278 



PROFESSOR C. PIAZZI SMYTH ON 



There are however some further deductions as to the annual cycle of Solar effects in 

 this country, which it may be worth while to allude to at this point, from Mr Heath's 

 peculiar Tables of Frost and Fire ; as thus, — 



(1) There are only two months in the year, July and August, when the exposed 

 temperature does not go down, on some one night or other, below 32° F., so that we may 

 say, Summer in Scotland lasts only 2 months. 



(2) But Winter lasts for 4 months, viz. December, January, February and March ; 

 the last named being specially the month of snow. 



(3) Spring lasts 3 months, viz. April, May and June ; and Autumn also for 3, viz. 

 September, October and November. 



(4) Or again it may be stated, that there is frost in the air of exposed places at night, 

 during the 6 first months of the year, and the last 4. Wherefore in the matter of frost, 



June pairs with September, 

 May with October, 

 April with November, 

 March with December, and 

 January with February ; 



these latter being the most frosty two, just as July and August are the least frosty two. 

 Not however the most fiery two ; for the occasional temporary heats in June, assisted by 

 the greater altitude then of the Sun ; — exceed those of August. 



(5) The actual numbers, nevertheless, may be more satisfactory to be perused; and 

 are given thus, together with the mean radiations by Black-bulbs every night ; and the 

 mean temperatures of the Shaded Thermometers, also on every night ; thus, but all in 

 terms of excesses below or above 32° F. 



"Frost" Returns, below or above 32° F. 





Jan. 



Feb. 



March. 



April. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Whole 

 Year. 



Radiation on one night pev 





























month 



-17-8 



-16-0 



-15-5 



-110 



-8-1 



- 17 



+ 2-1 



+ 0-8 



- 3-3 



-9-9 



-14-6 



-18-0 



-9-4 



Radiation on mean of all 





























the nights per month, . 



- 3-7 



- 2-8 



- 2-6 



+ 0-3 



+ 3-9 



+ 9-9 



+ 12-9 



+12-2 



+ 8-5 



+ 3-3 



- 1-8 



- 36 



+3-1 



Temperature, by shaded 





























thermometer on mean of 





























all the nights per month, 



+ 0-5 



+ 1-5 



+ 17 



+ 5-1 



+ 9-1 



+ 15-0 



+18-0 



+ 17-6 



+14-0 



+ 8-6 



+ 3-3 



+ 1-0 



+ 7-9 



"Fire" Returns, all above 32° F. 





Jan. 



Feb. 



March. 



April. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Whole 

 Year. 



Radiation on one day per 



month, .... 

 Radiation on mean of all 



the days, 

 Temperature, by shaded 



thermometer, on mean of 



all the days, . 



+34-0 

 +187 



+ 9-5 



+ 44-2 

 + 24-1 



+ 11-4 



+54-4 

 + 32-0 



+13-4 



+ 647 



+ 417 



+ 19-3 



+ 72-1 

 + 497 



+24-5 



+797 

 +581 



+30-6 



+80-6 

 +59-4 



+ 32-9 



+ 78-8 

 +56-9 



+32-0 



+ 71-8 

 +49 9 



+27-6 



+59-8 

 +36-4 



+20-5 



+ 43-1 

 +23-4 



+ 13-6 



+ 30-9 

 + 15-6 



+ 10-5 



+ 59-5 

 + 387 



+20-5 



