Manufacture of Bi-chromate of Potash. 269° 
the tension of water, to about 270° C., and that of turpentine to above 
° : 
over‘one-half or Siienthind full; and they should be short enough to be 
entirely covered by the oil when placed vertically in it; if to a 
heat, tubes of 50 to 60 centimetres are employed, and they are filled 
Tol TS or a_ mill (‘moulin a poix’’), and afterwards with water under 
siliceous millstones or of iron, bringing together the millstones, so as to 
obtain No, 90 :— 3), then made into a paste with carbonate of potash, 
the mixture and drying it completely at 100° C.:—(4), thus calcined, 
Ibis put into earthen retorts, which have at the lower part a head 
Metal provided with an opening for admitting air previously heated, for 
