In order to indicate any article to me Hill asked the question in the horizontal column in which the article appeared, and added the word or words at the head of the perpendicular column. Thus:—
“Tell me what this is,” meant a pipe.
“Can you tell us what this article is?” meant a photograph.
“Yes, what’s this one?” meant a strap. And so on. (The italics indicate the key words.)
The table given shows eighty articles. By prefixing the word “now” to his question, Hill let me know he was referring to a second series of eighty articles. “Now, tell me what this is,” did not mean a “pipe,” but it referred to the article in the corresponding position in the second series. Similarly a prefix of “now then” referred to a third series. And so on. The questions were very much alike and it required an acute observer to notice that no two were exactly the same.
The addition of the words “in my hand” indicated that only a portion of the article in the list had been shown. Thus when Slim Jim produced the stump of a candle Hill’s question was, “Do you know what this is in my hand?”
Each question in the horizontal columns also stood for a letter of the alphabet, so that it was possible (though slow) to spell out the name of an article.
Both the questions in the horizontal columns and the headings of the vertical columns were used to indicate numbers. Thus, “Tell me quickly if you can say what this number is? Come along! Don’t you know it?” is 6 5 2 0 1 4 1 2.
We had key words for decimals, fractions, subtraction, addition, and for repetition of the last-named figure. We also had key words to indicate any officer or man in the camp.
If the same thing was handed up to Hill twice in succession the question could nearly always be varied in form. Thus a “pipe” is indicated either by “Tell me what this is” or “Good! What’s this?”