Paste.—Soldering Sheet Iron. 379 
and mixed with warm water to a proper consistence. A 
pound of potatoes will make a quart of good yeast. Keep 
it moderately warm by fermenting. This recipe is in sub- 
stance from Dr. Hunter, who observes that yeast so made 
will keep well. No sugar is used by bakers when adding 
the pulp of potatoes to their rising.— Yorkshire Gazette. 
11. Paste-—Dr. McCulloch, in a paper on the power of 
i ting mouldiness, gives the following di- 
rections for the preparation of a paste, which, as it will keep 
12. Soldering Sheet Jron.—Sheet iron may be soldered by 
means of filings of soft cast iron applied with borax depri- 
ved of its water of crystallization and sal ammoniac. Tubes 
of sheet iron have been constructed at Birmingham lately 
means of a process of this kind, which according to Mr. 
Berkins and Mr. Gill is to be practised in the following 
manner :—Tbe borax is to be dried in a crucible, not till 
it fuses, but till it forms a white crust; then powdered, and 
mixed with the iron filings: the joint is to be made bright, 
and moistened with a solution of the sal ammoniac ; then: 
e mixture is to be made into a thick paste with water; 
and placed along the ee of the a and the whole 
till the cast iron fuses. 
PRET Tech. Rep. U1. 118. 
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