The use of rockets and other explosive fireworks for producing rain has been much discussed recently. Many writers deny the possibility of success by such means. There cannot be the slightest doubt, however, that given clouds in the right condition and altitude it is quite possible to cause rain. The writer has seen it done, not once but many times; generally it must be admitted when the rain was not wanted. Maroons fired in wide-mouthed mortars have been used on the Continent for some years to break up hail clouds and bring them down in the form of rain over the vineyards, where a hail storm is a serious calamity to the wine grower. The use of pyrotechnic signals in connection with aerial travel is gradually increasing. The stores used are practically those evolved and adopted during the great war, modified in some cases to suit peace time requirements, but substantially they are those described in the chapter on Military Pyrotechny. LIST OF THE PRINCIPAL INGREDIENTS USED IN PYROTECHNY AT THE PRESENT TIME. _Force and Sparks Compositions._ Saltpetre Sulphur Charcoal Mealed Gunpowder Iron Borings Steel Filings Zinc Filings Aluminium and Alloys Magnesium and Alloys Lampblack Orpiment (Sulphide of Arsenic) Black Antimony (Sulphide of Antimony) _Chlorate Colour Compositions._ Chlorate of Potash or Perchlorate of Potash. { Nitrate of Strontia Red { Carbonate „ „ { Sulphate „ „ { Nitrate of Baryta Green { Chlorate „ „ { Carbonate „ „ { Carbonate of Copper Blue { Sulphide „ „ { Arsenite „ „ { Calomel „ „ Yellow { Oxalate of Soda { Carbonate „ „ For extra brightness Magnesium added. Secondary tints obtained by mixtures of the above. _Non-Chlorate Colour Compositions._ Saltpetre Sulphur Charcoal Black Antimony White Arsenic Orpiment Aluminium Magnesium Sulphate of Copper Borax _Burnables._ Shellac Pitch Sterine Paraffin Sugar of Milk Linseed Oil _Agglutinants._ Shellac and Spirit Starch Paste Gum Water Linseed Oil Dextrine _Sound Producing._ Gunpowder Gun-cotton Picrate of Potash Chlorate of Potash Aluminium PYROTECHNIC BIBLIOGRAPHY _Manuscripts_ 1225. Treatise of the Ruses of War, the capturing of Towns and the Defence of Passes, according to the instructions of Alexander son of Philip (in the Leyden Library). 1432. Feuerwerksbuch (MS. 362 in the University Library of Freiburg i. B.). 1438. (about). Latin Manuscript, with enumeration of materials for all fires (No. 197 in the Royal Library, Munich). _Printed Books_ 1529. Strassburg. Anonymous: Buchsenmeisterei von Geschoss, Buchsenpulver, Salpeter und Feuerwerk. 1540. Venice. Vanuccio Biringuccio: De la pirotechnia.