200 MR ALEX. BUCHAN ON THE STORMS OF WIND WHICH OCCURRED 



Since storms generally travel to the N.E. at an average speed of about twenty 

 miles an hour, and since the distance of the S.W. of Ireland from any British 

 port does not exceed 500 miles, it follows that these storms might have been pre- 

 dicted at least twenty-four hours before their occurrence at the eastern seaports 

 of Great Britain ; and as their approach could have been foreseen some hours 

 before they burst upon the west of Ireland, they might have been predicted from 

 thirty-six to forty-eight hours beforehand. 



Comparison of the Barometric and Thermometric Lines. 



The observations of the thermometer do not equal in importance those of the 

 barometer, for this among other reasons, that while the barometer measures the 

 weight of the whole atmosphere pressing on it, the thermometer gives only the 

 temperature of that portion of the air which is in immediate contact with the 

 earth. There appears to be little apparent connection between these lines at first 

 sight ; for while the barometric lines approach more or less closely the curves of 

 the circle or the ellipse, the lines of equal thermometric disturbance present the 

 greatest possible irregularity of form. When, however, the attention is confined 

 to the region of greatest barometric disturbance, a remarkable connection is at 

 once observed. It will be seen that in all cases the temperature rose a few 

 degrees over the space toward which and over which the front part of the storm 

 was advancing, and fell at those places over which the front part of the storm 

 had already passed. In other words, the temperature rose as the barometer fell, 

 and fell as the barometer rose. Generally, the temperature in advance of the 

 storm was above the average, and in the rear of the storm below it. But if it 

 was considerably above the average in advance of the storm, it was still above 

 the average when the storm had passed, though lower than it was before. 



In one or two cases the temperature, after falling a little, rose in what ap- 

 peared to be the wake of a storm ; but in these cases the observations of the fol- 

 lowing day showed that another storm was advancing close upon the one already 

 past. The high temperature thus indicated the approach of the second storm, and 

 properly belonged to it. 



Observations of Rain and Cloud, 



We learn from the observations that as long as the barometer did not fall 

 below the mean, there was no continuous rain anywhere, but blue sky prevailed, 

 varied with partially clouded sky or with fog. But when the barometer fell, the 

 sky began to be obscured, and rain to fall at intervals ; and as the central de- 

 pression advanced, the rain became more general, heavy, and continuous. After 

 the centre of the storm had passed, or when the barometer had begun to rise, the 

 rain generally became less heavy, falling more in showers than continuously ; the 



