Dr Richardson on the Frozen Soil of North America. 115 



importance of searching for spiculae of ice in the looser and 

 dryer subsoil, or of ascertaining and registering its tem- 

 perature, the depth of the frost cannot be said to be yet per- 

 fectly ascertained at that place. I am indebted to him for a 

 register of the temperature of the atmosphere, carefully kept 

 at Fort- Simpson for three years, and for much useful verbal in- 

 formation respecting the Mackenzie, where he has wintered for 

 nearly eighteen years. He is now in this country, and should 

 he return to his old quarters, we trust that he will speedily 

 set the matter at rest as respects that locality. 



Pits were commenced at Fort-Chepewyan and Great Slave 

 Lake, but discontinued, I believe, on coming to the rocky 

 strata which lie near the surface, and no reports were made. 



Table containing the Geographical Position of the Posts named in 

 the subjoined Report, and the principal facts ascertained. 



