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room disengaged, which he may apply—if they are not sufficient, he could use his symbols over again in other apartments.
Useful as the above arrangement certainly is; its ingenuity may be further exemplified, by recollecting the precise position of every figure in the series: thus if asked to name the twelfth figure, the mnemonic students could, directly answer it was 5, and so with all the figures, if they had 200 or more of them. Although a very little practice would discover this, yet it may not be amiss if some trivial assistance were furnished on the present occasion.
By observing the diagram, page 43, in which are the mnemonical words, employed for recollecting the figures; the students will perceive that they are numbered 1, 2, 3, 4, &c. to 18; that the uneven numbers of the series uniformly commence each word, as No. 1, is the first consonant in the first compartment, No. 3 is the first in the second, No.5, the first in the third, &c.—the 7th, 9th, 11th, 13th, 15th, and 17th, being likewise uneven numbers, are the commencing consonants in their respective squares. The even numbers of the series are, with the same certainty, the last consonants in each compartment, 2, 4, 6, 8, 10, 12, 14, 16, 18 are all found in their proper squares, as the last consonants; by noting this, they know where to look for any particular number they may want and by also remarking that they have placed only two figures in each compartment, they can divide any given number by 2, which determines the compartment such figure is in. Thus, if asked, the 10th figure of their series of figures, page 42, they must in their mind divide 10 by 2, leaving the quotient 5, the fifth word; then apply to the fifth symbol for it, when Leo directly presents the word Rob;—now as 10 is an
