EXPERIMENT STATION BULLETINS. 



545 



nffllY flVFPRnF TFMPFRRTf/PF FOR NnVFMEFP - 1 912.. 



J2aZC (. ^_J! -f .f f y ^ f /(,,/> 1^ j;t /f. i^-r yf. yj- /■(» /f .^n ^/ .2^ 2,1 J^ 



69 



FIG. 15. 



