In speaking of this discovery, Miss Digby did not go into particulars, the whole matter being far beyond her understanding; but in stating its value she openly acknowledged that it was in the line of Mr. Cornell’s own work, and one which involved calculations and a formula which, if prematurely disclosed, would invalidate the contract Mr. Spielhagen hoped to make, and thus destroy his present hopes. Of this formula but two copies existed. One was locked up in a safe deposit vault in Boston, the other he had brought into the house on his person, and it was the latter which was now missing, having been abstracted during the evening from a manuscript of sixteen or more sheets, under circumstances which she would now endeavour to relate. Mr. Van Broecklyn, their host, had in his melancholy life but one interest which could be at all absorbing. This was for explosives. As consequence, much of the talk at the dinner-table had been on Mr. Spielhagen’s discovery, and possible changes it might introduce into this especial industry. As these, worked out from a formula kept secret from the trade, could not but affect greatly Mr. Cornell’s interests, she found herself listening intently, when Mr. Van Broecklyn, with an apology for his interference, ventured to remark that if Mr. Spielhagen had made a valuable discovery in this line, so had he, and one which he had substantiated by many experiments. It was not a marketable one, such as Mr. Spielhagen’s was, but in his work upon the same, and in the tests which he had been led to make, he had discovered certain instances he would gladly name, which demanded exceptional procedure to be successful. If Mr. Spielhagen’s method did not allow for these exceptions, nor make suitable provision for them, then Mr. Spielhagen’s method would fail more times than it would succeed. Did it so allow and so provide? It would relieve him greatly to learn that it did. The answer came quickly. Yes, it did. But later and after some further conversation, Mr. Spielhagen’s confidence seemed to wane, and before they left the dinner-table, he openly declared his intention of looking over his manuscript again that very night, in order to be sure that the formula therein contained duly covered all the exceptions mentioned by Mr. Van Broecklyn. If Mr. Cornell’s countenance showed any change at this moment, she for one had not noticed it; but the bitterness with which he remarked upon the other’s good fortune in having discovered this formula of whose entire success he had no doubt, was apparent to everybody, and naturally gave point to the circumstances which a short time afterward associated him with the disappearance of the same.