It was. He had it sliding along, and noticed that the falling sand/water didn't keep moving horizontally, but eventually moved vertically (because of gravity).

Sand and water were dripping out of the containers, and he was watching that fall, and seeing that eventually the sand and/or water would fall straight down.

My grandfather worked in copper mine. Shortly after the war started, he was called in, given a copy of the paperwork, and told: congratulations, you are critical worker, and as long as you work here, you won't have to enlist.

Is this where the chocolate comes from?

World's smallest balalaika.

Another point is, water teems with life and single cell organisms in water have been around a lot longer than we have, if only one new virus evolved each year, you would still have billions of different types of viruses.

Corpse fed fish are the tastiest fish.