t, and 'Un'
unknown. Down the column, 'En' seems to mean that the foreign-born can
speak English, 'Ot' that he can only speak some tongue other than
English. The year of immigration, of course, is obvious. But this
occupation, I can't make head or tail of!"

"That you have to learn," the instructor said. "There is a printed list
here for reference that contains the principal kinds of employment in
the United States and classifies them. In a very little while you will
find that you can remember the numbers which signify the more common of
these and you will need to refer to the list but seldom. All occupation
returns not contained in the printed list will be classified and punched
later by a special force of clerks. Holes punched for those out of work
and the number of weeks unemployed are all easy. At the top of the last
column, too, 'Emp' means Employer, 'W' Wage Earner, while 'OA' means
working on his or her own account, and 'Un' is for Unemployed."

"All right, sir," Hamilton replied, "I think I can do it now. I should
find it harder, though, if I hadn't been writing all those things just
exactly as they are here on population schedules for the last month."

"It makes an astonishing difference," the experienced man agreed, "you
know the why and wherefore of everything. Now you had better take this
old test schedule and I will give you fifty blank cards, and we will see
how they come out."

Through the rest of the afternoon, Hamilton worked steadily over this
set of cards, not only doing the work, but getting the principles of the
whole thing thoroughly in his mind, and, as he had said to the
sub-section chief, knowing just the manner in which the schedules had
been made up helped him to an extraordinary degree. He was well pleased,
therefore, when he came down to work the following morning, to find at
his machine a real schedule, not the test that he had been working on
the afternoon before; the exact number of cards required for his
schedule all ready in the hopper of the machine, and it was pointed out
to him that error was not permissible and that he must account for every
card.

"Why is that?" asked Hamilton, "what difference would a card or two
make?"

"It isn't the cards, it's the numbering," the other explained. "Don't
you remember that each card was numbered, and so, if one card is wrong
it would throw all the succeeding numbers out? Besides, you never have a
chance to see whether a card is right or no