432 



Proceedings of the Royal Irish Academy. 



Sun-spot 5'ear of 

 comparison. 



Date of 

 Eruption. 



Interval in 

 years. 



Corresponding multiple of the 

 sun-spot period ii'i 



Differ- 

 ence. 



- 1610-8 - 



1509-50 = 



101-2 



11-1 X 9 



= 



99-9 



1-30 



-1610-8 - 



1389 = 



221-8 



11-1 X 20 



= 



222-0 



0-20 



+ 1615-5 - 



1340-46 = 



275- 



-1889-6 - (+ 1615-5) 



= 



274-1 



0-90 



+ 1615-5 - 



1294 = 



321-5 



11-1 X 29 



= 



321-9 



0-4 



-1610-8 - 



1222 = 



388-8 



11-1 X 35 



= 



388-5 



0-3 



+ 1615-5 - 



1206 = 



409-5 



11-1 X 37 



= 



410-7 



1-2 



-1610-8 - 



1157 = 



453-8 



11-1 X 41 



= 



455-1 



1-3 



+ 1615-5 - 



1104 = 



511-5 



11-1 X 46 



= 



510-6 



1-2 



+ 1615-5 - 



1416 = 



199-5 



11-1 X 18 



= 



199-8 



0-3 



- 1610-8 - 



1310-07 = 



300-74 



11-1 X 27 



= 



299-7 



1-04 



+ 1615-5 - 



1262 = 



353-5 



11-1 X 32 



= 



355-2 



1-7 



- 1610-8 - 



1245 



365-8 



11-1 X 33 



= 



366-3 



0-5 



+ 1615-5 - 



1360 = 



255-5 



11-1 X 23 



= 



255-3 



0-2 



- 1610-8 - 



1188 



422-8 



11-1 X 38 



= 



421-8 



1-0 



+ 1615-5 - 



1151 



464-5 



11-1 X 42 



= 



466-2 



1-7 



+ 1615-5 - 



1536-33 = 



79-17 



11-1 X 7 



= 



77-7 



1-47 



- 1610-8 - 



1444 = 



166-8 



11-1 X 15 



= 



166-5 



0-30 



-1610-8 - 



1333 



277-8 



11-1 X 25 



= 



277-5 



0.30 



+ 1615-5 - 



1328-5 = 



287- 



11-1 X 26 



= 



288-6 



1-6 



1668-18 - 



1168-09 = 



500-09 



11-1 X 45 



= 



499-50 



0-59 



1168-09 - 



812 = 



356-09 



11-1 X 32 



= 



355-2 



0-89 



-1610-8 - 



812 = 



798-8 



11-1 X 72 



= 



799-2 



0-4 



+ 1615-5 - 



72 = 



1543-5 



11-1 X 139 



= 



1542-9 



0-6 



-1610-8 + 



477 = 



2087-8 



11-1 X 188 



= 



2086-8 



1-0 



- 1610-8 - 



1500 



110-8 



11-1 X 10 



= 



111- 



0-2 



+ 1615-5 - 



1306 = 



309-5 



11-1 X 28 



= 



310-8 



1-3 



+ 1615-5 - 



1138 



477-5 



11-1 X 43 



= 



477-3 



0-2 



+ 1615-5 - 



1049 



566-5 



11-1 X 51 



= 



566-1 



0-4 



+ 1615-5 - 



1306 = 



309-5 



11-1 X 28 



= 



310-8 



1-3 



+ 1615-5 - 



993 = 



622-5 



11-1 X 56 



= 



621-6 



0-9 



+ 1615-5 - 



685 = 



930-5 



11-1 X 84 



= 



932-4 



1-9 



- 1610-8 - 



612 = 



1098-8 



11-1 X 99 



= 



1098-9 



0-1 



+ 1615-5 - 



472 = 



1143-5 



11-1 X 103 



= 



1143-3 



0-2 



-1610-8 - 



203 



1407-8 



11-1 X 127 



= 



1409-7 



1-9 



- 1610-8 - 



78-65 = 



1532-15 



11-1 X 138 



= 



1531-18 



0-97 



