196 
A SYSTEM OF 
/. Ths fame calx, when precipitated from 
acids, by means of the fixed alcali, is of a 
greenifh colour •, but it becomes blue, when 
precipitated by means of an alcali united 
with phiogifcon, in which laft .clrcum- 
ilance the phlogifton unites with the iron : 
Thefe two precipitates lofe their colour in 
the fire, and turn brown. 
k. The vitriol of iron is green. 
/. It is the mofi: comiuon. metal in nature, 
and at the fame time the mofl ufeful in 
common life ; notwithflanding which, its 
qualities are perhaps very little known. 
SECT. CCIL 
Iron is found, 
A, In form of calx. Miner a ferri calciformis 
pirn. 
l. Pure. 
a. Loofe and friable, Minera ferri calcifor- 
mis pur a friabilis. Martial ochre, Mine- 
ra ochracea, 
1. Powdry, Ochra ferri j is commonly 
yellow or red, and is iron which has 
been dilTolved by the vitriolic acid. 
2. Concreted. Bog-ore. 
a. In form of round porous balls. 
b. More foiid balls, 
c. In fmail flat pieces, like cakes, or 
pneces of money. 
d. In frnall grains. 
e. In ium.ps of an indeterminate 
figure. 
All thefe are of a blackifli brown, 
or a light brown colour. They are 
found in lakes in the province of 
Smoland j 
