I have held off answering this post, because I was the one who put the value of the ECO 19 in print. I was hoping someone who may have sold what you have recently, would have more to say as to the value of what you have.
Air meters are much different than gas pumps. There are just not that many of them around, especially when you are talking about one made in 1924. Over the years, my first words to anyone who wants collect air meters is "Don't buy any air meter that is incomplete, thinking you will find the parts for it." Yes, I will sell you any part you need for the Model 90 series ECO, but that is the only meter you can buy parts for, and I have identified over 400 meters.
Buying an incomplete meter means you are looking for someone to sell you the parts you need to complete yours, but that is what he is waiting for.
While most people know me for the gas pump book, I collect air meters. I believe I know a great deal about air meters, but I don't know where to find the parts for some these old meters.
As for the value of what you have, it is not what it is worth, it is finding the person who has everything but what you have. Find that person and ask whatever you want.
By the way, I have never heard of any air meter that had porcelain on it. I have a stack of ECO literature, and nothing mentions porcelain. None of the other companies literature mentions porcelain either.
Jack Sim
Author, Gas Pump Identification book and Air Meter Identifiation book, both ready to order at:
www.petrolianacollectibles.com [This message has been edited by Jack Sim (edited 11-21-2008).]