1531. The classic Cold War-era "bug", this device could be hidden in a room to pick up sound and transmit it to a nearby receiver.
1532. A receiver and headphones that were used on the listening end of the "bug" transmitter.
1533. No answer yet for this tool, I think it might be a fish scaler.
1534. Compression blades on a J47 Turbojet Engine, it was used on many types of aircraft, including bombers, reconnaissance, interceptors, and fighter planes.
1535. A service table base, made to be used by any professional who needed an adjustable table. Someone sent me an email saying that he has a similar one that was used as a dentist's tool table, it was built by the Satellite Adjustable Table Company of Grand Rapids, Michigan. These tables were also used for typewriters and other office equipment.
1536. This is a trigger mechanism from a cannon. Someone who speaks Mandarin offered this translation for the text on it:
"The first character 安 is likely the phonetic rendering of some kind
of firearm (?) made by a company that starts with the sound "An"--
Anderson? The second character 式 means "style" or "kind".
Similar to the one seen below and at this link.
The owner's description: The thumb plate makes electrical contacts in the top unit, ie. the two outlets on the side. The trigger makes electrical contact with the two round outlets on the bottom.
Update from last week's set:
Thanks to Leon for finding the patent for a track hanger that looks very close to this hardware, patent number 1,214,177. Even though it's not an exact match I think that this is probably the correct answer, I've seen lots of patents where the drawings didn't look just like the finished product, since inventors are always trying to improve their designs.
To submit photos, send them to the address in my profile.
Last week's set is seen below, click here to view the entire post.
More discussion and comments on these photos can be found at the newsgroup rec.puzzles. Glenwood Gardens Park