Tempo Drop is a stylized version of storm glass. Or if, like me, you don't know what the Orville Redenbacher a storm glass is either, then the Tempo Drop is a stylized weather forecaster. The sealed glass container holds a mixture of distilled water, ethanol, and camphor (waxy, water-soluble solid) that changes in appearance based on supposed forthcoming weather conditions.
A clear substance indicates clear skies, cloudy denotes cumulo-something above, and the formation of crystal flakes suggest T-storms are rolling in. We've been having a ton of batty weather where I live on account of the changing seasons and global warming and butterflies flapping their wings in China and such, so I might like to see one of these Tempo Drops on my desk, apprising me of the need to don my Head Dome one day and then haul out the misting fan and sunscreen the next.
Except, like all weather forecasters, it may or may not be accurate in its assessments.
Tempo drops come in two sizes, small at 3.15" x 4.33" and large, 4.5" x 8".
Muchas danke to The Green Head.