280 
STATE AGEICULTURAL SOCIETY. 
rected bj adding a due proportion of clay,but the proper propor¬ 
tion of each can be ascertained only by experiment. When 
prepared, as they should be, a good road for ordinary country 
travel can be made from these substances. 
Loam .—By the term loam we mean clay with an admixture 
of line sand and generally a liberal proportion of vegetable 
matter. 
When the proportions of clay and sand are such that the 
soil will not bake, nor incrust when dry, nor become very ad¬ 
hesive when wet, it may properly be called loam. When the 
soil of a road-bed consists of loam, or the best soil obtainable, 
the directions for the use of clay are applicable, with the ex¬ 
ception that loam does not require the extreme degree of sur¬ 
face slope recommended for clay. 
The natural soil of the bed may be either clay or sand. 
The application of the other by hauling it on the bed and in¬ 
corporating it by means of the plow and harrow, will enable 
the engineer to produce from these two materials (each ill 
adapted alone) an artificial soil, which will answer the purpose 
of a road-bed quite satisfactorily. Gravpl, consisting of water- 
worn pebbles, without an admixture of clay by which to 
cement them, is a poor road material, as it rolls from under 
the feet of the animals and from beneath the wheels, making 
the labor of teams on such a road very severe. A proper 
amount of clay added to, and well mixed with gravel, will 
greatly improve it as road material. The characteristics of 
all these materials are so various in different localities that the 
proportions need to be modified according lo circumstances; 
and the proper proportions in each respective case will be most 
readily and satisfactorily determined by experimenting with a 
number of samples, say a cart load of each, in different propor¬ 
tions, which should be carefully noted, all being placed con¬ 
tiguously on the road-bed where they will be equally exposed 
to wet and to use. A few months’ experience, under such test 
of the various mixtures, will give the road-maker data which 
theory cannot furnish. 
In some sections of great area no other material than clay 
