The Engineer's and Mechanics Encyclopædia: (Lime.) Whiting.

The Engineer's and Mechanics Encyclopædia,
comprehending practical illustrations of the machinery and processes employed in every description of manufacture of the British Empire.
With nearly Two Thousand Engravings.
By Luke Hebert, civil engineer, edifor of the History and Progress of the Steam Engines, Register of Arts and Journal of Patent Inventions, etc.
In two volumes.
London: Thomas Kelly, 17, Paternoster Row.
Whiting is a fine carbonate of lime, made in some places by grinding soft chalk in a mill, separating the finer particles by washing them over in water, letting the water settle, and making up the sediment into loaves, which are exposed to the air to dry. There are numerous manufactories beside the river Thames, where whiting is thus prepared, the loaves being exposed on shelves in lofty sheds, which form, as it were, the vertical external walls of the buildings. In some places whiting is made from lime by slaking it with a little water, then grinding it in a mill with water, exposing the lime water to the air for some time to absorb the carbonic acid from the atmosphere, washing over the sediment, making it into loaves, and drying them. When made into small loaves it is called Spanish white; and if in small drops, prepared chalk; the creta preparata of the apothecaries. It is principally used as a white paint, either alone, or mixed with white lead; the inferior priced white lead has a large proportion of whiting mixed with it. Spanish white and prepared chalk are likewise extensively used to saturate acids in liquids in various chemical and manufacturing operations.

Ei kommentteja :