Correspondence with Professor M. Faraday, Dr Gladstone, the Revd R. Main, Herbert Airy and others on the Lighthouse Commission. The volume includes a pamphlet on lighthouse lenses; a model 'to illustrate the effect of the Rotating Prisms at the Calais Light House', with two photographs of the model; a questionnaire from the Royal Commission on Light-Houses; and a proof report from the said commission.