62 PROTECTION OF PLAINTS, 1920-21 



Diagonal Perforations 



This method consists of boring a number oT holes,, each about half an inch 

 in diameter and three inches deep, the holes being two or three inches above the 

 soil level and pointing in a slanting direction towards the base of the post. These 

 cavities are filled with some preservative,, such as a solution of sulphate of copper 

 or of mercuric chloride, and the mouth of the hole is afterwards closed. When 

 the liquid so enclosed has been absorbed into the wood, the operation is repeated, 

 Mr. Weiss does not recommend this method and gives as his reasons that the 

 boring of the holes weakens the wood, that the liquid enclosed does not reach all 

 parts of the wood,, and finally, that the results obtained do not always justify 

 the expense. 



Method of Applying Antiseptic Dressing by a Brush 



This is the most economical method of applying the dressing to the posts, 

 and it is from the point of view alone of economical application that it is to be 

 recommended. The method followed is simply to give to the lower part of the 

 post at least three dressings of hot creosote liquid by means of a paint brush, or 

 any other suitable brush. The creosote is warmed, and kept hot throughout 

 the process of treatment. In carrying out this method all cracks and holes in 

 the wood should be filled with the liquid used, and one coating should be allowed 

 to dry thoroughly before the next is laid on. While the dressing is drying, the 

 post is placed witli its base upwards so that the liciuid has additional opportu- 

 nity to soak up into the wood. So far as possible this drying should take place 

 while exposed to bright, warm sunshine. If the post is cold, or if the creosote 

 cools too quickly, it tends to solidify on the outside and does not soak into the 

 interior of the wood. If it is desired, a coating of creosote can also be given on 

 the part of the post that will remain above ground. It is customary to treat 

 only the lower part of the post, i. e. the portion that will be in the soil, and also 

 the part up to six inches above ground. This application of creosote by the 

 brush method causes the liquid to penetrate about a quarter of an inch into 

 the wood and this will increase the life of the posts by at least ten years in the 

 case of spruce, pine and poplar material. 



The Dipping Method 



This method is advised only in cases where there are but a few posts to be 

 treated. Creosote, or any preparation with creosote as a base, are the best 

 preservatives iio employ. The liquid in which the posts are dipped must be 

 warmed to a temperature of at least 150°F. and the time of each dipping should 

 be from 15 to 20 seconds. The lower portions of the stakes must be dipped two 

 or three times, from the base up to a point that will be a foot above the sur- 

 face of the earth when the post is fixed. Between these several immersions the 

 posts must be allowed to dry thoroughly, or in other woi-ds time must be given 

 for the liquid to penetrate the wood. 



