How to read (and understand!) old ledgers and account books
Account books and ledgers in the 18th century, as well as before and after in many cases, are generally arranged in what is called double entry accounting.
The left page of the book is generally marked "Dr" or "debtor." It shows the purchaser's name, the date, what was obtained, and the value of the exchange.
An example from a John L. Gardiner account book is:
Charles Long Dr
Feb 13 | To 3 Sides of Leather _______ 2|3|6
Octob 31 | To 2-1/2 lb Butter _____________ 0|5|0
This means that Charles Long received three side of leather from Gardiner on Feb. 13, 1800, and added a debt to Gardiner of 2 pounds, three shillings, and six pence to his account. And on Oct. 31, 1799, Long received two and half pounds of butter, and added an additional debt to Gardiner of five shillings to his account.
Notice that we use the words "received" and "added a debt"; you will see why when we address the other side of the account book next.
Cash was not the only way debts could be repaid. In fact in many 18th century and earlier account books, currency often does not change hands at all.
So, on the right page of this example, facing the list of what Charles Long received, are:
| By a Pair of Shoes for Julia. 1|6|0
May 13 | By 2 pair of Shoes for Peter & Peg ___ 1|6|0
By Cash __ in full ________________ 0|1|7
By Sundry Work for Me & c 3|9|3
The above means that Gardiner received a pair of shoes for Julia from Long valued at 1 pound 6 shillings sometime in 1797 and two pairs of shoes for Peter and Peg from Long valued at 1| pound 6 pence total on May 13, 1797.
Below that, we see that Long paid Gardiner 1 shilling and 7 pence sometime in 1798 and that Long had worked for Gardiner that year at total value of 3 pounds, 9 shillings, and 3 pence.
In all, by 1800, Long had a debt of 6 pounds, 10 shillings, 10 pence to Gardiner, which the two men settled on July 23, 1800.
Reading actual account books can be tricky, since entries are sometime not in chronological order, perhaps because the person doing the accounting wanted to keep all the transactions together and wrote in the margins or carried over transactions from other pages or even other books.
Once you know the basic concepts with which these account books were maintained, it is not that difficult to discover a wealth of information.