302 MARLING ESTIMATES. 



20 per cent, to the even measure. Yet 16 bushels (the measure 

 being thus heaped), were required to fill the cart even. (If thrown 

 in, as usual, by shovels, still more marl would have been put into 

 the same space, by its falling more heavily from the shovels than 

 from the half-bushel.) Upon this even filling of the cart (the 16 

 heaped bushels), more marl was added, to the amount of 5 bushels 

 of like heaping measurement, making 21 heaped bushels in all. 

 This raised the heaping of the cart higher than usual, though not 

 too much to be carried without waste. After being driven to the 

 field, rather more than 1J miles, the then heaping part of the load 

 alone was carefully taken off, and measured by even half-bushels; 

 but each filling being pressed into the measure moderately, which 

 was supposed to give a degree of compactness equal to the remain- 

 ing lower part of the load, caused by its weight and the travel. 

 This quantity made 3^ of such even bushels; the difference be- 

 tween which and the 5 heaped bushels put on in heaping at the 

 pit, was owing to the settling of the whole load by its weight and 

 the travel. 



The remaining even and compressed filling of the cart body, by 

 cubic measurement of its capacity, as stated above, was (21.36 

 cubic feet, or) 17.12 even bushels. Add to this the 3J even and 

 compressed bushels of the heaping (after its being settled by the 

 travel), and the quantity of the whole load is (17.12 -f 3.50=) 20.62 

 compressed and even bushels, equal to 21, loose and heaped, as 

 measured at the loading. Therefore it may be considered that a 

 heaped bushel of loose and moist marl is about equal, when com- 

 pressed, to the same measure even full. 



From all these and other trials and observations, combined and 

 compared, I consider the following quantities as sufficiently close 

 approximations to the truth : 



A heaped bushel of this and similar marl, loose, as dug, weighs 

 105.16 Ibs. 



An even bushel, compressed, weighs about the same. 



The load of a proper two-mule cart, for roads in good order and 

 over firm land not varying much from level, is 18 to 19 heaped 

 bushels or 1900 to 2000 Ibs. 



Weight of a cubic foot of this marl, in the bed, is 120 J Ibs. 

 (determined by trial of a smaller measured solid). By two differ- 

 ent trials, of pits measured by their cubic dimensions in the bed, 

 one of 1052 cubic feet yielded 1103 heaped bushels of marl, as dug, 

 and measured by the estimated cart-loads; and the other, of 1475 

 cubic feet in the bed, yielded 1675 heaped bushels. These esti- 

 mates would respectively make the cubic foot weigh about 111 and 

 119 Ibs. Of course these were not exact measurements, either in 

 the bed, of feet, or in the carts, of bushels. 



10 cubic feet of marl, measured in the cart body, and as 



