392 History of Luminescence 



parts of La Historia Medicinal de las Cosas que se traen de nuestras 

 Indias Occidentales que sirven en Medecina (Seville, 1574) . In a 

 chapter entitled " Of the Woode for the Evilles of the Raines and 

 of the Urine," Monardes merely wrote of a " white woodde which 

 gives a blewe color " when placed in water that was good " for them 

 that doeth not pisse liberally and for the paines of the Raines of the 

 stone. . . ." No mention of other colors noticed by later writers is to 

 be found in this account. 



A solution of this wood aroused the interest of Kircher (1646) , 

 who received a cup from the Procurator of the Society of Jesuits in 

 Mexico, and presented it to the Emperor. He said: ^ 



If one pours this water [of lignum nephriticum] into a glass globe and 

 exposes it to light, not the slightest trace of blue will appear, but, like 

 the pure water of a transparent fountain, it will show itself transparent 

 and clear to the beholder. When the glass vial is moved to a shadier 

 place the whole liquid will reflect the most pleasing of colors; in still 

 darker places it will become a reddish color and thus, according to the 

 conditions of the surroundings, it will miraculously change. But in the 

 dark or put in an opaque vase, it will resume its blue color. As far 

 as I know, I am the first to observe this spectacle of its chameleon-like 

 nature. . . . 



A similar play of colors, like an opal, was also described by Johan 

 Bauhin« (1541-1631). 



Grimaldi, Boyle, and Newton 



This account of many colors is not quite correct and was clarified 

 by Robert Boyle (1626-1691) in his treatise on Colours in 1664 

 (see fig. 37) , by Francesco Maria Grimaldi (1618-1663) in his book 

 Physico-Mathesis de Lumine, Coloribus et Iride (Bologna, 1665) 

 and by Isaac Newton (1642-1727) in 1672. All these men, and also 

 Robert Hooke, recognized that the tincture was blue by reflected 

 light and yellow by transmitted light. 



Boyle gave the best account. He noticed that after many infusions, 

 the wood lost its power to color water and concluded there must be 

 an " essential salt " in the wood responsible for the effect. He found 

 that this salt was not volatile and could not be distilled, since a 

 distillate was as clear as pure water. He found the blue color to be 

 abolished by the acid salts of vinegar and to return when a " sul- 



'' Ars magna lucis et umbrae, Book I, part III, p. 77, 1646. Translated by Mrs. A. 

 Holborn. 



® See his posthumous work, Historia universalis plantaruin nova (1650). Bauhin's 

 infusion was made from a wood called " Palura Indianum," 



