number-alphabet, the great mnemonic device for
recollecting numbers and dates. In this system each digit is
represented by a consonant, thus: 1 is _t_ or _d_; 2, _n_; 3, _m_; 4,
_r_; 5, _l_; 6, _sh, j, ch_, or _g_; 7, _c, k, g_, or _qu_; 8, _f_ or
_v_; 9, _b_ or _p_; 0, _s, c_, or _z_. Suppose, now, you wish to
remember the velocity of sound, 1,142 feet a second: _t, t, r, n_, are
the letters you must use. They make the consonants of _tight run_, and
it would be a 'tight run' for you to keep up such a speed. So 1649, the
date of the execution of Charles I., may be remembered by the word
_sharp_, which recalls the headsman's axe.

Apart from the extreme difficulty of finding words that are appropriate
in this exercise, it is clearly an excessively poor, trivial, and silly
way of 'thinking' about dates; and the way of the historian is much
better. He has a lot of landmark-dates already in his mind. He knows the
historic concatenation of events, and can usually place an event at its
right date in the chronology-table, by thinking of it in a rational way,
referring it to its antecedents, tracing its concomitants and
consequences, and thus ciphering out its date by connecting it with
theirs. The artificial memory-systems, recommending, as they do, such
irrational methods of thinking, are only to be recommended for the first
landmarks in a system, or for such purely detached facts as enjoy no
rational connection with the rest of our ideas. Thus the student of
physics may remember the order of the spectral colours by the word
_vibgyor_ which their initial letters make. The student of anatomy may
remember the position of the Mitral valve on the Left side of the heart
by thinking that L.M. stands also for 'long meter' in the hymn-books.

You now see why 'cramming' must be so poor a mode of study. Cramming
seeks to stamp things in by intense application immediately before the
ordeal. But a thing thus learned can form but few associations. On the
other hand, the same thing recurring on different days, in different
contexts, read, recited on, referred to again and again, related to
other things and reviewed, gets well wrought into the mental structure.
This is the reason why you should enforce on your pupils habits of
continuous application. There is no moral turpitude in cramming. It
would be the best, because the most economical, mode of study if it led
to the results desired. But it does not, and your older pupils can
readily b