Letters

I was very interested to read Philip Ball’s Ten most beautiful experiments in chemistry (Chemistry World, April 2005, p32). I agree that they all have elements of beauty in them. However I would like to suggest an addition to the list: the discovery of the element promethium.

Moseley’s Mendelevium-like prediction indicated that there should be a further element between neodymium and samarium, but it was not possible to identify it at the time that the other lanthanides were being isolated.

He was not to know about its instability, but it was ingenious of him to make that prediction. It was not until some 30 years later, when the new technique of ion exchange chromatography became available to further separate the lanthanides, that he was proved to be correct.

There is a beauty to that process.

B W J Shelley
Amersham, UK

In connection with the article Double, double, toil and trouble by Tom Keal in Chemistry World April 2005 (p80), concerning references to chemistry in literature, the following extract from Homer’s The Odyssey is of interest. It seems to indicate a very early use of Prozac.

’Helen, meanwhile, the child of Zeus, had had an idea. Into the bowl in which their wine was mixed, she slipped a drug that had the power of robbing grief and anger of their sting and banishing all painful memories.’

The substance was obtained in Egypt. No details of the chemistry are given (this apparently took place some 3000 years ago), but it was obviously a very powerful psychotropic drug. The text continues:

’No one that swallowed this, dissolved in wine, could shed a single tear that day, even for the death of his mother and father, or if they put his brother or his own son to the sword and he were there to see it done.’

T A Hamor MRSC
Bromsgrove, UK

I read the brief article by Steve Down on the detection of ⁹⁹Tc discharges in the January edition of Chemistry World (p23) with interest. It is reassuring to note that levels detected in the River Calder are no greater than those in the Irish Sea - and possibly, by implication, than anywhere else. However, I cannot help thinking that the piece does the developers of the technique a disservice by saying that the detection limits are ’relatively high’ at 0.05 Bq/L.

The activity of ⁹⁹Tc is approximately 6.28 ? 10⁸ Bq/g. The detection limit therefore represents a concentration of only 8 ? 10^-11 g/L, or 0.08 parts per trillion in old money. It is perhaps a little unfair to call this relatively high.

To put these figures into perspective, the natural radioactivity of an adult human is commonly taken to be 100 Bq/kg and that of granite to be 1000 Bq/kg. A domestic smoke detector may have an activity of 30 000 Bq, while powerful isotope sources used for medical treatment may be 1014 Bq (source: World Nuclear Association website). The truth is that the Bq (1 decay/s), is an extremely small unit.

S A Moore
by e-mail

I expect many members, like me, have enjoyed seeing Rough science on BBC2 television. This week I happened to read the little blurb about the programme in the Radio Times for Wednesday 30 March and was appalled to see that those taking part were ’a team of scientists and a chemist’.

In a letter to the editor of the Radio Times I have asked if he/she finds it acceptable to make such an invidious and insulting distinction between scientists and chemists, but I cannot say that I expect a meaningful answer. For all I know this phraseology has been used in advertising every episode of the programme.

C Robertson FRSC
Shanklin, Isle of Wight, UK

Nowadays I make frequent use of the television subtitles (ceefax or teletext 888), principally to avoid inappropriate background music. For pre-recorded material the subtitling is excellent, but the subtitling of live programmes still has some way to go.

Recently, for example, I was alarmed to see in a discussion of climate change that a major cause of global warming is a substance called Karen Dioxide.

I A Williams CChem FRSC
Royston, UK