BOOK VII. 253 



generally is ; I have written elsewhere of its nature^^. First the gold is 

 rubbed on the touchstone, whether it contains silver or whether it is obtained 

 from the mines or from the smelting ; silver also is rubbed in the same 

 way. Then one of the needles, that we judge by its colour to be of similar 

 composition, is rubbed on the touchstone ; if this proves too pale, another 

 needle which has a stronger colour is rubbed on the touchstone ; and if this 

 proves too deep in colour, a third which has a little paler colour is used. For 

 this win show us how great a proportion of silver or copper, or silver and 

 copper together, is in the gold, or else how great a proportion of copper is in 

 silver. 



These needles are of four kinds.^^ The first kind are made of gold and 

 silver, the second of gold and copper, the third of gold, silver, and copper, 

 and the fourth of silver and copper. The first three kinds of needles are 

 used principally for testing gold, and the fourth for silver. Needles of this 

 kind are prepared in the following ways. The lesser weights correspond 

 proportionately to the larger weights, and both of them are used, not 

 only by mining people, but by coiners also. The needles are made in 

 accordance with the lesser weights, and each set corresponds to a bes, 

 which, in our own vocabulary, is called a mark. The bes, which is employed 

 by those who coin gold, is divided into twenty-four double sextulae, which 



Hill's trans.) This humid " exudation of fine-grained stones in summer " would not sound 

 abnormal if it were called condensation. Pliny (xxxiii, 43) says : " The mention of 

 " gold and silver should be accompanied by that of the stone called coticnla. Formerly, 

 " according to Theophrastus, it was only to be found in the river Tmolus but now found in 

 " many parts, it was found in small pieces never over four inches long by two broad. That 

 " side which lay toward the sun is better than that toward the ground. Those experienced 

 " with the coticula when they rub ore (vena) with it, can at once say how much gold it contains, 

 " how much silver or copper. This method is so accurate that they do not mistake it to a 

 " scruple." This purported use for determining values of ore is of about Pliny's average 

 accuracy. The first detailed account of touchneedles and their manner of making, which we 

 have been able to find, is that of the Probierbiichlein (1527? see Appendix) where many of the 

 tables given by Agricola may be found. 



^^De Natura Fossilium (p. 267) and De Ortu et Causis Suhterraneorum (p. 59). The 

 author does not add any material mineralogical information to the quotations from 

 Theophrastus and Pliny given above. 



^'In these tables Agricola has simply adopted Roman names as equivalents of the 

 old German weights, but as they did not always approximate in proportions, he coined terms 

 such as " units of 4 siliquae," etc. It might seem more desirable to have introduced 

 the German terms into this text, but whOe it would apply in this instance, as we have 

 discussed on p. 259, the actual values of the Roman weights are very different from the 

 German, and as elsewhere in the book actual Roman weights are applied, we have con- 

 sidered it better to use the Latin terms consistently throughout. Further, the obsolete 

 German would be to most readers but little improvement upon the Latin. For convenience 

 of readers we set out the various scales as used by Agricola, together with the German : — 

 RoM.\N Scale. Old German Scale. 



translation as pfennig as applied to both German scales, but as they are of different values. 



