Mr Marshall's Meteorological Summary for ^ 828. 223 



few years. Thunder and lightning have oftener occurred 

 during the latter part of the year than is usual in winter. 

 Though it is only by simultaneous observations in different 

 parts of the globe, on a large and extensive scale, and by com- 

 paring these with each other, that great and important results 

 can be obtained, and fresh discoveries made in the imperfectly 

 developed science of meteorology, yet more humble efforts^ 

 confined to particular districts, are requisite to confirm and 

 establish them. Such labours are, therefore, needful and de- 

 cidedly auxiliary to forming the great outline, which every one 

 conversant in this science acknowledges to be a desideratum. 

 To decide on the causes which produce certain atmospheric 

 phenomena that are regularly occurring in any particular dis- 

 trict, has yet been imperfectly obtained ; and yet that they 

 depend on general principles, capable of producing those phe- 

 nomena, can hardly be denied. It is to be regretted that few 

 are willing to undertake the labour requisite for obtaining this 

 local information, and without which, the deductions derived 

 from more extended observations would be incomplete. 



I shall attempt in this paper, to make a comparison of the 

 weight of the atmosphere at different times of the year, for the 

 last six years, in which I have kept a regular register of the 

 weather, — point out the months in which the greatest and least 

 quantities of rain have been taken, &c. by which certain infe- 

 rences may be drawn of the meteorological facts of the dis- 

 strict. It is requisite, however, to state, that the situation in 

 which these observations have been taken is about forty-two 

 yards above the level of the sea ; that the time of registering 

 the daily observations is nine o'clock, a. m. ; and that the quan- 

 tity of rain which has fallen within the preceding twenty-four 

 hours (if any) is registered daily at that time. The mean 

 height of the barometer for 1828, is the exact average of the 

 last six years, including the year 1828^ The greatest height 

 which the barometer attained was on the 16th of September 

 and the 29th of October, 30.40 inches, in both which instan- 

 ces remarkably fine clear weather had preceded and followed, 

 though in September it was rather succeeded by fine weather, 

 than preceded by it, as before that date we had heavy rain, till 

 within two days of its having attained its greatest altitude. 



