Canadian Spessartite and Mountain Cork. 229 



Pyroxene crystals converted into asbestus have been 

 found at the same locality as the mountain cork in Buck- 

 ingham, and this suggests that the latter may also be a 

 secondary mineral derived from pyroxene, one of the most 

 constant constituents of the apatite-bearing veins. 



Soil Temperatures. 



By C. H. McLbod, Ma. E., and D. P. Penhallow, B. Sc. 



During the past two years, observations of soil tempera- 

 ture have been taken daily, at the McGill College Observa- 

 tory; the primary object being to establish somewhat more 

 definitely, the relation of such temperatures to vegetation. 

 An important part of this work relates to the changes at- 

 tending the penetration of frost in autumn ; the influence 

 of snow as a protective covering; and the changes incident 

 to the opening of the ground in spring. For this reason 

 the period of observation embraces the entire year, instead 

 of covering only the spring and summer months as is cus- 

 tomary. It may also be stated in this connection, that 

 observations are being made on root penetration and the 

 -movement of sap in trees, in order to complete the neces- 

 sary data. These will be published as soon as circum- 

 stances will permit. 



This work, which it is expected will be carried on con- 

 tinuously for some years, is conducted under the auspices 

 of the Natural History Society of Montreal. The expense 

 attending the construction of the necessary instruments, 

 was met by a grant from the Elizabeth Thompson Science 

 Fund. Eeference ma}- be made to the Annual Eeports of 

 the University, for further information concerning the 

 inauguration of this work. The following is a brief descrip- 

 tion of the instrument used : — Couples of copper and iron 

 are placed in the ground at the required depths. A wire 

 passes from each couple to a switch-board in the observing 

 room, and there is a return wire common to all the couples, 

 which, in the observing room passes through a delicate 



