750 Forestry Quarterly. 



for spruce and fir by first saturating the poles in a solution of a 

 metal salt, say sodium fluorid (Na Fe) and then pressing in creo- 

 sote oil until the sapwood is filled. The metal solution evaporat- 

 ing the creosote oil penetrates more deeply, and about 5 lbs. are 

 taken up. The process is, however, somewhat more expensive 

 than the Ruping or Rutger process. 



Another, Italian process, employing alternating hot and cold 

 baths, is briefly described. 



In North America, the author states, "the technique of wood 

 preservation is still in its infancy; but as in so many directions the 

 Americans understand by systematic trials to secure the experienc- 

 es of the old world." A brief review of what has been done in the 

 United States follows. 



The author then discusses a number of new preserving fluids, 

 which are to obviate the expense and other undesirable features 

 of those described. These have been found by systematic ex- 

 periments. There are two groups of such fluids, namely phenols 

 and their homologues, and fluorsalts or silico-fluoric salts. 



Among the first a B — naphtalin zinc sulfate [Zn (Cio H7 

 SO3) 2], known as Wiesesalz has been used by Rutgers with 

 mine timbers, which in 5-J years showed no sign of decay while 

 untreated rotted in i to 2 years. 



Dinitro salts of phenol and its variants show good antiseptic 

 properties and form the ingredients of a number of new fluids like 

 Antinonin, Antigermin, Mikrosol, etc., but they are all too ex- 

 pensive. Hence the attempt is made to secure their good proper- 

 ties by admixture of the same to cheaper preservatives, for in- 

 stance with the cheap sodium fluoride (Bellit or Bellit double 

 fluor) or with gas oils. A more promising antiseptic is the so-called 

 calcium cresol which is secured by mixing slaked lime with crude 

 cresol and water at a temperature of 40° C. This costs about 

 5 cents per lb. and has remarkable antiseptic effect (see table 

 above) 20 times that of copper sulfate and zinc chloride. 



This has been used experimentally in Sweden for railroad ties 

 and in Austria for telegraph poles, the latter coming 10% cheaper 

 than creosoting by Rutgers process. Per i cubic meter, 300 liter 

 of 2% solution, spec. gr. 1.0082 at I5°C, or 6 Kg (13.2 lbs.) of 

 the salt had been used. This salt was also used with creosote oil. 



More widely used are some of the fluoric and silico-fluoric acid 



