Instead of extracting all the gelatinous matter from degreased bones, the practice of extracting about one half and carbonizing the residue is frequently adopted. The bones are heated in horizontal cast-iron retorts, holding about 5 cwt., and the operation occupies about twelve to thirteen hours. The residue in the retorts is removed while still red-hot to air-tight vessels in which it is allowed to cool. It is then passed through grinding mills, and is subsequently riddled by revolving cylindrical sieves. The yield is from 55 to 60% of the bones carbonized, and the product contains about 10% of carbon and about 75% of calcium phosphate, the remainder being various inorganic salts and moisture (6-7%). Animal charcoal has a deep black colour, and is much used as a filtering and clarifying material. The vapours evolved during carbonization are condensed in vertical air condensers. The liquid separates into two layers: the upper tarry layer is floated off and redistilled; the distillate is termed “bone oil,”[1] and mainly consists of many fatty amines and pyridine derivatives, characterized by a most disgusting odour; the residue is “bone pitch,” and finds application in the manufacture of black varnishes and like compositions. The lower layer is ammoniacal liquor; it is transferred to stills, distilled with steam, and the ammonia received in sulphuric acid; the ammonium sulphate, which separates, is removed, drained and dried, and is principally used as a manure. Both during the carbonization of the bones and the distillation of the tar inflammable gases are evolved; these are generally used, after purification, for motive or illuminating purposes.
(C. E.*)
[1] Bone oil, also known as Dippel’s oil, was originally produced by the distillation of stags’ horns; it is of interest in the history of chemistry, since from it were isolated in 1846 by T. Anderson pyridine and some of its homologues.
BONE BED, a term loosely used by geologists when speaking generally of any stratum or deposit which contains bones of whatever kind. It is also applied to those brecciated and stalagmitic deposits on the floor of caves, which frequently contain osseous remains. In a more restricted sense it is used to connote certain thin layers of bony fragments, which occur upon well-defined geological horizons. One of the best-known of these is the Ludlow Bone Bed, which is found at the base of the Downton Sandstone in the Upper Ludlow series. At Ludlow itself, two such beds are actually known, separated by about 14 ft. of strata. Although quite thin, the Ludlow Bone Bed can be followed from that town into Gloucestershire for a distance of 45 m. It is almost made up of fragments of spines, teeth and scales of ganoid fish. Another well-known bed, formerly known as the “Bristol” or “Lias” Bone Bed, exists in the form of several thin layers of micaceous sandstone, with the remains of fish and saurians, which occur in the Rhaetic Black Paper Shales that lie above the Keuper marls in the south-west of England. It is noteworthy that a similar bone bed has been traced on the same geological horizon in Brunswick, Hanover and Franconia. A bone bed has also been observed at the base of the Carboniferous limestone series in certain parts of the south-west of England.
BONE-LACE, a kind of lace made upon a cushion from linen thread; the pattern is marked out with pins, round which are twisted the different threads, each wound on its own bobbin. The lace was so called from the fact that bobbins were formerly made of bone.
BONER (or Bonerius), ULRICH (fl. 14th century), German-Swiss writer of fables, was born in Bern. He was descended of an old Bernese family, and, as far as can be ascertained, took clerical orders and became a monk; yet as it appears that he subsequently married, it is certain that he received the “tonsure” only, and was thus entitled to the benefit of the clerici uxoriati, who, on divesting themselves of the clerical garb, could return to secular life. He is mentioned in records between 1324 and 1349, but neither before nor after these dates. He wrote, in Middle High German, a collection of fables entitled Der Edelstein (c. 1349), one hundred in number, which were based principally on those of Avianus (4th century) and the Anonymus (edited by I. Nevelet, 1610). This work he dedicated to the Bernese patrician and poet, Johann von Rinkenberg, advocatus (Vogt) of Brienz (d. c. 1350). It was printed in 1461 at Bamberg; and it is claimed for it that it was the first book printed in the German language. Boner treats his sources with considerable freedom and originality; he writes a clear and simple style, and the necessarily didactic tone of the collection is relieved by touches of humour.