12 MANUFACTURE AND CURING OF CHEESE. 
THE SUBEARTH DUCT. 
The conclusion, drawn from the work of these experiment stations, 
that low temperatures for curing could be profitably employed led to 
attempts to secure a lower range of temperature in the rooms already 
in use. An effort was made to provide better insulated curing rooms 
in which the temperature would not be greatly affected by hot weather 
outside. In a few instances in Wisconsin and in many instances in 
Canada some attempt was made to secure lower temperatures by 
artificial means. The best known of these devices is what is called the 
subearth duct, which is worthy of notice in any discussion of the sub- 
ject of temperatures in connection with cheese ripening. The principle 
of the subearth duct, as is well understood by cheese men acquainted 
with the subject, was based upon the fact that the temperature of the 
earth several feet below the surface remains practically stationary and 
is much below the average temperature of the atmosphere during the 
summer months. Several lines of tiles, such as are used for drain- 
age purposes, were laid at varying depths beneath the earth's surface 
and provided with a funnel which turned toward the wind at the 
opening where the pipe came to the surface. There was also a funnel 
which acted as a draft above the curing room and served to draw 
the air through these tiles and into the curing room. The room itself, 
of course, was well insulated, and it was found that by this means a 
fairly even temperature could be maintained at about 60° F. There 
were certain modifications of this duct, in some instances the curing- 
room air being drawn from near the bottom of a well in much the 
same manner. This was also a success in regulating the temperature. 
In this country this method of maintaining a suitable and even 
temperature was for various reasons never very extensively applied, 
there being a difference of opinion regarding its efficiency. A number 
of cheese makers who had cool-curing rooms believed that they could 
make a softer cheese than had been customary in hot weather, but 
when this cheese passed from the hands of the maker to the dealer and 
was brought in contact with higher temperatures it caused unfavor- 
able comment. This was wrongly and unreasonably charged to the 
subearth-duct curing room, when in fact it was the fault of the maker. 
There was also said to be considerably more trouble with mold than 
had been the case with the old-style curing rooms. 
Had there been any necessity for the continuation of this method 
for securing low temperatures there is little doubt that the subearth 
duct or some other artificial means of obtaining the same results would 
have come into general use in the better cheese districts, for at the 
present time the bad effects of any high degree of temperature in the 
curing of cheese are thoroughly understood. But other methods and 
systems of handling cheese were developed, founded on new discover- 
