Referee's report by John Frederick William Herschel, on a paper 'A mathematical theory of magnetism' by William Thomson, Lord Kelvin Recommended for publication in the 'Philosophical Transactions of the Royal Society'. Wonders if the paper is a continuation of another, possibly published in 1849, the volume of which the reviewer has not yet received. Suggests this paper would be best reviewed by whoever reviewed the first part. Subject: Mathematics [Published in the Philosophical Transactions of the Royal Society] 6 July 1850