So far I have not told the story of the things of Llantrisant, but rather the story of how I stumbled upon them and among them, perplexed and wholly astray, seeking, but yet not knowing at all what I sought; bewildered now and again by circumstances which seemed to me wholly inexplicable; devoid, not so much of the key to the enigma, but of the key to the nature of the enigma. You cannot begin to solve a puzzle till you know what the puzzle is about. “Yards divided by minutes,” said the mathematical master to me long ago, “will give neither pigs, sheep, nor oxen.” He was right; though his manner on this and on all other occasions was highly offensive. This is enough of the personal process, as I may call it; and here follows the story of what happened at Llantrisant last summer, the story as I pieced it together at last.
This is from “The Great Return” by Atthur Macken,
I don’t understand th meaning of this sentence.
“Yards divided by minutes will give neither pigs, sheep, nor oxen.”
I am glad if someone would kindly teach me.