14 CELERY CULTURE 



The construction of the roller marker should be 

 such that the rollers can be set any distance apart 



FIG. 8(a) LEATHER FIG. 8(&) HOME-MADE 



HORSE-BOOT HORSE-BOOT 



to provide for marking rows of various widths, and 

 it should also be equipped with .a device to indicate 



FIG. 9 MACHINE FOR MARKING DISTANCES TO PLANT 



