Letters: June 2022

Painting memories

Reading the profile of Ashley Ogden brought memories from summer 1966 flooding back. I was 18 years old, with a place at New Hall, University of Cambridge, to read natural sciences. My school was Tiffin Girls School, Kingston on Thames. Hawker Sydney aeronautics was just up the Richmond Road and opposite that was the Pinchin Johnson paint factory, which supplied aeroplane standard paints and coatings.

I had secured a summer job in the quality control department, testing the incoming solvents, pigments and other chemicals. The ‘recipes’ were on cards and one simply followed instructions and made sure the specs were within the prescribed limits. I had almost no direction or supervision, and no chemistry above O level, but all went well, and I was asked to return the following summer to cover for the supervisor’s holiday. Perhaps the fact that, during quiet periods, I had cleaned and relabelled all the reagent shelves also helped!

So in summer 1967 I found myself in charge of outgoing quality control – once again with a set of recipe cards and specifications but this time for the finished product. Again all went well, apart from the time when I had to reject a whole batch of coating, to the disbelief of the foreman. It turned out that it was a ‘half batch’ but one component had not been halved. (We’ve all done it but probably just with cake mix!) What a difference 52 years makes, but I guess Line-X is a rather larger operation than a local paint factory.

I did do chemistry A level in the end, and biology, to add to my physics and pure and applied mathematics and my first class in the natural science tripos, but that was so I could go to medical school in London. It was nice to be reminded of those few weeks of experience in the commercial world and the trust placed in me, and how grateful I am for the rich tapestry of science that was subsequently spread before me.

Katherine Bradnock
Via email 

Stolen anecdotes

I enjoyed Philip Ball’s reflections on the history of curly arrows in organic reaction mechanisms, as well as the editorial in the same issue. Ball cited the excellent textbook by Peter Sykes as an early exposition. The US counterpart was Elliot Alexander’s Principles of Ionic Organic Reactions, published a decade earlier in 1950, and I can remember the excitement it produced among our beginning organic graduate students when it appeared.

I used my copy for many years but later loaned it to a Princeton Hospital pathologist, Thomas Harvey, who did not return it – perhaps not surprisingly, since he was the man who stole Albert Einstein’s brain. I was happy to find that one can still read a used copy on the web.

Richard Hill
Athens, Georgia, US

I am sorry to say that Derek James Chadwick was misinformed about Christopher Ingold and curly arrows. Rather than opposing their use, Ingold was an early adopter, having used them in a paper as early as 1926. That means he was probably the second chemist after Robert Robinson, their pioneer, to use them in a publication. Ingold later wrote a highly influential paper in Chemical Reviews, published in 1934, which explained the use of curly arrows in detail, and is widely credited with encouraging their use in reaction mechanisms.

The quote ‘curved arrows never hit the mark’ is usually attributed to Henry Edward Armstrong, a reactionary chemist who opposed pretty much everything all of the time. This included the admission of women to the Chemical Society, and the Braggs’ use of x-rays to show that sodium chloride is not molecular. Armstrong typically came up with high sounding and quotable phrases; and was usually wrong.

I hope this clears Ingold’s name, while leaving the essence of a good story in place. 

John Nicholson CChem FRSC
Secretary, RSC Historical Group 

Causes and consequences 

Full marks to Vanessa Seifert for highlighting the subject of causation and chemical reactions. If chemists are asked ‘why do reactions happen?’ they often reply ‘because of the need to increase the Clausius entropy of the isolated system’. Since Clausius entropy (and Boltzmann entropy) can only be measured at equilibrium and we know that the systems that undergo spontaneous change are not (by definition) at equilibrium, we conclude that the increase in entropy is only a consequence (and not the cause) of a chemical reaction.

The only physical explanation that I know of that fits the bill lies in Boltzmann’s work – that during a spontaneous change the system seeks to increase the number of microstates and that this happens simply because given the opportunity (for example, if molecules of A and B are allowed to mix freely) the most probable outcome wins. But if a chemistry teacher is asked why (say) sodium reacts with water, the response is more likely to be ‘because sodium atoms badly want to lose electrons’. And maybe that is as good a pictorial explanation as any other! What do other readers think?

Rhobert Lewis FRSC
Brecon, UK

I am a quantum man

The article Listening to quantum beats could reveal rhythm of birds’ migratory compass prompted me to look out a poem that I wrote recently as I sat contemplating quantum theory. It may be amusing to fellow chemists as they also struggle to understand quantum issues.

I am a quantum man
No one knows who or where I am
When you see me I am there
But disappear if you stop and stare
I have a sibling twin or perhaps many more
But communicating with them is a bore
Faster than light messages are a breeze
For I can do it with great ease
For across the miles I can send a clue
And instantaneously we all turn blue
I only need to smile each day
And instantaneously so do they
Even when a million miles away
Or so they say.

Graham Gibbs
Via email

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