PREFACE. 
should say, he knew off hand, and thoroughly, all 
the words of the English dictionary, | Happily, it 
is not zécessary to recollect extemporaneously ei- 
ther all the Genera, or Aajf the Dictionary; so 
long as the former are systematically distributed, 
and while the latter submits to the dominion of 
the alphabet. f 
With respect to the collocation of the Genera 
and Species in the present Essay, the author does 
not flatter himself that it is the best that can be 
offered for the elucidation of the Saxifragéan 
Order; and it is with diffidence he ventures to 
propose it as an improvement only, of the old one. 
Perhaps, indeed, it is scarcely possible that any de- 
scriptive arrangement ou paper, that is at tbe same 
time necessarily a. continuous one, that is, in. a 
straight line, can ever be entirely unexceptionable. 
. Because every good Botanist may perceive that 
a perfectly natural distribution of the genera or the 
species, should be made, not continuously, but as 
it were cireuitously, somewhat resembling the face 
of a map ; such being the way of nature invariably, 
in arranging her manifold productions. For as 
well might Geographers endeavour to link king- 
doms and counties longitudinally, as a Botanist to 
place genera and species naturally, in the conti- 
nuous way of a straight line. For the Kingdoms 
and the counties in the one case, and the Genera 
and species in the other, mutually approximate, 
,not merely at one point, but almost invariably at 
many, a nos | 
