388 Dr. F. H. Hatch — Iron-ores of the United Kingdom. 



over £6 per ton, although (under the cloak of Government subsidies) 

 it figured at a lower level. At one period of the "War the supply 

 from these sources threatened to be cut off altogether. 

 • To meet this situation an increased development of the Jurassic 

 ironstones of this country was decided on. The chart shows the fall 

 in production to the end of 1916, and the subsequent rise due to the 

 introduction of this policy. 



These ironstones, although abundant and cheaply worked, are what 

 the ironmasters term "lean", that is to say they are low in iron, 

 averaging only 28 per cent of that metal. Moreover, they have 

 a high phosphorus and sulphur-content and, for the most part, are 

 rather siliceous. 



There are two classes of steel, which are named "acid" and 

 "basic" respectively, according to the process used in their manu- 

 facture. Acid steel is produced from haematite pig-iron, practically 

 free from phosphorus and sulphur, in furnaces provided with 

 a siliceous (or acid) lining. Basic steel, on the other hand, is produced 

 from pig-iron containing both these injurious ingredients, which are 

 removed in the course of manufacture by means of a basic lining to 

 the furnaces. The large increase in the production of phosphoric 

 ores was reflected in an increased output of basic steel as shown on 

 chart. 



The increased production of the domestic phosphoric ores brought 

 about by the War raised many difficult problems. In the first place 

 it necessitated a different metallurgical treatment. This involved, as 

 already explained, the substitution of basic-lined steel-furnaces for 

 those of the acid type, with consequent increased supplies of suitable 

 refractory materials. It also involved large additional supplies of 

 fuel for smelting and of limestone for fluxing the ore in the blast- 

 furnaces. 



Special difficulties arose with regard to magnesite and magnesite 

 bricks. Prior to the outbreak of war the magnesite brick industry 

 was almost wholly in the hands of the Austrians. The Austrians 

 possess in their own country extensive deposits of magnesite peculiarly 

 suited for brick-making, and they have devoted both skill and money 

 to the perfecting of their products, with the result that before the 

 War they commanded practically the entire custom of the steel trade 

 in this country. To make up for the loss of the Austrian material 

 arrangements were made by the Ministry of Munitions for the 

 manufacture in this country of magnesite bricks, and the raw material 

 was obtained from Euboea in Greece, and from Salem in Madras. 



To furnish the required dolomite and limestone new quarries were 

 opened up in this country. 



With regard to labour a new supply had to be found not only to 

 work the new quarries of ironstone, limestone, dolomite, etc., but also 

 to build the railways required to open them up, to erect extensions 

 to existing plant, to man the new works, to reline furnaces, etc., and 

 this in face of the incessant and urgent calls of the Army to fill the 

 gaps in the fighting line. 



Considerable use was made of prisoner labour. The difficulty with 

 prisoners was to induce them to work. On account of the Army 



