OF PERIODIC PHENOMENA. 365 



led to suspect, in this calendar, will be considerately 

 pardoned. The bulk of the observations having been 

 made and registered many years back, it is extreme- 

 ly probable that there may be some wrong entries by 

 mistake in the journal from which they are now 

 copied, though it is believed that they are generally 

 correct. It will also sometimes happen that the first 

 occurrence of a particular phenomenon is in re- 

 ality previous to the day of its being first noticed ; 

 and this is especially likely to be the case with re- 

 spect to the appearance of birds and insects, which 

 cannot be watched with the same exactness as plants, 

 and in regard of which the attention is not given 

 to any particular individuals but to the species gene- 

 rally. It may be added that the calendar here offered 

 to the public is of too comprehensive a kind to ad- 

 mit of being more than an approximation to a 

 true Calendar of Nature. To form such a calen- 

 dar, even for Natural History purposes alone, 

 would require a combination of observers, each 

 confining himself to one particular department, 

 and in the enjoyment of such advantages, in 

 the way of situation and leisure, as the under- 

 taking, in order to be at all successful, demands. 

 If the present imperfect attempt should anywise 

 be conducive to such an end, by stimulating others 

 to the prosecution of this subject, or should afford 

 either interest or instruction to young observers, 

 for whom principally this calendar has been ar- 

 ranged, the author will be well satisfied, as well 

 as repaid for the trouble which it has cost him, in 

 putting it together. 



