Columbia University Computing History
Hollerith Pantographic Card Punch
|1920 census form - Click to enlarge"
This 1940 photo (click on it to see in full size) shows a Pantographic punch
operator entering data from a 1920 census form like the one at left; these
are filled in by hand by the census takers. The form has been mounted on a
roll that can be turned so the current entry (person) is just above the
beveled edge of the wooden faceplate. Each punch requires the operator to
position the stylus over the corresponding hole, a labor-intensive,
painstaking, and error-prone operation. Hollerith himself said in one of
his patent applications: "When the various items have been thus transcribed,
it may be desirable or necessary to verify, entirely or in part, the
accuracy of such transcription." [Truesdell, p.37] In any case, the
pantographic punch in the Smithsonian museum says "THE TABULATING MACHINE
COMPANY, WASHINGTON, D.C., System Patented January 8, 1889", in plenty of
time for the 1890 census, and it was way more accurate and user-friendly
than the railroad ticket punch, and also allowed for more data per card.
By 1910, some error checking was done by the tabulators themselves... "If
the entire color, for example, was left unpunched the card would fail to
register and therefore fail to ring the bell for which the operator was
listening. Cards were also rejected if they were 'off gauge' or otherwide
mechanically defective. These rejected cards were examined and the omitted
items supplied — or new cards, conforming to the mechanical
requirements, were punched. In addition to these defective cards, there
were many cards containing items that were so far inconsistent as to raise
questions with respect to the accuracy either of the punching or of the
original returns from which they were punched. The verification run of 1900
was designed to take care of both types of defective cards, in advance of
the use of the cards in final tabulations, through a special machine wired
to reject not only incomplete and defective cards, but also those with
inconsistent items, items otherwise frequently subject to question of
accuracy, and a considerable number of items of infrequent occurrence, of
which it was desired to be doubly certain."
These verification runs were perhaps the first example of "programming
by wire", made possible by Hollerith's invention of the wiring panel for
his Type I Tabulator in 1906.
Overview, United States Census Bureau.
- 1920 Federal
Puplulation Census Schedule, raogk.org ("Random Acts Of Genealogical
- U.S. Bureau
of the Census Tabulating Machine, Smithsonian National Museum of
American History, which notes that the 1920 census was tabulated on machines
developed internally by the Census Burueau, to avoid paying rent to the
Hollerith company as it did in 1890 and 1900.
Pantographic Card Punch,
Smithsonian National Museum of American History.
- Truesdell, Leon E., The
Development of Punch Card Tabulation in the Bureau of the Census 1890-1940
, Bureau of the Census, US Government Printing Office, Washington