button to main menu  British Rainfall 1867, p.19

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British Rainfall 1867 page 19
Determination of the ratio of the rainfall in each of 22 years to the mean of the whole period 1845 to 1866.

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I do not intend, on the present occasion, to print the falls in the whole 23 years at all stations, but simply the results obtained by means of the ratios in the last column. When the new gauges have been at work for a year or two, we may perhaps be able to discontinue the more difficultly accessible gauges, and review in detail the accuracy, or otherwise, of our present deductions.
It may be well to give in detail a specimen of the mode by which the approximate means have been obtained. The fall at Wastdale Head was as follows:-
in.in.in.
1845 ...108.551848 ...115.321851 ...97.94
1846 ...105.931849 ...107.221852 ...109.58
1847 ...96.341850 ...108.761853 ...83.39
Mean of these nine years, 103.67
By rerefence to the last column of the ratio table, it will be found that the mean ratio of those nine years was 102.9; that is to say, the rainfall in those years was 3 per cent. above the average. It only remains, therefore, to divide the mean observed fall by the mean ratio to deduce the approximate true mean, e.g. 103.67÷1.029=100 inches.
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