duced by a brief action of sulphurous acid on cellulose, have been destroyed again by the prolongation of the action.
But, in the manufacture of the pulp, the wood chips are often given a preliminary treatment to soften and partially disintegrate them. It seems perfectly possible that a liquor might be obtained at this stage of the manufacture which could be worked up into alcohol.
The properties which an ideal denaturant should have may be summed up under five heads and they are as follows:
1. It must render the alcohol undrinkable.
2. It must be cheap, otherwise the advantages of 'free' alcohol are lost.
3. It must be separable from the alcohol only with difficulty and at considerable cost.
It seems to the writer that government officials show a tendency to be more cautious than necessary regarding this feature of denaturing agents. Such a thing as a denaturant which a chemist could not remove probably does not exist, and so it is wholly a question of the degree of difficulty, and the cost, of the purification. If this difficulty and cost be never so little more than those involved in the manufacture of new alcohol from raw materials, it should be considered as fulfilling the requirements. Dishonest individuals, bent on swindling the government out of its revenues, would set up illicit stills rather than attempt to 'renature' denatured alcohol. But the government demands are much in excess of this standard.
4. It must be readily detected, in order that revenue officers may determine with ease whether a given liquid contains denatured alcohol or not.
5. It must not interfere with the use of the alcohol for those purposes permitted by law.
It is by no means easy to find substances fulfilling all these requirements; in fact, although the list of possibilities has been gone over and over again by the ablest living chemists for a matter of twenty years or more, the subject is by no means closed. All the denaturants tried and proposed are unsatisfactory in one way or another, and the governments of Russia, France and Germany offer prizes ranging from $4,000 to $20,000 for any denaturant which can be proved to be a distinct improvement over those in use.
Wood spirit, by which is meant, as has already been said, a crude methyl alcohol containing many impurities, notably in the neighborhood of 25 per cent, of acetone, obtained as one of the products of the dry distillation of wood, is one of the most satisfactory denaturing agents. It is difficult to remove from ethyl alcohol, it is readily de-