1917] Lipman-Gericke : Smelter Wastes and Barley Growth 505 



those of many other investigators, among whom may be men- 

 tioned Effront.** It may be added here that the stimulating 

 effects of the salts studied with respect to germination of seed 

 were noted in the first and second crops. In the third crop there 

 was little, if any, superiority in germination of the seeds in the 

 treated as against the untreated pots. In other words, we have 

 noted that in regard to germination, as well as in respect to tiller- 

 ing and other superficial characters, the salts employed stimulated 

 the barley for one or two seasons at certain concentrations and 

 after that showed no marked effect in either direction. It should 

 also be observed that in cases in which such salts as CuSO^ at 

 higher concentrations retarded germination in the first crop, the 

 retarding effect disappeared in the second and third crops. 



YIELDS OBTAINED 



In studying the yields of barley in all the series, the weights 

 of straw, of grain, and of roots were determined in every case 

 after drying at 100° C and bringing to constant weight. All 

 such determinations are given in the tables which follow, to- 

 gether with other necessary data. It will be noted that the 

 yields of the single pots in every duplicate pair are given, as 

 well as the averages. This is for the purpose of pointing out 

 the large variations in yield frequently obtained in duplicate 

 pots of soil cultures and for that of allowing our colleagues to 

 study our data at first hand and reach their own conclusions. 

 The different salts will be considered separately below, with one 

 tyipe of soil at a time. 



Copper Sulfate — Greenhouse Soil 



Tables Ila, II&, and lie give the results obtained with CUSO4 

 in three successive crops on the greenhouse soil. Through an 

 error, as was stated above, a second application of CuSO^ equiva- 

 lent to the first was made to the soil prior to planting the 

 second crop, so that for the second and third crops, amounts of 

 CUSO4 were present in the soil which were far larger than those 

 intended for the study. While, therefore, we have obtained 



6 Effroiit, J., Comptes Eendus Acad. Sci. (Paris), vol. 141, p. 625, 1905. 



