BOOK V. 129 



mass of the mountains in order that the owners may lay out their plans, and 

 that their workmen may not encroach on other people's possessions. The 

 surveyor either measures the interval not yet wholly dug through, which 

 lies between the mouth of a tunnel and a shaft to be sunk to that depth, or 

 between the mouth of a shaft and the tunnel to be driven to that spot which 

 lies under the shaft, or between both, if the tunnel is neither so long as to 

 reach to the shaft, nor the shaft so deep as to reach to the tunnel ; and thus 

 un both sides work is still to be done. Or in some cases, within the tunnels 

 and drifts, are to be fixed the boundaries of the meers, just as the BergmeisUr 

 has determined the boundaries of the same meers above ground.*' 



Each method of surveying depends on the measuring of triangles. A 

 small triangle should be laid out, and from it calculations must be made 

 regarding a larger one. Most particular care must be taken that we do not 

 deviate at all from a correct measuring ; for if, at the beginning, we are drawn 



**The history of surveying and surveying instruments, and in a subsidiary way their 

 application to mine work, is a subject upon which there exists a most extensive literature. 

 However, that portion of such history which relates to the period prior to Agricola represents 

 a much less proportion of the whole than do the citations to this chapter in De Re Metallica, 

 which is the first comprehensive discussion of the mining application. The history of such 

 instruments is too extensive to be entered upon in a footnote, but there are some fundamental 

 considerations which, if they had been present in the minds of historical students of this subject, 

 would have considerably abridged the literature on it. First, there can be no doubt that 

 measuring cords or rods and boundary stones existed almost from the first division of land. There 

 is, therefore, no need to try to discover their origins. Second, the history of surveying and 

 surviving instruments really begins with the invention of instruments for taking levels, or 

 for the determination of angles with a view to geometrical calculation. The meagre facts 

 bearing upon this subject do not warrant the endless expansion they have received by 

 argument as to what was probable, in order to accomplish assumed methods of construction 

 among the Ancients. For instance, the argument that in carrying the Grand Canal over 

 watersheds with necessary reservoir supply, the Chinese must have had accurate levelling 

 and surveying instruments before the Christian Era, and must have conceived in advance a 

 completed work, does not hold water when any investigation will demonstrate that the canal 

 grew by slow accretion from the lateral river systems, until it joined almost by accident. 

 Much the same may be said about the preconception of engineering results in several 

 other ancient works. There can be no certainty as to who first invented instruments of 

 the order mentioned above ; for instance, the invention of the dioptra has been ascribed to 

 Hero, vide his work on the Dioptra. He has been assumed to have lived in the ist or 2nd 

 Century B.C. Recent investigations, however, have shown that he lived about 100 a.d. (Sir 

 Thomas Heath, Encyc. Brit, nth Ed., xiii, 378). As this instrument is mentioned 

 by Vitruvius (50 - o B.C.) the myth that Hero was the inventor must also disappear. In- 

 cidentally Vitruvius (vin, 5) describes a levelling instrument called a chorobates, which was a 

 frame levelled either by a groove of water or by plumb strings. Be the inventor of the 

 dioptra who he may. Hero's work on that subject contains the first suggestion of mine 

 surveys in the problems (xiii, xiv, xv, xvi), where geometrical methods are elucidated 

 for determining the depths required for the connection of shafts and tunnels. On the com- 

 pass we give further notes on p. 56. It was probably an evolution of the 13th Century. As 

 to the application of angle- and level-determining instruments to underground surveys, 

 so far as we know there is no reference prior to Agricola, except that of Hero. Mr. 

 Bennett Brough (Cantor Lecture, London, 1892) points outthat the Niiizliche Bergbiichlin (see 

 Appendix) describes a mine compass, but there is not the slightest reference to its use 

 for anything but surface direction of veins. 



Although map-making of a primitive sort requires no instruments, except legs, the oldest 

 map in the world possesses unusual interest because it happens to be a map of a mining 

 region. This well-known Turin papyrus dates from Seti I. (about 1300 B.C.), and it 

 represents certain gold mines between the Nile and the Red Sea. The best discussion is 

 by Chabas (Inscriptions des Mines d'Or, Chalons-sur-Saone, Paris, 1862, p. 30-36). 

 Fragments of another papyrus, in the Turin Museum, are considered by Lieblein (Deux 

 Papyras Huratiques, Christiania, 1868) also to represent a mine of the time of Rameses I. If 

 so, this one dates from about 1400 B.C. As to an actual map of underground workings (disre- 

 garding illustrations) we know of none until after Agricola's time. At his time maps were 

 not made, as will be gathered from the text. 



