** DECEMBER. 



acid ; let this stand also til! the effervescence ceases; 

 if anv arose upon pouring it in, continue to add 

 more acid in the same manner, until what was 

 poured in last, produces little effervescence, which 

 is often at the first, and generally at the second or 

 third half ounce. 



" After the effervescence has ceased, put the whole 

 in a filter ; let the solution filtrate through ; pour 

 half a pint of water upon what remains in the filter, 

 let that filtrate also in the same vessel ; add to the 

 solution thus filtrated, an ounce and a half of caus- 

 tic volatile alkali for every ounce of acid used ; if 

 any precipitation take place, there is magnesia, earth 

 of alum, or the calx of a metal (generally iron or 

 copper) contained in the soil ; after adding the vo- 

 latile alkali, the whole is to be thrown into a filter 

 again ; after the filtration has taken place, pour 

 into the liquor a solution of mild, fixed, vegetable 

 alkali, in water ; if there be any calcareous earth in 

 the soil, a precipitation will take place ; continue to 

 add the solution of the alkali till no fresh precipi- 

 tation ensues; throw the whole into a filter ; let the 

 liquor filtrate off; pour on by degrees a pint of 

 water ; let that filtrate off also ; dry what remains in 

 the filter ; it is the calcareous earth. 



" To know the proportion of sand and day. 



" Take what remains in the filter after the first so- 

 lution in the foregoing operation, and by elutriation 

 separate the sand from the clay, dry and weigh them ; 



if there be any pyrites it will appear 'in the^sand. 



la 



