ILLINOIS STATE DAIRYMEN’S ASSOCIATION. 
81 
refining influence that no other branch of farming does ; it acquaints our sons and 
mghters with the commercial world. 
In reviewing our own connection with the great achievements of dairying in the 
est, we find ourselves in the position of the worn-out ox, but with the privilege of 
anding by the cart, feeling proud of the fact that when our children read up the 
ory of dairying in the west they will there find recorded the fact that their father 
•lped to plant, water and prune this mighty dairy oak that stands to-day the proud, 
iumphant tree, challenging the admiration of the dairy world. 
PRACTICAL REFRIGERATION AND THE TRANSPORTATION OF 
DAIRY PRODUCTS. 
I BY C. F. DEXTER, OF CHICAGO. 
On this subject I am a student of principles rather than a practical experimental- 
t. Although in connection with my business I have observed somewhat closely the 
isults of the work of others, and during an extended intercourse with men whose 
isiness requires refrigeration, I have observed a lack of knowledge of the nature of 
3 at and the atmosphere, and their relation to each other and to moisture, which gives 
se to crude theories and ill-founded experiments. A knowledge of the nature of 
?at and its relation to the atmosphere, makes the problem of refrigeration, so far as 
le securing of a cool, dry atmosphere is concerned, as simple as the warming of a 
>om with a fire or the cooling of a pitcher of water with ice. 
Heat is not a substance—is not matter in any form, so far as known, and cannot 
k seen, weighed or measured (its effect in expanding mercury may be measured). 
Years of scientific research have failed to induce it to materialize. The scientist 
aows nothing of it except its effects. Prof. Tyndall writes a treatise on “ Heat as a 
ode of Motion.” To him, the term signifies a vibratory condition of matter. Warm 
id cool, hot and cold, merely indicate relative degrees of this vibratory condition. 
Warm” at the Arctic circle may be “cold” at the equator. The force of gravity, 
lerefore, has no effect on heat, nor on its relative negative, “cold,” any more than it 
is on light or darkness, and the use of the terms “ heat” and “ cold 1 to indicate dis- 
nct substances, the one lighter, the other heavier than the atmosphere, is unscientific 
id misleading to the last degree, giving rise to the false theory that “ cold” is a heavy 
ibstance, which, when extracted from ice, falls like an apple or a brick. 
The atmosphere is a very elastic fluid, sensitive to the slightest change in temper- 
ure, expanding on a rising and contracting on a falling temperature, to such extent 
id with such force that caloric engines are operated by utilizing this principle. Air 
as weight like all other matter, and when a part of a body of air contracts by cool- 
lg, it becomes denser,—more solid,—contains more matter, and is consequently lieav- 
:r, bulk for bulk, than the surrounding air. Because of this, and not because it is 
bid. it has a tendency to sink into warmer, lighter air. If a part of the air be warmed 
expands, becomes lighter than the adjacent air, and therefore rises, by the same 
i,w in obedience to which the balloon rises—not because it is heated. A bar of iron 
eighs the same, whether red-hot or ice-cold. Water expands and becomes lighter on 
)oling from 36 to 32 deg. 
The air is rarely or never entirely still. In summer there is a current of warm 
Lr rising on the sunny side of your room. In winter the expanded air which rises 
’om your heated stove is replaced by the colder air which flows toward the stove from 
II points of the compass, and all the air of the room is warmed, xl block of ice in 
le upper part of the room would reverse the currents and cool all the air of the room, 
b has been argued that a room cannot be cooled unless the ice be placed above the 
)om. As well insist that a room cannot be warmed unless the stove be placed below 
;. The same laws govern the circulation in both cases, reversing the currents. 
At the house of a friend of mine there is a back room opening out of the sitting- 
Dom, the floor of which is two steps lower than the floor of the sitting-room. The 
ead of the family balanced a toy balloon by tying a button to it. _ The balloon rose 
dth the air rising from the stove, crossed the ceiling and dropped just below the cas- 
lg of the doorway between the rooms, rose to the ceiling of the back room, crossed 
then down the farther wall, back across the floor, tumbled up the two steps as if 
ndowed with an intention, and made its way toward the stove, making the circuit in 
ve or eight minutes. The rooms were both closed except the doorway between them, 
'ry this easy experiment. You can get more education out of it for the children, to 
ay nothing of the adults of the family, than you ever bought before for the same 
loney. If you try it, do not allow the balloon to touch the hot stove. If you do, it 
dll explode and blow the isinglass out of the stove doors. I know it will do this, be- 
ause I tried it. 
Whenever the uniform density of the air is disturbed by a change m temperature, 
moves freely and quickly to restore the equilibrium. It is the great natural com- 
lon carrier for the distribution of temperature and moisture, not only over the sur- 
