318.  Besides all these, there are some prepositions that have so many meanings that they require separate and careful treatment:  on (upon), at, by, for, from, of, to, with.

No attempt will be made to give all the meanings that each one in this list has:  the purpose is to stimulate observation, and to show how useful prepositions really are.

At.

319.  The general meaning of at is near, close to, after a verb or expression implying position; and towards after a verb or expression indicating motion.  It defines position approximately, while in is exact, meaning within.

Its principal uses are as follows:—­

(1) Place where.

     They who heard it listened with a curling horror at the
     heart.—­J.F.  COOPER.

     There had been a strike at the neighboring manufacturing
     village, and there was to be a public meeting, at which he was
     besought to be present.—­T.W.  HIGGINSON.

(2) Time, more exact, meaning the point of time at which.

     He wished to attack at daybreak.—­PARKMAN.

     They buried him darkly, at dead of night.—­WOLFE

(3) Direction.

     The mother stood looking wildly down at the unseemly
     object.—­COOPER.

     You are next invited...to grasp at the opportunity, and take
     for your subject, “Health.”—­HIGGINSON.

Here belong such expressions as laugh at, look at, wink at, gaze at, stare at, peep at, scowl at, sneer at, frown at, etc.

     We laugh at the elixir that promises to prolong life to a
     thousand years.—­JOHNSON.

     “You never mean to say,” pursued Dot, sitting on the floor and
     shaking her head at him.—­DICKENS.

(4) Source or cause, meaning because of, by reason of.

     I felt my heart chill at the dismal sound.—­T.W.  KNOX.

     Delighted at this outburst against the Spaniards.—­PARKMAN.

(5) Then the idiomatic phrases at last, at length, at any rate, at the best, at the worst, at least, at most, at first, at once, at all, at one, at naught, at random, etc.; and phrases signifying state or condition of being, as, at work, at play, at peace, at war, at rest, etc.

Exercise.—­Find sentences with three different uses of at.

By.

320.  Like at, by means near or close to, but has several other meanings more or less connected with this,—­