Referee's report by James Clerk Maxwell, on a paper 'On the sensitive state of electrical discharges through rarefied gases' by William Spottiswoode and John Fletcher Moulton, Baron Moulton Recommended for publication in the 'Philosophical Transactions of the Royal Society'. The paper does not indicate well the progression of thought from the beginning to the end. Suggests adding dates to the experimental discussion, or altering the beginning to show the whole theory. Suggests adding historical details instead of altering the earlier part, to show how and why the authors came to follow the line of research. Subject: Physics and Chemistry [Published in the Philosophical Transactions of the Royal Society, 1879] 12 June 1879