1885.] CREOSOTING TIMBEB. 249 



tion of solid material within the pores of the wood. There are two 

 types of creosote in the market. The one called " London oil " is 

 made from the tars of the Newcastle district, and contains less of the 

 carbolic and cresylic acids, but more of the semi-solid substance 

 which solidifies within the pores of the timber, and more of the 

 antiseptics which only volatilize at high temperatures. The other, 

 called " country oil," is obtained from tlie tar of the Midland and 

 other coals ; and being lighter and thinner, and containing a larger 

 percentage of these tar acids, was preferred by the late Dr. Letheby, 

 for instance, as a preservative agent. If the destruction of germs 

 alone solves the timber preservation problem, the good results noted 

 in the Albanij Cultivator, when wooden palings or buildings are 

 thoroughly washed with crude petroleum, may be accounted for. In 

 any case, the amateur requires skUled advice both as to the liquid 

 used, and the method of its injection. Let us, then, turn to the 

 experience of the great French railway company : — 



At their most important sleeper-preserving works at Amagne, 

 near liethel, in the Ardennes, they employ fifty workmen, who 

 prepare 500,000 to 600,000 sleepers yearly. The sleepers are 

 arranged in piles sheltered from rain, but so as to allow the air to 

 play freely through them to dry : after two years or so oakwood 

 loses 20 per cent, of water, — a sleeper weighing originally 81 

 kilogrammes wiU then be no more than 65 kilogrammes. The 

 process begins by sleepers laid on little waggons being introduced 

 into a hot-air stove in which the highest temperature is 75 degrees, 

 the middle 60 degrees, and the lowest heat 40 degrees. After two 

 days, the weight of each sleeper is reduced Ijy 1 kilogramme and a 

 little more, rarely 2 kilogrammes. The waggons are next removed 

 to the injection cylinders, which can hold about 180 sleepers. 

 These being hermetically closed, a vacuum of about 65 degrees 

 is made by the air - pumps, and creosote admitted from a 

 reservoir open to the atmosphere, and kept at a temperature of 

 70 to 75 degrees by means of steam. When the cylinder is 

 full of the liquid to be injected into the wood, communication 

 with the reservoir is cut off, and steam to the pressure of 5 

 kilogrammes blown in. Five operations can be performed in a 

 day in each cylinder, the time for each operation being about two 

 hours. 



Square oak sleepers fi-om France, Galicia, and Eussian Poland 

 are used. When the oak contains little sap, it absorbs about 5 

 kilogrammes the sleeper ; but Polish oak, which is a little soft, 

 takes a little more in. This preparation costs 1 franc a sleeper. 

 Since 1877, the railway company have mostly eschewed the more 

 tender woods, as sleepers abounding in sap absorbed 1 7 kilogrammes 



