Feb. 1, 1865.] THE TECHNOLOGIST. 



TIN AND ITS USES. 329 



given rise to great research on the part of many writers and antiquarian 

 students ; and Mr. Hawkins, in a volume of 'Transactions of the Corn- 

 wall Geological Society,' has given the world an interesting and in- 

 structive essay thereupon. That the Romans worked tin mines in 

 Cornwall there is no room to doubt, and Roman coins have frequently 

 been discovered in mines and stream works. Touching the tin trade of 

 Cornwall in the middle ages, Mr. Hawkins remarks, that there appears 

 at all times to have been a steady demand for it in the markets of the 

 East, from the invariable usage in those countries of tinning the inside 

 of their kitchen utensils, which are composed of copper, and that a 

 great increase of demand arose in the eighth century, when bells of 

 great size were frequently cast for cathedrals and churches, and when 

 their use became general. In the thirteenth century the mines were 

 very productive, for Richard, Earl of Cornwall, then possessed immense 

 wealth derived from that source. The introduction of brass guns for 

 field artillery in the fifteenth century created also a new demand for the 

 main ingredient in the composition of that metal. 



It may be stated, that there is a court for the administration of 

 justice, exclusively devoted to the tinners of Cornwall, and this is called 

 the Stannaries (from stannum, Latin for tin). The rights and privileges 

 of the tinners are confirmed by a charter of very ancient date — of the 

 reign, indeed, of Edward I. There is a volume called the ' Laws of the 

 Stanneries,' and these go into the minutiae of the working of mines, 

 buying and selling their produce, &c. 



By far the larger portion of tin ore raised in Cornwall is found in 

 lodes, and, consequently, mineralised with the contents of those lodes, 

 whatever they may be, but which are generally sulphur, lead, iron, 

 blende, &c, and always combined with oxygen for a base. The miner's 

 occupation does not cease until he has prepared it for the smelting- 

 house, by stamping, washing off the matrix, and evaporating the sulphur 

 by calcination ; and in this condition it is brought to the smelter, who 

 purchases an oxide of tin, according to the quantity of metal contained, 

 and its quality, by assay ; this, when smelted, is called block, or techni- 

 cally, common tin. It is used for making pewter, piping, plumbers' 

 solder, &c, and it is also cast into small strips, and called bar tin ; and 

 so exported, chiefly to Turkey, from whence it finds its way into the 

 interior of Asia Minor, where it is used in the fabrication of culinary 

 and other articles. ' 



The refined and purest tin is that which is used in the manufacture 

 of tin plate, the tin being used for this purpose in a molten state, and 

 thin plates of iron dipped into it, just like dipping thin boards of wood 

 into liquid varnish. The metal plates for tinning are made of the best 

 charcoal iron. . All the oxide is first removed from them, then they are 

 scoured bright, and kept in soft water rea'dy to be dipped in the molten 

 tin. The tin is melted in an iron pot over a fire, and its surface is • 

 covered with about four inches of molten tallow. The prepared plates 



