276,020. Marconi's Wireless Telegraph Co., Ltd., (Assignees of Ranger, R. H.). Aug. 14, 1926, [Convention date]. Copying-telegraphs. - Comprises a heat-sensitive recording material such as paper which is so sensitized that it can be marked by a hot gas jet, electric spark, or other heating device. The material is suitable for use in the copying-telegraph described in Specification 276,009. It comprises a short-fibre paper coated with gelatine associated with an oxidizing agent. The following examples are given : (a) Aniline-hydrochloride 9.8 gm., water 99 cc., gelatine 0.26 gm., potassium nitrate 8 gm. or other oxidizing agent. (b) Water 100 cc., nickel nitrate 5 gm., sodium thiosulphate 3.9 gm., sodium nitrate 3.6 gm., one-per-cent gelatine solution 5 cc. The heat reaction may take the form of a, slight scorching of the paper, the formation of a metallic pigment, a polymerization reaction yielding a dyestuff, or minute and confined explosions. Substance (a) above is suitable for heating with a spark at 10,000 volts and 20 or 25 watts, the electrodes being 0.02 inches apart; and substance (b) can be used with a hot gas jet of temperature from 480‹ to 520‹ F. travelling at a speed of 1.5 inches per second, a brownish pigmentation being produced. The Specification as open to inspection under Sect. 91 (3) (a) described also the following composition : Water 100 parts, phenol gelatine 10, salt 5, phenol-phthalein 0.5. This subject-matter does not appear in the Specification as accepted.