OF PERIODIC PHENOMENA. 361 



posed to commence observations on the plan recom- 

 mended by M. Quetelet, but who are not in pos- 

 session of his lists, it has been thought useful in the 

 following calendar to mark with an asterisk (*) all 

 those periodic phenomena which are included in the 

 number proposed by him to be attended to. Certain 

 others are distinguished by a dagger (-)-), which, 

 though not given by him, appear also to be deserving 

 of notice, or at least by observers in this country, 

 from their being, as it has been termed, " more than 

 ordinarily prognostic" of the season at which they 

 occur. 



(24.) It has been endeavoured in this calendar, as 

 before stated (18), to ascertain, so far as the observa- 

 tions would allow, the mean time of the occurrence of 

 the several phenomena therein noted. At least there 

 are many of the phenomena, in the case of which 

 this endeavour has been more particularly made. 

 The observations were all made in the immediate 

 neighbourhood of Swaffham Bulbeck, for a number 

 of years consecutively, commencing with 1820, 

 and ending with 1831. During this period, there 

 were some seasons as remarkably forward as others 

 were backward ; there were also some very hot and 

 fine summers, as well as cold and wet ones. The 

 observations therefore extend over a period of twelve 

 years. Those which have been repeated each year, 

 or during any number of years short of the whole, 

 but exceeding one, have their dates registered under 

 the columns of mean, earliest, and latest, to the first 

 of which is attached a subordinate column indicating 

 what the exact number of years may have been, 



R 



