While we make use of many varieties of data, our primary sources come
from county tabulations drawn from the U.S. censuses of population
and agriculture. We have collected those data for the decennial
population censuses from 1880 through 2000, as well as for the
agricultural censuses (which were decennial until 1920 and then more
frequent thereafter) from 1880 through 1997.3 In addition to
census-based sources, we have collected other county-level
tabulations of social characteristics. We use the population and
social indicators data to understand population structure and
change, and the agricultural census data to understand agricultural
land use. Their consistency, as well as the effectiveness and
long-term quality of the U.S. census, have made this part of our
project straightforward. Some of these data were available to us in
digital form, and others we collected in print form and then
hand-keyed into our database. All of these data are described in
Gutmann et al.
(1998). Since that document was published, we have added
data from recent censuses (1997 agriculture and 2000 population),
while maintaining their content and structure. Although our study
area is not coterminous with the 10 states, we have collected data
that covered the entire area of the 10 Great Plains states, and
often neighboring states, especially Iowa and Minnesota.
Equal rights, unalienable rights, undermining the legal consensus, right to bear arms
The correct answer to this open question is the following.
Although the question is incomplete because it does not provide a specific reference about the author of the letter or any other reference, we can comment on the following.
A primary source is the piece of information that was written by a character or an individual that lived in the moment of the event, was part of the event, or witnessed the event. This individual could have written a letter, or a document -including a book. Or he/she took a photograph. Or was part of an interview. The secondary source includes information from a third person who was not part of the time or event but has found information through other resources. It is the case of an encyclopedia or researchers/historian books.
Answer:
The depression was caused by a number of serious weaknesses in the economy. ... America's "Great Depression" began with the dramatic crash of the stock market on "Black Thursday", October 24, 1929 when 16 million shares of stock were quickly sold by panicking investors who had lost faith in the American economy.