May 12, 1923 
Effect of Decomposition on Concrete Tile 
497 
DISINTEGRATION IN HIGH-DIME PEATS 
In the high-lime peats the situation is much more complex. Water still 
is a controlling factor. At St. Peter, Minn., a rather poor grade of tile 
broke down in a season. This was in a so called running slough in 
Prairie Country which would therefore be high in lime, but flie bottoms 
of the tile were wet throughout the season. At Coon Creek, during the 
two and one-half seasons they were in the ground, the tile disintegrated 
most rapidly where there was a gentle flow or soakage of water regardless 
of the presence of lime in the form of marl. Where the flow of ground 
water was stronger, even though marl was not present, disintegration was 
not so great. Where the tile were well above the ground water level 
throughout the greater part of the season, disintegration amounted to 
very little. 
On University Marsh the conditions were very unusual. The marsh 
surface was below the level of Lake Mendota. There is, in addition, 
heavy seepage from the surrounding hills. This seepage coming through 
the marl bed was so strong that the peat was prevented from attacking 
the bottoms of the tile. This is the reverse of what is commonly found. 
The tops of the tile were, however, above the seepage water and were 
destroyed after six years. This is the more remarkable in the light of 
the fact that during the winter the seepage was sufficiently strong to 
turn the deeper peat strongly alkaline and almost neutralize it to the 
surface. 
In Ozaukee County the least proportional disintegration was found. 
The marsh in this case was narrow and the main ditch comparatively 
deep. The tile would be above the water level throughout the greater 
part of the season. As was to be expected, the greatest disintegration 
was found where the tile were kept continuously moist. In none of the 
three observations made in this county was there any serious disinte¬ 
gration after four years. 
PRODUCTION OF ORGANIC ACID 
One of the most interesting facts brought out by the investigation 
was the extremely rapid production of organic acids where moist peat 
was kept at a warm temperature. In the laboratory culture of peats from 
University Marsh, both the peat from the surface, which was very faintly 
acid, and the peat from 5 feet deep, which was strongly alkaline, in 10 
days became strongly acid. In another 10 days the surface peat 
contained 5 times as much acid as it did at the end of the first 10 days. 
The deep peat in the second 10 days not only increased its acidity to 7 
times what it was at the end of the first 10 days but actually outstripped 
the shallow peat. The northern peat which was but faintly acid in the 
beginning became violently acid at the end of 10 days. 
The same thing was done during this past winter with peat from Coon 
Creek. The peat culture in distilled water required a week to overcome 
its original alkalinity, after which time the increase in acid was rapid. 
It is not assumed that exactly the same sort of accumulation of acid 
will occur in nature though the process of production may be identical. 
What will occur will be the production on an enormous scale of the prod¬ 
ucts of decay. Much of these will naturally escape and be carried away 
by ground water. In the cooler months, particularly in the winter, the 
escape of the products of decay will probably more than keep pace with 
