He unrolled the blue-prints, from a drawer he produced a sliding-rule. He slid this rule up; he slid it down; he gazed through his glasses at space; he made microscopic Spencerian figures in neat rows and columns. He seemed to pluck his results from the air with necromantic cunning, and what had taken the young man at his elbow days and nights of cruel effort to accomplish--what had put haggard lines about his mouth and eyes--the engineer accomplished in a few hours by means of that sliding-rule. Meanwhile, with one weary effort of will, his visitor summoned his powers and cross-examined him adroitly. Here was the very man to supply the one missing link in the perfect chain; but Mr. Dell would not talk. He did not like Americans nor American methods, and he made his dislike apparent by sealing his lips. Mitchell played upon his vanity at first, only to find the man wholly lacking in conceit. Changing his method of attack, Mitchell built a fire under Mr. Dell. He grilled everything British, the people, their social customs, their business methods, even English engineers, and he did it in a most annoying manner. Mr. Dell began to perspire. He worked doggedly on for a while, then he arose in defense of his country, whereupon Mitchell artfully shifted his attack to English steel-mills. The other refuted his statements flatly. At length the engineer was goaded to anger, he became disputative, indignant, loquacious. When Louis Mitchell flung himself into the dark body of his cab, late that evening, and sank his legs knee-deep into those hateful blue-prints, he blessed that engineer, for Dell had told him all he wished to know, all he had tried so vainly to discover through other sources. The average "overhead" in British mills was one hundred and thirty per cent., and Dell _knew_. The young man laughed hysterically, triumphantly, but the sound was more like a tearful hiccough. To-morrow at ten-thirty! It was nearly over. He would be ready. As he lolled back inertly upon the cushions he mused dreamily that he had done well. In less than two weeks, in a foreign country, and under strange conditions, without acquaintance or pull or help of any sort, he had learned the names of his competitive firms, the dates of their bids, and the market prices ruling on every piece of steel in the Krugersdorpf job when those bids were figured. He had learned the rules governing English labor unions; he knew all about piece-work and time-work, fixed charges and shop costs, together with the ability of every plant figuring on the Robinson-Ray contract to turn out the work in the necessary time. All this, and more, he had learned legitimately and without cost to his commercial honor. Henceforth that South-African contract depended merely upon his own ability to add, subtract, and multiply correctly. It was his just as surely as two and two make four--for salesmanship is an exact science.