484 THE COLLIERY GUARDIAN. March 9, 1917. CURRENT SCIENCE AND TECHNOLOGY. Bauxite as a Refractory. In the Revue de Aletallurgie, M. Henry le Cliatelier contributes a letter, written by his father 50 years ago, on the use of bauxite as a refractory lining for furnaces. The idea suggested itself in connection with attempts then being made to produce aluminium on a manu- facturing scale, and was communicated at the time to the principal French and British metallurgists. Experi- ments were made at Bordeaux, but the employment of the bauxite bricks in steel furnaces was abandoned, owing to the difficulty of obtaining a sufficiently high firing temperature to prevent their subsequent con- traction in use, and also in consequence of the excessive porosity of the bricks, which absorbed slag and scoriae too readily. The high basicity of bauxite was considered to impart greater resistance than any other refractory material known at the time, to the highly calcareous slags in blast furnaces, puddling furnaces, Bessemer furnaces, &c. In order to counteract the contraction in firing, it was proposed to calcine a portion of the material at a high tumperatuie before mixing it with the remainder. Another difficulty was the lack of cohesion, but this, it was considered, could be overcome by using very plastic clay as a binding medium, or—since ’-this increased the proportion of silica at the expense of the alumina—adding to the mixing water a small amount of milk of lime, or preferably . calcium chloride or common s .