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Attempt at reconstruction of prehistoric forging processes Chemical analysis and microscopic examination of prehistoric iron implements can give valuable information about the processes used in their production. But more precise information can be gained by attempting to reproduce the processes suggested by analysis.Prehistoric iron contains considerable quantities of slag and of phosphorus, and these impurities cause difficulties in the use of processes employed in more modem times. It is therefore necessary to use in the experiments iron of "Iron-Age" quality. For the following experiments iron from a board of 20 iron bars found at Hedeby in 1964 was used as a basis of comparison, while the raw material for the reconstruction experiments was small pieces of iron from the iron extraction experiments carried out by Varde Steelworks (5).Longitudinal and cross sections were sawn through the three bars from Hedeby, and the resultant surfaces polished and then etched with nitric acid to reveal the structure of the iron. From this it could be seen that all the bars consisted of many small pieces of iron welded together, some weighing less than 10 grams.In addition to the normal microstructure of ferrite and perlite the iron contained large quantities of non-metallic inclusions the characteristic form of this slag being visible in Figs. 7 and 8.The welding seams show a considerable charcoal content. For example at point b-b there is on either side of the seam a perlite area with high carbon content. At several points (Fig. 6) welding has been unsuccessful, and cracks can be seen full of a black substance which must be the charcoal which caused the carburization, while outside this carbonrich zone, at some places 1 mm. wide, the structure is purely ferritic. The section in Fig. 2 shows that the areas rich in carbon only occur at the surface.A chemical analysis was made of the Hedeby iron, and tests of phosphorus content carried out at intervals of 50 mms. along the edge of

Mudhouses The author describes some reconstruction experiments which were made in 1956, 1957 and 1958 near the village of Allerslev, near Roskilde, Zeeland. An attempt was made to re-erect some houses found on a site called "Troldebjerg" in the neighbourhood of Rudkøbing, Langeland, at the end of the 'thirties', and excavated by Mr. Jens Winther of that town. Several houses, a score or so of "apse-shaped" huts and: a single rectangular house were excavated. The settlement was dated to about 2200 B.C., and gave valuable information on the appearance of dwelling houses of the middle Neolithic period owing to the fine state of preservation. The information culled on this occasion must, however, be treated with some caution, as the houses were discovered at a period when the excavation technique of remains of dwellings in Danish settlements was only in its beginnings.This, together with a yet more important fact, viz. that so little of these dwellings had been preserved at all, made the correct appearance of the houses a problem exceedingly difficult to solve.In 1956 there was only one approach possible: to start on the long apprenticeship which was a necessary preliminary before any experience could be gained. This method has been the fundamental principle on which all the experiments have been based; a deeper comprehension of prehistoric building methods has been attained by the rejection or confirmation of theory by practical experiment.A series of observations then follows, a result of the knowledge acquired from the work of reconstruction of the first five years.The construction of the walls and their subsequent, gradual decay as a result of the weather must be specially mentioned.The walls were borne by wall posts which were either supported by stones placed in a trench or were dug down in holes. Osier wattling was then made up to the top of the wall and, although the posts were not sunk particularly deep in the earth, they supported the wattling sufficiently to b

Trial reconstruction of an early process of iron extraction In KUML 1962 were presented the results of certain new investigations of prehistoric iron extraction plants 1) which have made it possible to put forward a new basis for reconstruction of the plants which were used for iron smelting in the first centuries A. D. It has unfortunately not been possible to demonstrate by excavation every detail in the proposed reconstruction, as, for example the height of the shaft and details in the construction of the connection between the shaft and the slagpit.All the remains of furnaces hitherto investigated have been more or less altered by the actual process of the smelting, and we are therefore without evidence of the appearance of the furnace at the start of the process. Only a fortunate combination of circumstances could allow us to discover such evidence, but it should be possible to gain a degree of knowledge if the smelting process could be successfully imitated in a reconstructed furnace. The chief importance of such successful experiments would, however, be to provide a reliable basis for calculations of production and consumption.Experiments in smelting were begun at Drengsted in the autumn of 1963 by the Aarhus University Institute of Prehistoric Archeology and Ethnography and were later carried further at the Varde Steelworks Limited. The following is an account of the experiments at the latter place.Considerations before the start of the experiments To convert iron ore into iron is a very easy task. All that is needed is a suitable temperature and a suitable reducing agent, that is, a substance which is able to remove the oxygen which is in chemical combination with the iron of the ore. One of these reducing agents is the gas carbon monoxide.The chemical process in the reduction of iron ore may in simplified form be writtenFeO +CO à Fe+ C02.The reaction begins to take place at about 650° C, and speeds up at higher temperatures.Now, as luck will have it, burni