B-184 GRAVITY INCLINOMETER. Rufus Porter. Incredibly rare first type of the inclinometer invented around 1847 by Porter, noted inventor, painter and founder of Scientific American. All known examples have an engraving, presumably by Porter, showing two masons using the inclinometer to build a brick wall; in the first type the engraving lacks the fine detail found in the later versions. The engraving is clear and mostly complete with some water damage and two small missing points in the lower left, the indicator needle still has about 50% of original bluing and most gilding on the weight. In 8-3/4" square frame, glass looks original. Porter inclinometers of any type are very rare and the first type is almost unknown; we know of only a couple of examples and this may be the nicest one. Destined to be the highlight of any advanced collection of inclinometers.Good+ 3000-6000 NOTE: Absentee bidding ends 5:00pm EST on Friday, March 29, 2019. Live auction is at Camp Hill Radisson, 9:00am, March 30, 2019, Camp Hill, PA.