562 



FOURTH REPORT — 1834. 



On comparing these ratios with those obtained in 1832, it is 

 impossible not to be struck with their wintry character, which 

 agrees with the fact of the months of February, March, April, 

 October, November, and December, being almost diurnally 

 rainy. In 1832-3 the greatest part of the rain fell in the warm 

 months; but in 1833-$ the cold months were most rainy. In 

 1832-3 the mean diminution of rain was 



on the Minster id) 33*9 per cent. 



and on the Museum {d') . . . 14*7 

 but in 1833—4 these numbers were, 



41-8 

 22-8 

 In 1832-3 the mean annual value of the function of the height 

 was h'^", — in 1833-4 it was h '*^. By uniting the observa- 

 tions of thirty months, (to August 30, 1834,) h'^^. 



It is hence very apparent that a few years' observations will 

 give this mean value very accurately, determine the limits of its 

 variation, and the dependence of this upon the monthly tem- 

 perature and other causes. I shall, however, purposely abstain 

 from discussing the subject any further at present, because the 

 experiments will be continued under the present arrangement 

 six months longer, and thus any conclusions which may be 

 offered rendered more trustworthy. Besides, I do not wholly 

 despair of being furnished with some aid from other observers 

 in different regions and under various circumstances, for I am 

 far from thinking that all the conditions of this curious problem 

 can be determined at one locality, however favourably situated*. 



• My friend Mr. W. D. Littledale has established three gauges at Bolton-Hall, 

 in Craven, and Mr. A. Halliday has obliged me by undertaking a similar labour 

 at Manchester. 



I 



