I'm not entirely sure how the system works, in terms of volume held vs how much you blow into it when you speak, but having used speaking tubes, I can tell you they do indeed work---assuming that there's somebody at the other end.

This is despite the several references to the speaking tube on the Californian and it's captain's failure to rescue the people on the Titanic (the Californian's speaking tube is also seen in one of the Titanic movies.)  Speaking tubes appear to have been used on ships as late as WWII.

As interesting as the house on 162nd Street was, I'd be careful doing ANYTHING with my lips, especially in realtion to anything remotely described as tubular, with those guys.  If you get my drift.

Will continue to look for speaking tube literature.  Ebay has patent literature on them now and then, and if I could get a digital camera, I could conceivably post a picture.

Ralph

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