B63-271. SALESMAN'S SAMPLE. L.L. Davis Vial Adjustment. A Davis No. 6 mahogany 15" level with the side cut away to demonstrate the use of Davis's two patents for adjustment of the level and plumb vials. The level surround plate is marked with a March 17, 1867, patent date which is an error - the actual patent date for the vial adjustment is 3/17/68 (Davis's patent for his mantle clock design was 9/17/67 so the mistake is understandable). There are a handful of these known, but this is as nice an example as we've seen. Fine 300-600