On, Upon.
324. The general meaning of on is position or direction. On and upon are interchangeable in almost all of their applications, as shown by the sentences below:—
(1) Place: (a) Where.
Cannon were heard close on the left.—Parkman.
The Earl of Huntley ranged his host
Upon their native strand.
—Mrs. Sigourney.
(b) With motion.
It was the battery at Samos firing on the boats.—Parkman.
Thou didst look down upon the naked earth.—Bryant.
(2) Time.
The demonstration of joy or sorrow on reading their letters. —Bancroft.
On Monday evening he sent forward the Indians.—Parkman.
Upon is seldom used to express time.
(3) Reference, equal to about, concerning, etc.
I think that one abstains from writing on the immortality of the soul.—Emerson.
He pronounced a very flattering opinion upon my brother's promise of excellence.—De Quincey.
On my life, you are eighteen, and not a day more.—Aldrich.
Upon my reputation and credit.—Shakespeare
(5) Idiomatic phrases: on fire, on board, on high, on the wing, on the alert, on a sudden, on view, on trial, etc.
Exercise.—Find sentences with three uses of on or upon.