CONTINUITY OF STRUCTURE ILLUSTRATED. 229 



number of intermediate buildings, passing from the 

 pure Grecian to the pure Gothic architecture. The 

 continuity, whatsoever as to space the buildings 

 intermediate in structure may occupy, will be per- 

 fect as far as relates to the gradation of form. 

 And yet there must ever be some difference between 

 the two structures nearest each other, in form : for 

 if no interval exists, then these two must have the 

 same structure, and one of them will thus produce 

 no effect in continuing the chain of structure. In 

 this kind of continuity, therefore, intervals between 

 different forms are absolutely necessary; and if they 

 do not exist, there is only one form. But in space 

 or time an interval is impossible, and their con- 

 tinuity depends on this impossibility. On the other 

 hand, continuity in gradation of structure depends 

 on the existence of intervals ; but requires, in order 

 that the gradation be more distinct, that these 

 intervals be extremely small and numerous. If 

 only one mean be interposed between two extremes, 

 there will be two chasms, but no saltus, and the 

 three objects will be in continuity. Augment the 

 number of various intermediate objects, and you 

 only get the chasms more numerous, and the con- 

 tinuity more perfect. To argue, therefore, about 

 the innate impossibility of the law, is absurd : the 

 only question for us now to examine, being, whether 

 such a continuity as I have described can be shown 

 to exist in nature. I think I have proved this in my 

 Analysis and Synthesis of Petalocerous Coleoptera ; 

 and what the Linnaeans call natural genera, such as 

 Rosa and Erica, are likewise all proofs of it: so 

 that, if continuity manifestly holds good in these 

 a 3 



