100 OX TH2 AMARANTH WOOD 



by their surfaces when they hare been once polished. The exterior 

 colour of the wood is a red violet, or rather a colour less purple than 

 that of the preceding woods. The colour in this case is merely superfi- 

 cial; towards the centre it becomes greyish, and approaches to the hue of 

 walnut wood. When exposed to the air, the colour changes gradually 

 to purple. This wood abounds in the forests of the Andes, and is especially 

 plentiful in the original seats of vegetation, and not far from the great 

 rivers which flow through that region. It is used for turnery, mill- 

 wheels, sugar mills, and even for fuel. 



The Palo morado, violet wood of Paraguay. The specimen from which 

 the observations are drawn formed part of the collection of natural pro- 

 ducts sent from Paraguay to the Paris Universal Exhibition of 1855. I 

 owe it to the kindness of M. Laplace, Consul-General of that Republic at 

 Paris. The characteristics of this wood are very similar to the one just 

 described ; sometimes it is not quite so heavy ; its fibres, although un- 

 dulating, are not so much interlaced, and its superficial colour is of a 

 more intense violet red. But as is the case with the " Tananeo,'' this 

 colour does not extend far into the interior, the wood below that of the 

 superficial layer is of a greyish white hue, and by exposure to the air 

 soon becomes a light blue. The tree which produces this wood should 

 be of a large size, judging from the specimen which I possess, the dia- 

 meter of which is more than two decimetres. It appears to be rather 

 plentiful on the banks of the Paraguay, the Parana, and the Uruguay. 



Lastly, 1 have examined a wood which I have been told is much used 

 for cabinet-making, and a piece of which I obtained from the saw-mills 

 in the Faubourg St. Antoine. This wood comes from the Rio de la 

 Plata, and is something between the " purple heart " and the " Palo 

 morado." All these woods burn generally with a clear flame, and leave 

 very little ash. 



It will be remarked from the short descriptions just given, that all 

 these woods contain a colouring matter, which is a red violet. There is 

 this difference, however, between them, that in some it penetrates 

 through the whole mass of wood, in others it is merely superficial, as if 

 in the former the colouring matter were developed in the course of vege- 

 tation ; in the latter, circumstances prevent its being so produced. Bat 

 everything necessary to produce this colour is present in the tissues, for 

 it requires but a very short exposure to what is called atmospheric 

 action, to bring colour in those woods that were previously free from it. 

 After having proved that transformation, it becomes necessary to inquire 

 to what physico-chemical agent the colouring matter in woods is owing, 

 especially what causes the phenomenon just mentioned. With that 

 design I have made on the wood of amaranth experiments of which 

 the following are the results : With the wood and air rarefied or 

 exhausted by— the pneumatic machine, it was found that when kept in 

 darkness for fifteen days no change took place, as was also the case when 



