I was able to identify this John E Hand & Son gauge because I found one on the internet which still has the label on the box lid - a copy of the label is included with the piece. This "Improved Depth Gauge" was patented in 1918 and will measure the water depth from five to one hundred fathoms without stopping or slowing the boat being ridden on. I was only able to find two of these online, so I assume they are rare to a large extent. The box is original and in good condition - it has lost the "breadboards" on the ends of the lid - any decent woodworker could replace them easily. I believe the instrument is complete - it includes the little thin triangular rule/ gauge which I believe is used in the  main piece and two seals for the lid of the main gauge (in their original glass container). Everything is in really very nice condition, especially considering it's age (100 yrs or so). The plating on the main gauge is not perfect - it has some small areas where the plating is a little deteriorated (but NOT to any large degree) - the gauge has a great appearance and patina -  seems like it could be used today. ANY INFO ABOUT IT WOULD BE GREATLY APPRECIATED. Thanks for looking - if you have a few minutes, I have quite a few other antique tools listed in my Ebay store, including a few nautical-related pieces. (LS1/   Bx-1019)