DEPARTMENT OF ASTRONOMY AND COSMlCAL PHYSICS. 501 



peveutiea, the liiglieot meau ibr auv inuutli in any decade. 'Rainy days' give no 

 break in Soptember. 



To test for any relation to solar activity tbe whole-year and monthly falls 

 were taken for the three years nearest each of the six maxima and the six minimjv 

 between 1831 and 1901. The object of what follows is to get opinions whether 

 there is justification for examining the matter further. 



The whole-year fall showed an excess for the eighteen years at maxima of 50 

 inches over the 4l'o-73 inches of the eighteen years at minima. This is + 12 per 

 cent. 



Each maximum exceeds the preceding minimum, except in the case of the 

 seventies' minimum. 



Nine of the months contributed to this excess. August only is markedly 

 reversed. The eighteen ye&ia 217G inches (or -SUw per cent.) at maxima 

 to .38-02 for the eighteen years at minima. The September values are AolB 

 ( + 48 per cent.) and 30-53 respectively; October, 49*61 ( + 39 per cent.) and 35-G2 

 inches. 



The relation is so regular from cycle to cycle that mere coincidence seems 

 improbable. 



The monthly and whole-year values were next sorted out for tbe six cycles, 

 according as they came in the first, second, third, &c., year of the cycle. Year I. 

 was taken for minimum solar activity (as shown by "Wolf and AVolfer"s sun-spot 

 values), and VI. for maximum, each cycle being reduced to a mean length of 

 eleven years. The whole-year results showed a strong minimum in II. and 

 maximum in VI., with a secondary maximum at III. practically equal. 



The three -bloiamed curve gives the minimum at I. and maximum at V. The 

 three autumn months again give tlie most striking monthly values, August being the 

 reverse of the other two. This, indeed, is very marked if the curves from year to year 

 are three-bloxamed, and the relation to solar activity is strikingly brought out by the 



three curves combined on the formula —A. Similar curves for — ~ — A 



for Aysgarth (Yorks) and Street (Somerset) also resemble that for York, the short 

 period at Aysgarth following the solar curve very closely. 



Combining the six cycles, we get for —^^ A at York, 1831-1904, a fo?i- 



tinuous curve. The minimum is —1-8 inches in I. ; the maximum + O'G inches in 



VI. to A'lII. A lag like this and tendency to hump at about IX. is not infrequent. 



London (from 1797), Exeter (1815, on), and Rothesay (1800) give similar 



curves for — ^— -A. The early Uppingham series (173G-98) give similar, 



though less accentuated, results. 



York rainy days (three-bloxamed) again correspond, but the mean temperature 

 is less certain ( -G 9° at II. to -9° at V., unbloxamed). 



Similar comparisons were made for Bruckner's thirty-five-year cycle. Starting 



from 1831 and 18GG, the solar activity curve, after eliminating the eleven-year 



cycle, showed a strong maximum in VI. (active years from II. to XIX.) and 



minimum at XXV. York rainfall values again indicate correspondences, with, 



h + 

 as a rule, excess of rain from II. to XIX. Again the curve for ——— —A is sug- 



gestively similar to that of solar activity. 



G. Some Barometric and Rainfall Changes of an Oscillatory Kature. 

 % William J. S. l.ocK\^^y M.A.,' Ph.D., F.K.A.S. 



This paper referred, in the first place, to the barometric changes taking place 

 in the earth's atmosphere of durations the length of which amounted to three or 

 nearly four years. 



The author pointed out the see-saw nature of these changes at opposite sides 



