Reed water tube boiler straight tubes through which water and steam circulated more freely, it was considered by some contemporary writers on the subject such as Leslie S. Robertson as "behind" in its circulation because of the absence of down-comers. Whereas the Yarrow boilers fitted to the armoured cruiser of 1905 evaporated 11.664 pounds (5.291 kg) of water per pound (454 g) of coal at 100 degrees centigrade (212 degrees Fahrenheit) with natural draught, by the same measure a Reed boiler as fitted to the torpedo boat destroyer of 1896 evaporated 12 pounds (5.44 kg). An advantage of the Yarrow boiler was in weight:
Centigrade 232 another Centigrade 232 poem ("Ode To A Crystal Set") appear on the CD's opening track "Second Degree Soul Sparks". In October 2007, Voiceprint Records re-issued "Centigrade 232" in a package containing both a reprint of the 1977 book and a CD of the 1986 recitations. Voiceprint Records label head Rob Ayling passed a copy of the cassette tape of Calvert's recitations to Dave Brock and asked him to set some of the titles to music. The music was played by the then current line-up of Hawkwind, but some titles were lost at the mixing stage delaying the release until August