Made for communications the turn of the last century, speaking tubes incorporated whistles to call the other end person. Somehow the caller had to get the person on the other end of the tube to go to the tube to talk — layed out in houses, boats, cars, trains etc. — to talk back in the tube prior to the telephone and in situations where phones were poor communication means. So the whistle incorporated into the tube opening (and removable) would call them to the opening. Blowing air through by some form of pressure would alert the other side to respond.We will not be highlighting speaking tubes nor their whistles. However we do have a few to compare to what is seen in the field. Perhaps we will add to this category in time.