As an active spectroscopist and user of Michael Hollas' excellent texts, I agree wholeheartedly with his comments about the usage of "spectra" ("Singularly annoying", Letters, 19 July). However, while he has concentrated on the improper use of spectra as a singular noun, the case for the plural is if anything even worse. In my experience, it is more common to see both "spectrums" and "spectras" than "spectra". While the use of "spectrums" is at least understandable given the near-universal adoption of "referendums" rather than "referenda" (as recommended by the Oxford English Dictionary), there is no excuse for "spectras". Therefore, it may be that pedantic spectroscopists are the last bastion of the proper use of "um" and "a": keep up the good work, folks!
Nigel Young, University of Hull