THE METEOBOLOGY OF EDINBURGH. 91 



thunderstorms, and fog, were distinctly below the average. Gales were slightly in 

 excess during the years of low pressure. 



1781 to 1800. — Pressure was above the mean till 1787, and then below the normal 

 as a whole. Temperature was low during the period of high barometer, but thereafter 

 much above the average. Speaking broadly, the temperature was below the normal from 

 October to March, and above it during the other half of the year, the exceptional warmth 

 of the summers being a striking feature. The unusual depression of temperature during 

 some of the Marches and the Decembers is also of interest, the cold being brought about 

 by the unusual excess of polar winds during these months. During most of the period 

 rainfall was in excess. There was a marked deficit of westerly winds till about 1794. 

 Snowstorms were frequent. Hail was just the average, and thunderstorms, gales, and 

 fog, very much below their normal frequency. 



1801 to 1820. — The weather of this period was characterised by a low barometer, a 

 low mean temperature, a deficiency of rainfall, and a marked deficiency of westerly 

 winds. Warm summers continued to prevail till about 1808, but thereafter the 

 depression of temperature manifested itself in a prominent degree throughout the 

 months and the seasons. In the heart of this great cold occurred some of the worst 

 harvests of the century. The outstanding feature of the meteorology of the period 

 under review was, however, the frequency of hyperborean storms of the first order, 

 these snowstorms being of a severity, extent, and duration which have not been 

 equalled since. Hail was above, but thunderstorms on the whole below, the average. 

 Gales were greatly above the normal, while fogs were rare, except from 1805 to 

 1811. 



1821 to 1840. — The characteristic features of this period were a rather high pressure, 

 normal rainfall, and excess of temperature. West winds were above the normal from 

 1820 to 1826 and from 1831 to 1836. Snowstorms show a decided excess from 1836 to 

 1840, during which time polar winds prevailed with a low temperature. Pressure was 

 also low, and rainfall above the average during the time. With regard to the non- 

 instrumental phenomena, hail, thunderstorms, gales, and fog, were all above their average 

 frequency. 



1840 to 1860. — Low pressure prevailed with a very high temperature and small 

 rainfall. The wet Junes and dry Aprils, Septembers, and Decembers, are striking 

 features of the meteorology of this period. West winds show a marked excess after 

 1848. Snow and hail storms were infrequent; thunderstorms about the average ; and 

 fog much in excess of the normal. Gales were of common occurrence till 1850. 



1861 to 1880. — Pressure was above the average with but few and unimportant 

 interruptions. Temperature was below the average from 1861 to 1866, and after 1876. 

 During most of the time cold summers prevailed, the winters on the whole being mild. 

 Rainfall was much above the average. West winds were greatly in excess during the 

 first cold period, but in defect during the second spell of low temperature. Snowstorms 

 were on the whole infrequent. Thunderstorms show an enormous excess after 1868 



