Sentence:  All cane juice is liable to rapid fermentation. As soon, therefore, as the clarifier is filled, the fire is lighted, and the <WSD>temper</WSD> (white lime of Bristol) is stirred into it. The alkali of the lime having neutralized its superabundant acid, a part of it becomes the basis of the sugar. 
Meaning of the word marked with <WSD> tags:  Milk of lime, or other substance, employed in the process formerly used to clarify sugar.