“Silence until such time as the Baron Savitch shall have ceased to exist?”

“That will suffice,” said Rapperschwyll. “For when he ceases to exist I die. And your conditions?”

“The whole story, here and now, and without reservation.”

“It is a terrible price to ask me,” said Rapperschwyll, “but larger interests than my pride are at stake. You shall hear the story.

“I was bred a watchmaker,” he continued, after a long pause, “in the Canton of Zurich. It is not a matter of vanity when I say that I achieved a marvellous degree of skill in the craft. I developed a faculty of invention that led me into a series of experiments regarding the capabilities of purely mechanical combinations. I studied and improved upon the best automata ever constructed by human ingenuity. Babbage’s calculating machine especially interested me. I saw in Babbage’s idea the germ of something infinitely more important to the world.

“Then I threw up my business and went to Paris to study physiology. I spent three years at the Sorbonne and perfected myself in that branch of knowledge. Meanwhile, my pursuits had extended far beyond the purely physical sciences. Psychology engaged me for a time; and then I ascended into the domain of sociology, which, when adequately understood, is the summary and final application of all knowledge.

“It was after years of preparation, and as the outcome of all my studies, that the great idea of my life, which had vaguely haunted me ever since the Zurich days, assumed at last a well-defined and perfect form.”

The manner of Dr. Rapperschwyll had changed from distrustful reluctance to frank enthusiasm. The man himself seemed transformed. Fisher listened attentively and without interrupting the relation. He could not help fancying that the necessity of yielding the secret, so long and so jealously guarded by the physician, was not entirely distasteful to the enthusiast.

“Now, attend, Monsieur,” continued Dr. Rapperschwyll, “to several separate propositions which may seem at first to have no direct bearing on each other.

“My endeavors in mechanism had resulted in a machine which went far beyond Babbage’s in its powers of calculation. Given the data, there was no limit to the possibilities in this direction. Babbage’s cogwheels and pinions calculated logarithms, calculated an eclipse. It was fed with figures, and produced results in figures. Now, the relations of cause and effect are as fixed and unalterable as the laws of arithmetic. Logic is, or should be, as exact a science as mathematics. My new machine was fed with facts, and produced conclusions. In short, it reasoned; and the results of its reasoning were always true, while the results of human reasoning are often, if not always, false. The source of error in human logic is what the philosophers call the ‘personal equation.’ My machine eliminated the personal equation; it proceeded from cause to effect, from premise to conclusion, with steady precision. The human intellect is fallible; my machine was, and is, infallible in its processes.