Good Day, Sunshine

If you’re in the northern hemisphere, there’s a good chance it’s sunny where you are.  How sunny is it?  Well, our local chamber of commerce claims we have at least 360 days a year with at least partial sun.  That’s pretty sunny for the Pacific Northwest!

Measuring the amount of sunshine received in a day has been around since the nineteenth century.  Two surprisingly different men furthered the science. John Francis Campbell first invented a sunshine recorder in 1853.  He was best known as a Gaelic linguist, author, and folklorist, traveling around Scotland to collect the old stories, but he also served as a barrister and a government official as well as a scientist.  His recorder, sometimes called a heliograf, was a glass sphere set in a wooden bowl.  The sunlight shining through the glass burned a line on the wood.  The longer and deeper the line, the longer and stronger the light.

Perhaps physicist Sir George Gabriel Stokes wanted a bit more quantification.  A talented scientist dedicated to education, he changed Campbell’s stand to metal and added a changeable card that records the line made by the light. 

The result is the Campbell-Stokes Recorder, which measures the number of hours of bright sunlight in a certain period. The UK Met Office stores cards from various locations dating back to the nineteenth century, and the design is still widely used today. Hammacher Schlemmer even sells a version. 

But if you’d like something more than measuring sunlight to occupy your time, you might check out my summer bonus, which I posted this week.  “Master Thief” is a free, short online story set between Art and Artifice (formerly La Petite Four) and the soon-to-be-released Ballrooms and Blackmail.  More on that soon.  In the meantime, have some fun in the sun!