The Wealth of Nations by Part 5 Chapter 2 Page 177

countries the tax is still higher. Leather is a real necessary of life. The use of linen renders soap such. In countries where the winter nights are long, candles are a necessary instrument of trade. Leather and soap are in Great Britain taxed at three halfpence a pound, candles at a penny; taxes which, upon the original price of leather, may amount to about eight or ten per cent; upon that of soap to about twenty or five-and-twenty per cent; and upon that of candles to about fourteen or fifteen per cent; taxes which, though lighter than that upon salt, are still very heavy.

As all those four commodities are real necessaries of life, such heavy taxes upon them must increase somewhat the expense of the sober and industrious poor, and must consequently raise more or less the wages of their labour.