NOTES AND QUERIES. 525 



rate, to prevent it far more effectually tban any other known 

 appliance, it would seem to follow that a locomotive not fitted with 

 it cannot be held to satisfy the legal rule of immunity. No Act 

 of Parliament should be needed to compel the adoption of this or 

 any other appliance. The law as it stands requires that a peccant 

 locomotive should be shown to be fitted with the best-known 

 appliances. This cannot possibly be shown so long as a completely 

 efficient appliance is known to be in existence and has not been 

 fitted to the locomotive in question. How the railway companies 

 can escape damages in these circumstances it is not .easy to see. 



Impregnation of Timber in an Open Boiler. 



{From information supplied by Mr D. M'Laren, Overseer on the 



Sundrum Estate, Ayrshire.) 



The apparatus consists of an open iron boiler, bedded in brick 

 or stonewoi'k, with a furnace below it. At one end is the 

 furnace-door, divided horizontally into two parts, in order to 

 permit better regulation of the draught. At the opposite end 

 rises the chimney-stalk. The masonry is very carefully built 

 with good fireclay, in which the boiler is laid, as lime-mortar 

 would not stand the heat. The platform into which the boiler 

 is bedded is 26 feet long, 5 feet wide, and 5 feet high, and must 

 be substantially built to withstand the forces of expansion and 

 contraction to which it is subjected. 



The oil used is creosote, costing 4d. a gallon. 



The oil and wood are placed together into the boiler, and are 

 boiled for two days, daring which time great care is needed to 

 prevent the oil from boiling over and taking fire. Slabs of wood 

 are laid across the boiler. As the oil is gradually absorbed into 

 the wood it has to be replenished, usually on the second day, for 

 the wood must be always completely immersed in oil. 



On the Sundrum Estate the apparatus is usually employed for 

 impregnating stobs 5 f t. x 3 ins. x 3 ins. When these are of beech- 

 wood, they become fully impregnated to the centre; but the result 

 is much less satisfactory with dry than with green beech, since 

 the former, after impregnation, becomes hard and brittle. But 

 spruce-wood, seasoned for at least twelve months, is much better 

 than dry wood of that species. Larch and oak wood are not 

 well penetrated by the oil, but they are very durable without 

 treatment. Creosoted beech stobs will last twenty years, and are 



