Charcoal pack wood

The reversibility of this reaction was discovered by Deville 3 in 1864. and its study receives renewed interest in view of recent developments in the theory of the combustion of carbon in oxygen to which reference has already been made (see p. 71). By circulating carbon dioxide continuously over purified wood charcoal packed in a porcelain tube heated to a high temperature, and subsequently analysing the gas when equilibrium had been reached, Rhead and Wheeler4 obtained the following results ... 

Straighmess and a lack of protrusions - these features make it easier to create a low voidage, closely packed wood slack and to maximise the mass of charcoal made in each batch. 

A piece of wood will burst into flames, for instance, if it is made very hot (such as with a red-hot iron, or when focused under solar rays), but it will only do so if abundant air is present to drive on the reaction. Since Hooke saw heat as motion-related - for example, caused by agitated corpuscles - he saw the hot iron or solar rays as teeming with motion. Yet fire will not result if the wood and the red-hot iron are in vacuo or even in a limited air space. To take this line of thinking further, Hooke packed fresh wood chips into a tightly sealed iron vessel, and placed the vessel in a hot furnace. If he then pulled the vessel out of the fire while still red-hot, he noticed that at first the hot wood was still unburnt and its cellular structure intact as it slowly toasted to charcoal, but as soon as the ambient air was able to get at it, it burst into spontaneous flame, and rapidly burnt itself to ash. Clearly the wood while still contained in the sealed vessel was intensely hot, but it had insufficient air to break out into flame. But as soon as an abundance of atmospheric air could get at it, up it went in flames. ... 

One of the first modem commercial processes was the "fast method" or "German method", first practised in Germany in 1823. In this process, fermentation takes place in a tower packed with wood shavings or charcoal. The alcohol-containing feed is trickled into the top of the tower, and fresh air supplied from the bottom by either natural or forced convection. The improved air supply in this process cut the time to prepare vinegar from months to weeks. 

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