stillness

quiet / still, unmoving

置く: to put / (following a て-form verb) to do in advance; to do for some future purpose

evening / night

evening, night / late

nights, evenings

all night

to do an experiment

one day

one, 1 / the first in order, foremost / the beginning / the best / a kind of; one of something / (card games) an ace / unity / the bottom string of a shamisen or other Japanese musical instrument