1917] Lipman-Gericlce : Smelter Wastes and Barley Growth 501 



selves. As further evidence of the general nature of the effects 

 of the salts in question in soils on the color of the leaves of 

 plants, we may cite again the observations on that point made 

 by both Pammel - and Van Slyke.'' Those investigators reported 

 marked deepening of the color of the leaves of tomatoes and 

 other plants due to treatment of the culture soil with CuSO^. 

 Other kinds of plants, therefore, as well as other soil types than 

 those employed by us seem to be similarly influenced by CUSO4 

 with reference to color production in leaves. 



Tillering 

 During the first two crops grown, the amount of tillering 

 occurring in the plants on the greenhouse soil was studied. This 

 was done with the idea of noting if any close correlation existed 

 between the amount of growth and dry matter produced by the 

 treatment and the number of tillers formed. Our observations 

 give a negative reply to this query. Thus in the first crop of the 

 copper series the number of tillers per pot of four plants varied 

 from thirteen to thirty-one over the whole range of concentra- 

 tions of copper sulfate employed. This in itself would of course 

 be of little significance in connection with the question under 

 consideration if there was a decrease or an increase in the 

 number of tillers with a change in concentration of CuSO^. This 

 was not strictly the case, however, and to illustrate we may say 

 that the largest number of tillers in the first crop of the CUSO4 

 series was in one of the pots receiving 1500 p. p. m. CUSO4 ; 

 the smallest number of tillers was produced in the pots remain- 

 ing untreated. Moreover, there was but little agreement in that 

 respect between duplicate pots receiving CuSO^. Thus the 

 duplicate of the pot above mentioned as producing the largest 

 number of tillers (thirty-one) produced onlj^ twenty-one, and 

 such large discrepancies between duplicate pots were common. 

 The fact remains, nevertheless, that while small concentrations 

 and large concentrations of CuSO^ do not differ in their effects 

 on the number of tillers, some CuSO^ as against no CuSO^ ap- 

 pears to be of definite effect in the first crop. Thus in the large 



- Iowa Agr. Exp. Sta. BuU. no. 16, 1892. 



3 N. Y. (Geneva) Agr. Exp. Sta. Bull. no. 41, 1892. 



