218 
depression of the Thermometer ;* as, on the other hand, there 
may be a rapid rise of temperature from a sudden change of wind 
bringing in a south-westerly current next the earth to take the 
place of a north or north-easterly one. But the Tables in question 
have reference rather to those interchanges of the day and night 
temperatures, which though regular and of general occurrence are 
so much more marked in some localities than others. Where the 
contrast between day and night is very great it is much felt by 
invalids, and is prejudicial to health in many ways ; where it is 
within moderate limits there is much less risk incurred by 
exposure to the outward air. Just as in a house, if we pass from 
a heated room to one that is much colder we feel the discomfort 
immediately, whereas if the whole house be warmed, though not 
to the extent of the particular room from which we come, we 
move about with less inconvenience. Indeed it has been 
thought that the rate of mortality is largely determined by the 
range of temperature of a climate. 
TABLE V. Showing the Mean Daily Range of Temperature taken from the 
mean of all the Maxima, and the mean of all the Minima, of each month. 
Jan. | Feb. | Mar. | April} May | June} July | Aug. | Sept.| Oct. | Nov. | Dec. | Means. 
— | | | | | 
ES ed ee ee ee 
1866 | 10.0 | 11.4 | 12.2 | 14.0 | 19.3 | 17.0 | 16.2 | 14.2 | xx.2 | r1.0 | 12.8 | 13.1 | 13.4 
1867 | 11.8 9-5 | 10.4 | rr. | 15.8 | 16.5 | 16.4 | 15.9 | 15.1 | 13-4 | 13.9 | 11.0 | 13.4 
Monthly} 9.6 | x0.0 | 12.7 | 16.x | 17.6 | 17.4 | 17.8 | 16.7 | 15.0 | 13-7 | 11.5 | 10.0 | x4.0 
*Professor Loomis mentions, in Silliman’s Journal, for July last (1875), an 
instance of a fall of temperature of 48° im one hour, at Denver, which, he 
conceives, could not have been produced otherwise than by some displacement 
of the air in a vertical direction.—(‘“‘The Academy,” Oct. 2, 1875, p. 362.) 
a 
okie ata 
