306 THE UTILISATION OF WOODLAND PRODUCE. 



fence-posts, &c.) that can be subjected to a pressure of 100 Ibs. 

 per square inch in about three hours. On absorption under 

 that pressure ceasing, the door is unscrewed and the superfluous 

 creosote run off, and the timber is taken out next day. When 

 creosoting is done thus on a large scale, the total cost comes to 

 about 3d. to 4d. a cubic foot, varying of course with the price 

 of creosote. On the average, 2| gallons or 27 J Ibs. of creosote are 

 considered enough for Scots Pine sleepers 9 ft. x 10 in. x 5 in. = 

 3 J cubic feet, or 8-f Ibs. per cubic foot ; while when Oak sleepers 

 are treated, the specification varies from 4 to 6 Ibs. per cubic 

 foot. 



On the Continent one of Rueping's creosoting processes is to 

 first subject the wood to a pressure of 60 to 65 Ibs. in order to 

 compress the air into the interior cells ; and on warm creosote 

 being run into the cylinder, the pressure is increased to 105 to 

 225 Ibs. according to the size and the quality of the timber ; 

 and under this high pressure any creosote not adhering to the 

 cell-walls is forced out again and run off, thus effecting a sav- 

 ing in creosote, while giving a more thorough impregnation. 

 Another of Ruepincjs processes now much used for steri- 

 lising sleepers on the Continent, is impregnation with an 

 emulsion of creosote and resin soap, as it has been found to 

 penetrate the wood more easily and deeply than creosote alone. 

 The sleepers are first steamed for J an hour under a 21 Ibs. 

 pressure (1^ atmospheres), and the air evacuated before the 

 emulsion is run in and a pressure of 100 Ibs. per square inch 

 applied (7 atmospheres). By this method less creosote is 

 absorbed, yet it penetrates deeper into the wood. Another 

 recent Continental process (BucJmer's) consists in first boiling 

 the wood under pressure to get rid of the resin and soluble 

 constituents, and then treating it with a solution of chromic 

 oxide salts, which hardens and tans the fibres, and renders 

 them immune from fungus attacks. 



Naphthalining. Immersion in an open tank containing 



