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also diluted with its own weight of water (theacids employed should be freed from all conta-mination of the vitriolic acid;) the next daythe flask with its contents being again weighed,the difference between the weights of the in-gredients and the weights now found, will ex-press the quantity of air that escaped duringthe solution. Thus, in the above case, theearth weighing 385 grs. the acid 577,5 grs.and the water 577,5 grs. in all 1540 grs. theweight after solution should also be 1540, ifnothing escaped; but if the soil contains cal-careous matter, a loss will always be found aftersolution. Let us suppose it to amount to 60grains.

The weight of air that escaped, furnishes uswith one method of estimating the quantityof calcareous matter contained in the earthessayed; for mild calx generally contains 40per cent, of air; then if 40 parts air indicate100 of calcareous matter, 6'0 parts air will in-dicate 150*.

10°- The solution is then to be carefully

* I take no account of magnesia, as in agriculture Ibelieve it of little importance.