Julia put down the tray, but upset some of the coffee.  Seeing that excitement had not usually the effect of making her hand unsteady, it is possible accident had not much to do with it.  However, it happened; she carefully wiped it up, and the two chemists, paying no more attention to her than if she had been a cat, went on speaking of the explosive.  It was the explosive; their talk told her that before she had finished the wiping.

“The formula I would give for it?” Van de Greutz was saying; as she sopped up the last drops, he gave the formula.

She lifted the full bottle of Schiedam from the tray, and carried it away with her—­in the hand farthest from the chemist’s, certainly, but with as little concealment as ostentation.  Near the door she glanced at the German, or rather, at what he held, the sample of the explosive.  It was a white powder in a wide-necked, stoppered bottle of the size Julia herself called “quarter pint.”  The bottle was not more than two-thirds full, and had no mark on it at all, except a small piece of paper stuck to the side, and inscribed with the single letter “A.”  This may have been done in accordance with some private system of Herr Van de Greutz’s, or it may have been for the sake of secrecy.  The reason did not matter; the most accurate name would have been no more informing to Julia, but decidedly more inconvenient.

She went out and shut the door quietly; then she literally fled back to the kitchen with the Schiedam.  Scarcely waiting to set it down, she seized a slip of kitchen paper, and scribbled on it the string of letters and figures that Herr Van de Greutz had given as the formula of his explosive.  She did not know what a formula was, nor in what relation it stood to the chemical body, but from the talks she had heard between the chemist and his friends, she guessed it to be something important.  Accordingly, when he said the formula, she was as careful to remember it accurately as she was to remember the place of the bottle on the shelf.  Now she wrote it down just as he spoke it, and, though perhaps not exactly as he would have written it, still comprehensible.  She pinned the piece of paper in the cuff of her dress; it would not be found there if, by ill luck, she was caught and searched later on.  Next she went to the kitchen cupboard; there were several wide-necked stoppered bottles there, doubtless without the chemist’s knowledge, but Marthe found them convenient for holding spices, and ginger, and such things.  She took the one nearest in shape and size to the one which she had seen in the German’s hand; emptied out the contents, dusted it and put in ground rice till it was two-thirds full.  Then, with the lap-scissors, she trimmed a piece of paper to the right size, wrote “A” upon it, and stuck it to the side of the bottle with a dab of treacle—­she had nothing else.  She was hastily wiping off the surplus stickiness when the bell rang again.  She finished what she was doing, and shrouded the bottle in a duster, so that there was another summons before she could set out.  She took the Schiedam with her—­of course it was that which was rung for, but also the bottle in the duster.