172 



Mr. Hinds on Climate in connexion 



heat. From observations on two occasions, I found the mean 

 to be 81°-9; and as this result was obtained at sea and under 

 unexceptionable circumstances, it tends strongly to support 

 the opinion of Humboldt and Forbes. Within the tropics 

 the mean temperature is everywhere very similar, distance 

 from the equator exerting a very feeble influence. After 

 passing their limits, latitude is of greater importance, and the 

 decrease more rapid. If implicit confidence can be piaced in 

 the details of the calculated table of Sir John Leslie, the mean 

 temperature varies most with the parallel, between the thir- 

 tieth and fiftieth degrees. Though this table cannot be relied 

 on for ascertaining the mean of any given place, it is yet highly 

 useful in showing its value in any situations removed from 

 disturbing causes ; and we discover the importance of these 

 last in the difference between the observed and the calculated 

 result. 



If some difficulty has been experienced in fixing the mean 

 temperature at the equator, we are much more at a loss at the 

 poles. No navigator has ever yet made, or perhaps ever will 

 have it in his power to make, a conclusive series of observations 

 to establish the point. Conjectures, drawn from observed tem- 

 peratures in lower latitudes, are all we possess at present, and 

 these are at great variance. Sir John Leslie considers it to 

 be 32°, or the freezing point of water ; Kirwan places it a 

 degree less ; Mr. Atkinson, w T ho seems partial to extremes, at 

 10°*53 below the zero of Fahrenheit. Inferring its amount 

 from the temperature of the old world, it appears likely to be 

 about 10°; whilst corresponding inductions from the new 

 world place it considerably below zero. M. Arago has given 

 the subject his attention, and after comparing the observations 

 of Parry, Franklin, and Scoresby, he fixes it at 13°. Here, 

 then, we have various opinions, which state a set of means 

 having a range of forty-two degrees and a half. Among such 

 conflicting statements every one will desire to judge for him- 

 self; and the following observations, the first by Franklin, 

 and the others by Parry, may be of some assistance. They 

 may be considered as intervals of five degrees : — 



Fort Enterprise Lat. N. 64^° Mean temp. 15°*5 



Igloolik ... 69^ 7 



Melville Island . . . 74f -1-5 



It is not unlikely that Sir Edward Parry at Melville Island 

 had attained the greatest depression of temperature, and that 

 had he even been able to reach the pole, the alteration, if any, 

 would have been exceedingly trifling, the arctic regions, like 

 the tropics, through their extent, most probably offering no 

 great variations. Recently an opinion has been advanced^ 



