Phosphorescence of Precious Stones 65 



been unknown to them, if that artificial process were ever really applied 

 to stones. 



Also from India we receive an intimation as to alleged acquaintance 

 with the fact of phosphorescence before Boyle. The learned Hindu 

 Praphulla Chandra Ray, 1 professor of chemistry at the Presidency 

 College, Calcutta, has this to say: "It is sometimes asserted that the 

 phosphorescence of diamond was first observed in 1663 by the cele- 

 brated Robert Boyle. Bhoja (eleventh century a.d.), however, men- 

 tions this property." Fortunately for us, the Sanskrit text of this 

 passage is added, which reads, "andhakare ca dlpyate" (translated 

 by Ray, "it phosphoresces in the dark"); but these words simply 

 mean, "it shines in the dark." It is accordingly not the case of Bhoja 

 being familiar with the phosphorescent property of the diamond, but 

 the subjective case of Professor Ray, who knows of Boyle's discovery, 

 and projects this knowledge into his author. It reflects more credit 

 on the well-meant patriotism of the Hindu than on his power of logic. 

 His interpretation being conceded, we could as well infer from the 

 numerous passages of classical and Chinese authors, where precious 

 stones luminous in the dark are spoken of, that also Greeks, Romans, 

 and Chinese possessed an intimate acquaintance with the phenomenon 

 in question. 2 But serious science cannot afford to speed its conclusions 

 up to this rapid tempo; and if the fact remains that no Greek, Roman, 

 Sanskrit, or Chinese text has as yet come to the fore, from which such 

 an inference as to conscious knowledge of the phosphorescence of 

 precious stones can reasonably and without violence be deducted, it is 

 safer to hold judgment in abeyance or to regard the result as negative. 8 



1 A History of Hindu Chemistry, Vol. II, p. 40 (2d ed., Calcutta, 1909). 



* It is noteworthy that neither the Arabic nor the Indian mineralogists have 

 accounts of precious stones luminous at night. What the Arabs offer of this sort is 

 an entirely different affair. The lapidarium of Pseudo-Aristotle mentions a fabulous 

 stone under the name "strange stone," which is found in the dark ocean, has rays 

 in its interior, and is visible at night, its veins being brilliant as though they were 

 laughing faces (a corrupted reading which originally was "brilliant like a mirror;" 

 J. Ruska, Steinbuch des Aristoteles, pp. 20, 167). The "stone bringing sleep" is 

 red, and large pieces of it radiate at night a glow of fire, and in the daytime smoke 

 emanates from it {ibid., p. 166). 



1 In the passage of the Orphica, "the diamond-like crystal, when placed on an 

 altar, sent forth a flame without the aid of fire," Kunz (Curious Lore of Precious 

 Stones, p. 163) believes he sees an indication that the phosphorescence of the dia- 

 mond had already been noted before the second or third century of our era; but the 

 plain text does not bear out this far-fetched, interpretation. The Greek author has 

 in mind the well-known burning-lenses of crystal, described also by Pliny (see the 

 writer's article on' this subject in T'oung Poo, 19 15, pp. 169-228), and compares their 

 reflective power with that of the diamond; he says nothing further than that the 

 lustre of the diamond vies with that of a crystal lens. There is no allusion to the 

 fact that this happens in darkness, and consequently no reference to phosphorescence. 



