114 On the Horary Oscillations of the Barometer at Rome. 



lar to separate the small diurnal changes from the mass of 

 adventitious variations of pressure which we experience in the 

 temperate zone. I afterwards noticed that some additional 

 results, included with the rest by rather a circuitous operation, 

 (with a view of enabling me to include the whole of my obser- 

 vations) appeared to increase these discrepancies ; I shall there- 

 fore give the results obtained both with and without these sup- 

 plementary numbers ; but more of this when we come to the 

 table of final reductions. 



When I found that my computations did not produce such 

 clear results as I had hoped, I was tempted to relinquish the 

 idea of ever presenting them to the public ; and I may be al- 

 lowed to state, in a few words, why I now hazard them for 

 insertion in this Journal, "[st, then, from the very imperfec- 

 tions of this branch of science, and the discrepancies which 

 evfery where occur in the best journals of barometrical oscilla- 

 tions in the more northern latitudes, I am bold enough to 

 hope that these observations as they stand may add a faint 

 glimmering to the weak light already thrown upon this phe- 

 nomenon. Sc?, No observations have, I believe, been yet 

 made in Italy with a view of elucidating this point, and there 

 are no results from the latitude of Rome, or in any part of 

 Italy in Humboldt''s table. 3g^, Though I cannot pretend to 

 determine to a nicety the hours of maximum and minimum, 

 and to trace the precise progress of oscillation from hour to 

 hour, yet a general idea will easily be obtained on both these 

 points, and the range of variation be the same within a 

 minute fraction of what we should have inferred it to be 

 from independent observations. Lastly^ I am in hopes that 

 this memoir may stimulate to exertion travelling and other 

 meteorologists in this department of their study, than which 

 none requires more continued exertion and minute accura^ 

 cy ; and to such as have time and inclination I trust that 

 my type of calculation and reductions may serve as a guide in 

 treating their observations in that rigorous manner which 

 is so highly desirable * It will now be proper to make a few 



• I am encouraged to express the latter hope, from observing how 

 deeply Mr Daniell recommends a very studious attention in this parlicu- 

 lar. '' Let tlie meteorologist/' says he, " be assured, that it is only by the 

 same painful care to minutia; that his own favourite science can ever ue 



