Miscellanies. 373 
From these and other trials, the fact appears to be established, 
that, circumstances being equal with respect to color and condition 
of surface, the absorbing power af a body is greater as its conducting 
power is less.—Rev. Encyc. Sep. 1831. Hi 
29. Advantages of Bored Wells in communicating heat.—The 
temperature of the water which rises from considerable depths in the 
earth, being almost constantly, winter and summer, at about 54° Far. 
the application of this temperature to economical purposes was sug- 
gested by M. de Bruckmann, of Wirtemberg, and it has met with com- 
plete success. Bored wells, from which the water rises to the sur- 
face by some internal force, and flows in a constant stream, are now 
common or at least numerous, in the north of Europe. This able 
engineer had bored a number of these wells for the supply of vari- 
ous establishments for spinning, paper-making, bleaching, &c. in which 
the water flowing from them, is used as a motive power. 
In the winter of 1830, he was consulted in relation to the best 
means of keeping the wheels clear of ice, in one of the manufactories 
of Heilbsonn, when the congelation was so great as to oblige them to 
use the axe in clearing the wheel. Recourse had been had to cur- 
rents of hot air, and to cylinders filled with ignited charcoal, but with 
only imperfect success. Dr. Bruckmann introduced the current 
from a bored well into a cylinder, pierced full of holes from which the 
water fell in a shower upon the wheel, and in less than an hour, the 
wheel which was so encased in ice as to be immovable was as 
clear of it as it is in the month of July, and from that time no fur- 
ther obstruction was experienced. ‘This beneficial application of the 
warm water of bored wells, was soon extended to all the manufac- 
tories where such wells existed. 
But the engineer did not rest there. He conceived and executed 
the plan of warming the manufactories themselves by this water, prior 
to its falling on the wheel. This was done by the simple process of 
causing the water to circulate in open tubes (troughs?) throughout the 
several rooms of a papermill and thence to fall on the wheel. A dif- 
ference of nearly thirty five degrees, in very cold weather, was thus 
produced between the interior and exterior of the building, although 
the doors were frequently opened by the ingress and egress of the 
workmen, and it enabled the proprietor to dispense with the stoves and 
furnaces, withoul any inconvenience to the laborers either on account 
Vou. XXII.—No. 2. 48. 
