Chemical Algebra

The Case of the Poisonous Socks by William Brock is a collection of historical vignettes about chemistry. I’ve learned some interesting factoids. For example, the design of the chemistry laboratory in educational settings owes much to the work of Justus von Liebig (1803-1873), professor at the University of Giessen. More importantly, by “demanding and obtaining a subsidy from the government to cover the expenses of running a laboratory, Liebig overcame the assumption that laboratory instruction that laboratory instruction was a professor’s personal expense.”

I also learned that laboratory instruction in chemistry acted as a template for both biology and physics. Brock describes the contribution of two individuals I had not heard of: George Carey Foster (1835-1919) and Frederick Guthrie (1833-1886). Both started out as chemists. Both were appointed professors of ‘natural philosophy’, in Anderson’s College at Glasgow and the Royal College of Mauritius respectively. Foster studied with the famed Kekule who apparently dreamt up the snake eating its own tail while pondering the structure of benzene. Guthrie, on the other hand, is infamously portrayed as a terrible teacher by H.G. Wells, his one-time student, later famous in sci-fi world.

One short chapter that caught my attention was Chemical Algebra, recounting the formulation of our modern day chemical symbols and formulae. The hero of this story is Jons Jakob Berzelius (1779-1848) although the father of modern atomic theory, John Dalton (1766-1844), was horrified by the symbols used, complaining that “a young student in chemistry might as soon learn Hebrew as to make himself acquainted with them. They appear like a chaos of atoms. They equally perplex the adepts of the science, discourage the learner, as well as cloud the beauty and simplicity of the Atomic Theory.” But it turned out that the symbols of Berzelius were much more adaptable than Dalton’s, and I can’t imagine a better system.

Brock writes: “Symbols and a symbolic language mark the chemist from all of the other scientific disciplines apart from mathematics. While most outsiders know that H₂O means water, they would be defeated by CH₃COOH, and totally mystified by the more complex arrays of symbols chemists regularly use to portray molecules in three dimensions.” Introduction to the language of chemistry is one corner of the ‘iron triangle’ (known as Johnstone’s Triangle) that makes learning chemistry challenging for the novice. The need for a symbolic shorthand arose thanks to an explosion of new chemical compounds, thanks to Liebig’s development of combustion analysis.

The symbolic system could have been much more complicated, if William Whewell (1794-1866) had his way. Whewell was rooting for a “truly algebraic” system. “The compound AⁿBⁿ should be formulated as nA + nB, with lots of brackets for more complex molecules. Other, more pragmatic chemists soon objected that this was quite unnecessary and made matter too complicated.” Thank goodness for that. Chemistry might have become even more obtuse. Although we now know much more about the atom, and that it is the valence electrons that are responsible for chemistry, we still retain the simple chemical symbols introduced by Berzelius.

Back in 1922, Neils Bjerrum wrote: “We may be convinced that even when the electron theory has reached perfection, the chemical formulae of the nineteenth century will still continue to be the ideal instrument of stating the composition of substances and of understanding their interactions.” A hundred years later, I’m inclined to agree! So does Brock, as he writes: “The twenty-first century chemist, faced by the fleeting quasi-molecular species revealed by spectroscopy, would find it impossible to work without a symbolic system.”