[CALLENDAR] OBSERVATIONS OF SOIL TEMPERATURES 73 
epoch. The values obtained in this manner agree as closely as can be 
expected with those found for longer intervals at greater depths ; but 
owing to the rapid variations of temperature in the surface layers, greater 
uncertainty attaches to the curves from which they are deduced. 
Sis 
The values of ~ above given for the sandy soil of the McGill College 
grounds may be compared with the following results obtained by differ- 
ent observers for similar soils : 




AUTHORITY. MATERIAL. Value of 2 
Bord elViINEe 2 sees = eo Yd ote GATA CODES Al Ope sae Ae ete as ca ‘0087 
OA PE AE RER PRE  -NCraisleithiSanAs toner PAPE UE ‘0231 
NGUTDAN TERRES tn ee | Sandy AIO rch tae rue ‘0136 
letwoyi, IMMO RS E O0 Mh we | Greemwichteravelinm sense eae. ‘0125 
nes trames Vas teks. os +L Al SE AA RARE) Lea a RS CI yao eset een le 0057 
Come pe Ns 3 He atts PE CIC Aroilllaceousisandiss: een EP “0045 
eg Pe où ss RNA RE Coarse Sand EPP ee ‘0094 
FRE ere pelt asa! niet) eres pte De Ves that hs easter ys à 0061 
CRT RAA EN UE NE UN, Po Wy ee eke 0072 
Hose Acs COMMMIGLE Ce Hae eee ee Wiet: Sandee rebecca re ‘0144 
sé tr in MID) LV AS ATION EE PR ual Ae | ‘0036 



The majority of the above results are deduced from buried ther- 
mometers, and include the effect of percolating water. The different 
results for “coarse sand” by Angstrôm, Rudberg and Quetelet are de- 
duced from observations of the same thermometers in the same situation dur- 
ing different years, and may be taken as an illustration of the divergence 
of results obtained from the annual range. The results of the B. A. 
Committee were obtained by direct laboratory experiments. 
The condition of the sandy soil of the McGill College gardens was 
tested about the beginning of May. It was found to be powdery and 
nearly dry to a depth of 5 feet, increasing in wetness below that depth. 
This probably accounts for the higher value, ‘00635, obtained from the 
observations between May 5th and 10th, which, from the nature of the 
curves, would be more affected by the wetness of the lower soil. 
BOTANICAL ASPECT OF THE INVESTIGATION. 
In connection with the observations on soil temperatures, it is pro- 
posed to conduct a series of studies relative to the progress of vegetation 
at different seasons, in order to establish, as nearly as may be, the rela- 
tions of soil temperatures to the various phenomena of growth in plants. 
