METEOROLOGY. 



297 



4. A simple cyliudrical gan![>e 25.2 aperture, or /„ .square meter, 

 wliicb, of course, liaviug uo conical surface, vsliould give results free from 

 any error the latter mny introduce. 



This latter proved wholly unreliable in drifting snow ; the comparison, 

 tUereibre, between these as snow-gauges was given up for the present, 

 but as regards rainfall during the summer months the following results 

 are expressed in percentage of the catch given by No. 1, namely: Xo. 1, 

 100; No. 2, 97.5; No. 3, 95 ; Iso. 4, 99. The small catch of No. 3 may be 

 due partly to the general poor results given by small apertures, but if pre- 

 vious hypotheses were correct must also be partly due to the increased 

 ratio between the inclined conical surface and the aperture of the gauge. 

 These two results, however, suggest that so far as the heavier rainfall of 

 the year is concerned one need not be very anxious about the instruments, 

 provided they are not too small ; the more important question will be as 

 to the proper exposure of the gauges and radical difl'erences in the struct- 

 ure or shapes of the gauges. At Munich th^ gauges of the Central 

 Meteorological Station, and that at the Observatory of Bogenhausen 

 2.7 kilometers apart, on the average of several years, with comparable 

 instruments of this same pattern, show that 8.6 per cent, less precipita- 

 tion fell on the right than on the left bank of the river Isar, while for a 

 period of nine months of special comparative observations 10 per cent, 

 less fell on the right than on the left side. Si)ecial observations are now 

 being made in this region at three other stations, namely, on the roof 

 of one of the public buildings of the city and on the grounds of two of 

 the observatory buildings. The differences between the records are such 

 that at least live stations would seem necessary if we would have a cor- 

 rect result as to the distribution of rain over a spnce of one English mile 

 s(iuare, or at the rate of 3,500 stations for one division of Bavaria. We 

 must conclude, then, that meteorology will profit least of all by the ordi- 

 nary rainfall measurements, although for hydrography and engineering 

 they are very important. (Z). M. Z., i, j). 431.) 



145. G. J. Symons, in the British Rainfall for 1880, gives a collation 

 of results as to the effect of elevation above the ground u})ou the quan- 

 tity of rain caught by the rain-gauge. The following table shows the 

 percentage of the upper gauge as compared with the amount caught by 

 a aauge at the surface of the ground : 



