ON THE RAINFALL OF THK BRITISH ISLES. 173 



l-ith ; the fall in 24 hours exceeded 1 inch at 252 stations, 2 inches at 109, 

 3 inches at 39, 4 inches at 7, and 5 inches at 3 stations. 



Ncv) Irish Stations.— We reported last year the success of our efforts to 

 improve the geographical distribution of Rainfall Stations in Ireland, showed 

 that ihe gauges started at the cost of the Association had been supplemented 

 by many others established at the cost of private individuals, and gave a map 

 showing the present complete distribution of stations. Almost all the ob- 

 servers have proved good ones, and, as the table shows, the returns have 

 been forwarded with regularity. The period is too short to yield precise 

 results, but a good system has been inaugurated and is in full operation. 



At the commencement of this report it was stated that there was one very 

 important exception to the otherwise satisfactory completion of the work up 

 to the present time. This exception is the classilied list of stations, and the 

 results of the " position-returns " which we intended to have incorporated 

 therewith. In 1865 we published a complete list of every station in the 

 British Isles at which rainfall observations were known to have been made, 

 giving the observei-s' names, the height of the stations above mean sea-level, 

 the epoch of the observations, and various other details. Owing to the large 

 development of rainfall work during the subsequent 10 years, the list has 

 become very imperfect, and the Committee have been actively engaged in the 

 preparation of a revised list. In addition to the details previously given, the 

 list was also to have contained other most valuable information. The 

 "position-returns" obtained from the various stations, and which have been 

 mentioned in previous reports, were to have been summarized, and the results 

 indicated by symbols affixed to the stations in the classified list, and references 

 to publications in which the records could be found were also to have been 

 added. The classified list of stations would thus have formed a complete 

 catalogue raisonne of all the existing rainfall data, and have given most 

 useful information at present non-existent. To the great regret of the Com- 

 mittee, the Association declined to publish the portion of this list presented 

 last year, and the Committee have therefore felt compelled to relinquish its 

 completion. They the more deeply regret this, as they consider that the 

 publication of this list would have been a fitting termination of their work, 

 and would have redounded to the credit of the Association. 



Notwithstanding the above most important omission, the Committee feel 

 they have done good service to rainfall work. When they commenced their 

 labours, the weakest part of rainfall observations was the defective geographi- 

 cal distribution of the stations. This defect has now been very materially 

 lessened. By the grants of the Association nearly 250 gauges have been 

 erected in districts hitherto without observations. The work done in the inspec- 

 tion of stations has already been mentioned. A definite unit has been adopted 

 for the term " rainy day," namely, any day on which one 100th of an inch of 

 rain falls. A complete code of rules has been drawn up, so as to secure uni- 

 formity of practice among observers. The secular variation of the rainfall of 

 the British Isles has been investigated. A determination of the average 

 proportion of the total yearly rainfall which occurs in each month has 

 been effected. Elaborate observations have been made and discussed on the 

 relative quantity of rain indicated by gauges of various sizes and shapes, and 

 erected at different heights above the ground. 



To sum up their labours in a sentence, your Committee have aimed — they 

 hope not without success — primarily at obtaining unimpeachable records ; 

 and, secondarily, at so discussing and arranging these records as to render 

 them as useful as possible to physical inquirers and hydraulic engiiieers. 



