signs, and cannot easily be fixed in the memory; the understanding having no exercise. The elements of words must, therefore, be sought for Dr. Grey changed figures into letters, and thus made words; but these words could not be fixed in the memory without constant repetition, and strenuous application; the different words required to be remembered in his Memоria Technica, being almost equally burthensome with the facts and dates which they were intended to imprint upon the memory. The mode of changing figures into letters was known long before the time of Dr. Grey. The substitution of letters for figures was practised by most antient nations; in the Hebrew and Greek languages, there are no arithmetical signs, but the letters of the alphabet are used in their place. Shopkeepers and others, from an early period, had been in the habit of marking the articles which they had to sell, with certain letters, as arbitrary symbols, for the prices in pounds, shillings, and pence.
We now take the consonants, and attach one or more to the series of figures, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0; each figure having its appropriate consonant. (See Plate I. fig. 2. The consonants only are resorted to, for they compose, like the skeleton of the human body, the
