Monday, 4. October 2010
I am a fan of older technology because of its resilience as well as it’s elegance in many cases. This particular item is an advanced form of a tool nearly everyone is familiar with.. the sundial. This of course measures time by the position of the sun, assuming you factor in a bunch of corrections for time of the year as well as latitude. They are also not very portable in many cases. as you’d have latitude to correct for and have to know true north. Far too many calculations to mess up. Thus enters the ring dial.
This folding little piece of genius was developed supposedly around 500 years ago although most versions you will currently find available are 18th century. It was quite useful for finding time when sailing due to it being usable while hanging and quite stable in this regard. The ring dial needs to be adjusted for both the northern and southern hemisphere, the users latitude, and the date. From there, the light shining through the hole onto the inner ring displayed the time.
There are several vendors who make these, and most are reasonably priced considering the amount of work that goes into them. Most of us however, aren’t going sailing in the 18th century however and can’t afford to play around with this cool little piece of equipment unless we’re using it for an artwork display or to talk about history.
Or you could use a bit of innovation and the Internet, and look up a nice little piece of work by Wee-Meng LEE. He put together a Origami ring dial that reverses the time and latitude rings. This particular one is printed (preferably on card stock), cut out, printed and then hung by a finger on the inner ring and the position is adjusted to shine on the outer for time. Great toy to play around with, and a good kids project if nothing else.