The environs of Creil (Oise) and Chteau-Landon (Seine-et-Marne) are noted for their freestone (pierre de taille), which is also abundant at Euville and Lrouville in Meuse; the production of plaster is particularly important in the environs of Paris, of kaolin of fine quality at Yrieix (1-Jaute-Vienne), of hydraulic lime in Ardche (Le Teil), of lime phosphates in the department of Somme, of marble in the departments of HauteGaronne (St Beat), Hautes-Pyrnes (Campan, Sarrancolin), Isre and Pas-de-Calais, and of cement in Pas-de-Calais (vicinity of Boulogne) and Isre (Grenoble).
Phosphates and chemical manures; calcitim carbide; explosivi powder; dynamite and other explosives.
The ordinary ammonium molybdate, used as a test reagent for phosphates, is a salt of composition (NH4)10M012041; it has been examined physicochemically by J.
Deficiency of nutritive salts, especially nitrates and phosphates; the presence of poisonous salts of iron, copper, &c., or (in the soil about the roots of trees in towns) of coal-gas and so forth.
The salts of all the metals of this group usually crystallize well, the chlorides and nitrates dissolve readily in water, whilst the carbonates, phosphates and sulphates are either very sparingly soluble or are insoluble in water.