TOPIC: Help... what is this?!

Just did an inspection on a house built in 1951.  Home still has original galvanized plumbing.  This contraption was on the ground of the crawlspace and was occasionally leaking a bit of water.  Enough that there was an area (about 4 feet X 8 feet) where the dirt was moist.  It was attached to an aluminum water line and coming off of a galvanized pipe.  Can anyone tell me what this is so I know how to write it up in my report?  Thanks guys!!

Looks like a water line vent. That should be mounted up off the ground. It is used to help reduce water hammer. Just my guess based on the pictures.

Thank you Michael.  That sounds like exactly what that was.  I will write it up as such... thanks!