But Sprot, alas, had a religious conscience. He had a soul to be saved. The preachers had prayed with him. When death was but forty-eight hours distant, he feared to die with a lie in his mouth. So _now_, at last, he spoke of Letter IV as his real model. Perhaps he hoped that it would not be found, and probably it was in some secret drawer or false bottom of his kist. It was found, and was used, along with the confessed forgeries (which even Sprot could not have anticipated), to destroy the inheritance of the children, at Logan’s posthumous trial in 1609. But the obvious reply to this hypothesis is, that Letter IV, by the evidence of modern experts (evidence unanimous and irresistible), is just as much forged as all the rest, is just as certainly in Sprot’s imitation of Logan’s handwriting. This being so, why did Sprot keep it back so long, and why, having kept it back, did he, almost in his last hour, produce it, and say (if he did) that it was genuine, and his model, as it certainly was? This is the last enigma of Sprot. His motives defy my poor efforts to decipher them. Even if the substance of IV is genuine, what were Sprot’s motives? I do not feel assured that Sprot really maintained the genuineness of the _handwriting_ of Letter IV. His remark that he kept Logan’s letter only _till_ he forged others on it, as a model, certainly implies that he did not keep it _after_ he had done his forgeries, and therefore that our Letter IV is, confessedly, _not_ Logan’s original. Certainly it is not. XVI. WHAT IS LETTER IV?