BOOK X. 477 



that the one fits in a mortise in the middle of the other, and the other Ukewise 

 fits in the mortise of the first, thus making a kind of a cross ; these sills are 

 three feet long and one foot wide and thick. The crane-post is round at its 

 upper end and is cut down to a depth of three palms, and turns in a band 

 fastened at each end to a roof-beam, from which springs the inclined chimney 

 wall. To the crane-post is affixed a frame, which is made in this way : first, at a 

 height of a cubit from the bottom, is mortised into the crane-post a small 

 cross-beam, a cubit and three digits long, except its tenons, and two palms in 

 width and thickness. Then again, at a height of five feet above it, is another 

 small cross-beam of equal length, width, and thickness, mortised into the 

 crane-post. The other ends of these two small cross-beams are mortised 

 into an upright timber, six feet three palms long, and three-quarters wide 

 and thick ; the mortise is transfixed by wooden pegs. Above, at a height of 

 three palms from the lower small cross-beam, are two bars, one foot one palm 

 long, not inclu iing the tenons, a palm three digits wide, and a palm thick, 

 which are mortised in the other sides of the crane-post. In the same manner, 

 under the upper small cross-beam are two bars of the same size. Also in the 

 upright timber there are mortised the same number of bars, of the same length 

 as the preceding, but three digits thick, a palm two digits wide, the two 

 lower ones being above the lower small cross-beam. From the upright 

 timber near the upper small cross-beam, which at its other end is mortised 

 into the crane-post, are two mortised bars. On the outside of this frame, 

 boards are fixed to the small cross-beams, but the front and back parts of the 

 frame have doors, whose hinges are fastened to the boards which are fixed 

 to the bars that are mortised to the sides of the crane-post. 



Then boards are laid upon the lower small cross-beam, and at a height 

 of two palms above these there is a small square iron axle, the sides of which 

 are two digits wide ; both ends of it are round and turn in bronze or iron 

 bearings, one of these bearings being fastened in the crane-post, the other in 

 the upright timber. About each end of the small axle is a wooden disc, of three 

 palms and a digit radius and one palm thick, covered on the rim with an iron 

 band ; these two discs are distant two palms and as many digits from each 



" and lead. It is considered better in quality the nearer it approaches to a golden colour 

 " and the less lead there is in it ; it is also friable and moderately heavy. When it is boiled 

 " with oil it becomes liver-coloured, adheres to the gold and silver furnaces, and in this state 

 " it is called metallica." From these two passages it would seem that molybdaena, a variety 

 of litharge, might quite well be hearth-lead. Further (in xxxiv, 47), he says: " The metal 

 " which flows hquid at the first melting in the furnace is called stannum, at the second melt- 

 ing is silver, that which remains in the furnace is galena." If we still maintain that molybdaena 

 is hearth-lead, and galena is its equivalent, then this passage becomes clear enough, the 

 second melting being cupellation. The difficulty with Pliny, however, arises from the 

 passage (xxxiii, 31), where, speaking of silver ore, he sa37s : " It is impossible to melt it 

 except with lead ore, called galena, which is generally found next to silver veins." 

 Agricola (Bermannus, p. 427, &c.), devotes a great deal of inconclusive discussion to an 

 attempt to reconcile this conflict of Pliny, and also that of Dioscorides. The probable 

 explanation of this conflict arises in the resemblance of cupellation furnace bottoms to lead 

 carbonates, and the native molybdaena of Dioscorides ; and some of those referred to by Pliny 

 may be this sort of lead ores. In fact, in one or two places in Book IX, Agricola appears 

 to use the term in this sense himself. After Agricola's time the term molybdaenum was applied 

 to substances resemblinglead, such as graphite, and what we now know as molybdenite (Mo S2). 

 Some time in the latter part of the i8th century, an element being separated from the latter, it 

 was dubbed molybdenum, and confusion was five times confounded. 



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