J. J. GKiFFiTir 3S9 



towards the underside to a very marked extent. There was not much 

 difference in the rate of growth at this period. Later on the curling 

 effect gradually disappeared but the leaves slowly developed a reddish 

 hue and afterwards acquired a very dark-red colour. The development 

 of this red colour was accompanied by distinct evidence of the harmful 

 effects of lead upon the growth of the plant. Up to the end of December 

 the rate of growth appeared inversely proportional to the amount of 

 lead added to the soil and to the development of the red colour. See 

 Photograph "C," taken January .5th, 191-5. 



From this time onwards to the end of March the plants in Pots .31, 

 32, 33 and 34 gradually became weaker, in fact leaf by leaf they steadily 

 perished towards the end of March. On the other hand, the crop in 

 Pots 29 and 30 slightly improved, and rather suggested some measure 

 of success in an attempt to withstand the unfavourable influence of the 

 lead. See Photograph "D," taken March 25th, 1915. 



The crop was cut on April 2nd. Table XII gives the weight of air- 

 dried crop. 



No. of pots 



27 and 28 

 29 „ 30 

 31 „ 32 

 33 „ 34 



It was found also that the roots of the trifoliuni plants growing in 

 the treated soils were quite abnormal in appearance. They had but few 

 root hairs. They were very stunted and most of them appeared to be 

 in a semi-decayed condition. Nodules, although not abundant, were 

 present on most of the plants. See Photograph "E." 



3. Influence upon second crop of Oats. 



In order to ascertain whether lead mixed with the soil in the form of 

 galena may, as a result of chemical changes, in the course of time become 

 more harmful a second crop of oats was grown in Pots 27-34. The 

 results are given in Table XIII. 



Time of sowing April 14th, 1915. 



Time of cutting August 23rd, 1915. 



A dressing of complete manure was given to all pots. 



Journ. of Agric. Soi. ix 26 



