Balduin's 'Phosphorus'Back to luminous substances .
Christian Adolf Balduin [1632-1682] prepared, sometime before 1675, a phosphorescent form of calcium nitrate which he called the 'hermetic phosphorus'. His Aurum superius et inferius aurę superioris et inferioris hermeticum Amsterdam,1675 (with another edition printed at Frankfurt, 1675), contains a section entitled 'Phosphorus hermeticus, sive magnes luminaris'.
In this Balduin says "When a few years ago I was engaged in making the alkahest, after the distillation was over I found the cooled glass retort shining inside like red-hot iron". He had made a solution of chalk in nitric acid, and distilled it to dryness, then exposed the resulting calcium nitrate to air and moisture, and as it is deliquescent, it absorbed water and turned into a liquid. He believed the water distilled from this was the 'spiritus mundi'. When overheated the calcium nitrate became a yellow substance which shone in the dark after exposure to sunlight. Balduin sent an account of his discovery and a specimen of the 'phosphorus Balduini' to the Royal Society in 1676, and for this was elected a Fellow of the Society.