538 Royal Society. 



various tabular results deduced from the meteorological observations, 

 reserving for future notice those deduced from the magnetical series. 

 His chief object has been to determine the corrections which are 

 applicable to the results obtained by different observers at various 

 times, so as to render them comparable with one another. The 

 barometrical and thermometrical observations here recorded have 

 been made at every hour of Gottingen mean solar time, during the 

 whole of five years, namely, from the end of 1840 to that of 1845. 

 The mean of each hour represents the results deduced from about 

 150 observations; those for each month represent about 1800 ob- 

 servations ; and those for the year represent upwards of 21,000 ob- 

 servations of each element. 



Tables are given representing the excess of the mean value of each 

 element at every hour of observation, in every month, above the mean 

 value for the month; and also the mean of the numbers so found, 

 arranged for the different years, and likewise for the same hours in 

 every month. The numbers were then laid down on paper, as ordi- 

 nates to a curve of which the times were the abscissae, and a curve 

 passed through, or very near each point ; and the ordinates at every 

 Greenwich hour were measured from that curve, and their values 

 given in a table. The accordance of the results thus obtained for 

 the same hours in the same months of the different years is very 

 close and satisfactory ; and shows that observers may obtain very 

 valuable approximate results, by taking a comparatively small num- 

 ber of observations in each day at hours by no means inconvenient 

 in ordinary life, furnishing a close apjjroximation to the mean and 

 extreme values, as well as to the diurnal and annual variations of 

 atmospherical phenomena. 



March 9 and 16. — " Report of Experiments made on the Tides in 

 the Irish Sea ; on the similarity of the Tidal phenomena of the Irish 

 and English Channels ; and on the importance of extending the ex- 

 periments round the Land's-End and up the English Channel." 

 Embodied in a letter to the Hydrograj)her, by Captain F. W. 

 Beechey, R.N., F.R.S. Communicated by G. B. Airy, Esq.,F.R.S., 

 Astronomer Royal. 



The author commences by stating, that the set of the tides in the 

 Irish Sea had always been misunderstood, owing to the disposition 

 to associate the turn of the stream with the rise and fall of the water 

 on the shore. This misaj)prehension, in a channel varying so much 

 in its times of high water, could not fail to produce much mischief ; 

 and to this cause may be ascribed, in all probability, a large proportion 

 of the wrecks in Caernarvon Bay. 



The present inquiry has dispelled these errors, and has furnished 

 science with some new and interesting facts. It has shown that, 

 notwithstanding the variety of times of high water, the turn of the 

 stream throughout the north and south Channels occurs at the same 

 hour, and that this time happens to coincide with the times of high 

 and low water at Morecombe Bay, a place remarkable as being the 

 spot where the streams coming round the opposite extremities of 

 Ireland finally unite. These experiments, taken in connexion with 



