In 1774, Joseph Priestley ran an experiment that seemed simple — but changed everything.
He placed a burning candle and a mouse under a glass jar. Minutes later, the flame died, and so did the mouse. To most, it would look like failure. To Priestley, it sparked curiosity.
What if nature held the key? He added a sprig of mint and tried again. This time, the candle burned longer — and the mouse lived.
Without knowing it, he had uncovered oxygen — what he called “dephlogisticated air.” He was witnessing photosynthesis, plants turning sunlight, water, and carbon dioxide into food and releasing the breath of life.
By 1779, Jan Ingenhousz proved sunlight was essential to the process, laying the foundation for modern biology.
From a candle, a mouse, and a plant, humanity began to glimpse one of nature’s greatest truths: plants sustain life on Earth.
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