We bought a house in March, and so far it's been relatively smooth sailing, maintenance wise. However, I recently noticed an occasional, slow drip coming from a pipe in the basement. My question is, what is the thing on top of the pipe? This is where the leak appears to be coming from, but I have no idea what it is, let alone how serious a problem it might be. If anyone who recognizes what is in the pictures and could let me know I'd appreciate it. I tried to include a picture of the top in case that helps to identify it. The pipe looks like it is running into the furnace.