It's a verticle feed mixer. Inside there's an auger that goes round and round, and mixes up the feed before spitting it out of the chute below. I saw these things fairly often from the time I was ten. We have a fairly large one lying sideways in our front yard, and we used to climb in it and pretend it was a space ship. It greatly resembled part of a rocketship, as we remembered it from the movie Apollo 13. We also pretended it was a submarine.
One year, for Christmas, we got the most remarkable present. Our parents got us the 10th Anniversary Collector's Edition of Myst: which included the DVD version of the first three games in the series. We'd played an old version of Myst on an even older laptop (it ran Windows 98, as I recall) and we were very eager to play the sequel; Riven.
Riven did not disappoint. It was an amazing game. Except that we wandered through the entire game wondering why on earth Gehn needed a feed mixer, and where was this telescope everyone kept talking about?