There was an aviation pioneer called Col Carl Crane, he spent much of his life in San Antonio
Tx. I had the pleasure of flying with him on many occasions when he was nearing the end of his life.
In the ‘old days', he spent a lot of his time making people believe in their instruments; trying to counter the "they stop working when we go into cloud" mentality. He often lectured at Randolph Advanced instrument flying school. Most of his lectures were trips down memory lane...but very exciting stories.
He had several US patents. One of these was a little double cross made of brass. It was called ‘the nose knows.' I guess that the second horizontal was to allow for a change of speed, but I don't know.