Timers, Hourglasses, and Egg Timers

Measuring how long it takes for sand (or other fine granular substances, including ground eggshells) to flow from one blown glass bulb through a narrow neck to another glass bulb has been used for centuries as an accurate way of determining the passage of time. Most famously, hourglasses measure an hour. Short times, especially for cooking eggs, have been measured with similar, smaller hourglass-shaped timers since the 1800s, maybe earlier. Three minutes is a standard. A “three-minute egg” has a cooked white and soft yolk. These glass timers typically are set in a decorative wooden cylinder with windows or are protected by dowels connecting flat bottom and top, so the device can be flipped to double the time or start over. Other timers revolved within a decorative frame. One such device struck a bell after sufficient sand tipped the glass. Around 1910 one kitchen supply company, Silver’s, sold a wall-mounted timer. Marked on a plaque behind the rotatable timer were levels denoting “hard boiled,” “well done,” “medium cooked,” and “soft boiled.”