Beport on Temperature and Rainfall. 



88 



and it was thought that the position of the instrument, on the 

 top of a bank about 9 feet high, might account for it. The 

 observer therefore established a second gauge at the foot of the 

 bank some 20 feet from the old one, and registered the rain 

 by both gauges. The result was, that in 1885 the amount 

 collected by the new gauge was between 5 and 6 per cent, 

 greater than by the old. In this case the bank faced S.S.W, ; 

 and there can be no doubt that, in a driving rain from the south- 

 west, the up -draft of air caused by the bank carried some of the 

 ram over and past the mouth of the old gauge without its 

 entering it. 



Simple and easy as it may seem to find the true rainfall for 

 any place, it is not always so in practice. The gauge may be 

 perfect, the observer most careful, and yet after aU the record 

 may be misleading. It is sometimes impossible to secure perfect 

 exposure with adequate protection for the instrument. Again, 

 the growth of trees may so influence local currents of air as to 

 cause a greater or a less amount of rain to be collected on any 

 one spot near them, although there has been no alteration in the 

 total amount, only a different distribution. Some such causes 

 seem to have been in operation in one or two cases, in con- 

 sequence of which the returns have been excluded from the 

 tables of selected stations. 



The fall of rain was under the average if the 45-year mean at 

 Greenwich be accepted as a standard for the district ; for from 

 1841 to 1885 inclusive it was 24-67 mches, and from 1881 to 

 1885 only 22-97 inches. The annual rainfall of the twenty-one 

 selected stations collectively was as under : — 



Mean 27.02 



The chief point for remark here is the great deficiency of rain 

 in 1884. 



The grouping of the stations into zones in the latter tables 

 brings out some very interesting results. 



Taking the groups successively and representing the rainfall 



