I NT ROD UCTION. 



perature as well as to 42° F., with the slight modification of the numerical 

 coefficients mentioned in the last rule. 



Rules for Computing the Accumulated Temperature above or below 

 42° F. from the observed Maximum and Minimum. 



1. Multiply the dl£ference between the maximum and minimum by the proper co- 

 efficient for the month shown in Section 11. {see aiove), and the result will be the differ- 

 ence between the mean temperature for the day and the minimum. 



2. Then the accumulated temperature will be obtained as follows : 



3. The quantities thus obtained must be multiplied by the number of days in the 

 period, that is by 7 for a weekly period. 



4. If the base temperature be 32° F. or 42° F., the multiplier in Rule 2 for a weekly 

 period is four-tenths ; if 52° F. it is 0-33 ; if 62° F. it is 0-25. 



A full explanation oftliese rules will be found in Appendix II. to tlie Quarterly 

 Weather Report for 1878. 



Accumulated rainfall. Local variations in climate are very largely de- 

 pendent on differences of rainfall. A striking example of this is found in 

 Skye on the west and the Laigh of Moray on the east coast of Scotland 

 at a distance of 70 or 80 miles apart, but in the same latitude. The mean 

 temperature of these two regions in no month of the year differs so much 

 as two degrees, and for several of the months they are nearly identical 



