1890.] On Wind Pressure upon an Inclined Surface. 233 



One cubic inch of water (as above) = grains 252'286 + 0'002, 



of which grains the imperial pound (t = 02. b = 30 inches) contains 

 7,000. 



IV. " On Wind Pressure upon an Inclined Surface." By W. H. 

 DINES, B.A. Communicated by the Meteorological Council. 

 Keceived June 12, 1890. 



In accordance with a plan suggested in a memorandum drawn up 

 by Professor Darwin, I have made the following experiments upon 

 this subject, using for the purpose the large whirling machine of 

 56 feet diameter erected at Hersham. 



The apparatus was made by Mr. Munro, and the general arrange- 

 ment is shown in figs. 1, 2, and 3. 



Fig. 1 gives a view as seen from the point towards which the 

 pressure plate P is moving ; fig. 2 as seen from the centre of the 

 whirling machine ; and fig. 3 as seen from a point vertically above it. 



VOL. XLVIII. 



