on tlie Temperature of Soils. 
141 
24 inches broad at top, 12 inches at bottom, and 36 inches deep. 
Previously to opening these drains the plot had been surrounded 
by a catchwater drain, 38 inches deep, communicating with a 
main drain 40 inches deep. The pulverized surface was then 
drawn to a heap, the enclosed plot dug 3 feet deep, the inter- 
mediate drains opened out, and the superficial soil replaced. In 
this state it remained through the winter of 1836 and 1837. 
Had the thermometers been ready, they would have been sunk 
in the bed as soon as prepared, but 1 could not obtain them from 
the maker and plant them, till June 1st, 1837. 
The thermometers were five in number, each being enclosed, 
throughout its length inserted in the ground, in an iron tube open 
at the bottom, with holes perforated round the bulb. They were 
firmly connected together by iron clamps, and the whole formed 
a stiff portable frame. The glass stems rose 10 inches above the 
ground. These were sustained against the wind or accident by 
a skeleton framinff of metal carrving the scales divided into de- 
grees and tenths. A hole being dug in the centre of one of the 
plots, the frame was let into it and set in the line of the meridian, 
so that the stems above ground might cast the least possible 
shadow on it at noon. The soil was carefully replaced about the 
thermometers so as to preserve, as nearH as might be, the order of 
its texture and consistence throughout the mass of the bed. At 
the same time a naked thermometer was inserted to the depth of 
7 inches in the natural bog adjoining. 1 did not commence any 
regular register of the indications until June 7th, being desirous 
that the thermometers should first become well settled in the soil, 
and arrive at what may be called a true working state. 
It is necessary to state that, on the bed in question, there was 
no kind of seed sown, nor a plant of any kind growing; my 
purpose having been to ascertain, in the first instance, the in- 
fluence of the sun's rays, of rain, dew, and other atmospheric 
agents, upon the naked natural soil ; and, subsequently, with 
other sets of thermometers, to acquire some knowledge of the 
effect which might be produced on the temperature of such 
soil by the admixture of manure and foreign substances. Whether 
this be the proper mode of proceeding, abler judges will 
decide ; but, it would appear to be difhcult to detect the true 
physical characteristics of a soil, by apparatus applied in the 
middle of a corn-field ; and 1 thought it desirable to attempt to 
discover the properties of the natural soil first, and then of mixed 
soil, before proceeding to investigate similar phenomena on 
similar soils under crop. An industrious experimenter might 
carry on all these separate investigations at the same time ; since, 
after his sets of thermometers are placed, he has only to observe 
and record : — 
