CRYSTALLINE DEPOSIT OCCURRING IN TIMBER. ] 89 



this tree, or perhaps, peculiar to the genus, and if so, its 

 identification would become of some assistance towards 

 correct diagnosis, especially as no other body appears to be 

 present in the deposit which might contaminate it, and 

 thus interfere with the ready isolation and purification of 

 the crystals. 



The peculiarity of this body in what appears to be perhaps 

 an example of dynamic isomorphism in a natural chemical 

 substance, shown by its varying melting points under 

 different conditions, has made its study somewhat interest- 

 ing, and, so far as the material at disposal would allow, 

 considerable work has been done with it. 



The following data will show how great were the differ- 

 ences between the melting points of the crystals and those 

 of the same substance after melting : — 



(a) When the crystals were prepared by crystallisation 

 from alcohol, or from boiling water, they were quite 

 anhydrous, and melted at 122° C, to a transparent resin- 

 like body, without alteration in weight. This fused 

 material was, at first, strongly electric, and had the power 

 of attracting light particles of filter paper, etc., very 

 energetically. The melting point of this glassy substance 

 had, by fusion, been reduced to 62 - 63° C, and so long as 

 it remained in the glassy condition in the lump, the melting 

 point did not rise, even after many weeks, but if the fused 

 substance was powdered the melting point commenced to 

 rise at once, and after a comparatively short time this had 

 reached about 120-121°, but did not appear to revert quite 

 to the melting point of the original crystals. 



(b) When the fused substance was powdered and the 

 melting point taken at once, this powder melted at the 

 same low temperature as the spangles of solid material, 

 but if the temperature was continually raised, when this 

 had reached to about 100°, the melted substance became 



