6 z Vegetable § taticks . 
numb. < 5 , 24 inches under ground. And that 
the heat of the earth, at thefe feveral depths, 
may the more accurately be known, it is 
proper to place near each Thermometer a 
glafs-tube fealed at both ends, of the fame 
length with the ftems of the feveral Ther- 
mometers 5 and with tinged fpirit of wine 
in them, to the fame height, as in each 
correfponding Thermometer 5 the fcale of 
degrees, of each Thermometer , being mark- 
ed on a Aiding ruler, with an index at the 
back of it, pointing to the correfponding 
tube. When at any time an obfervation is 
to be made, by moving the index, to point 
to the top of the fpirit in that tube, an ac- 
curate allowance is hereby made, for the 
very different degrees of heat and cold, on 
the ftems of the Thermometers , at all depths , 
by which means the fcale of degrees will 
fnew truly the degrees of heat in the balls 
of the Thermometers , and consequently, the 
refpeftive heats of the earth at the feveral 
depths where they are placed. The ftems 
of thefe Thermometer which were above 
ground, were fenced from weather and in- 
juries by fquare wooden tubes;. the groiind 
they were placed in was a brick earth in 
the middle of my garden. 
