e
person who turns it can move, than he could do without it." "Well," said
Tommy, "I see it is a fine thing indeed to acquire knowledge, for by
these means one not only increases one's understanding, but one's bodily
strength. But are there no more, sir, of these ingenious contrivances,
for I should like to understand them all?" "Yes," answered Mr Barlow,
"there are more, and all of them you shall be perfectly acquainted with
in time; but for this purpose you should be able to write, and
comprehend something of arithmetic."

_Tommy._--What is arithmetic, sir?

_Mr Barlow._--That is not so easy to make you understand at once; I
will, however, try to explain it. Do you see the grains of wheat which
he scattered in the window?

_Tommy._--Yes, sir.

_Mr Barlow._--Can you count how many there are?

_Tommy._--There are just five-and-twenty of them.

_Mr Barlow._--Very well. Here is another parcel; how many grains are
there?

_Tommy._--Just fourteen.

_Mr Barlow._--If there are fourteen grains in one heap, and twenty-five
in the other, how many grains are there in all? or, how many do fourteen
and twenty-five make?

Tommy was unable to answer, and Mr Barlow proposed the same question to
Harry, who answered, that, together, they made thirty-nine. "Again,"
said Mr Barlow, "I will put the two heaps together, and then how many
will there be?"

_Tommy._--Thirty-nine.

_Mr Barlow._--Now, look, I have just taken away nineteen from the
number; how many, do you think, remain?

_Tommy._--I will count them.

_Mr Barlow._--And cannot you tell without counting? How many are there,
Harry?

_Harry._--Twenty, sir.

_Mr Barlow._--All this is properly the art of arithmetic, which is the
same as that of counting, only it is done in a much shorter and easier
way, without the trouble of having the things always before you. Thus,
for instance, if you wanted to know how many barley-corns were in this
sack, you would perhaps be a week in counting the whole number.

_Tommy._--Indeed, I believe I should.

_Mr Barlow._--If you understood arithmetic you might do it in five
minutes.

_Tommy._--That is extraordinary, indeed; I can hardly conceive it
possible.

_Mr Barlow._--A bushel of corn weighs about fifty pounds; this sack
contains four bushels; so that there are just two hundred pounds weight
in all. Now, every pound contains sixteen ounces, and sixteen times two
hundred makes thirty-two hundred ounces. So that you have not