viii PREFACE 



practical man the weights and measures to which he 

 is accustomed this has been done. In any case the 

 relation between the two systems hardly requires 

 a greater knowledge than that i kilogram (kg.) = 

 2-2 lbs. ; i litre = if pints ; I oz. = 28 grms. (g.). 



W. Goodwin. 



South-Eastern Agricultural College, 

 Wye, Kent. 



