INTROOl I II'. 



rate to tl test distance some objects which naturally I 



other ; bow much more impossible must it I"- to folio* the ju I 

 matter iu treating of the solid contents of a sphi 



An arrangement, then, which shall be 

 of the plan of nature as to justify it- being called the Natural Syst< tn 

 chimera.* All thai the Naturalist can il<> is to carry into the prin- 



ciples above explained, with a greater or less amount of skill ; tin- result of 

 which "ill be •' Natural SjBtem. 



When LinnsBus attempted to form a Natural System, he mi 



ther such genera ae he knew into 67 groups, which bo called Fra 

 and which wen- equivalent to the Natural Oi Modern Botany, 



lieu advanced a step further, by forming 15 Classes, under which he pi 

 100 Natural Orders. At a later period the uame Class « i for 



the th ee great divisions of Acotyledons, Monocotyli dons, and Dicotyli d 

 and the Orders were collected into smaller groups called Sub-classes; and 

 thus, by degrees, the forming thri les of distinctive charac 



luperior to genera was i sed. But our countryman, Dr. Robert 



:i, whose sagacity is uot the least remarkable part of I otitic 



character, long ago pointed out the insufficiency of even this amount 

 division, and proposed the combination of Natural Orders into 

 intermediate between Orders and Sub-classes. The necessity of this 



sure i- now universally acknowledged : attempts have been mad 

 some years, by vario to work out the problem : and 1 think 



it must be conceded that a real advance has thus been made, by tl 

 of various independent observers, to the accomplishment of so very desirable 

 an object. To such attempts th nt work is an addition. 



The leading idea which has been kept in view in the compilation of it 

 been this maxim of Fries : Singula- sphcera (i learn quondam em 



<"•!•■, Hmplici optime exp\ . not but 



think that the true characto ill natural assemblages are extremely 



simple : nothing can be mure certain than that their value diminish 

 proportion to their complexity. It' two objects are not to be (listing 

 by a few simple circumstances, they can hardly be called distinguishable at 

 all. In the highest groups or classes it is alwaj (see p. 1 ; and there 



apparent reason why the same rule should not obtain in groups ■ 

 minor rank. Nevertheless, we find that this is too often lost sigl 

 and that long detail- of structure are substituted for precise words 

 tinction. 



It may be, and certainly is in some measure, true, that insuj 

 difficulties are. in the present Btate of our know' :rict 



definitions of Natural Orders, and d fortiori oi their Alliances, & But 

 that is no reason why we should not endeavour t" render their di{ 

 character- as precise a- the nature of the subject will permit. \ E 

 unctions, which are at once the bane and opprobrium of Natural Hisl 

 so repulsive to the understanding as to deter the mass inkind I 



giving it their attentive study. Ami it is not too much to 

 this vagueness - mure frequently out of the prejud 



the Naturalist's own mind than out <>t' things th( 

 happen that two groups may stand, by common i 

 eeivable relation to each other; it is quite possible, by one ■ 



illud nature ipshu abaolutnm human* caper 



i <xi dam supra naturale cuj 

 tantuui tenet Naturae uuAor.—Friet I 



