35 



ture of the j'ear mny be not far from — 5° Centigrade, 

 equivalent to 23° Fahrenheit. It cannot possibly l)e so 

 hio-h as the zero isotlicrnial lino Centiurade. For the 

 year, that of Montreal is 40° ; and the isothermal line of 

 45° passes a little south of Mount Washington, while the 

 summit enjoys the climate of southern Greenland. 



The highest observed temperature was 66'^ ; and the 

 lowest reliable reading of the mercurial thermometer was 

 — 54°. On the 5th of February at 3 o'clock in the morn- 

 ing the reading was — 59.° That it should read correctly 

 at — 54° may be questioned. The freezing point of mer- 

 cury is not yet well established. Dr. Kane says that 

 "thermometers correct at — 40° and agreeing would show 

 a difference of 15° or 20° at —60°." So it was found by 

 Sir James Ross at Leopold Harbor. Nor does Dr. Kane 

 regard "the contraction of colored alcohol at very low 

 temperatures, as sufficiently investigated to enable us to 

 arrive at the cause or quantity of error." "The freezing 

 point of mercury varied" with him "from between — 38.5° 

 and 41.5°." Sir Edward Belcher obtained results where 

 the mercury descended as low as — 44°. Our thermom- 

 eters were the Smithsonian standard in the winter, and 

 later tiie standard instrument made by James Green, of 

 New York — all excellent instruments. In the case under 

 consideration the fall to — 54° was gradual ; but this is 

 admitted to be no proof that the fall was not due to the 

 contraction of the mercury after it became solid, as this 

 frequently occurred in Dr. Kane's observatory. Of one 

 thing I am fully assured ; and it is, that there is much to 

 be learned regarding the freezing point of mercury. 



Nothing is more certain than the fact that the rise and 

 fall of temperature, as a rule, is tirst obtained here. For 

 instance, a low temperature, accompanying the easterly 

 movement of the high, cold, upper wind current, is from 



