hoarfrost

hoarfrost (usually uncountable, plural hoarfrosts)

1. Alternative form of hoar frost
   • 1785, Patrick Wilson, “[Account of Some Experiments on Cold]”, in Andrew Duncan, compiler, Medical Commentaries, for the Years 1783–84. […], volume IX, London: […] J[ohn] Murray, […], and C[harles] Dilly, […]; Edinburgh: W. Gordon and C. Elliott, →OCLC, section III (Medical News), page 426:

     […] It is moſt remarkable on the ſurface of ſnovv, vvhen covered vvith hoarfroſt, and on other bodies vvhere hoarfroſt moſt abounds. In ſuch caſes, I have often found the ſurface to be ſeven degrees colder than the air at the diſtance of tvvo feet; […]

   • 1817, John Murray, “Of Caloric”, in Elements of Chemistry. […], 4th edition, volume I, Edinburgh: […] Francis Pillans, […]; London: Longman, Hurst, Rees, Orme, & Brown, →OCLC, book II (Of Repulsion, and the Powers by which It is Produced), section III (Of the Communication and Diffusion of Caloric), page 146:

     This striking fact, of the lower temperature of the surface on which dew and hoarfrost are forming, it was always found difficult to explain; for the transition of a body from the state of vapour to the fluid or solid form is always accompanied with an evolution of heat, […] The surface is not warmer in consequence of the formation of the dew or hoarfrost, but the dew or hoarfrost is deposited because the surface is previously cold; and its low temperature, compared with that of the air above, is owing to the discharge of heat by radiation.

   • 2005, Manh-Cuong Pham, “Conclusions and Policy Implications”, in Land-use Change in the Northwestern Uplands of Vietnam: Empirical Evidence from Spatial Econometric Models and Geo-referenced Analyses and Policy Implications for Sustainable Rural Development, Göttingen: Cuvillier Verlag, →ISBN, page 331:

     However, high mountains with a long winter and long dry spells, hoarfrosts and infertile soils are not an ideal environment for some annual crops but are well suited for perennial industrial crops and forest species.