And in the old English use of the word, the alarum refers more often to
a bell than to any thing else.

The introduction of the military word into English can be traced, as to
time, with a certain probability. In 1579, Thomas Digges published his
_Arithmeticall Militare Treatise named Stratioticos_, which he informs
us is mainly the writing of his father, Leonard Digges. At page 170. the
father seems to finish with "and so I mean to finishe this treatise:"
while the son, as we must suppose, adds p. 171. and what follows. In the
father's part the word _alarm_ is not mentioned, that I can find. If it
occurred anywhere, it would be in describing the duties of the
_scout-master_; but here we have nothing but _warning_ and _surprise_,
never _alarm_. But in the son's appendix, the word _alarme_ does occur
twice in one page (173.). It also occurs in the body of the _second_
edition of the book, when of course it is the son who inserts it. We may
say then, that, in all probability, the military technical term was
introduced in the third quarter of the sixteenth century. This, I
suspect, is too late to allow us to suppose that the vernacular force
which Shakspeare takes it to have, could have been gained for it by the
time he wrote.

The second edition was published in 1590; about this time the spelling
of the English language made a very rapid approach to its present form.
This is seen to a remarkable extent in the two editions of the
_Stratioticos_; in the first, the commanding officer of a regiment is
always _corronel_, in the second _collonel_. But the most striking
instance I now remember, is the following. In the first edition of
Robert Recorde's _Castle of Knowledge_ (1556) occurs the following
tetrastich:--