170 Mr. H. L. Pattinson on Smelting Lead Ore, &;c. 



inch wide, and 7 or 8 inches long, is cut out between the front of the 

 breast and the test ring, in order that the Litharge may flow down from 

 the test, without coming in contact with the iron. 



Instead of bone and fern ashes, mixed together in the proportions 

 stated, it is a better practice, and one gradually coming into general 

 use, to make the tests of a mixture of one part of the best American 

 pearl ashes, to forty parts of bone ashes, by weight. The pearl ashes, 

 reduced to fine powder, and perfectly dry, are thoroughly incorporated 

 with the bone ashes, and the compound is then moistened to the proper 

 degree with water, after which the test ring is filled in the usual man- 

 ner. From four to five pounds of pearl ashes are required for each test, 

 the bone ashes for which weighs from 12 to IS stones avoirdupois. 



The test, thus constructed, is applied to the opening in the iron plate 

 already described ; the flat part of its circumference, being previously 

 smeared over with a luting of bone ashes and water of the consistence 

 of paste, and it is then firmly secured in its place by four iron wedges 

 i i, Figs. 3 and 4, which rest upon the iron bars c c. 



When the test is properly fixed in this situation, and thoroughly dried 

 by the application of a gentle heat, it is ready for the reception of Lead, 

 which is poured into it, with an iron ladle, through the channel D, Fig. 

 % being previously melted and kept nearly at a red heat in the pot JS. 

 About 5cwt. of Lead is required to fill a new test to the working level. 

 A mode of feeding the test is sometimes practised, which consists in 

 suspending a pig of Lead, or an iron weight, from a beam above the 

 melting pot, by means of a chain, and allowing it to dip into the melt- 

 ed Lead when made to descend, so as to force the Lead displaced by 

 its introduction, directly into the test through the channel D ; which 

 in that case must be a little lower than the lip of the melting pot. 

 Some refining furnaces are not constructed with the channel D ; but, 

 instead of it, have an opening in the brick-work of the furnace, on each 

 side of the test, through one of which a whole pig of Lead is introduced, 

 and gradually melted down into the test by the heat of the fire ; being 

 pushed further in, from time to time, as the lead is consumed. An 

 opening on each side of the test is considered necessary, in order that 



