WALCHNER ON COPPER AND ARSENIC. 27 



their salutary effects, either by collecting them myself on the spot, 

 or by employing trustworthy persons to do this for me. I took all 

 necessary precautions in the analysis ; and all the materials employed 

 were carefully purified. In this manner I have examined the acidu- 

 lated ferruginous waters of the Black Forest (of Griesbach, Rip- 

 poldsau, Teinach, Rothenfels, and Cannstadt), and also the ochres 

 of the thermal springs of Wiesbaden, of the acidulated waters of 

 Schwalbach, Ems, Pyrmont, Lamscheid, and the Brohl valley near 

 to Andernach. All these ochres have yielded precipitates, the exact 

 analysis of which has clearly proved that they contain copper and 

 arsenic. Besides, I have found antimony in the deposits from the 

 thermal springs of Wiesbaden. 



" Hence all these mineral springs, whose salubrity is well known 

 and celebrated for a long time, contain these two metals, but, observe, 

 in proportions so minute, that they scarce rise to millionth parts. 

 This destroys all fear of dangerous consequences. Should it happen 

 that these metals in very small doses have a beneficial effect in 

 certain diseases, we might attribute part of the salutary effects of 

 these waters to their presence. 



'♦ Although this confirmation of my inferences might have been 

 expected, nevertheless the results of my analyses have surprised me. 

 I have repeated them myself several times, and have caused them to 

 be also repeated by other able chemists, and in all cases with the 

 same results. 



" There is still one question remains : How does it happen that 

 these metals have not previously been found in chalybeate mineral 

 waters, which have been so often analysed ? We answer, because 

 they have not been looked for ; or the experiments have been made 

 on too small quantities of water, without analysing the deposits, 



" Having once found that copper and arsenic always accompany 

 iron, I could not fail in finding them in the earthy substances which 

 contain the latter metal. 



" I began my experiments with the arable soils of Wiesloch and 

 Nussloch near to Heidelberg, which are sufficiently rich in iron, and 

 I soon obtained indisputable proof of the presence of copper and 

 arsenic in these soils, fertile in corn and wine. The deleterious action 

 of the arsenic is wholly suspended by its intimate combination v/ith 

 the iron ; it is in the state of arsenic acid, when it forms a subarse- 

 niate of peroxide of iron, which is wholly insoluble in \vater. 



'' Finally, the analysis of a great number of claj^s, muds and marls, 

 and, among the last, of the marls of the Loss of the valley of the 

 Rhine, of solid argillaceous rocks, more or less ferruginous, have 

 furnished me with as many proofs that the two metals mentioned are 

 everywhere mixed with iron. It is thus evident that they are no 

 less common and no less generally dispersed over the surface of the 

 globe than the latter metal. 



" It now remained to demonstrate that these metals were equally 

 contained in meteoric iron ores*. My first experiments were made 



* M. Rummler of Vienna has found the arsenious acid in the peridot of the 

 meteoric iron of Pallas. (Pogg. Annal. 1840, No. 4.) 



