358 Mr. J. Glaisher's Remarks on the Weather 



epidemic complaint. This disease has been fatal during the 

 last quarter to a great number of persons. The number of 

 deaths in London and in its vicinity, according to the weekly 

 Reports of the Registrar-General, exceeded the average num- 

 ber of deaths in July by 2515, in August by 4464, and in 

 September by 4322, out of a population of 2,206,076 ; a mor- 

 tality unprecedentedly great. 



I have no means of judging of the amount of illness, but it 

 must have been great. 



If epidemics be due to atmospheric causes acting upon local 

 circumstances, it is to the successful cultivation of medical 

 meteorology that we can hope to contend with them with 

 success. 



Those causes of sickness which depend upon temperature, 

 humidity, pressure or movement of the air, admit of measure- 

 ment; and it must be considered as a most valuable circum- 

 stance, that nearly forty educated gentlemen — known and 

 trustworthy observers, with good instruments — were daily 

 engaged, long before the epidemic came, in collecting this in- 

 formation. Without this organization our knowledge of the 

 meteorological particulars of the period would have been as 

 deficient as it is of the year 1832, when the cholera was before 

 prevalent. 



The results thus collected may now be compared with those 

 of former years, as far as the previous years will furnish the 

 materials of comparison, with those for instance when epi- 

 demics prevailed, as in 1832, and with those of non-epidemic 

 years, as in 1842, a year which was unusually free from epi- 

 demic diseases. Those gentlemen who may wish to investigate 

 the connexion which may have existed between the sickness 

 and mortality of the seasons, with their meteorological parti- 

 culars, will find the monthly values of the subjects of meteor- 

 ological research in the Quarterly Reports of the Registrar- 

 General, with the names of the gentlemen who have furnished 

 the observations; and most of those gentlemen would be 

 happy to furnish detailed copies from their registers for short 

 periods to any gentleman who would use them in connexion 

 with sickness or mortality. 



The quarterly meteorological returns for the past quarter, 

 furnished to the Registrar-General and myself^ have been 

 received from thirty-eight different places, whose returns have 

 been found on examination to be good. These have all been 

 examined and reduced by myself. 



At Greenwich the mean daily temperatures of the air from 

 July 1 to July 17 were above their average values; the mean 

 excess was 3°*2. From July 18 to August 5 they were below 



