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the sixteenth or it may have been in the first years of the following 
century he received from his learned colleague, Dr. Schopff, physician 
to the Duke[Friederich I.] of Wiirttemberg, and by the order of the 
Duke, a cup made of ‘ Palum Indianum,’ almost a span in diameter 
and of unusual beauty, and with it chips of the same wood of a 
reddish colour and without any definite taste. Of this he says In 
soaked in water coloured it in a short time wonderfully blue and 
presented it to the Emperor. He gave a full account of his 
experiments in his Ars Magna Lucis et Umbrae, which appeared 
at Rome in 1646. As this book is somewhat rare, and at the same 
from Ximenes’ ‘Quatro libros.’ The chapter (p. 77) is headed 
Experimentum de ligno quodam admirabili aquam in omne genus 
colorum tingente,” and runs thus :— 
“In this place we think we ought not to pass over a certain kind 
of white Mexican wood, called Coatl and Tlapazatli by the natives, 
intensely blue, of the colour of the flower. of 
and the longer the water stands in them, the 
n Opaque vessel it will regain its blue colour. 
e€, to have observed this chamaeleon wonder 
tand the cause of the curious phenomenon which I 
at the colour could neither be classed as an 
