732 REPORT— 1902. 



5. An All-stations Exj^ress Train. By J. Brown, F.R.S. 



The working model exhibited illustrated the automatic working, by means 

 of appropriate self-acting switches and couplings, of the scheme for an electric 

 railway described in the ' Journal of the Institute of Electrical Engineers,' 

 vol. XXX., part 148 (1901), together with a newly added protective signalling 

 device indicating to the driver in a car following another car, which it is about to 

 pick up, the distance between such cars. This consists of a resistance fixed along 

 the side of the track in contact with brushes or sliders on the cars. The brush 

 on the car in advance is joined, say, to the positive of the main electric supply ; 

 that on the following car to the negative. The current consequently flowing 

 through the resistance, being inversely proportional to the distance between the 

 cars, may indicate this distance on appropriate instruments under the driver's eye 

 in each car. 



6. The Rainfall of Ireland. 

 By Hugh Robert Mill, D.Sc, LL.D., F.R.S.E. 



In order to determine the true mean annual rainfall of any region it is neces- 

 sary to have uniform, continuous, and prolonged observations at a large number 

 of well-distributed stations. 



It is now possible for the first time to give a fairly satisfactory account of 

 Irish rainfall, though the observing stations at work are only one for every 

 170 square miles as compared with one for every twenty square miles in England, 

 The number of stations in Ireland has increased from 83 in 1874 to 190 in 1901, 

 an increase of 140 per cent. ; while the number of stations in England and Wales 

 increased only by 120 per cent., and in Scotland only by 32 per cent., in the same 

 period. In 1874 there was not a single record of rainfall from the counties of 

 Clare, Kildare, Leitrim, Limerick, Longford, or Monaghan ; now there is at least 

 one rain record from every county. The number of stations is still far too small, 

 especially in Connaught ; and after the stimulus of the British Association in 

 Belfast produced its eftect in 1875 the number in Ulster ha.s ceased to grow: — 



While 1,400 additional stations would be necessary to place Ireland on the same 

 footing as an equal area of England, only 185 additional observers are required to 

 give the same number of rain-gauges per thousand of population. 



Perfect records for the ten years 1890-99 exist for 108 stations in Ireland, and 

 by computation thirty-one additional records can be made available. Of these 

 twenty-one records are perfect for the thirty years 1870-99, and fifty-six records 

 of somewhat shorter duration can be computed with reasonable accuracj'. The 

 distribution is not satisfactory, the western half of the country and all the moun- 

 tainous districts being very poorly represented. Maps have been constructed, 

 however, which give a better representation of Irish rainfall than anything pre- 

 viously compiled. 



The map for the thirty years 1870-99 may be taken as showing the true mean 

 fall so far as the limited number of stations makes it possible to do so. There are 

 only three small areas with a fall exceeding 50 inches per annum in the west of 

 Kerry, of Mayo and Galway, and of Donegal respectively. Possibly some parts 

 of the eastern mountains may also have a fall exceeding 50 inches. More than 



