752 



Ijcrrics were found to be very large and brightly colored on the soil saturated 

 with calcium chlorid. The fruit, liowever, tasted of calcium chlorid and 

 did not keep vvelP. 



Barium Chlorid. 



This is a comparatively less important element, which is found only at 

 times in the waste waters of hard coal mines. Its [joisonous action has been 

 proved by Haselhofif- in water cultures of niaisc and horsebeans. (irowth in 

 height was arrested; the leaves wilted and fell. In nature, however, direct 

 injury will occur only rarely, because the sulfurous salts rapidly transform 

 it into insoluble and non-injurious barium sulfate. 



Waste Watkr Containing Zinc Sulfate. 



Konig'' has paid especial attention to the investigations of such waters 

 from Zinc Blend Mines. It was proved that the brooks which take up the 

 waste water contained sulfurous zinc oxide in solution. An evident retro- 

 gression in the yield and in places a \Qvy poor growth was noticed on 

 meadows thus watered. The grasses grown on such sterile places, as well 

 as the deformed, bushy beech and maple trees, contained up to 2.78 per cent, 

 of their ash in zinc, while the ash of normal meadow plants did not contain 

 this metal. Vegetation dies in places where zinc ore happens to be deposited 

 accidentally. Only one specific zinc plant (the "white mineral blossom") 

 was still visible. This "mineral copper blossom" contained not less than 1 1 

 to 15 per cent, zinc oxid in its ash. It is thus seen how differently the 

 various plants behave and what high concentrations may often be endured. 

 The injuries appear only after a considerable number of years, after the 

 zinc oxid present in very small amounts in the water of the brook has accu- 

 mulated to considerable quantities. Konig is justified in concluding from 

 this that the requirement made upon mines by the Concession Department 

 that only clear water be allowed to flow away into the streams is not enough 

 protection to the owners of meadows. 



The books supplement the discoveries mentioned, one of w'hich by 

 A. Baumann"* treats exclusively of the effects of zinc salts on plants and soil ; 

 while another, by Nobbe, Bassler and Will"' takes up injuries due to arsenic 

 and lead as well as zinc. 



It must be emphasized, from the results of Baumann's experiments, that 

 the zinc sulfate in solution is much more injurious to plants than had been 

 supposed up to that time. Small amounts (possibly .1% zinc, that is, 4.4 mg. 

 zinc vitriol in a litre) have been proved absolutely non-injurious in all the 

 plants under experimentation (13 species from 7 families) with the excep- 



1 Denkschrift, p. 161. 



2 Landwirtsch Jahrbiicher 1895, p. 962. 



3 Konigr, Untersuchung-en iiber Beschadiffungen von Boden u. Pflanzen durch 

 industrielle Abflusswasser und Case; cit. in Biedermann's Centralbl. 1S79, p. 564. 



4 Baumann, A., Das Verhalten von Zinksalzcn ffofren Pflanzen und im Boden. 

 I'reisschrift 1S84. Landwirtsch. Versuchsstat. Vol. XXXI, Part 1, p. 1. 



5 Nobbe, Bassler und Will, Untersuchung-en iiber die Giftwirkung- des Arsen, 

 Blei und Zink im pflanzlichen Organismus. Landwirtsch. Versuchsstat. Vol. XXX, 

 Parts 5 and 6. 



