NOTE. 



The measurements used throughout in this book are those of what 

 is known as the metrical system, of which the unit is the meter, which 

 is equal to 39-37079 inches in English. This is now largely employed 

 by the scientific writers of every nation, and I regard it as a duty to 

 promote by all possible means the use of the system, which must 

 assuredly, sooner or later, be universally adopted. To facilitate its use 

 by those who may not be familiar with it I have added the following 

 scale showing on the upper line the metrical, and on the lower the 

 English measurements : — 



Eoughly speaking, the 



Meter is equal to 3 ft. 3 in. and 3-8ths, or 1 yard and 1-lOth. 

 Decimeter ,, 4 inches. 

 Centimeter ,, about four-tenths of an inch. 

 Millimeter ,, about one-twenty-fifth of an inch. 



Where two measurements are given, as for example " stem 15-85 

 cm. high," or "leaves 3-7 cm. long," it is to be imderstood that these 

 are the extremes of size seen by the writer, and that the average length 

 is probably nearly midway between the two. 



The abbreviation met. is used for meter; cm., for centimeter ; mill., 

 for millimeter. 



