4:24 Sir Xonnan Lnrkyrr ami Dr. W. J. S I.urkyer. 



of solar temperature. Comparing them also with tin- Iloiul.ay ami 

 .Mauritius curves for the same period, it is found that the pulses in- 

 dicated at Bombay occur simultaneously with those pf 1*7* ami 

 luit in the case of Mauritius the effect of each of the pulses is felt about 

 a year or so earlier, namely, 1877 and 1882. 



The rainfall curve for Batavia for this period has its most prominent 

 maximum in the year 1882, like that of Mauritius, thus preceding by a 

 year the pulse felt at the Cape, Cordoba, and Bombay in 1883. 



Thf Time Conditions of the Pttl*>.<. 



The various curves which we have drawn for the purposes of study 

 have been compiled from yearly means, and so far, in these curves the 

 rainfall in months has not been considered. That will have to come 

 later. Hence if the rainfall which most influences the yearly mean 

 occurs in the last three months at one place, and in the first three 

 months of the next year at another, they are shown as being a year 

 apart, whereas they have actually been continuous. 



With regard to the travel of the pulses over large areas under the 

 influence of the 8.E. trade, it may be gathered from the pressure 

 charts that the + and - conditions of pressure are apt to lie over 

 the centres of land and water areas, and not generally over coast 

 lines. In the case of water surfaces, the effect of a sudden change in 

 the solar radiation on the pressure might be expected to be felt not at 

 the point where the pressure is least or greatest at the time, and of 

 the most general type, but where the equilibrium is most unstable. 

 On the other hand, more time would be required for the new pulse to 

 establish itself where the conditions are more complicated. 



Hence we should expect the pulses to be felt first in the eastern part 

 of the Southern Ocean, and this seems generally to be the case. Thus 

 after the mean solar temperature of 1876, the - pulse was felt first at 

 .Mauritius, then in India, and the Cape. After the mean of 1881, the 

 + pulse was felt first at Mauritius, then in India, and the Cape. Cor- 

 doba felt both pulses in the same year as India and the Cape. 



StibsitJuiry Pnlxe*. 



In a normal sun-spot curve we find a sharp rise, generally taking 

 three or three-and-a-half years, to maximum, and a slow decline to 

 minimum, on which the remaining years of the cycle are spent. 



The curve on the upward side rises generally regularly and con- 

 tinuously ; on the -down ward portion the regularity of the curve is 

 very often broken by a " hump " or sudden change of curvature. 

 There has not yet been a complete discussion of the number and 

 character of the prominences associated v/ith the spots during the cycle ; 



