EXPERIMENTAL PLOTS » 
Four inches of gravel were placed upon the surface of two plots, 
one exteudiug 62^ feet at the westerly end and the other 112^ 
feet at easterly end ; 125 feet of the middle were macadamized 
or covered with a layer of broken stone to a depth of five 
inches after rolling. Of this 125 feet, twenty-five, commencing 
at west end, had gravel foundation. The next 62^ feet had a 
rock foundation divided as follows : The south half was laid 
with flattish stone eight to ten inches deep, set on larger end, 
and securely wedged together by smaller stone driven into the 
spaces between. The north half required an average fill of 
about one and one-third feet and larger stone were used there, 
being packed together as closely as possible and spaces between 
filled with smaller stone and gravel. Plate 2 shows how these 
stone appeared before they were covered in. The smaller 
wedged stone of the south half of the road, forming a regular 
Telford foundation, had already been covered and do not show 
in the illustration. 
Easterly from the stone foundation, for twenty-five feet in 
length, the south half was built up with some six inches of 
gravel foundation while the north half was raised an average 
of ten inches by clay overlaid with two inches of gravel. The 
last twelve and one-half feet of macadamized road were o-raded 
from three to twelve inclies in depth Avith clay and the broken 
stone was placed directly on this foundation. The hardened 
surface was what is called light macadam, consisting of a layer 
of broken stone from one and one-fourth to two and one-half 
inches largest dimension, three and one-half inches in depth, 
well rolled, followed by a layer from one-half to one and one- 
quarter inches in diameter, two inches in depth, also well 
rolled. As the amount of stone dust available for surfacing 
was limited, a layer of good packing gravel one-half inch in 
depth was then added, followed by a layer of stone dust nearly 
one-half inch in depth and both were thoroughly rolled. During 
all rollings the surface was kept well sprinkled. 
The crushed stone for this experiment was given by the 
Massachusetts Broken Stone Co. of 235 Franklin street, Bos- 
ton, Mass., and was from their quarries at Salem, Mass., the 
