THE TECHNOLOGIST. [Feb. 1, 1865. 



326 TIN AND ITS USES. 



is best developed by solution of a small quantity of the oil in dilute 

 alcohol, in which it is but sparingly soluble. In taste this substance is 

 disagreeably hot and bitter, with a slight trace of the flavour of the oils 

 of turpentine and rue. Iodine when brought in contact with it gives- 

 rise to an explosion. 



Irrespective of the odour which the blossoms of this plant exhale, it 

 is a highly ornamented bush, which would flourish well in the South of 

 France, and the distillers of essences and perfumes in that country might 

 cultivate it with great advantage, as it is easily raised from seed, and 

 blooms with great profusion, and would afford a new and agreeable per- 

 fume. 



Its habitat in "Victoria is Gipps Land ; it is also found in New South 

 Wales. The seed vessels contain an essential and a fat oil. 



This species of Pittosporum is the first likely to be of practical im- 

 portance ; its leaves yield a very bitter extractive principle, as in a 

 still higher degree do also those of the Pittosporum phillyroides. 



TIN AND ITS USES. 



For many years the chief resources for the supply of tin, which enters 

 so largely into the uses of common life, were some parts of Cornwall 

 and some of the eastern islands on the equator ; but this is now no 

 longer the case, for it has been added to the catalogue of discoveries of 

 the great deposits of copper and gold in Australia ; and it is more than 

 likely, as civilisation extendi, other localities will be discovered possess- 

 ing sufficient of this useful article to satisfy the exigencies of the day. 

 It is therefore not unimportant, at a time like the present, when the 

 enterprising minds of Englishmen are concentrated upon exploring the 

 resources of our colonies, especially Australia and New Zealand, to in- 

 dicate, as an incentive and a guide to research, some of the characteristics 

 of this branch of metallurgy as practised in Cornwall. 



Tin is a crystalline metal, and its quality variable in accordance with 

 the quantity and description of alloy with which it is permeated ; thus, 

 mechanically judging, a piece of tin cast in a mould of sandstone, if 

 maintaining a spotless surface, will be very ductile, because no abrasion 

 occurs to its crystals in separation ; but if the surface is clouded, it is 

 the presence of some extraneous matter hardening the metal, causing 

 in deflection a fracture of the crystals. It is thus, by comparison, that 

 a quality or condition is determined, which places the varied products of 

 a wide range of lodes and deposits into a classification, under the follow- 

 ing denominations of common, refined, tin-plate, and best grain tin. 



Tin, as Robert Hunt informs us, was obtained at a very early period 

 from these islands. The Cassiterides, or Tin Islands, were celebrated in 



