478 
Journal of Agricultural Research 
Vol. XXIV. No. 6 
One entire new tile was taken from the marsh, wiped with a towel, and 
weighed while still wet. It was then dried to constant weight in an 
electric oven at i io° C. and again weighed. The loss was 11.90 per cent, 
representing the proportion 6f water contained. 
Similarly two new pieces of new tile were weighed in their natural air-dry 
condition, dried in an electric oven at 110° C., weighed again, boiled for 
two hours in water, and weighed again. The results are tabulated in 
Table III. 
Table III .—Percentage of uaier absorbed by old and new tile 
Samples. 
Weight at 
110° C. 
Water 
absorbed 
in ground. 
Water 
absorbed 
from air. 
Water 
absorbed 
on boiling. 
Tile from marsh. 
Per cent. 
100 
100 
100 
Per cent. 
II. 90 
Per cent. 
Per cent. 
New tile, sample (a). 
I- S 5 I 
I-S 4 S 
6.631 
7 -09s 
New tile, sample (b). 
From this table it will be seen that the tile which was taken from the 
marsh had nearly double the porosity of the new tile. How much this 
porosity was altered during the time* it was buried in the ground it is 
impossible to say. From ^e maker’s statement there is no doubt that 
the tile was less carefully made than that now turned out by the same 
manufacturer. An absorption of 12 per cent would indicate a good 
average tile at the time these were made, and is about the average of 
material turned out by the less careful manufacturers at the present 
time. 
COMPARATIVE AEKATINITY OF TITE 
The next step was to compare the alkalinity of the old and new tile. 
It would be natural to assume that any free alkali would be very quickly 
neutralized after the tile was placed in the ground. A quantity of the 
old tile and of the new tile were pulverized and 2 gm. taken from each. 
Then 200 cc. of distilled water was added to eaci sample and phenol- 
phthalein used as an indicator. The solution was titrated by adding at 
successive intervals normal solution of sulphuric acid, extreme care 
being used, particularly toward the end of the operation, not to permit 
the solution to contain any free acid and so expel carbonic acid. The 
operation was carried on over 2 days, titrating about every half hour 
with results as shown in Table IV. 
Table IV .—Amounts of normal acid solution required to neutralize free alkali in 2 
gm. each of old and new tile^ and percentages of free alkali indicated 
Item. 
Old tile. 
New tile. 
Grams of tile used. 
2.00 
2. 00 
Cubic centimeters of 3^ H2SO4 solution used. 
17.70 
• 0354 
1.770 
40. SO 
. 0810 
Equivalent grams free CaO or equivalent. 
Per cent free CaO or equivalent. 
4. 050 
