54 History of Luminescence 



Many of the receipts were for " a light which does not go out 

 in a house, whether closed or open, or in water," essentially for a 

 continually luminous liquid. One of these (no. 18) , translated from 

 the Liber Ignium of Mark the Greek, who flourished in the second 

 half of the thirteenth century, reads as follows: ^^ 



R. Bile of tortoise, bile of mollusc or of a fish [loup d'eau], with which 

 one colors leather purple. Mix them with four times the amount of 

 luminous insects deprived of heads and wings. Place all in a vase of 

 lead or glass and surround with horse-dung. Collect the oil . . . [or] 



Mix equal parts of the above mentioned biles and luminous insects 

 and place in horse manure for 15 days. Collect and make a paste with 

 the root of the herb called " cyrogaleo," which also shines at night, and 

 soak with this licquor. Take a vase of stone or iron, wash with water 

 extracted from this herb and pour a little of the preceeding liquor in it. 

 Or, if you prefer, place all in a vase of glass and continue as above men- 

 tioned. On placing the vase anywhere, it will furnish a continuous light. 



Some of the receipts called for mixing glowworms with oil of 

 " Zambac," infusing in horse manure, then placing the oil in a 

 lamp and lighting it, when a flame of long duration would be 

 obtained. Such wonders, taken from the writings of Hermes and 

 Ptolemy, undoubtedly furnish the basis for the " liquor lucidus " of 

 Porta and others, described in Chapter HI. 



The idea that water contains light was expressed by Perscrutator 

 or Robert of York, who flourished or died around 1348. In writing 

 about " stars that appear in the air," the word " comet " is not used 

 but Perscrutator said that " some had tails and others not "; and 

 also that " they are made of earthly vapor mixed with water so that 

 it can glow. He asserts that all water has light in it which may be 

 proved by stirring water placed in a dark vase at night, whereupon 

 light will appear." ^^ It is possible that the statement on water re- 

 ferred to sea water containing phosphorescent organisms, but it was 

 made in regard to water in general. 



Comment 



It will thus be seen that during the Dark and Middle Ages no 

 new discovery or new phenomenon important for the history of 

 luminescence had been made. A few mysterious and miraculous 

 stories appeared, which were to be later refuted, but the end of 



of willow charcoal, salt, aqua vitae, sulphur, pitch and camphor. Another formula 

 is quicklime and a volatile petroleum, which took fire because of the heat generated 

 in contact with water. 



^^ M. Berthelot, La chemie au moyen age 1: 112-113, Paris, 1893. 



^"See Lynn Thorndike, History of magic and experimental science 3: 115-116, 1934. 



