46 THE WORK OF THE FOREST DEPARTMENT IN INDIA. 



A short account of the actual distillation of pine-resin as- 

 carried out at the modern Government turpentine factory 

 (managed by the Punjab Forest Department), Jallo, North 

 Western Eailway, Lahore District, may be of interest. The 

 resin received from the forest is taken out of the air-tight 

 receptacles, loaded into tip-waggons and conveyed along an ele- 

 vated tramway to large melting and mixing vats. There the 

 resin is melted and mixed, steam heat only being used, the melt- 

 ing being assisted by the addition of turpentine from a previous 

 distillation. The specific gravity of the resin is thereby 

 reduced, so that, when the melting and mixing is finished, a 

 period of rest enables the water and dirt, etc., to sink by gravity 

 to the bottom of the vat, the clean light resin floating on the top. 

 Evaporation is prevented by the lids of the vats being fitted into 

 water-joints. The next stage consists in drawing off the clean 

 resin to a storage tank, whence a measured quantity is taken 

 over, as required, into a steam elevator and thence into the- 

 still. 



In the still, which is steam jacketted and kept hot by steam 

 under pressure, giving one command of a wide range of temp- 

 eratures, the turpentine in the resin is driven off by injecting; 

 steam. The water and turpentine vapours first pass into a trap- 

 still to prevent any resin or rosin accidentally driven over from, 

 going further, and then through a huge condenser in which they 

 liquefy and whence they flow into a mechanical separator, the 

 turpentine being pumped to bulk storage, while the water runs 

 to waste. 



To ensure standard qualities the turpentine is redistilled: 

 in a subsidiary still, passed through lime water to remove any 

 traces of resinous acids, and de-hydrated by filtration through 

 anhydrous sodium sulphate. As however this last mentioned 

 process is thought to be a possible source of contamination it has 

 recently been replaced successfully by a period of rest in bulk 

 storage tanks. Experiments are also in progress to dispense- 

 with redistillation by accurately fractionating the distillate in 

 the primary distillation. The turpentine is put up for sale in 

 five gallon drums bearing distinctive stencil marks, bung-hole- 

 discs and labels, to prevent tampering by retail traders. 



