100 THE ALCOHOL PROBLEM 
twice the alcoholic strength of beer, pays 3s. per gallon, 
or only 3°5 pence for each 1 per cent. of alcohol. Port 
and sherry pay rather more for each 1 per cent. of 
alcohol than average beer, whilst spirits, which pay 
72s. 6d. per proof gallon, or 5os. gd. per gallon when 
at the usual strength of 30° under proof, pay at a rate 
which is three or four times greater—for each 1 per cent. 
of alcohol—than that paid by beer, and nearly five times 
greater than that paid by claret. It will be shown in 
Chapter VII. that the intoxicating power of a liquid 
depends almost entirely on its alcoholic content, and 
is scarcely influenced by the small quantities of other 
non-alcoholic constituents. The intoxicating proper- 
ties increase in more rapid proportion than the per- 
centage of alcohol present. Hence it follows that 
a scientific scheme of differential taxation ought to be 
so arranged that the tax, per unit of alcohol, increases 
regularly in proportion to the concentration. Suppos- 
ing, for instance, that the above scheme of taxation is 
held to be correct in so far as it applies to spirits and to 
beer, then it is clear that the taxation on claret, port, 
and sherry is much too low, and ought to be about 
double its present figure.