Drang & Fage Time Table Rule

English, c.1880, stamped to the top 'TIME TABEL DRING FAGE MAKERS 145 STRAND LONDON' with a dagger trade mark stamped inot the brass scale, length 42cm

The Dring & Fage Time Table Rule was designed to calculate the number of weeks between two dates, spanning up to two years. They were commonly used by dock companies in the England to determine storage charges for goods at British ports. Here's a closer look at how it operates:

Design and Structure

The rule is composed of a flat wooden surface, likely yew or boxwood, known for its durability and fine grain. Along one side of the rule, there's a brass slide, a key functional component of the device. The rule features a continuous calendar spanning 24 months, arranged in rows, each containing seven days. The months are listed twice, from January to December, along the right edge of the rule, allowing the user to account for dates in any month across two years.

How It Works

1. Identifying Dates:
To calculate the time interval between two dates, the user would first locate the start date on the calendar printed on the wooden surface. The calendar is organized with each month corresponding to specific rows of numbers representing days.

2. Using the Brass Slide:
Once the start date is identified, the brass slide, which is numbered from 1 to 104 (representing the number of weeks in two years), is moved to align with the start date.

3. Determining the Interval:
After aligning the brass slide with the start date, the user would then locate the end date on the calendar. The number on the brass slide corresponding to the end date gives the total number of weeks between the two dates. This straightforward method eliminates the need for complex mental calculations, allowing for quick and efficient determination of storage durations.

Practical Application

In practice, this rule was particularly useful in the shipping industry. Dock companies needed an accurate and easy method to calculate how long goods were stored before being shipped or after arriving at a port. By determining the number of weeks goods were in storage, companies could then calculate charges based on the duration, ensuring proper billing for storage services.

The addition of a hanging ring marked "TIME TABLE" suggests that the rule was intended to be easily accessible, possibly hung near a workspace for quick reference.