler Pump and Heinrich Geissler invented the mercury displacement pump in 1855, achieving a partial vacuum of about 10 Pa (0.1 Torr).". Is that enough to answer the question?
Answer: no