A.l.s. to Faraday from Abbadie, written at 31 rue Bellechasse, Paris. Requests information on the materials and equipment used by Faraday to make heavy glass. Abbadie is planning to have some such glass made by Messrs. Maes & Clemandot of Paris, for researches into astronomical instruments. He also points out that the only Frenchman to produce glass adequate for his researches is now dead.