192 HOW CROPS FEED. 
eter placed at a depth of a little more than one inch, gave 
these results: 
In quartz sand . 22... cose eens ame et 6 cee 126° 
Tn erystalline lime soil: ..... 4. 6. 3.7 20a 115° 
In parden 809s 0). .(..c cdi we Se seca pie a ade ee 114° 
In yellow sandy clay............... o +, im ae ein Se oe 100° 
In pipe clay .... 25. cee eens tees se ce se a eee 94° 
In chalk soil... 5... 2 0. 87° 
Here we observe a difference of nearly 40° in the noon- 
day temperature of the coarse quartz and. the chalk soil. 
Malaguti and Durocher found that the temperature of the 
garden soil, just below the surface, was, on the average 
of day and night together, 6° Fahrenheit higher than that 
of the air, but that this higher temperature diminished at 
a greater depth. A thermometer buried four inches indi- 
cated a mean temperature only 3° above that of the at- 
mosphere. 
The experimenters do not mention the influence of wa- 
ter in affecting these results; they do not state the degree 
of dryness of these soils. It will be seen, however, that 
the warmest soils are those that retain least water, and 
doubtless something of the slowness with which the fine’ 
soils increase in warmth is connected with the fact that 
they retain much water, which, in evaporating, appropri- 
ates and renders latent a large quantity of heat. 
The chalk soil is seen to be the coolest of all, itg tem- 
perature in these observations being three degrees lower 
than that of the atmosphere at noonday. In hot climates 
this coolness is sometimes of great advantage, as appears 
to happen in Spain, near Cadiz, where the Sherry vine- 
yards flourish. “The Don said the Sherry wine district 
was very small, not more than twelve miles square. The 
Sherry grape grew only on certain low, chalky hills, where 
the ith being light-colored, is not so much burnt; did 
not chap and split so much by the sun as darker and 
heavier soils do. A mile beyond these hills the grape de- 
teriorates,”—(Dickens’ Household Words Noy, 18, 1858.) 
see eg: rns 
mr 
