proportion of time passed in sleep differs in different persons, and at
different ages. From six to nine hours may be reckoned about the average
proportion. Men of active minds whose attention is engaged in a series
of interesting enjoyments, sleep much less than the listless and
indolent, and the same individual will spend fewer hours in this way,
when strongly interested in any pursuits, than when the stream of life
is gentle and undisturbed. The Great Frederic of Prussia, and John
Hunter, who devoted every moment of their time to the most active
employments of body and mind, generally took only four or five hours'
sleep. A rich and lazy citizen, whose life is merely a chronicle of
breakfast, dinners, suppers, and sleep, will slumber away ten or twelve
hours daily. When any subject strongly occupies us, it keeps us awake in
spite of ourselves. The newly born child sleeps most of its time, and
seems to wake merely for the purpose of feeding. Very old persons sleep
much of their time; in the natural progress towards death, the animal
faculties are first extinguished; accordingly, when they begin to
decline in decrepit old age, the periods of their intermissions are
longer. The celebrated De Moivre, when eighty-three years of age, was
awake only four hours out of the twenty-four; and Thomas Parr at last
slept the greatest part of his time. An eye-witness relates that some
boys, completely exhausted by exertion, fell asleep amid all the tumult
of the battle of the Nile; and other instances are known of soldiers
sleeping amid discharges of artillery, and all the tumult of war.
Couriers are known to sleep on horseback, and coachmen on their coaches.
A gentleman who saw the fact, reported, to the writer of this article,
that many soldiers in the retreat of Sir John Moore, fell asleep on the
march, and continued walking on. Even stripes and tortures cannot keep
off sleep beyond a certain time. Noises at first prevent us from
sleeping, but their influence soon ceases, and persons rest soundly in
the most noisy situations. The proprietors of some vast iron-works, who