UK

On May 29, 1897, Jenny Feist, a spinster of Wiesbaden, Germany, was awarded a patent for an improved tear-open envelope with perforated edges. By gumming the space between the perforations, her design prevented the letter inside from slipping into the tear line and being damaged when the strip was removed.

On May 29, 1897, Jenny Minnie of Haeltert, Belgium, patented an improved incubator with a simple hot-water heating system and built-in air channels. Circulating warm water kept the temperature even, while fresh air was drawn in and gently warmed before reaching the eggs, improving incubation reliability.