102 ON THE AMARANTH WOOD 



inexhaustible ; it arrives at the completion of its purposes by ways the 

 most diverse, and it is to the agreement of these differences that the har- 

 mony of creation is owing. 



The preceding experiments were made at the ordinary temperature 

 which had no sensible influence on the result. I ascertained in the same 

 manner that a temperature of 100°, even where sustained for some hours, 

 developed no trace of colouring. Sometimes, however, when ascertaining 

 the nature of the flame produced by the combustion of those woods in the 

 open air, I have found that those portions of the wood closest to the 

 point of ignition, before becoming carbonized, take a purple tinge. This 

 colour forms a violet-coloured belt shading off on one side into black, 

 and on the other turning gradually to grey, the original colour of the 

 wood. From this phenomenon I deduced the discovery of the formation 

 of the colouring matter by means of heat, which I now proceed to show : 

 I submitted to the action of heat at about 100° small pieces of woods 

 without colour, in different mediums, hydrogen gas, &c. ; at the same 

 time, I raised the temperature to 130° without perceptible change, but 

 when it reached between 140° and 150°, there showed itself in all a 

 magnificent purple colour. 



The observations I had made on these woods induced me to examine 

 into the effects of different solvents on their extracts. Dissolved in warm 

 water it is of a light brown yellow colour, and deposits when cold a 

 slate-coloured sediment. I took four equal quantities, A. B. C. D., of 

 that solution, in a perfectly limpid state, and kept them as follows : the 

 quantity A. in vacuo and in darkness, B. in darkness only, C. exposed to 

 the light, was separated into two portions, one open to the air, the other 

 guarded from it ; lastly, the quantity D. was exposed to the action of 

 heat. The following were the results : 



A. No colour, no precipitate ; the liquor is still, after several years, 

 as limpid as before the experiment. 



B. No red colour, but a slaty grey sediment, the hue of which 

 changed gradually to a brown. 



C. After some minutes a light violet colour made its appearance on 

 the side directly exposed to the light, but no perceptible difference be- 

 tween the portions respectively exposed to and protected from the air. 



D. Boiling prolonged up to 100° developed no colour either in vacuo 

 or not. These experiments demonstrate that air has some effect on the 

 solution, but that light or heat up to 140" have none, and that light 

 produces a purple colour in the matter dissolved in water. 



Examination of the effects on these solutions of the wood of ama- 

 ranth by the different reactive agents have shown me that the acids and 

 the salt acids, even when very much diluted, produce at the end of a 

 certain time an extraordinary phenomenon in the formation of the purple 

 colouring matter. Whilst the action of light alone produces only a very 

 small quantity of colouring matter. In the liquid exposed to the rays 



