It takes a lot of prospecting, a lot of false leads, a lot of patient drilling. When you do strike oil, however, the fulfilment of a single moment will suddenly indemnify all the barren endeavour in between. And that's equally true whether you are a geologist, trying to read the complexion of the land above mineral deposits; or a horseman, trying to find that latent seam of class beneath the surface hints of pedigree and conformation. Al Stall, Jr., having filled both roles in his time, recognizes the analogy. "Oh,...