Referee's report by James Clerk Maxwell, on a paper 'On the thermal resistance of liquids' by Frederick Guthrie Recommended for publication in the 'Philosophical Transactions of the Royal Society'. Suggests clarifying and defining the term 'thermal resistance'. Refers to work of Balfour Stewart. Suggests the Proceedings as an alternate place for publication, as the research 'should not be lost to the public'. However, the author's statements about "'arrested heat" and methods of calculation should [not] receive any sanction from the Royal Society as they stand. He should either defend them, modify them or withdraw them'. Subject: Physics and Chemistry [Published in the Philosophical Transactions of the Royal Society] 20 April 1869