Strange sounds

     Though the house has been much quieter than normal for this time of year, I did have some strange sounds today that I could not find the source of. Those of you who remember the old porch swings of yesteryear that were hung with chains from the porch ceiling; know that they made a very characteristic sound when someone was swinging in them. I heard what sounded like that for roughly half an hour today. It could be heard in the kitchen, diningroom and library; but not outside on the sideporch which is where it sounded like it was coming from when I was inside. The weather today was sunny most of the day and the temperatures in the low 40s. There was a very slight breeze. I never found a source for the sounds though there could be, very easily, a natural source for them.