Its ſpecific gravity is 7,800. All the acids readily diſſolve it; but the vitriolic muſt be diluted, otherwiſe it may be boiled almoſt to dryneſs, without effecting it. The phlogiſton, diſlodged from centenary of ductile iron, may, as experiments now ſtand, be called 342; and this is ſo feebly retained, that this metal, with a few others, holds the eleventh, or loweſt place in the ſeries.
It requires an intenſe degree of heat to fuſe it, viz. 1601, if the uſual compariſon betwixt the mercurial thermometer, and the metallic one of Mortimer, be true. Iron is red hot at 1050 degrees of heat.
FERRUM nativum (iron) native. Native.
It can hardly be doubted, but that the great maſs of iron, brought by Pallas, from Siberia, into Europe, is the product of nature. Its compoſition reſembles that of forged iron; for 100 parts of it yield, by means of the muriatic acid, 49 cubic inches of inflammable air; and from many experiments upon ductile iron, that is found to yield from 48 to 51[70].
FERRUM nativum (iron) native, united to arſenic. Arſenical.
Cronstedt Min. § 243. B. Miſspickel.
FERRUM (iron), with the power of attracting other iron. Loadſtone.
Cronstedt Min. § 211. b. Magnes.
The cauſe of this property is yet unknown.
FERRUM (iron), with phlogiſton enough to render it magnetic. Magnetic.
Cronstedt Min. §§ 212, 213.
But the quantity of phlogiſton is far ſhort of that which is neceſſary to render it ductile, for a centenary hardly contains more than three cubic inches of inflammable air.
FERRUM calciforme (iron calciform), ſimply deprived of phlogiſton. Ochrous.
Cronstedt Min. §§ 202–206. Bloodſtone.
FERRUM (iron), mineralized by aerial acid, calcareous earth, and manganeſe. White.
Cronstedt Min. § 20. Minera ferri alba.
FERRUM (iron), mineralized by ſulphur. Pyritical.
Cronstedt Min. § 152. Pyrites.
FERRUM (iron) intimately united to a new brittle metal[71], or to a peculiar modification of iron, rendering it brittle when cold. Cold-ſhort.
In cold-ſhort iron, a brittle metal exiſts, readily uniting to ductile iron, by the aſſiſtance of heat, but rendering it brittle when cold. This ſubſtance, diſſolved in acids, forms Pruſſian blue with phlogiſticated alkaly, but it is not magnetic: it affords a white calx, richer in phlogiſton than the yellow calx of good iron.
I hope, by more experiments, ſoon to become better acquainted with it.
FERRUM calciforme (iron calciform), phlogiſticated in a peculiar manner. Blue.
Cronstedt Min. § 208. Cæruleum Berolinenſe nativum.
Clay and mould are sometimes coloured ſuperficially by a dilute blue, and ſometimes the former, when newly dug up, is found to acquire this colour upon expoſure to the air. It is evident that the baſis of this colour is an irony matter, full of phlogiſton; for, by ignition upon a charcoal fire, it flames, turns red, and becomes magnetic. With a gentle heat it becomes green, but when melted gives black ſcoriæ.
Alkalies, as well as acids, diſſolve it, and the colour vaniſhes, but appears again, if precipitated from the former by acids, and from the latter by alkalies; but it has then a greenish caſt, and ſoon becomes white. This white ſediment, immerſed in an infuſion of galls, or of tea, recovers its former colour.
From what has been ſaid, it appears that this colour, although analogous to the artificial Pruſſian blue, differs from it in its intensity, in the mode of its production, and in various properties. It keeps its colour in water, but turns black with oil.