544 Intelligence and Miscellaneous Articles. 



The final result takes the form — 

 Mean annual temperature 



=A-((e + «)±(a 1 cosw + /3 1 sinoi)e), (1) 



where 



h — constant, 



6 = mean annual temperature of place, 

 a = " control"* temperature of atmosphere at place. 



a t and /3, are defined by the following equations : — 



2Va 1 a +/3 1 2 == range of annual temperature ; 



/3j _ f tangent of the arc which represents the retarda- 

 ^~ ' \ tion of the maximum and minimum temperature ; 



u> a longitude of earth's perihelion ; 



e = eccentricity of earth's orbit. 



Using Ferrel's temperature-tables, Dr. Haughton finds the fol- 

 lowing maximum secular ranges of mean annual temperature : — 



Maximum Secular Range. 

 T j., ,. Northern Southern 



hemisphere. hemisphere. 



0° 0-185 F. 6-185 F. 



10 0-375 „ 0-585 „ 



20 1-100 „ 0-875 „ 



30 2-065 „ 1-110 „ 



40 2-750 „ 0-985 „ 



50 . 3-685 „ 0-710 „ 



60 4-610 „ 0-540 „ 



70 4-985 „ 



80 4-925 „ 



This table shows that the average maximum effect of the astro- 

 nomical causes involved in perihelion longitude and eccentricity 

 never can exceed 5° F. in the northern hemisphere, and barely ex- 

 ceeds 1° F. in the southern. At particular localities, where there 

 is a great range of annual temperature, the effect may be somewhat 

 greater. For example, at North Grrinnell Land the range becomes 

 6°-5 F. It will be seen how little benefit this would confer upon 

 that locality, when it is remembered that the present mean annual 

 temperature of North Grrinnell Land is 2°-42 F. below zero, and 

 that, by the secular range it could be raised to Ot 21 F. above zero, 

 or depressed to 6 0, 29 below zero. 



At Discovery Harbour, Tertiary plant-beds were found by the 

 Arctic explorers, which indicate a July temperature greater than 

 63°-7 F. ; the present July temperature of Discovery Harbour is 

 37°*2 F. above zero, or only Jive degrees above the freezing-point of 

 water. How is this remarkable change in climate to be accounted 

 for ? Geologists cannot much longer evade answering such ques- 

 tions as these. 



* By this is meant the temperature of the upper layers of the atmo- 

 sphere of place, which controls the radiation ; this temperature varies 

 with the latitude, and is probably always below zero Fahrenheit. 



