590 DR A. LOCKHART GILLESPIE ON 



for the seven years, and did not show any marked diurnal variations. Throughout the 

 course of the epidemic the type continued to be almost exclusively cyclonic, with a 

 heavy rainfall, a high temperature, and a great deficiency of sunshine. The four weeks 

 immediately following were also chiefly cyclonic, but with a smaller precipitation. The 

 wind throughout was westerly, except during the last week of the epidemic and the next 

 two, when it was from the east. (The actual figures for these statements will be found 

 in Table V.) 



2. The summer epidemic of 1891, from 13th April to 11th July, followed a fine 

 winter and spring, during which anticyclonic conditions were largely prevalent. Anti- 

 cyclones reigned supreme from the middle of November to the end of February, 

 practically without a break. The extremes of temperature were widely separated from 

 each other, and the rainfall was small. In March barometric depressions from the 

 Atlantic governed the type of weather, with an increased rainfall. It was during this 

 weather that the respiratory cases in the Infirmary began to increase, but it was not 

 until the type again changed to the anticyclonic that the epidemic could be said to have 

 commenced. A study of the figures for the six weeks preceding shows that the rainfall 

 was above the normal, the temperature low, and the percentage of sunshine small. 

 When the epidemic began, the type was anticyclonic. While the epidemic lasted the 

 type remained largely anticyclonic, or with small local cyclones, the rainfall was not 

 excessive, and the sunshine plentiful. During the last two weeks the rainfall became 

 very heavy, and continued so for the four following weeks, with cyclonic weather and 

 west winds. The temperature throughout remained high. In this case, then, the 

 epidemic was preceded by wet weather and a low barometer, took place in dry weather 

 (if the last two weeks be missed out, when the attack was declining), and was followed 

 by wet, cyclonic weather in its turn. 



3. The great winter epidemic of 1891-92 (25th October to 13th February) followed 

 an extremely wet and broken autumn. September and October were particularly wet, 

 though not cold, while the chief type of weather was cyclonic. If the figures for the 

 six weeks preceding this epidemic be consulted, it will be seen that their mean rainfall 

 was nearly an inch and a half, and the weather cyclonic throughout. The maximum 

 temperatures registered during these weeks were above 60°. Simultaneously with the 

 establishment of an anticyclone, with east wind, practically no rain, and a diminution 

 in the temperature, the epidemic commenced. The anticyclone only lasted for two 

 weeks, and during the rest of the epidemic the type was mainly cyclonic. The rainfall 

 and amount of sunshine registered varied very markedly, but had no influence on the 

 course of the disease. The maximum thermometer never rose above 60°, while the 

 minima on several occasions fell below 10°. As the epidemic subsided the weather 

 changed its character, not so much in its type, which was very variable, as in the 

 diminished rainfall and the presence of great extremes in the temperature. The advent 

 of warmer weather and more equable days saw the disappearance of the epidemic. A 

 long period of cyclonic conditions, extending over ten weeks, in the autumn of the 



