FREEZING 485 



FRAXTXXiXlcrXTx:. A mineral related to magnetic iron-oro, crystallising in 

 regular octahodra of an iron-black colour and metallic lustre. When scratched, it 

 affords a dark reddish -brown streak. Its spec. grav. is 5' 05 to 5'16. Franklinite is 

 a combination of the sesquioxides of iron and manganese, with protoxide of zinc. The 

 following figures give the mean of several recent analyses by Mr. F. C. Van Dyck 

 ('Geology of New Jersey, 1868 '); the excess in these analyses is probably due to the 

 oxidation of the iron, which appears to exist partly in the state of protoxide ; the 

 magnetic properties of this species have also been attributed to the presence of pro- 

 toxide of iron : 



i n 



Sesquioxide of iron . ... . . 68'3 74'8 



Oxide of zinc . , ... . . 24'8 217 



Bed oxide of manganese . .,/.,. 10-5 7'8 



103-6 104-3 



I. Prom Stirling Hill Mine, N. J. II. From Mine Hill, N, J. 



These are the two principal localities of franklinite. It occurs associated with red 

 oxide of zinc (spartalite) and silicate of zinc (willemite) in metamorphic limestones of 

 Silurian age. At Stirling Hill it forms the main constituent of the irregular deposit 

 known as the ' Franklinite Vein.' 



Franklinite was at first employed for the production of zinc ; but for that purpose 

 it did not answer commercially. It was then employed in combination with iron, and 

 Major Farrington of New Jersey thus speaks of it: 'Many experiments have been 

 made under my superintendence upon the ores of franklinite, and I have also wit- 

 nessed several others of an interesting character made by other parties in mixing 

 franklinite with pig iron in the puddling furnace, and also a mixture of franklinite- 

 pig with other irons in their conversion to wrought iron. The result in all cases has 

 been a great improvement in the quality of iron as manufactured. The most marked 

 and, as I consider, the most valuable result is obtained by using from 10 to 15 per 

 cent, of the weight of pig iron to be puddled with pulverised franklinite ore in the 

 furnace at each heat. Iron of the most inferior quality when thus treated is converted 

 into an article of No. 1 grade. The volatile nature of zinc at a high temperature, 

 combining with the sulphur, phosphorus, and other volatile constituents of the coal, 

 or that may be in the iron, being carried off mechanically, I consider is one of the 

 causes of the improvement ; the manganese also of the ore combines with silica at a 

 high temperature, and pig iron that contains silica is thus freed from it. The great 

 advantage to be obtained by using the pulverised ore in the puddling furnace is, that 

 a high grade of iron may be made ; and where re-heating has been hitherto deemed 

 indispensable, one heating is found sufficient for such uses as wire billets, nuts, bolts, 

 horseshoe iron, and nails. A particular selection of fuel is not required, coke and 

 charcoal can be dispensed with, and bituminous or anthracite coal used.' 



Franklinite is now employed by the New Jersey Zinc Company for the production 

 of zinc, which is converted into oxide, whilst the cindery residues are smelted for 

 Spiegeleisen. See IRON. 



FREE3TO WS, A term used to denote any stone which is capable of being worked 

 freely in every direction, and, which has no tendency to break in one direction more 

 than another. In the counties of Wicklow and Dublin, and also in Cornwall, the 

 term is applied to granite which works freely. H.W.B. 



FREEZING. (Congelation, Fr. ; Gefrierung, G-er.) The three general forms, 

 solid, liquid, and gaseous, under one or other of which all kinds of matter exist, are 

 referrible to the influence of heat, modifying, balancing, or subduing the attraction of 

 cohesion. Nearly every solid may be liquefied, and every liquid may be vaporised, 

 by a certain infusion of heat, whether this be regarded as a moving power, or an 

 elastic essence. The converse of this proposition is equally true ; for many gases, till 

 lately styled permanent, may be liquefied, nay, even solidified, by diminution of their 

 temperature, either alone, or aided by a sufficient mechanical condensation, to bring 

 their particles within the sphere of aggregative attraction. When a solid is trans- 

 formed into a liquid, and a liquid into a gas or vapour, a quantity more or less con- 

 siderable of heat is absorbed, or becomes latent, to use the term of Dr. Black. When 

 the opposite transformation takes place, the heat absorbed is again emitted, or what 

 was latent becomes sensible. See HEAT for the more recent hypotheses. 



The production of cold is a curious and interesting branch of physical inquiry. A 

 few general laws may be distinctly named. 



If a solid body suddenly liquefies, without the application of external heat, it ab- 

 stracts from the surrounding bodies the heat necessary for its liquefaction. 



