Cisoussion.The AUTHOR remarked that he wished to take the opportunity n e Bnthor.of cxpressing his gratitude to the Bridge House Estates Committee of the City of London, who had sanctioned the use of the Tower Bridge for the experiments described, and also to thank Mr. John Class, M.Inst.C.E., the engineer, who had given all possible facilities for carrying out the work.Committee and Mr. Gass would appreciate the Author's remarks. It might be of interest t.0 recall that in the discussion on Dr. Stanton's first communication on Wind-Pressure, ' Sir Benjamin Baker asked how it was that windows did not, get blown in by high winds. Sir Benjamin determined the breaking point of ordinary glass windows by inserting a window in the bottom of a water-tank, which was gradually filled with water until the window failed ; and he estimated that ordinary windows would not bear a heavier pressure, on the average, than 30 lbs. per square foot.seemed to be no doubt of the persistence, without appreciable decay, of a definite gust of high intensity between the extreme stations, which were about 14 miles apart. That was somewhat contrary to meteorological views on the stmcture of gusts. In the first place, he would like t o explain the difference between what' was called a gust and what was called a squall. Referring to the Kew anemometer record shown in Figs. 13, Plate 1, during t h first hour of that record the wind was gusty ; the mean vclocity was about 25 miles per hour, but the record fluctuated within wide limits above and below that line. Each excursion mas of the order of about 1 minute in duration.Those excursions were termed gusts. A t 2.45 p m . the mean wind-velocity rose from 25 to 35 miles per hour. That rise, which lasted for 5 or 10 minutes, was called a squall and its nature was fundamentally different from that of a gust, A gust was almost certainly due to the obstruction of that part of the air which passed over objec,ts on the surface of the earth, such as trees and buildings. The certainty of that statement arose from the fact that the wind was much less gusty over the sea, where there were no obstructions, than over the land, and was also less gusty over fla.t, The PRESIDENT said he was sure the Bridge Housc Estates TIIC rre.;llirllt.Nr. J. S. DINES remarked that on p. 137 it was stated that, there 31r. Dines.
