276 TIMBEE 



a number of small orifices in the woodwork in order to 

 prevent decay, and even so late as the nineteenth century 

 so history repeats itself a famous north-country engineer 

 recommended the coating of piles from the ground level to 

 about low water with whale oil as a preventative against 

 the sea worm. The Ephesians were probably successful, 

 the engineer was not. 



The first English patent for the artificial preservation of 

 timber appears to have been taken out in 1738, since which 

 time, as has been truly said, " almost every chemical 

 principle or compound of any plausibility has been sug- 

 gested for the purpose." Britton, in his treatise on " Dry 

 Eot in Timber," enumerates twenty-nine different sub- 

 stances which had been used for preserving wood ; at the 

 present time they probably number 200. Over 120 patents 

 exist in America alone. Those dealt with here may be 

 called " the survival of the fittest." 



Burnettizing was invented by Sir William Burnett in 1838, 

 and has kept its ground ever since. 



It consists of an injection of chloride of zinc in the pro- 

 portion of one part of the zinc solution, having a specific 

 gravity of 1'6, to 40 parts of water, and it is forced into the 

 wood under pressure of 150 Ibs. to the square inch. It was 

 claimed for it that it hardens the fibre and prevents decay. 



The process was for some time favoured by the English 

 Government, but is not now, so far as the author knows, 

 employed in this country. It is still, however, either in the 

 original form or with various modifications, extensively 

 used in the case of sleepers on the German, Austrian, 

 Dutch, and French railways, and is the chief method used 

 for the preservation of sleepers on the United States rail- 

 ways, where it is called the zinc chloride process, owing to 

 its cheapness, although creosote is now largely used. 



