of some Species of Sylviadce. 89 



operation. It must not be forgotten, that the past season has 

 been equally unpropitious for the development and increase of 

 the insect tribe ; and the deficiency of lepidopterous, as well as 

 other insects, must have struck every one who pays any attention 

 to these details of nature. This failure in a department of nature 

 so essential to the economy of most of the sylviadce, and which 

 constitutes the principal food of the particular species I have 

 enumerated, combined with the coldness and ungenial nature of 

 the weather, at a time when they were about to undergo the 

 debilitating effects of a moult, appears to me the proximate cause 

 of their early departure : for, so long as that ardour existed 

 which influences and supports them during the season of repro- 

 duction, they contrived to brave the inclemency of the weather, 

 and remained stationary in those situations they had first selected, 

 instinctively impelled to fulfil a great and imperious call ; but, that 

 at an end, they immediately yielded to circumstances, or, rather, 

 by another instinctive feeling, were driven to seek, in a more 

 southern latitude, that congeniality of climate and food necessary 

 to their wellbeing at that particular juncture, and which, in a 

 season so unusual, appears to have failed them in those latitudes 

 where, under usual circumstances, they had been accustomed to 

 remain till the middle of September, or beginning of October. 



I may add, that the season was not only fatal to the eggs and 

 broods of the few species I have named, but affected, in a greater 

 or less degree, every kind of bird. The rare occurrence of the 

 young of all our well known songsters, and the solitary aspect 

 of our gardens and orchards, at a period when they used to 

 exhibit a scene of life, activity, and joy, cannot have escaped the 

 notice of the observant pupil of nature ; nor will the sportsman 

 be slow in deploring, or giving his testimony to the universal 

 lack of feathered game. 



ART. III. — Baron Cuvier's Lectures on the History of the 

 Natural Sciences. — (continued from p. 26.) 



On the Luxury of the Romans. 



We have seen that the Roman writers, at the time of the 

 republic, had spoken very little of natural history. Those who 

 flourished during the empire treated of it more fully ; but the 

 works they have left us on this subject contain iew original remarks. 

 They are, indeed, little else than mere compilations ; a circumstance 

 which appears the more strange, that few people have had better 

 opportunities for observation. 



At the earliest period of the republic, in addition to the institutions 

 in general being unfavourable to every kind of study, the prevail- 

 ing simplicity of manners was particularly opposed to the progress 



VOL. III. M 



