Industrial chemicals

This is the only category on the list whose members are defined by not being the product. Every other commodity here is wanted for itself; an industrial chemical is wanted for what it does to something else, and is usually destroyed in the doing. That gives the category a single clean test — a substance belongs here when it is consumed as a reagent in a process, and belongs elsewhere when it is the thing being sold. Because the same compound can be either, use governs: copper sulfate sold to a vineyard to kill fungus is a poison, and the identical compound sold to a plating shop as a reagent is here.

The category is anchored on alum, and alum is a mordant rather than a dye — without it most natural dyes will not fix to wool. So the whole European textile trade depended on a mineral for which it had no substitute, which is the recipe for inelastic demand meeting concentrated supply. The Ottomans held the Phocaean source, and the corpus already records the Genoese maona at Chios holding the alum trade. Then alunite was found at Tolfa in the Papal States around 1461, the papacy took the deposit as a monopoly, farmed its marketing to bankers, and backed it with prohibitions on alum brought from Ottoman sources. A substance nobody wanted for its own sake became one of the most politically consequential commodities in fifteenth-century Europe, for no reason except that cloth could not be dyed without it.

The industry proper begins with the second anchor, Roebuck's lead chamber process of 1746, which made sulfuric acid cheap. And it establishes the category's permanent economic character: nobody wants sulfuric acid. They want fertilizer, or bleached cloth, or refined metal. Reagent demand is derived demand, which is why the volumes here track other industries and never lead them — and why sulfuric acid consumption served for the better part of a century as a serviceable proxy for a country's industrial output.

It also produced the first environmental regulation anywhere. The Leblanc process made soda ash from salt and released hydrogen chloride into the air; through the 1850s British alkali works decomposed some 250,000 tons of salt a year and discharged about 115,000 tons of acid gas, stripping woodland and cutting the value of land around the works. The Alkali Act received royal assent on 28 July 1863 and came into force on 1 January 1864. It required works to condense ninety-five percent of their acid gas and appointed an Inspector, Robert Angus Smith, with four sub-inspectors under the Board of Trade, who could enter works and set sealed self-acting aspirators into the flues to measure what came out. A pollution standard with a technical inspectorate to enforce it, in 1864, written about this category. The Alkali Acts ran in amended form until the Environmental Protection Act of 1990.

What finished the problem, though, was not the Act. The Solvay process displaced Leblanc entirely within a generation, being both cleaner and cheaper, so the regulated nuisance ended because the process that produced it was abandoned for commercial reasons. That sequence is worth holding onto when reading the category's later history: the rule arrives first and establishes that the harm is the maker's problem, and the substitution arrives second and is what actually removes it.

The governing change since has been an inversion of proof. The European Union's REACH regulation, in force from 2007, reversed the default: a substance may not be sold unless its maker has registered a dossier establishing that its uses are safe. Every earlier regime, the Alkali Acts included, regulated an identified harm once it had appeared. REACH regulates the absence of information, which is why the category's live disputes are now arguments about data rather than about emissions.

The boundaries all follow from the reagent test. Monomers and polymerization feedstocks are here, the polymers made from them are plastics and polymers, and the naphtha they were cracked from is fuels, lubricants, and sealants. Sulfuric acid and the sulfur compounds sold as reagents are here while elemental sulfur is sulfur. Ammonia, urea, and nitric acid are here while the nitrate salts are saltpeter and nitrates. A catalyst is here and the metal it was made from is that metal. A dye or pigment is a colorant, and the mordant that fixes it is here. Surfactants and preservatives sold as reagents are here, while the same compounds blended for the face are cosmetics. Anything sold in order to kill is a poison, which by the use-governs rule includes the copper fungicides and bacteriostats. An explosive is a weapon. The date is c. 1460, on the Tolfa alum monopoly.