422 Proceedings of the Royal Irish Academy. 



(11 Nov.) jusqu'a la fin de Janvier, et si apre qui les racines des 

 vignes, et des arbres fruitiers gelerent." The year 1408 may there- 

 fore be taken as a maximum, for this reason at least. 



The interval between 1407-83 and 1370-60 is 37-23 years, which 

 may be considered as a regular interval, 33-3 + 3'90, that is, an interval 

 between two maxima or minima and an interval from a maximum to a 

 minimum, or vice versa. Thus we have the interval between - 1610-8 

 and 1370-6 = 240-2, while we have the interval between a known 

 maximum and minimum- 1889-6 and + 1649 = 240-6. This would 

 suggest that the year in question was a minimum. There is no record 

 of the weather for this year in the works already referred to. As regards 

 the year 1333, it is interesting, in the first place, to compare it with 

 1444, as regards the interval, 111 years, that is 99-99 +11 years, which 

 occurs sufS.ciently frequently in these records to merit attention. It is 

 also notable that the interval between 1370-6 and 1333 = 37-6 is practi- 

 cally the same as that between 1408 and 1370-6 = 37-4, and should lead 

 to the same conclusion, that is that 1333 was aminimum sun-spot year. 

 This is further borne out by the interval between- 1610-8 and 1333 

 = 277-8, which is practically the normal interval 11-1 x 25, and occurs 

 between the years - 1889-6 and - 1610-8 = 278-8. The weather 

 record for this year helps to bear out this interpretation. The Annals 

 of Ulster give under this date : — " 1333. A most seasonable summer." 

 (Grace's Annals.) " It happened to be so dry a summer that at the 

 feast of St. Peter ad Vincula (29th June) there was bread made of new 

 wheat." — Camden's Annals. 



The interval between the year 1328-5 and the preceding is 4-50 

 years, which may point to this year having been a maximum. Thus 

 comparingit with+1615-5 the interval is + 1615-5 -1328-5 = 287 years, 

 which represents sulficiently closely the normal interval ll'l x 26 

 = 288-6, and allows of the year in question being taken as a maximum 

 sun-spot year. Tliere is no record in Arago's work as to the weather 

 of this year. The interval between the year 1285 and the preceding 

 is 43-5, which approximates closely to 44-4, the normal interval and 

 would point to the year having been a maximum also. The record of 

 the weather goes some way to support this reading, as, under the head 

 of the year 1285-6, the Annals of Ulster state : — " There was great 

 snow this year, which continued from Christmas to St. Bridget's 

 day" (" Annals of Clonmacnoise"). The interval between the year 

 1181 and the preceding one is 104 years, which is not a normal 

 interval, but may be compared with the interval - 1889-6 and - 1784*8 

 = 104-8, which would allow of its being taken as a minimum year of 



