304 
with the wood and attempted an explanation of the phenomenon ; 
but by this time the wood must have been already very rare, and 
after him no physicist seems to have had a chance of wor ing 
ith it. 
The writer’s own experiments in this direction were mainly 
intended to make sure that the wood under examination was 
actually the Lignum nephriticum of the 16th, 17th and 18th centuries, 
and especially that of Bauhin, Kircher and Boyle, and they 
consisted, therefore, chiefly in the repetition of their experiments. 
And in so far they were perfectly satisfactory and conclusive. It 
Cuevas, to the south of the city of Mexico, also near Guanajuato, 
a 
the place to which Ximenes refers in’ the passage “and 
almost the whole of the unhealthy country of Coyohuaca.” Of the 
other localities mentioned by Ximénes, Chimalhuacan is the name 
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teas In the neighbourhood of Mexico and the adjacent states, 
ysenhardtia amorphoides 18 fairly uniform, and forms a tree, or 
Kunth,* and also the same on whi i ; 7 
> : ch Ortegat based his Viborquia 
polystachya, F arther north, however, it is replaced by a foi 
a ge Stowe the name is misleading in so far as’ the original 
i “tt ‘ e was, in 
ue just as e nam 
oon n to distinguish this North Mexican plant from the 
— — et Species Plantarum, vol. vi., p. 491, tab. 592. 
ie aoe Nov. Rar. Plant. Dec. p. 66, tab. 9. 
? 9m Smithson. Contrib., vol. v, (1853), p. 37. 
