1018 



TOBACCO 



surface is not plunged at once in cold -water, but if it be partially cooled by sprinkling 

 water on it, the crystallisation will be finely variegated with large and small figures. 

 Similar results will be obtained by blowing cold air through a pipe on the tinned 

 surface, while it is just passing from the fused to the solid state ; or a variety of 

 delineations may be traced by playing over the surface of the plate with the pointed 

 flame of a blowpipe. 



Export of Tin Plates in the Year ending 1872 and the two previous years. 



TITANIUM (Sym. Ti ; At. wt. 25) is a rare metal, discovered by Klaproth, iu 

 Menaccanite, in 1794. Small cubes of a copper-red colour, and so hard as to scratch 

 quartz, which have been found in some of the blast-furnaces in Yorkshire, Wales, and 

 Cumberland, were thought to be titanium ; they have recently been shown to be a 

 cyano-nitride of that metal, represented by TiCy,3Ti 3 N (TiCy 2 .3Ti 8 MT 2 j. This metal 

 is very brittle, so hard as to scratch steel, and very light, having a specific gravity of 

 only 5'3. It will not melt in heat of any furnace, nor dissolve, when crystallised, 

 even in nitro-muriatic acid ; but only when in fine powder. According to Hassenfratz, 

 it presence in small quantity does not impair the malleability of iron. By calcination 

 with nitre, it becomes oxygenated, and forms titanate of potash. Traces of this 

 metal may be detected in many irons, both wrought and cast. The principal 

 minerals containing titanium, are sphcne, brookite, anatase, rutilc, iserine and menac- 

 canite. Eutile has been used, with doubtful advantage, in the preparation of steel. 



TOAD'S-EYE TX1T. A pale hair-brown variety of wood-tin, found near 

 Tregarthy Moor in Cornwall. 



TOAST. When bread in thin slices is held in front of a bright fire it is converted 

 into ' toast,' and acquires a characteristic flavour. This appears, according to the 

 experiments of Piesse, to be a product of the destructive distillation of diastase, which 

 all bread contains. When diastase is obtained from bread by alcoholic infusion and 

 precipitation with water, and then heated to 330, an intense odour of 'toast' is 

 produced. 



TOBACCO. It is said that the name ' tobacco ' was given by the Spaniards to the 

 plant, because it was first observed by them at Tabasco, or Tabaco, a province of 

 Yucatan in Mexico. Others derive the name from Tabac, an instrument used by the 

 natives of America in smoking this herb. In 1560, Nicot, the French ambassador to 

 Portugal, having received some tobacco from a Flemish merchant, showed it, on his 

 arrival in Lisbon, to the grand prior, and on his return to France, to Catherine of 

 Medicis, whence it has been called Nicotiana by the botanists. Admiral Sir Francis 

 Drake, having on his way home from the Spanish Main, in 1586, touched at Virginia, 

 and brought away some forlorn colonists, is reported to have first imported tobacco 

 into England. But, according to Lobel, this plant was cultivated in Britain before 

 the year 1570; and was consumed by smoking in pipes by Sir Walter Raleigh and 

 companions, so early as the year 1584. 



Tobacco is prepared as follows : The plants arc hung up to dry during four or five 

 weeks ; taken down out of the sheds in damp weather, for in dry v.iey would be apt 

 to crumble into pieces ; stratified in heaps, covered up, and left to sweat for a week or 

 two, according to their quality and the state of the season ; during which time they 

 must be examined frequently, opened up, and turned over, lest they become too hot, 

 take fire, or run into putrefactive fermentation. 



Respectable tobacconists arc very careful to separate all the damaged leaves before 

 they proceed to their preparation, which they do by spreading them in a heap upon a 

 stone pavement, watering each layer in succession with a solution of sea-salt, of spec. 

 grav. 1-107, called sauce, till a ton or more be laid; and le.-iving their principles to 

 react on each other for three or four days, according to the temperature and tlio nature 

 of the tobacco. It is highly probable that ammonia is the volatilising agon 6 of many 



