112 Dr Richardson on the Frozen Soil of North America. 



The " Extracts of letters"' printed in the following pages 

 contain all that each observer reports on the state of the pits 

 dug in 1835 and 1836 ; but although the zeal with which the 

 trials were made cannot be too highly commended, yet it is 

 to be regretted that the reports are in some instances too con- 

 cisely drawn up, and a few minute but important particulars 

 have been omitted or overlooked. 



Professor Baer remarks that, " If we examine ground which 

 contains only very little moisture in a frozen state, it is very difficult to 

 detect the ice, as it forms an extremely thin partition between the single 

 particles of earth. Should the moisture he more considerable before the 

 freezing comes on, we perceive in its frozen state small pieces of ice, 

 wherever the spaces between the particles are large enough to admit of 

 them. These pieces of ice, which look like small crystals, I have parti- 

 cularly noticed between the upper layer of soil which is thawed, and the 

 lower layer in a frozen state." Attention to these remarks will be 

 very useful in examining a pit dug in sandy soil. A thermo- 

 meter (as in the case of the observations made in the York 

 Factory) plunged into the soil at the bottom of the pit, will 

 preclude mistake, and should it stand above + 32° F., will 

 shew that the earth in which it is placed is not frozen. The 

 effect of warming at the fire pieces of hard earth chipped up 

 by the pickaxe, may also be tried. On one occasion, when 

 exploring the banks of the Mackenzie, I broke off a piece of 

 a solid stratum by a smart blow of my hammer, and on exa- 

 mining its grain, concluded that it was a very hard sandstone. 

 Having labelled the specimen and deposited it in my pocket, 

 it was shortly thawed by the heat of my body, and I disco- 

 vered that it was merely sand containing much frozen water 

 in its interstices. The thawing of this stratum causes a con- 

 stant crumbling of the cliff at the mouth of Bear Lake River. 

 " The farther we go east" (in Europe and Siberia), says Professor 

 Baer, " the more southerly do we find the limit of perpetual ground ice. 

 It has not been observed in Lapland out of the mountainous districts, nor 

 did I ever hear of it at Archangel, though Herr Schrenk assured me that, 

 on the Petehora, the ground at a certain depth is never free from ice. 

 Humboldt found in the district of Boguslowsk, in Lat. 59|° N., Long. 

 60° E., at the foot of the Ural Mountains, small pieces of ice at the depth 

 of six feet in summer ; but Boguslowsk lies very high. No permanent 

 ice has been found in Tobolsk in 58° N. At Berezov, in 64° N., where 

 Erman found the temperature of the ground, at the depth of twenty-three 

 feet, to exceed ( + 1° R.) +34.22° F., a dead body was found in 1821, 



