42 



of its readings, to remark, after any unusual rise or fall in the mercurial 

 column, that they never before saw "the glass" so high, or so low, as the 

 case may be. It is therefore, perhaps, worthy of note, that the highest 

 reading in the 15 years occured on the 6th March, 1874, and was 

 30.834 inches; and the lowest on the 19th January, 1873, when it was 

 28.176 inches; the range for the period thus being 2-658 inches (a little 

 over 2}^ inches). 



Comparing one year with another, the greatest difference in mean 

 pressure occured on two consecutive years, 187 1 and 1872, when there 

 was an average of rather more than ^^ inch between them ("274 inch ) 

 These two years were also, as will be seen, remarkable in another respect, 

 as being the driest and the wettest years of the period of observation. 



I may add for the information of any one who may wish to compare 

 my results with his own, that all the readings have been corrected for 

 index error, capillarity and temperature, and reduced to the mean sea 

 level. 



Table I. 

 BAROMETRIC SUMMARIES. 



